Reading Brain CT and MRI: Bleed vs. Infarct with Temporal Staging

#!/usr/bin/env python3
"""
Brain CT & MRI Reference Guide PDF Generator
Uses ReportLab to create a comprehensive, visually rich reference guide.
"""

from reportlab.lib.pagesizes import A4
from reportlab.lib import colors
from reportlab.lib.styles import getSampleStyleSheet, ParagraphStyle
from reportlab.lib.units import cm, mm
from reportlab.platypus import (
    SimpleDocTemplate, Paragraph, Spacer, Table, TableStyle,
    HRFlowable, KeepTogether, PageBreak
)
from reportlab.platypus.flowables import Flowable
from reportlab.lib.enums import TA_CENTER, TA_LEFT, TA_JUSTIFY
from reportlab.graphics.shapes import Drawing, Rect, String, Line, Circle, Polygon, Path
from reportlab.graphics.shapes import PolyLine, Group
from reportlab.graphics import renderPDF
from reportlab.platypus import Image as RLImage
import io
import math

# ── Color Palette ─────────────────────────────────────────────────────────────
C_NAVY      = colors.HexColor('#0D1B2A')
C_BLUE      = colors.HexColor('#1B4F72')
C_LIGHTBLUE = colors.HexColor('#2E86AB')
C_TEAL      = colors.HexColor('#17A589')
C_RED       = colors.HexColor('#C0392B')
C_ORANGE    = colors.HexColor('#E67E22')
C_YELLOW    = colors.HexColor('#F1C40F')
C_GREEN     = colors.HexColor('#1E8449')
C_PURPLE    = colors.HexColor('#7D3C98')
C_DARK_GRAY = colors.HexColor('#2C3E50')
C_MID_GRAY  = colors.HexColor('#7F8C8D')
C_LIGHT_GRAY= colors.HexColor('#ECF0F1')
C_WHITE     = colors.white
C_BLACK     = colors.black
C_CREAM     = colors.HexColor('#FDFEFE')

# CT density shades
C_CT_BLOOD  = colors.HexColor('#F0F0F0')   # hyperdense (bright white)
C_CT_BRAIN  = colors.HexColor('#AAAAAA')   # normal brain gray
C_CT_INFARCT= colors.HexColor('#606060')   # hypodense (dark)
C_CT_CSF    = colors.HexColor('#222222')   # very dark (CSF/old infarct)

PAGE_W, PAGE_H = A4

# ── Helper Flowable: SectionHeader ───────────────────────────────────────────
class SectionHeader(Flowable):
    def __init__(self, title, subtitle="", bg=C_BLUE, w=None):
        Flowable.__init__(self)
        self.title    = title
        self.subtitle = subtitle
        self.bg       = bg
        self.w        = w or (PAGE_W - 4*cm)
        self.h        = 1.4*cm if subtitle else 1.1*cm

    def draw(self):
        c = self.canv
        c.setFillColor(self.bg)
        c.roundRect(0, 0, self.w, self.h, 5, fill=1, stroke=0)
        c.setFillColor(C_WHITE)
        c.setFont("Helvetica-Bold", 13)
        c.drawString(0.4*cm, self.h - 0.55*cm, self.title)
        if self.subtitle:
            c.setFont("Helvetica", 9)
            c.setFillColor(colors.HexColor('#D6EAF8'))
            c.drawString(0.4*cm, 0.2*cm, self.subtitle)

    def wrap(self, aw, ah):
        return self.w, self.h

# ── Helper Flowable: LegendBox ────────────────────────────────────────────────
class LegendBox(Flowable):
    """Small colored square + label pair"""
    def __init__(self, items, cols=3, w=None):
        Flowable.__init__(self)
        self.items = items   # list of (color, label)
        self.cols  = cols
        self.w     = w or (PAGE_W - 4*cm)
        rows = math.ceil(len(items)/cols)
        self.h = rows * 0.55*cm + 0.2*cm

    def draw(self):
        c   = self.canv
        col_w = self.w / self.cols
        for i, (clr, lbl) in enumerate(self.items):
            col = i % self.cols
            row = i // self.cols
            x   = col * col_w
            y   = self.h - (row+1)*0.55*cm
            c.setFillColor(clr)
            c.setStrokeColor(C_DARK_GRAY)
            c.rect(x, y+0.05*cm, 0.45*cm, 0.38*cm, fill=1, stroke=1)
            c.setFillColor(C_DARK_GRAY)
            c.setFont("Helvetica", 8)
            c.drawString(x + 0.55*cm, y+0.1*cm, lbl)

    def wrap(self, aw, ah):
        return self.w, self.h

# ── Flowable: CT Brain Schematic ─────────────────────────────────────────────
class CTBrainSchematic(Flowable):
    """
    Side-by-side CT schematic: Left = hemorrhage (bright), Right = infarct (dark)
    """
    def __init__(self, w=None, h=None):
        Flowable.__init__(self)
        self.w = w or (PAGE_W - 4*cm)
        self.h = h or 6.5*cm

    def draw(self):
        c   = self.canv
        w, h = self.w, self.h
        mid = w / 2
        r   = min(h*0.42, mid*0.7)

        # ---- LEFT: HEMORRHAGE ----
        cx1 = mid * 0.5
        cy  = h * 0.52

        # Skull ring
        c.setFillColor(colors.HexColor('#E8E8E8'))
        c.setStrokeColor(C_BLACK)
        c.setLineWidth(0.5)
        c.circle(cx1, cy, r+0.18*cm, fill=1, stroke=1)

        # Brain background
        c.setFillColor(C_CT_BRAIN)
        c.circle(cx1, cy, r, fill=1, stroke=0)

        # Ventricles (dark)
        c.setFillColor(C_CT_CSF)
        c.ellipse(cx1-0.25*cm, cy-0.15*cm, cx1+0.25*cm, cy+0.3*cm, fill=1, stroke=0)
        c.ellipse(cx1-0.18*cm, cy-0.4*cm, cx1-0.02*cm, cy-0.15*cm, fill=1, stroke=0)
        c.ellipse(cx1+0.02*cm, cy-0.4*cm, cx1+0.18*cm, cy-0.15*cm, fill=1, stroke=0)

        # Hemorrhage spot - bright white
        c.setFillColor(C_CT_BLOOD)
        c.setStrokeColor(colors.HexColor('#CCCCCC'))
        c.setLineWidth(0.3)
        c.circle(cx1+0.55*cm, cy+0.25*cm, 0.45*cm, fill=1, stroke=1)

        # Surrounding edema halo
        c.setFillColor(colors.HexColor('#888888'))
        # Draw as a ring manually
        c.saveState()
        c.setFillColor(colors.HexColor('#888888'))
        c.circle(cx1+0.55*cm, cy+0.25*cm, 0.62*cm, fill=1, stroke=0)
        c.setFillColor(C_CT_BLOOD)
        c.circle(cx1+0.55*cm, cy+0.25*cm, 0.45*cm, fill=1, stroke=0)
        c.restoreState()

        # Arrow + label
        c.setStrokeColor(C_RED)
        c.setLineWidth(1.2)
        c.line(cx1+0.85*cm, cy+0.55*cm, cx1+1.5*cm, cy+1.1*cm)
        c.setFillColor(C_RED)
        c.setFont("Helvetica-Bold", 7.5)
        c.drawString(cx1+1.55*cm, cy+1.08*cm, "HYPERDENSE")
        c.setFont("Helvetica", 7)
        c.drawString(cx1+1.55*cm, cy+0.88*cm, "(Acute Blood ~60-80 HU)")

        # Title
        c.setFillColor(C_RED)
        c.setFont("Helvetica-Bold", 10)
        c.drawCentredString(cx1, 0.3*cm, "HEMORRHAGE on CT")

        # ---- DIVIDER ----
        c.setStrokeColor(C_MID_GRAY)
        c.setLineWidth(0.8)
        c.setDash(4, 3)
        c.line(mid, 0.1*cm, mid, h-0.1*cm)
        c.setDash()

        # ---- RIGHT: INFARCT ----
        cx2 = mid + mid * 0.5
        c.setFillColor(colors.HexColor('#E8E8E8'))
        c.setStrokeColor(C_BLACK)
        c.setLineWidth(0.5)
        c.circle(cx2, cy, r+0.18*cm, fill=1, stroke=1)

        c.setFillColor(C_CT_BRAIN)
        c.circle(cx2, cy, r, fill=1, stroke=0)

        # Ventricles
        c.setFillColor(C_CT_CSF)
        c.ellipse(cx2-0.25*cm, cy-0.15*cm, cx2+0.25*cm, cy+0.3*cm, fill=1, stroke=0)
        c.ellipse(cx2-0.18*cm, cy-0.4*cm, cx2-0.02*cm, cy-0.15*cm, fill=1, stroke=0)
        c.ellipse(cx2+0.02*cm, cy-0.4*cm, cx2+0.18*cm, cy-0.15*cm, fill=1, stroke=0)

        # Infarct - wedge shaped, dark
        c.setFillColor(C_CT_INFARCT)
        # Draw wedge (MCA territory) using a path
        c.saveState()
        p = c.beginPath()
        cx_off = cx2 - 0.3*cm
        p.moveTo(cx_off, cy+0.1*cm)
        p.lineTo(cx2 - r*0.85, cy + r*0.45)
        p.lineTo(cx2 - r*0.55, cy + r*0.78)
        p.lineTo(cx2 - r*0.1, cy + r*0.75)
        p.lineTo(cx2 + r*0.1, cy + r*0.55)
        p.lineTo(cx_off, cy+0.1*cm)
        p.close()
        c.setFillColor(C_CT_INFARCT)
        c.drawPath(p, fill=1, stroke=0)
        c.restoreState()

        # Sulcal effacement hint (lines closer together)
        c.setStrokeColor(colors.HexColor('#777777'))
        c.setLineWidth(0.4)
        for i in range(3):
            angle = 110 + i*15
            rad = math.radians(angle)
            x1 = cx2 + (r*0.55)*math.cos(rad)
            y1 = cy + (r*0.55)*math.sin(rad)
            x2 = cx2 + (r*0.72)*math.cos(rad)
            y2 = cy + (r*0.72)*math.sin(rad)
            c.line(x1, y1, x2, y2)

        # Arrow + label
        c.setStrokeColor(C_BLUE)
        c.setLineWidth(1.2)
        c.line(cx2 - r*0.5, cy + r*0.65, cx2 - r*0.9, cy + r*1.05)
        c.setFillColor(C_BLUE)
        c.setFont("Helvetica-Bold", 7.5)
        # left-align label
        lx = cx2 - r*0.9 - 1.8*cm
        c.drawString(lx, cy + r*1.05, "HYPODENSE")
        c.setFont("Helvetica", 7)
        c.drawString(lx, cy + r*0.85, "(Ischemic territory, <30 HU)")

        # Title
        c.setFillColor(C_BLUE)
        c.setFont("Helvetica-Bold", 10)
        c.drawCentredString(cx2, 0.3*cm, "INFARCT on CT")

        # Top labels
        c.setFillColor(C_DARK_GRAY)
        c.setFont("Helvetica-BoldOblique", 8)
        c.drawCentredString(w/2, h-0.2*cm, "NON-CONTRAST CT — Axial Brain Window   |   Left = Hemorrhage   |   Right = Infarct")

    def wrap(self, aw, ah):
        return self.w, self.h

# ── Flowable: CT Timeline Diagram ────────────────────────────────────────────
class CTTimelineDiagram(Flowable):
    """Timeline bar showing CT changes for hemorrhage and infarct"""
    def __init__(self, w=None, h=None):
        Flowable.__init__(self)
        self.w = w or (PAGE_W - 4*cm)
        self.h = h or 5.8*cm

    def draw(self):
        c   = self.canv
        w, h = self.w, self.h

        phases = [
            ("0-6 hrs\nHyperacute", 0.18),
            ("6-24 hrs\nAcute",     0.18),
            ("1-7 days\nSubacute",  0.22),
            ("1-3 wks\nLate\nSubacute", 0.22),
            (">3 wks\nChronic",    0.20),
        ]

        hem_colors = [
            colors.HexColor('#F5F5F5'),  # hyperacute - bright white
            colors.HexColor('#EEEEEE'),  # acute - white
            colors.HexColor('#AAAAAA'),  # isodense
            colors.HexColor('#888888'),  # becoming darker
            colors.HexColor('#555555'),  # chronic - dark
        ]
        hem_labels = [
            "BRIGHT\nHyperdense",
            "BRIGHT\nHyperdense",
            "ISODENSE\n(may be missed!)",
            "ISODENSE\n→ Hypodense",
            "HYPODENSE\n(dark)",
        ]
        inf_colors = [
            colors.HexColor('#AAAAAA'),   # normal / subtle
            colors.HexColor('#888888'),   # early hypodense
            colors.HexColor('#666666'),   # clearly dark
            colors.HexColor('#555555'),   # fogging
            colors.HexColor('#3A3A3A'),   # chronic dark
        ]
        inf_labels = [
            "NORMAL or\nSubtle",
            "HYPODENSE\nGray-white blur",
            "CLEARLY\nHypodense",
            "FOGGING\n(may look normal)",
            "ENCEPHALO-\nMALACIA",
        ]

        # Row heights
        label_h = 0.8*cm
        row_h   = 1.6*cm
        gap     = 0.25*cm
        y_hem   = h - label_h - row_h
        y_inf   = y_hem - row_h - gap
        bar_top = h - label_h

        # Phase separators & labels
        x = 0.0
        for i, (phase_label, frac) in enumerate(phases):
            bw = w * frac
            # Phase header box
            bg = C_LIGHT_GRAY if i%2==0 else colors.HexColor('#D5D8DC')
            c.setFillColor(bg)
            c.setStrokeColor(C_DARK_GRAY)
            c.setLineWidth(0.4)
            c.rect(x, bar_top - label_h, bw, label_h, fill=1, stroke=1)
            c.setFillColor(C_DARK_GRAY)
            c.setFont("Helvetica-Bold", 7)
            lines = phase_label.split('\n')
            for li, ln in enumerate(lines):
                c.drawCentredString(x + bw/2, bar_top - 0.25*cm - li*0.28*cm, ln)

            # Hemorrhage row
            c.setFillColor(hem_colors[i])
            c.setStrokeColor(C_DARK_GRAY)
            c.setLineWidth(0.4)
            c.rect(x, y_hem, bw, row_h, fill=1, stroke=1)
            c.setFillColor(C_DARK_GRAY if hem_colors[i].hexval() > '#999999' else C_WHITE)
            # text color contrast
            hex_v = hem_colors[i]
            # just use dark text for bright backgrounds, white for dark
            r_val = int(hem_colors[i].hexval()[1:3], 16)
            txt_c = C_DARK_GRAY if r_val > 160 else C_WHITE
            c.setFillColor(txt_c)
            c.setFont("Helvetica-Bold", 6.5)
            lns2 = hem_labels[i].split('\n')
            for li, ln in enumerate(lns2):
                c.drawCentredString(x + bw/2, y_hem + row_h - 0.28*cm - li*0.28*cm, ln)

            # Infarct row
            c.setFillColor(inf_colors[i])
            c.setStrokeColor(C_DARK_GRAY)
            c.setLineWidth(0.4)
            c.rect(x, y_inf, bw, row_h, fill=1, stroke=1)
            r_val2 = int(inf_colors[i].hexval()[1:3], 16)
            txt_c2 = C_DARK_GRAY if r_val2 > 160 else C_WHITE
            c.setFillColor(txt_c2)
            c.setFont("Helvetica-Bold", 6.5)
            lns3 = inf_labels[i].split('\n')
            for li, ln in enumerate(lns3):
                c.drawCentredString(x + bw/2, y_inf + row_h - 0.28*cm - li*0.28*cm, ln)

            x += bw

        # Row labels on right
        c.setFillColor(C_RED)
        c.setFont("Helvetica-Bold", 8)
        c.drawRightString(-0.15*cm, y_hem + row_h*0.45, "BLEED")
        c.setFillColor(C_BLUE)
        c.drawRightString(-0.15*cm, y_inf + row_h*0.45, "INFARCT")

        # Bottom note
        c.setFillColor(C_MID_GRAY)
        c.setFont("Helvetica-Oblique", 7)
        c.drawString(0, y_inf - 0.35*cm, "* Fogging effect: ~1-3 wks post-infarct, CT can appear falsely normal due to macrophage infiltration")

    def wrap(self, aw, ah):
        return self.w, self.h

# ── Flowable: MRI Sequence Grid ───────────────────────────────────────────────
class MRISequenceGrid(Flowable):
    """
    Grid showing simulated MRI signal for each sequence across phases
    for HEMORRHAGE.
    """
    def __init__(self, w=None, h=None):
        Flowable.__init__(self)
        self.w = w or (PAGE_W - 4*cm)
        self.h = h or 7.5*cm

    def draw(self):
        c   = self.canv
        w, h = self.w, self.h

        phases = ["Hyperacute\n0-6 h\nOxyHb", "Acute\n1-3 d\nDeoxyHb",
                  "Early\nSubacute\n3-7 d\nIntracel\nMetHb",
                  "Late\nSubacute\n7-30 d\nExtracel\nMetHb",
                  "Chronic\n>14 d\nHemosiderin"]
        seqs   = ["T1", "T2", "SWI/GRE"]
        # signal: 0=dark, 0.5=iso, 1=bright
        # Based on standard MRI hemorrhage table
        signals = {
            "T1":  [0.5, 0.5, 1.0,  1.0,  0.2],
            "T2":  [0.8, 0.1, 0.15, 0.9,  0.0],
            "SWI/GRE": [0.3, 0.05, 0.05, 0.1, 0.0],
        }
        labels_map = {
            "T1":  ["Isointense\n(Gray)", "Isointense\n(Gray)", "BRIGHT\n(White)", "BRIGHT\n(White)", "Hypointense\n(Dark)"],
            "T2":  ["Bright\n(Lt Gray)", "DARK\n(Black)", "DARK\n(Black)", "BRIGHT\n(White)", "BLACK\n(Very dark)"],
            "SWI/GRE": ["Dark", "Very Dark\n'Blooms'", "Very Dark\n'Blooms'", "Dark", "BLACK\n'Blooms'"],
        }

        n_phases = len(phases)
        n_seqs   = len(seqs)
        header_w = 1.5*cm
        col_w    = (w - header_w) / n_phases
        row_h    = (h - 1.2*cm) / (n_seqs + 1)  # +1 for phase header row

        # Draw phase headers
        x = header_w
        for i, ph in enumerate(phases):
            bg = C_LIGHT_GRAY if i%2==0 else colors.HexColor('#D5D8DC')
            c.setFillColor(bg)
            c.setStrokeColor(C_DARK_GRAY)
            c.setLineWidth(0.4)
            c.rect(x, h - row_h, col_w, row_h, fill=1, stroke=1)
            c.setFillColor(C_DARK_GRAY)
            c.setFont("Helvetica-Bold", 6.0)
            lines = ph.split('\n')
            n = len(lines)
            for li, ln in enumerate(lines):
                c.drawCentredString(x + col_w/2,
                    h - 0.18*cm - li*(row_h/(n+0.5)), ln)
            x += col_w

        # Corner cell
        c.setFillColor(C_NAVY)
        c.setStrokeColor(C_DARK_GRAY)
        c.setLineWidth(0.4)
        c.rect(0, h - row_h, header_w, row_h, fill=1, stroke=1)
        c.setFillColor(C_WHITE)
        c.setFont("Helvetica-Bold", 7)
        c.drawCentredString(header_w/2, h - row_h/2 - 0.1*cm, "SEQ")

        # Draw sequence rows
        for si, seq in enumerate(seqs):
            y = h - (si+2)*row_h
            # Seq label
            c.setFillColor(C_NAVY)
            c.setStrokeColor(C_DARK_GRAY)
            c.setLineWidth(0.4)
            c.rect(0, y, header_w, row_h, fill=1, stroke=1)
            c.setFillColor(C_WHITE)
            c.setFont("Helvetica-Bold", 8)
            c.drawCentredString(header_w/2, y + row_h/2 - 0.1*cm, seq)

            x = header_w
            for pi in range(n_phases):
                sig = signals[seq][pi]
                # signal → gray shade (0=black, 1=white)
                shade = sig
                cell_color = colors.Color(shade, shade, shade)
                c.setFillColor(cell_color)
                c.setStrokeColor(C_DARK_GRAY)
                c.setLineWidth(0.3)
                c.rect(x, y, col_w, row_h, fill=1, stroke=1)
                # text
                txt_c = C_WHITE if shade < 0.55 else C_DARK_GRAY
                c.setFillColor(txt_c)
                c.setFont("Helvetica-Bold", 6.0)
                lns = labels_map[seq][pi].split('\n')
                n_l = len(lns)
                for li, ln in enumerate(lns):
                    c.drawCentredString(x + col_w/2,
                        y + row_h - 0.22*cm - li*0.26*cm, ln)
                x += col_w

        # Title
        c.setFillColor(C_DARK_GRAY)
        c.setFont("Helvetica-BoldOblique", 8)
        c.drawCentredString(w/2, 0.05*cm,
            "Signal shade = actual MRI appearance (white = bright, black = dark/signal void)")

    def wrap(self, aw, ah):
        return self.w, self.h


# ── Flowable: MRI Infarct Timeline ────────────────────────────────────────────
class MRIInfarctTimeline(Flowable):
    """Timeline of ischemic infarct on MRI sequences"""
    def __init__(self, w=None, h=None):
        Flowable.__init__(self)
        self.w = w or (PAGE_W - 4*cm)
        self.h = h or 6.0*cm

    def draw(self):
        c   = self.canv
        w, h = self.w, self.h

        phases = ["Hyperacute\n0-6 h", "Acute\n6h-5d",
                  "Subacute\n5-14 d", "Late Sub\n14-21 d", "Chronic\n>3 wks"]
        seqs   = ["DWI", "ADC", "FLAIR/T2", "T1"]
        # signal shade 0=dark/black, 1=bright/white
        signals = {
            "DWI":      [0.95, 0.95, 0.85, 0.7,  0.1],
            "ADC":      [0.05, 0.05, 0.1,  0.55, 0.85],
            "FLAIR/T2": [0.3,  0.8,  0.9,  0.85, 0.85],
            "T1":       [0.45, 0.3,  0.3,  0.4,  0.3],
        }
        labels_map = {
            "DWI":      ["BRIGHT\n★", "BRIGHT\n★", "Bright\n(fading)", "Fading\nT2 shine", "DARK"],
            "ADC":      ["DARK\n★", "DARK\n★", "Dark\n→ pseudo\nnormalizing", "Pseudo-\nnormal", "BRIGHT"],
            "FLAIR/T2": ["Normal/\nSubtle", "BRIGHT\n★", "BRIGHT\n+mass\neffect", "Bright", "Bright\nGliosis"],
            "T1":       ["Normal", "Hypo-\nintense", "Hypo-\nintense", "Gyral\nenhance\n(+Gd)", "Hypo-\nencephalo"],
        }

        n_phases = len(phases)
        n_seqs   = len(seqs)
        header_w = 1.6*cm
        col_w    = (w - header_w) / n_phases
        row_h    = (h - 1.1*cm) / (n_seqs + 1)

        # Phase headers
        x = header_w
        for i, ph in enumerate(phases):
            bg = colors.HexColor('#EBF5FB') if i%2==0 else colors.HexColor('#D6EAF8')
            c.setFillColor(bg)
            c.setStrokeColor(C_DARK_GRAY)
            c.setLineWidth(0.4)
            c.rect(x, h - row_h, col_w, row_h, fill=1, stroke=1)
            c.setFillColor(C_NAVY)
            c.setFont("Helvetica-Bold", 6.5)
            lns = ph.split('\n')
            for li, ln in enumerate(lns):
                c.drawCentredString(x+col_w/2, h - 0.22*cm - li*0.3*cm, ln)
            x += col_w

        # Corner
        c.setFillColor(C_TEAL)
        c.setStrokeColor(C_DARK_GRAY)
        c.setLineWidth(0.4)
        c.rect(0, h - row_h, header_w, row_h, fill=1, stroke=1)
        c.setFillColor(C_WHITE)
        c.setFont("Helvetica-Bold", 7)
        c.drawCentredString(header_w/2, h - row_h/2 - 0.1*cm, "SEQ")

        # Seq rows
        for si, seq in enumerate(seqs):
            y = h - (si+2)*row_h
            c.setFillColor(C_TEAL)
            c.setStrokeColor(C_DARK_GRAY)
            c.setLineWidth(0.4)
            c.rect(0, y, header_w, row_h, fill=1, stroke=1)
            c.setFillColor(C_WHITE)
            c.setFont("Helvetica-Bold", 8)
            c.drawCentredString(header_w/2, y + row_h/2 - 0.1*cm, seq)

            x = header_w
            for pi in range(n_phases):
                sig = signals[seq][pi]
                cell_color = colors.Color(sig, sig, sig)
                c.setFillColor(cell_color)
                c.setStrokeColor(C_DARK_GRAY)
                c.setLineWidth(0.3)
                c.rect(x, y, col_w, row_h, fill=1, stroke=1)
                txt_c = C_WHITE if sig < 0.5 else C_DARK_GRAY
                c.setFillColor(txt_c)
                c.setFont("Helvetica-Bold", 5.8)
                lns2 = labels_map[seq][pi].split('\n')
                for li, ln in enumerate(lns2):
                    c.drawCentredString(x+col_w/2,
                        y + row_h - 0.2*cm - li*0.24*cm, ln)
                x += col_w

        c.setFillColor(C_DARK_GRAY)
        c.setFont("Helvetica-BoldOblique", 7.5)
        c.drawString(0, 0.1*cm, "★ = Diagnostic window: DWI bright + ADC dark = ACUTE INFARCT (confirmed restricted diffusion)")

    def wrap(self, aw, ah):
        return self.w, self.h


# ── Flowable: DWI-ADC Schematic ───────────────────────────────────────────────
class DWIADCSchematic(Flowable):
    """3-panel: Acute infarct | Chronic gliosis | Hemorrhage on SWI"""
    def __init__(self, w=None, h=None):
        Flowable.__init__(self)
        self.w = w or (PAGE_W - 4*cm)
        self.h = h or 5.5*cm

    def draw(self):
        c   = self.canv
        w, h = self.w, self.h
        n   = 3
        pw  = w / n
        r   = min(h*0.35, pw*0.38)
        cy  = h * 0.53

        panels = [
            {
                "title": "ACUTE INFARCT",
                "subtitle": "DWI bright + ADC dark\n= INFARCTION",
                "tc": C_RED,
                "dwi_lesion": 1.0,   # bright
                "adc_lesion": 0.0,   # dark
                "label_d": "DWI",
                "label_a": "ADC",
            },
            {
                "title": "CHRONIC / GLIOSIS",
                "subtitle": "DWI dark + ADC bright\n= T2 shine-through\n(NOT acute infarct)",
                "tc": C_GREEN,
                "dwi_lesion": 0.15,
                "adc_lesion": 0.9,
                "label_d": "DWI",
                "label_a": "ADC",
            },
            {
                "title": "HEMORRHAGE",
                "subtitle": "SWI/GRE: BLACK\n'blooming'\n= Blood product",
                "tc": C_PURPLE,
                "dwi_lesion": None,  # SWI panel
                "adc_lesion": 0.0,   # very dark
                "label_d": "SWI",
                "label_a": "T2*",
            },
        ]

        for i, p in enumerate(panels):
            cx = pw * i + pw/2

            # Panel bg
            c.setFillColor(colors.HexColor('#F8F9FA'))
            c.setStrokeColor(p["tc"])
            c.setLineWidth(1.2)
            c.roundRect(pw*i + 0.1*cm, 0.4*cm, pw - 0.2*cm, h-0.5*cm, 4, fill=1, stroke=1)

            # Brain circle
            brain_bg = 0.65  # gray
            c.setFillColor(colors.Color(brain_bg, brain_bg, brain_bg))
            c.setStrokeColor(C_DARK_GRAY)
            c.setLineWidth(0.5)
            c.circle(cx, cy, r, fill=1, stroke=1)

            # Lesion
            if p["dwi_lesion"] is not None:
                lv = p["dwi_lesion"]
                c.setFillColor(colors.Color(lv, lv, lv))
                c.setStrokeColor(C_DARK_GRAY)
                c.setLineWidth(0.3)
                c.circle(cx + r*0.25, cy + r*0.2, r*0.38, fill=1, stroke=1)
            else:
                # SWI bloom effect - add bright ring + dark center
                c.setFillColor(colors.Color(0.3, 0.3, 0.3))
                c.circle(cx + r*0.25, cy + r*0.2, r*0.42, fill=1, stroke=0)
                c.setFillColor(colors.Color(0.02, 0.02, 0.02))
                c.circle(cx + r*0.25, cy + r*0.2, r*0.32, fill=1, stroke=0)
                # bloom glow
                c.setFillColor(colors.Color(0.0, 0.0, 0.0))
                c.setStrokeColor(colors.HexColor('#555555'))
                c.setLineWidth(0.5)
                c.circle(cx + r*0.25, cy + r*0.2, r*0.38, fill=0, stroke=1)

            # Sequence labels
            c.setFillColor(p["tc"])
            c.setFont("Helvetica-Bold", 7)
            c.drawCentredString(cx, 0.65*cm, p["label_d"] if p["dwi_lesion"] is None else
                (p["label_d"] + " " + ("BRIGHT" if p["dwi_lesion"] > 0.5 else "DARK")))

            # Title
            c.setFillColor(p["tc"])
            c.setFont("Helvetica-Bold", 8.5)
            c.drawCentredString(cx, h-0.2*cm, p["title"])

            # Subtitle
            c.setFillColor(C_DARK_GRAY)
            c.setFont("Helvetica", 6.8)
            lns = p["subtitle"].split('\n')
            for li, ln in enumerate(lns):
                c.drawCentredString(cx, h - 0.58*cm - li*0.26*cm, ln)

    def wrap(self, aw, ah):
        return self.w, self.h


# ── Flowable: Hemorrhage Types Diagram ───────────────────────────────────────
class HemorrhageTypesDiagram(Flowable):
    """
    Schematic cross-section showing EDH, SDH, SAH, ICH locations
    """
    def __init__(self, w=None, h=None):
        Flowable.__init__(self)
        self.w = w or (PAGE_W - 4*cm)
        self.h = h or 7.0*cm

    def draw(self):
        c   = self.canv
        w, h = self.w, self.h
        cx  = w / 2
        cy  = h * 0.52

        # Skull outer
        skull_r = min(h*0.44, w*0.28)
        c.setFillColor(colors.HexColor('#D5D8DC'))
        c.setStrokeColor(C_BLACK)
        c.setLineWidth(1.0)
        c.circle(cx, cy, skull_r, fill=1, stroke=1)

        # Skull inner (diploe)
        c.setFillColor(colors.HexColor('#BDC3C7'))
        c.circle(cx, cy, skull_r*0.88, fill=1, stroke=0)

        # Dura
        c.setFillColor(colors.HexColor('#C0392B'))
        c.circle(cx, cy, skull_r*0.87, fill=0, stroke=1)
        c.setLineWidth(2.0)
        c.setStrokeColor(colors.HexColor('#C0392B'))
        c.circle(cx, cy, skull_r*0.87, fill=0, stroke=1)

        # Brain parenchyma
        c.setFillColor(C_CT_BRAIN)
        c.setStrokeColor(colors.HexColor('#888888'))
        c.setLineWidth(0.5)
        c.circle(cx, cy, skull_r*0.75, fill=1, stroke=1)

        # Gyri texture
        c.setStrokeColor(colors.HexColor('#999999'))
        c.setLineWidth(0.6)
        for angle in range(0, 360, 30):
            rad = math.radians(angle)
            x1 = cx + skull_r*0.66*math.cos(rad)
            y1 = cy + skull_r*0.66*math.sin(rad)
            x2 = cx + skull_r*0.74*math.cos(rad)
            y2 = cy + skull_r*0.74*math.sin(rad)
            c.line(x1, y1, x2, y2)

        # Ventricles
        c.setFillColor(C_CT_CSF)
        c.ellipse(cx-0.28*cm, cy-0.1*cm, cx+0.28*cm, cy+0.35*cm, fill=1, stroke=0)
        c.ellipse(cx-0.2*cm, cy-0.45*cm, cx-0.03*cm, cy-0.1*cm, fill=1, stroke=0)
        c.ellipse(cx+0.03*cm, cy-0.45*cm, cx+0.2*cm, cy-0.1*cm, fill=1, stroke=0)

        # ── EDH (lenticular / biconvex) at top right ──
        edh_angle = 50  # degrees from top
        edh_rad   = math.radians(edh_angle)
        edh_cx    = cx + skull_r*0.82*math.cos(edh_rad)
        edh_cy    = cy + skull_r*0.82*math.sin(edh_rad)
        c.setFillColor(colors.HexColor('#E74C3C'))
        c.saveState()
        c.translate(edh_cx, edh_cy)
        c.rotate(edh_angle - 90)
        c.ellipse(-0.35*cm, -0.12*cm, 0.35*cm, 0.12*cm, fill=1, stroke=0)
        c.restoreState()

        # ── SDH (crescent) at upper left ──
        sdh_angle = 130
        sdh_rad   = math.radians(sdh_angle)
        # Draw crescent as thick arc
        c.setFillColor(colors.HexColor('#E67E22'))
        c.saveState()
        c.translate(cx, cy)
        c.setFillColor(colors.HexColor('#E67E22'))
        # approximate crescent with a wide stroke arc
        c.setStrokeColor(colors.HexColor('#E67E22'))
        c.setLineWidth(5.0)
        c.arc(-skull_r*0.80, -skull_r*0.80, skull_r*0.80, skull_r*0.80,
              startAng=95, extent=85)
        c.restoreState()

        # ── SAH (thin layer in subarachnoid) at bottom ──
        c.setFillColor(colors.HexColor('#F39C12'))
        c.saveState()
        c.translate(cx, cy)
        c.setStrokeColor(colors.HexColor('#F39C12'))
        c.setLineWidth(3.5)
        c.arc(-skull_r*0.76, -skull_r*0.76, skull_r*0.76, skull_r*0.76,
              startAng=210, extent=60)
        c.restoreState()

        # ── ICH (parenchymal) - bright spot in right basal ganglia area ──
        ich_x = cx + 0.35*cm
        ich_y = cy + 0.1*cm
        c.setFillColor(colors.HexColor('#ECF0F1'))
        c.setStrokeColor(colors.HexColor('#BDC3C7'))
        c.setLineWidth(0.3)
        c.circle(ich_x, ich_y, 0.32*cm, fill=1, stroke=1)

        # Labels with arrows
        label_data = [
            (cx + skull_r*0.95, cy + skull_r*0.6,  cx + skull_r*1.3, cy + skull_r*0.9,  "EDH\n(Biconvex)\nArt. bleed", colors.HexColor('#E74C3C')),
            (cx - skull_r*0.92, cy + skull_r*0.55, cx - skull_r*1.35, cy + skull_r*0.9, "SDH\n(Crescent)\nVenous", colors.HexColor('#E67E22')),
            (cx - skull_r*0.55, cy - skull_r*0.85, cx - skull_r*0.8, cy - skull_r*1.25, "SAH\n(Cisterns/\nSulci)", colors.HexColor('#F39C12')),
            (cx + 0.35*cm, cy + 0.1*cm, cx + skull_r*1.15, cy - skull_r*0.5, "ICH\n(Parenchymal)\nBasal ganglia", colors.HexColor('#AAAAAA')),
        ]
        for x1, y1, x2, y2, lbl, clr in label_data:
            c.setStrokeColor(clr)
            c.setLineWidth(0.8)
            c.line(x1, y1, x2, y2)
            c.setFillColor(clr)
            c.setFont("Helvetica-Bold", 7.5)
            lns = lbl.split('\n')
            align_right = x2 < cx
            for li, ln in enumerate(lns):
                if align_right:
                    c.drawRightString(x2, y2 - li*0.25*cm, ln)
                else:
                    c.drawString(x2, y2 - li*0.25*cm, ln)

        # Title
        c.setFillColor(C_DARK_GRAY)
        c.setFont("Helvetica-BoldOblique", 8)
        c.drawCentredString(w/2, 0.1*cm,
            "Schematic cross-section of cranium showing types & locations of intracranial hemorrhage")

    def wrap(self, aw, ah):
        return self.w, self.h


# ── Flowable: HU Scale Bar ────────────────────────────────────────────────────
class HUScaleBar(Flowable):
    def __init__(self, w=None, h=None):
        Flowable.__init__(self)
        self.w = w or (PAGE_W - 4*cm)
        self.h = h or 2.2*cm

    def draw(self):
        c   = self.canv
        w, h = self.w, self.h
        bar_h = 0.6*cm
        bar_y = h*0.5
        bar_x = 1.0*cm
        bar_w = w - 2.0*cm
        n     = 200

        # Gradient bar: black → white
        for i in range(n):
            frac = i / n
            shade = frac
            c.setFillColor(colors.Color(shade, shade, shade))
            c.setStrokeColor(colors.Color(shade, shade, shade))
            c.rect(bar_x + frac*bar_w, bar_y, bar_w/n + 0.5, bar_h, fill=1, stroke=0)

        # Border
        c.setStrokeColor(C_DARK_GRAY)
        c.setLineWidth(0.5)
        c.rect(bar_x, bar_y, bar_w, bar_h, fill=0, stroke=1)

        # Tick marks & labels
        ticks = [
            (0.0,   "< -100\nFat/Air"),
            (0.15,  "0\nWater/CSF"),
            (0.32,  "~25-40\nBrain"),
            (0.52,  "~50-80\nBlood"),
            (0.68,  "~100\nCalcification"),
            (1.0,   ">400\nBone"),
        ]
        for frac, lbl in ticks:
            tx = bar_x + frac*bar_w
            c.setStrokeColor(C_DARK_GRAY)
            c.setLineWidth(0.5)
            c.line(tx, bar_y-0.05*cm, tx, bar_y-0.25*cm)
            c.setFillColor(C_DARK_GRAY)
            c.setFont("Helvetica", 6.5)
            lns = lbl.split('\n')
            for li, ln in enumerate(lns):
                c.drawCentredString(tx, bar_y - 0.32*cm - li*0.2*cm, ln)

        # Arrow labels above bar
        blood_x = bar_x + 0.52*bar_w
        c.setFillColor(C_RED)
        c.setFont("Helvetica-Bold", 7)
        c.drawCentredString(blood_x, bar_y + bar_h + 0.2*cm, "BLOOD\n(Hyperdense)")

        c.setFillColor(C_BLUE)
        infarct_x = bar_x + 0.22*bar_w
        c.drawCentredString(infarct_x, bar_y + bar_h + 0.2*cm, "INFARCT\n(Hypodense)")

        c.setFillColor(C_DARK_GRAY)
        c.setFont("Helvetica-Bold", 8)
        c.drawString(0, bar_y + bar_h*0.2, "HU:")
        c.drawString(w - 0.8*cm, bar_y + bar_h*0.2, "DENSE")
        c.setFont("Helvetica", 8)
        c.drawString(0, bar_y - 0.1*cm, "")

    def wrap(self, aw, ah):
        return self.w, self.h


# ── Build PDF ─────────────────────────────────────────────────────────────────
def build_pdf(output_path):
    doc = SimpleDocTemplate(
        output_path,
        pagesize=A4,
        leftMargin=2*cm, rightMargin=2*cm,
        topMargin=2*cm,  bottomMargin=2*cm,
        title="Brain CT & MRI: Bleed vs Infarct - Reference Guide",
        author="Orris Medical Reference"
    )

    styles = getSampleStyleSheet()
    avail_w = PAGE_W - 4*cm

    # Custom styles
    title_style = ParagraphStyle('Title2',
        fontName='Helvetica-Bold', fontSize=20, leading=24,
        textColor=C_WHITE, alignment=TA_CENTER, spaceAfter=4)
    subtitle_style = ParagraphStyle('Subtitle2',
        fontName='Helvetica', fontSize=11, leading=14,
        textColor=colors.HexColor('#AED6F1'), alignment=TA_CENTER, spaceAfter=6)
    h2_style = ParagraphStyle('H2',
        fontName='Helvetica-Bold', fontSize=11, leading=14,
        textColor=C_NAVY, spaceAfter=4, spaceBefore=8)
    body_style = ParagraphStyle('Body2',
        fontName='Helvetica', fontSize=8.5, leading=12,
        textColor=C_DARK_GRAY, spaceAfter=4, alignment=TA_JUSTIFY)
    small_style = ParagraphStyle('Small',
        fontName='Helvetica', fontSize=7.5, leading=10,
        textColor=C_DARK_GRAY, spaceAfter=2)
    callout_style = ParagraphStyle('Callout',
        fontName='Helvetica-BoldOblique', fontSize=8.5, leading=12,
        textColor=C_NAVY, spaceAfter=3,
        borderPad=6, borderColor=C_LIGHTBLUE,
        backColor=colors.HexColor('#EBF5FB'))
    note_style = ParagraphStyle('Note',
        fontName='Helvetica-Oblique', fontSize=7.5, leading=10,
        textColor=C_MID_GRAY, spaceAfter=4)

    story = []

    # ══════════════════════════════════════════════════════════════════════════
    # COVER PAGE
    # ══════════════════════════════════════════════════════════════════════════
    class CoverPage(Flowable):
        def __init__(self):
            Flowable.__init__(self)
            self.w = avail_w
            self.h = PAGE_H - 4*cm

        def draw(self):
            c = self.canv
            w, h = self.w, self.h

            # Background gradient block
            c.setFillColor(C_NAVY)
            c.rect(0, h*0.45, w, h*0.55, fill=1, stroke=0)
            c.setFillColor(C_BLUE)
            c.rect(0, h*0.3, w, h*0.15, fill=1, stroke=0)
            c.setFillColor(C_LIGHTBLUE)
            c.rect(0, 0, w, h*0.3, fill=1, stroke=0)

            # Title
            c.setFillColor(C_WHITE)
            c.setFont("Helvetica-Bold", 22)
            c.drawCentredString(w/2, h*0.82, "BRAIN CT & MRI")
            c.setFont("Helvetica-Bold", 18)
            c.drawCentredString(w/2, h*0.74, "READING GUIDE")
            c.setFont("Helvetica", 12)
            c.setFillColor(colors.HexColor('#AED6F1'))
            c.drawCentredString(w/2, h*0.66, "Hemorrhage vs. Infarction")
            c.drawCentredString(w/2, h*0.61, "Acute • Subacute • Chronic")

            # Decorative CT circle (brain schematic)
            brain_cx = w/2
            brain_cy = h*0.44
            brain_r  = 1.8*cm
            c.setFillColor(colors.HexColor('#1A1A2E'))
            c.circle(brain_cx, brain_cy, brain_r*1.15, fill=1, stroke=0)
            c.setFillColor(colors.HexColor('#888888'))
            c.circle(brain_cx, brain_cy, brain_r, fill=1, stroke=0)
            c.setFillColor(colors.HexColor('#111111'))
            c.ellipse(brain_cx-0.3*cm, brain_cy-0.1*cm, brain_cx+0.3*cm, brain_cy+0.35*cm, fill=1, stroke=0)
            # Bleed spot
            c.setFillColor(colors.HexColor('#F0F0F0'))
            c.circle(brain_cx+0.6*cm, brain_cy+0.3*cm, 0.38*cm, fill=1, stroke=0)
            # Infarct
            c.setFillColor(colors.HexColor('#555555'))
            c.circle(brain_cx-0.55*cm, brain_cy+0.2*cm, 0.32*cm, fill=1, stroke=0)

            c.setFillColor(C_WHITE)
            c.setFont("Helvetica-Bold", 7)
            c.drawCentredString(brain_cx+0.6*cm, brain_cy+0.1*cm, "BLEED")
            c.drawCentredString(brain_cx-0.55*cm, brain_cy+0.02*cm, "INFARCT")

            # Bottom section
            c.setFillColor(C_WHITE)
            c.setFont("Helvetica-Bold", 10)
            c.drawCentredString(w/2, h*0.22, "Complete Timeline Reference")
            c.setFont("Helvetica", 9)
            c.setFillColor(colors.HexColor('#1B2631'))
            c.drawCentredString(w/2, h*0.15,
                "CT Density | MRI Signal | DWI/ADC | SWI | Hemorrhage Types")
            c.drawCentredString(w/2, h*0.09,
                "Based on: Adams & Victor's Neurology • Bradley & Daroff • Grainger & Allison")

            c.setFillColor(C_NAVY)
            c.setFont("Helvetica-Oblique", 7.5)
            c.drawCentredString(w/2, h*0.02, "Orris Medical Reference  |  For educational purposes only")

        def wrap(self, aw, ah):
            return self.w, self.h

    story.append(CoverPage())
    story.append(PageBreak())

    # ══════════════════════════════════════════════════════════════════════════
    # PAGE 2: CT FUNDAMENTALS
    # ══════════════════════════════════════════════════════════════════════════
    story.append(SectionHeader("1.  HOW TO READ A BRAIN CT",
        "Non-contrast CT (NCCT) — First-line for ALL stroke and head injury presentations", bg=C_NAVY, w=avail_w))
    story.append(Spacer(1, 0.3*cm))

    story.append(Paragraph("The Hounsfield Unit (HU) Scale", h2_style))
    story.append(Paragraph(
        "Every CT pixel is assigned a Hounsfield Unit (HU) value representing tissue density. "
        "Air = −1000 HU, water = 0 HU, bone = ~700+ HU. <b>Blood clots are denser than brain "
        "(~60–80 HU vs ~35 HU), so they appear bright white (hyperdense). Infarcted brain loses "
        "fluid equilibrium and becomes hypodense (dark, &lt;30 HU).</b>", body_style))
    story.append(HUScaleBar(w=avail_w, h=2.4*cm))
    story.append(Spacer(1, 0.5*cm))

    story.append(Paragraph("CT Window Settings", h2_style))
    win_data = [
        ["Window Setting", "Width (WW)", "Level (WL)", "Best For"],
        ["Brain window",        "~80",  "~35",  "Parenchyma, gray-white differentiation, blood"],
        ["Bone window",         "~2000","~300", "Skull fractures, calvarium"],
        ["Stroke window",       "~35",  "~35",  "Subtle early ischemia, improves gray-white contrast"],
        ["Subdural window",     "~200", "~60",  "Subdural hematoma vs. brain"],
    ]
    win_table = Table(win_data, colWidths=[3.5*cm, 2.2*cm, 2.2*cm, 8.1*cm])
    win_table.setStyle(TableStyle([
        ('BACKGROUND', (0,0), (-1,0), C_BLUE),
        ('TEXTCOLOR',  (0,0), (-1,0), C_WHITE),
        ('FONTNAME',   (0,0), (-1,0), 'Helvetica-Bold'),
        ('FONTSIZE',   (0,0), (-1,-1), 8),
        ('ROWBACKGROUNDS', (0,1), (-1,-1), [C_CREAM, C_LIGHT_GRAY]),
        ('GRID',       (0,0), (-1,-1), 0.4, C_MID_GRAY),
        ('VALIGN',     (0,0), (-1,-1), 'MIDDLE'),
        ('TOPPADDING', (0,0), (-1,-1), 3),
        ('BOTTOMPADDING', (0,0), (-1,-1), 3),
    ]))
    story.append(win_table)
    story.append(Spacer(1, 0.4*cm))

    story.append(Paragraph("CT Schematic: Hemorrhage vs. Infarct", h2_style))
    story.append(CTBrainSchematic(w=avail_w, h=6.5*cm))
    story.append(Spacer(1, 0.3*cm))

    story.append(Paragraph(
        "<b>Key early CT signs of ischemic stroke (first 6 hours):</b> "
        "(1) Loss of gray-white differentiation at the basal ganglia or insular cortex.  "
        "(2) <b>Insular ribbon sign</b> — loss of sharp insular cortex outline (MCA territory).  "
        "(3) <b>Sulcal effacement</b> — swollen gyri obliterate normal sulci.  "
        "(4) <b>Hyperdense vessel sign</b> — bright MCA or basilar artery = acute thrombus.  "
        "(5) <b>1/3 MCA rule</b> — if >1/3 MCA territory is already hypodense, IV tPA is contraindicated.",
        body_style))

    story.append(PageBreak())

    # ══════════════════════════════════════════════════════════════════════════
    # PAGE 3: CT TIMELINE
    # ══════════════════════════════════════════════════════════════════════════
    story.append(SectionHeader("2.  CT TIMELINE — HEMORRHAGE vs. INFARCT",
        "How CT appearance changes over time for each pathology", bg=C_RED, w=avail_w))
    story.append(Spacer(1, 0.3*cm))

    story.append(CTTimelineDiagram(w=avail_w, h=5.8*cm))
    story.append(Spacer(1, 0.4*cm))

    story.append(Paragraph("Detailed CT Timeline Table", h2_style))
    ct_data = [
        ["Phase", "Time", "Hemorrhage on CT", "Infarct on CT"],
        ["Hyperacute", "0–6 hrs",
         "HYPERDENSE (white, ~60-80 HU)\nClot formed, protein concentrated",
         "NORMAL or very subtle\nPossible sulcal effacement only"],
        ["Acute", "6–24 hrs",
         "HYPERDENSE\nPeripheral edema halo may appear",
         "HYPODENSE territory\nGray-white differentiation lost\nInsular ribbon sign"],
        ["Early Subacute", "1–7 days",
         "HYPERDENSE → becoming ISODENSE\nEdema increases, mass effect",
         "CLEARLY HYPODENSE\nMass effect peaks day 3–5\nMidline shift possible"],
        ["Late Subacute", "1–3 wks",
         "ISODENSE — can be MISSED!\nLook for mass effect clue",
         "FOGGING EFFECT (~1-3 wks)\nMay look falsely normal\n(macrophage infiltration)"],
        ["Chronic", ">3 wks",
         "HYPODENSE (dark)\nMay calcify; subdural → crescent",
         "ENCEPHALOMALACIA\nHypodense cavity\nEx-vacuo ventricular dilation"],
    ]
    ct_table = Table(ct_data,
        colWidths=[2.8*cm, 2.0*cm, 6.2*cm, 5.0*cm])
    ct_table.setStyle(TableStyle([
        ('BACKGROUND', (0,0), (-1,0), C_DARK_GRAY),
        ('TEXTCOLOR',  (0,0), (-1,0), C_WHITE),
        ('FONTNAME',   (0,0), (-1,0), 'Helvetica-Bold'),
        ('BACKGROUND', (2,1), (2,-1), colors.HexColor('#FDFEFE')),
        ('BACKGROUND', (3,1), (3,-1), colors.HexColor('#EBF5FB')),
        ('FONTSIZE',   (0,0), (-1,-1), 7.5),
        ('ROWBACKGROUNDS', (0,1), (1,-1), [colors.HexColor('#FDEBD0'), colors.HexColor('#FEF9E7')]),
        ('GRID',       (0,0), (-1,-1), 0.4, C_MID_GRAY),
        ('VALIGN',     (0,0), (-1,-1), 'TOP'),
        ('TOPPADDING', (0,0), (-1,-1), 4),
        ('BOTTOMPADDING', (0,0), (-1,-1), 4),
        ('FONTNAME',   (2,1), (2,-1), 'Helvetica-Bold'),
    ]))
    story.append(ct_table)
    story.append(Spacer(1, 0.3*cm))

    story.append(Paragraph(
        "<b>Pitfall — Isodense Subdural Hematoma:</b> "
        "At ~7–14 days, subdural blood becomes isodense with brain on CT. "
        "Clues: asymmetric sulci, displaced cortex, midline shift without visible hyperdensity. "
        "MRI (T1) will show it as bright (methemoglobin).", callout_style))

    story.append(PageBreak())

    # ══════════════════════════════════════════════════════════════════════════
    # PAGE 4: HEMORRHAGE TYPES
    # ══════════════════════════════════════════════════════════════════════════
    story.append(SectionHeader("3.  TYPES OF INTRACRANIAL HEMORRHAGE",
        "Location determines shape, likely etiology, and clinical presentation", bg=C_RED, w=avail_w))
    story.append(Spacer(1, 0.3*cm))

    story.append(HemorrhageTypesDiagram(w=avail_w, h=7.0*cm))
    story.append(Spacer(1, 0.4*cm))

    hem_type_data = [
        ["Type", "CT Shape", "Location", "Typical Cause", "Key Clue"],
        ["EDH\n(Epidural)", "BICONVEX\n(lens-shaped)", "Between skull & dura\nDoes NOT cross sutures",
         "Middle meningeal\nartery (temporal\nfracture)", "Lucid interval\nTemporal fracture"],
        ["SDH\n(Subdural)", "CRESCENT\n(concave inner edge)", "Between dura & brain\nCrosses sutures freely",
         "Bridging veins\n(shear force)", "Elderly, falls\nAnticoagulants"],
        ["SAH\n(Subarachnoid)", "Fills sulci/basal\ncisterns — 'star'\npattern", "Subarachnoid space",
         "Ruptured Berry\naneurysm, AVM,\nTrauma", "Thunderclap HA\nFisher grade"],
        ["ICH\n(Intracerebral)", "Round/oval\nparenchymal", "Basal ganglia\nThalamus, pons,\ncerebellum",
         "HTN (most common)\nAmyloid angiopathy", "Location predicts\ncause: deep=HTN\ncortical=amyloid"],
    ]
    hem_t = Table(hem_type_data, colWidths=[2.0*cm, 2.8*cm, 3.2*cm, 3.2*cm, 4.8*cm])
    hem_t.setStyle(TableStyle([
        ('BACKGROUND', (0,0), (-1,0), C_RED),
        ('TEXTCOLOR',  (0,0), (-1,0), C_WHITE),
        ('FONTNAME',   (0,0), (-1,0), 'Helvetica-Bold'),
        ('FONTSIZE',   (0,0), (-1,-1), 7.5),
        ('ROWBACKGROUNDS', (0,1), (-1,-1),
         [colors.HexColor('#FDEDEC'), colors.HexColor('#FEF9E7'),
          colors.HexColor('#FEF5E7'), colors.HexColor('#FDFEFE')]),
        ('GRID',       (0,0), (-1,-1), 0.4, C_MID_GRAY),
        ('VALIGN',     (0,0), (-1,-1), 'TOP'),
        ('TOPPADDING', (0,0), (-1,-1), 4),
        ('BOTTOMPADDING', (0,0), (-1,-1), 4),
        ('FONTNAME',   (0,1), (0,-1), 'Helvetica-Bold'),
        ('TEXTCOLOR',  (0,1), (0,-1), C_RED),
    ]))
    story.append(hem_t)

    story.append(PageBreak())

    # ══════════════════════════════════════════════════════════════════════════
    # PAGE 5: MRI SEQUENCES
    # ══════════════════════════════════════════════════════════════════════════
    story.append(SectionHeader("4.  MRI SEQUENCES — WHAT EACH ONE SHOWS",
        "Understanding each sequence is key to accurate interpretation", bg=C_TEAL, w=avail_w))
    story.append(Spacer(1, 0.3*cm))

    mri_seq_data = [
        ["Sequence", "TE/TR", "Bright (hyperintense)", "Dark (hypointense)", "Best Used For"],
        ["T1", "Short TE\nShort TR",
         "Fat, methemoglobin,\nprotein-rich fluid,\ngadolinium (contrast)",
         "CSF, edema,\ndeoxyhemoglobin,\nacute infarct",
         "Anatomy, subacute\nblood, contrast\nenhancement"],
        ["T2", "Long TE\nLong TR",
         "CSF, edema, gliosis,\nlate subacute blood\n(extracellular methHb)",
         "Acute blood (deoxy),\nhemosiderin,\ncalcification, cortical bone",
         "Infarcts, edema,\ntumors, inflammation"],
        ["FLAIR", "Long TE\nLong TR\n+inversion",
         "Edema, gliosis,\nSAH (bloody CSF bright),\nperiventricular lesions",
         "Normal CSF\n(suppressed — black)",
         "Periventricular MS,\nSAH, infarct age\n(DWI-FLAIR mismatch)"],
        ["DWI", "EPI\nsequence",
         "ACUTE INFARCT ★\n(restricted diffusion)\nAlso: abscess, epidermoid",
         "Chronic lesions,\nblood after several days,\nCSF",
         "ACUTE STROKE\ndiagnosis — positive\nwithin minutes"],
        ["ADC", "Derived\nfrom DWI",
         "Vasogenic edema,\nchronic gliosis\n(unrestricted diffusion)",
         "ACUTE INFARCT ★\n(true restriction)\nAlso abscess",
         "Confirm restricted\ndiffusion; exclude\nT2 shine-through"],
        ["SWI/GRE", "T2*\ngradient\necho",
         "None significant",
         "ALL blood products\n★ 'Blooms' dark\nCalcification, iron, veins",
         "Microhemorrhages,\nvenous thrombosis,\nhemorrhagic transform."],
        ["MRA", "TOF or\ncontrast",
         "Flowing blood\n(patent vessel)",
         "Thrombosed vessel\n(flow void lost)",
         "Intracranial\nvessel patency,\naneurysm, LVO"],
    ]
    mri_t = Table(mri_seq_data, colWidths=[1.8*cm, 1.5*cm, 4.0*cm, 3.8*cm, 4.9*cm])
    mri_t.setStyle(TableStyle([
        ('BACKGROUND', (0,0), (-1,0), C_TEAL),
        ('TEXTCOLOR',  (0,0), (-1,0), C_WHITE),
        ('FONTNAME',   (0,0), (-1,0), 'Helvetica-Bold'),
        ('FONTSIZE',   (0,0), (-1,-1), 7.5),
        ('ROWBACKGROUNDS', (0,1), (-1,-1),
         [colors.HexColor('#E8F8F5'), colors.HexColor('#FDFEFE')]*5),
        ('GRID',       (0,0), (-1,-1), 0.4, C_MID_GRAY),
        ('VALIGN',     (0,0), (-1,-1), 'TOP'),
        ('TOPPADDING', (0,0), (-1,-1), 4),
        ('BOTTOMPADDING', (0,0), (-1,-1), 4),
        ('FONTNAME',   (0,1), (0,-1), 'Helvetica-Bold'),
        ('TEXTCOLOR',  (0,1), (0,-1), C_TEAL),
    ]))
    story.append(mri_t)
    story.append(Spacer(1, 0.3*cm))

    story.append(Paragraph(
        "<b>The DWI-ADC Rule (most important concept in acute stroke MRI):</b><br/>"
        "• <b>DWI bright + ADC dark</b> = TRUE restricted diffusion = ACUTE INFARCTION ✓<br/>"
        "• <b>DWI bright + ADC bright/normal</b> = T2 shine-through (NOT acute infarct)<br/>"
        "• <b>DWI dark + ADC bright</b> = chronic gliosis / encephalomalacia",
        callout_style))

    story.append(DWIADCSchematic(w=avail_w, h=5.5*cm))

    story.append(PageBreak())

    # ══════════════════════════════════════════════════════════════════════════
    # PAGE 6: MRI HEMORRHAGE TIMELINE
    # ══════════════════════════════════════════════════════════════════════════
    story.append(SectionHeader("5.  MRI HEMORRHAGE SIGNAL TIMELINE",
        "Signal depends on hemoglobin oxidation state and RBC integrity", bg=C_PURPLE, w=avail_w))
    story.append(Spacer(1, 0.3*cm))

    story.append(Paragraph(
        "Hemoglobin undergoes a predictable series of chemical transformations after bleeding. "
        "Each stage has unique magnetic properties that create characteristic MRI signal patterns. "
        "The key variable is whether hemoglobin has <b>unpaired electrons</b> (paramagnetic = shortens T2) "
        "and whether it is <b>intracellular or extracellular</b> (determines T1 effect).",
        body_style))

    story.append(MRISequenceGrid(w=avail_w, h=7.5*cm))
    story.append(Spacer(1, 0.3*cm))

    mri_hem_data = [
        ["Stage", "Time", "Hb Form", "Location", "T1", "T2", "SWI", "Mechanism"],
        ["Hyperacute", "0–6 hrs", "Oxyhemoglobin\n(OxyHb)", "Intracellular",
         "Gray\n(iso)", "Lt Gray\n(slightly\nbright)", "Dark", "OxyHb has NO unpaired electrons\n→ no T1 shortening; T2 bright from\nwater in intact RBCs"],
        ["Acute", "1–3 days", "Deoxyhemoglobin\n(DeoxyHb)", "Intracellular",
         "Gray\n(iso)", "DARK\n(black)", "VERY\nDARK", "DeoxyHb has 4 unpaired electrons\n→ strong T2 shortening; intact cell\nmembrane prevents T1 effect"],
        ["Early\nSubacute", "3–7 days", "Intracellular\nMethemoglobin", "Intracellular",
         "BRIGHT\n(white)", "DARK\n(black)", "DARK", "MetHb has 5 unpaired electrons\n→ strong T1 shortening; RBCs still\nintact → T2 still dark"],
        ["Late\nSubacute", "7–30 days", "Extracellular\nMethemoglobin", "Extracellular\n(RBC lysis)",
         "BRIGHT\n(white)", "BRIGHT\n(white)", "Dark", "RBC lysis → MetHb disperses\nextracellularly → T2 shortening\nrelieved → both T1 & T2 bright"],
        ["Chronic", ">14 days", "Hemosiderin +\nFerritin", "In macrophages\n(outer rim)",
         "Dk Gray\n(hypo)", "BLACK\n(very\ndark)", "BLACK\n'Blooms'", "Hemosiderin = highly paramagnetic\n→ profound T2* susceptibility\neffect → 'blooming' on SWI/GRE"],
    ]
    mri_h_t = Table(mri_hem_data,
        colWidths=[1.7*cm, 1.5*cm, 2.2*cm, 2.0*cm, 1.2*cm, 1.2*cm, 1.2*cm, 5.0*cm])
    mri_h_t.setStyle(TableStyle([
        ('BACKGROUND', (0,0), (-1,0), C_PURPLE),
        ('TEXTCOLOR',  (0,0), (-1,0), C_WHITE),
        ('FONTNAME',   (0,0), (-1,0), 'Helvetica-Bold'),
        ('FONTSIZE',   (0,0), (-1,-1), 7),
        # Color-code T1/T2 columns by signal
        ('BACKGROUND', (4,2), (4,2), colors.HexColor('#888888')),  # hyper T1
        ('BACKGROUND', (5,2), (5,2), colors.HexColor('#111111')),  # dark T2 acute
        ('TEXTCOLOR',  (5,2), (5,2), C_WHITE),
        ('BACKGROUND', (4,3), (4,3), colors.HexColor('#F0F0F0')),  # bright T1 early sub
        ('BACKGROUND', (5,3), (5,3), colors.HexColor('#111111')),  # dark T2
        ('TEXTCOLOR',  (5,3), (5,3), C_WHITE),
        ('BACKGROUND', (4,4), (4,4), colors.HexColor('#F5F5F5')),  # bright T1 late sub
        ('BACKGROUND', (5,4), (5,4), colors.HexColor('#F5F5F5')),  # bright T2 late sub
        ('BACKGROUND', (5,5), (5,5), colors.HexColor('#111111')),  # black chronic
        ('TEXTCOLOR',  (5,5), (5,5), C_WHITE),
        ('BACKGROUND', (6,5), (6,5), colors.HexColor('#000000')),  # SWI black
        ('TEXTCOLOR',  (6,5), (6,5), C_WHITE),
        ('ROWBACKGROUNDS', (0,1), (3,-1),
         [colors.HexColor('#F9EBF8'), colors.HexColor('#F5EEF8'),
          colors.HexColor('#EBF5FB'), colors.HexColor('#E8F8F5'),
          colors.HexColor('#FDFEFE')]),
        ('GRID',       (0,0), (-1,-1), 0.4, C_MID_GRAY),
        ('VALIGN',     (0,0), (-1,-1), 'TOP'),
        ('TOPPADDING', (0,0), (-1,-1), 3),
        ('BOTTOMPADDING', (0,0), (-1,-1), 3),
        ('FONTNAME',   (0,1), (0,-1), 'Helvetica-Bold'),
        ('TEXTCOLOR',  (0,1), (0,-1), C_PURPLE),
    ]))
    story.append(mri_h_t)
    story.append(Spacer(1, 0.2*cm))
    story.append(Paragraph(
        "<b>Memory aid — T1/T2 for hemorrhage:</b>  "
        "<i>\"It's Bright After Bleeding\"</i> — "
        "Iso → Iso → <b>T1 Bright</b> → <b>Both Bright</b> → Dark (hemosiderin ring)",
        note_style))

    story.append(PageBreak())

    # ══════════════════════════════════════════════════════════════════════════
    # PAGE 7: MRI INFARCT TIMELINE
    # ══════════════════════════════════════════════════════════════════════════
    story.append(SectionHeader("6.  MRI INFARCTION TIMELINE",
        "How ischemic infarct evolves on each MRI sequence", bg=C_TEAL, w=avail_w))
    story.append(Spacer(1, 0.3*cm))

    story.append(MRIInfarctTimeline(w=avail_w, h=6.0*cm))
    story.append(Spacer(1, 0.4*cm))

    mri_inf_data = [
        ["Phase", "Time", "DWI", "ADC", "T2/FLAIR", "T1", "Clinical Note"],
        ["Hyperacute", "0–6 hrs",
         "BRIGHT ★\n(from 5 min)", "DARK ★",
         "Normal or\nvery subtle", "Normal",
         "DWI+/ADC− = infarction\nconfirmed. CT often normal.\nStart tPA workup."],
        ["Acute", "6 hrs–5 days",
         "BRIGHT ★", "DARK ★",
         "Clearly\nBRIGHT\n+ mass effect", "Hypointense",
         "Full extent visible on DWI.\nMass effect may mimic tumor.\nPeak cytotoxic edema."],
        ["Subacute\n(early)", "5–14 days",
         "Fading\n(T2 shine-\nthrough)", "Pseudonorm-\nalizing\n(~day 7-10)",
         "BRIGHT\nMass effect\nresolvingv", "Hypointense\nGyral\nenhancement",
         "ADC PSEUDONORMALIZATION\nTrap! ADC looks normal but\nT2/FLAIR still bright."],
        ["Chronic", ">3 wks",
         "DARK\n(unrestricted)", "BRIGHT\n(free water)",
         "BRIGHT\ngliosis\n(permanent)", "Hypointense\n(cavity)",
         "Encephalomalacia.\nEx-vacuo dilation of\nadjacent ventricle."],
    ]
    mri_inf_t = Table(mri_inf_data,
        colWidths=[2.2*cm, 1.8*cm, 1.8*cm, 1.8*cm, 2.2*cm, 2.2*cm, 4.0*cm])
    mri_inf_t.setStyle(TableStyle([
        ('BACKGROUND', (0,0), (-1,0), C_TEAL),
        ('TEXTCOLOR',  (0,0), (-1,0), C_WHITE),
        ('FONTNAME',   (0,0), (-1,0), 'Helvetica-Bold'),
        ('FONTSIZE',   (0,0), (-1,-1), 7.5),
        ('ROWBACKGROUNDS', (0,1), (-1,-1),
         [colors.HexColor('#E8F8F5'), colors.HexColor('#FDFEFE'),
          colors.HexColor('#EBF5FB'), colors.HexColor('#F0F9FF')]),
        ('GRID',       (0,0), (-1,-1), 0.4, C_MID_GRAY),
        ('VALIGN',     (0,0), (-1,-1), 'TOP'),
        ('TOPPADDING', (0,0), (-1,-1), 4),
        ('BOTTOMPADDING', (0,0), (-1,-1), 4),
        ('FONTNAME',   (2,1), (3,2), 'Helvetica-Bold'),
        ('BACKGROUND', (2,1), (2,2), colors.HexColor('#F5F5F5')),  # DWI bright
        ('BACKGROUND', (3,1), (3,2), colors.HexColor('#111111')),  # ADC dark
        ('TEXTCOLOR',  (3,1), (3,2), C_WHITE),
        ('BACKGROUND', (2,4), (2,4), colors.HexColor('#333333')),  # DWI dark chronic
        ('TEXTCOLOR',  (2,4), (2,4), C_WHITE),
        ('BACKGROUND', (3,4), (3,4), colors.HexColor('#EEEEEE')),  # ADC bright chronic
    ]))
    story.append(mri_inf_t)
    story.append(Spacer(1, 0.3*cm))

    story.append(Paragraph(
        "<b>DWI-FLAIR Mismatch (Wake-up Stroke):</b> "
        "If DWI is bright but FLAIR is normal/subtle → infarct is likely &lt;4.5 hours old "
        "→ consider thrombolysis even if time of onset is unknown. "
        "If both DWI and FLAIR are bright → infarct is probably &gt;4.5–6 hours.", callout_style))
    story.append(Spacer(1, 0.2*cm))
    story.append(Paragraph(
        "<b>ADC Pseudonormalization Trap:</b> "
        "Around days 7–14, vasogenic edema water dilutes the restricted diffusion signal "
        "and ADC may normalize. Do not mistake this for normal or resolving infarct — "
        "FLAIR and clinical history will clarify.", callout_style))

    story.append(PageBreak())

    # ══════════════════════════════════════════════════════════════════════════
    # PAGE 8: MASTER COMPARISON + WORKFLOW
    # ══════════════════════════════════════════════════════════════════════════
    story.append(SectionHeader("7.  MASTER COMPARISON: BLEED vs. INFARCT",
        "Quick-reference summary for clinical decision-making", bg=C_NAVY, w=avail_w))
    story.append(Spacer(1, 0.3*cm))

    master_data = [
        ["Feature", "HEMORRHAGE", "INFARCT"],
        ["CT density\n(acute)", "HYPERDENSE (white)\n~60–80 HU", "HYPODENSE (dark)\n<30 HU (after 6 hrs)"],
        ["CT visibility", "Immediately visible", "Subtle <6 hrs; clear >6 hrs"],
        ["CT shape", "Round/oval, well-defined", "Wedge-shaped, follows\nvascular territory"],
        ["Location clue", "Deep (HTN): BG, thalamus\npons, cerebellum", "Cortex + subcortex\nfollowing arterial supply"],
        ["MRI T1", "Iso → Iso → BRIGHT →\nBRIGHT → Dark (rim)", "Normal → Hypo → Hypo"],
        ["MRI T2", "Bright → DARK → DARK\n→ BRIGHT → BLACK", "Normal → BRIGHT →\nBRIGHT (permanent gliosis)"],
        ["MRI DWI", "Dark (blood quenches\nDWI after few days)", "BRIGHT ★ (from 5 min\nonset — gold standard)"],
        ["MRI SWI", "BLACK 'blooms'\n(all stages)", "Negative\n(unless hemorrhagic Tx)"],
        ["Mass effect", "Yes, immediate +\nsurrounding edema", "Peaks day 3–5 (large\ninfarcts)"],
        ["Enhancement\n(+contrast)", "Peripheral ring in\nsubacute phase", "Gyral enhancement\n>1–2 weeks"],
        ["Chronic\nappearance", "Hypodense cavity ±\ncalcification; hemosiderin\nring on MRI", "Encephalomalacia\nEx-vacuo dilation"],
    ]
    master_t = Table(master_data, colWidths=[3.5*cm, 6.5*cm, 6.0*cm])
    master_t.setStyle(TableStyle([
        ('BACKGROUND', (0,0), (-1,0), C_NAVY),
        ('TEXTCOLOR',  (0,0), (-1,0), C_WHITE),
        ('FONTNAME',   (0,0), (-1,0), 'Helvetica-Bold'),
        ('FONTSIZE',   (0,0), (-1,-1), 8),
        ('BACKGROUND', (1,1), (1,-1), colors.HexColor('#FDEDEC')),
        ('BACKGROUND', (2,1), (2,-1), colors.HexColor('#EBF5FB')),
        ('ROWBACKGROUNDS', (0,1), (0,-1),
         [C_LIGHT_GRAY, colors.HexColor('#D5D8DC')]*10),
        ('GRID',       (0,0), (-1,-1), 0.4, C_MID_GRAY),
        ('VALIGN',     (0,0), (-1,-1), 'TOP'),
        ('TOPPADDING', (0,0), (-1,-1), 4),
        ('BOTTOMPADDING', (0,0), (-1,-1), 4),
        ('FONTNAME',   (0,1), (0,-1), 'Helvetica-Bold'),
        ('FONTNAME',   (1,1), (1,-1), 'Helvetica'),
        ('FONTNAME',   (2,1), (2,-1), 'Helvetica'),
    ]))
    story.append(master_t)
    story.append(Spacer(1, 0.4*cm))

    # Emergency workflow
    story.append(SectionHeader("8.  EMERGENCY IMAGING WORKFLOW",
        "Step-by-step approach for acute stroke / head injury", bg=C_GREEN, w=avail_w))
    story.append(Spacer(1, 0.3*cm))

    workflow_data = [
        ["Step", "Modality", "Question Asked", "Action Based On Result"],
        ["1", "NCCT Brain\n(Non-contrast CT)",
         "Is there hemorrhage?\nIs there a mass?",
         "YES hemorrhage → manage accordingly, NO tPA\nNO hemorrhage → proceed to step 2"],
        ["2", "CT Angiography\n(CTA) Arch→Skull",
         "Is there a Large\nVessel Occlusion (LVO)?",
         "LVO present → consider thrombectomy\nCheck for hyperdense vessel sign"],
        ["3", "CT Perfusion\n(if available)",
         "Is there salvageable\npenumbra vs. core?",
         "Mismatch (large penumbra) → proceed with\nthrombectomy even at extended time window"],
        ["4", "MRI DWI+ADC\n+FLAIR+SWI\n(if CT negative\nor wake-up stroke)",
         "Confirm infarct?\nHow old? Microbleeds?",
         "DWI+/ADC− → acute infarct\nDWI-FLAIR mismatch → <4.5 hrs window\nSWI dark → hemorrhagic component"],
        ["5", "MRA or CTA\nfollow-up",
         "Vessel patency?\nRecanalisation?",
         "Assess response to thrombolysis/thrombectomy\nLook for residual stenosis"],
    ]
    wf_t = Table(workflow_data, colWidths=[0.7*cm, 3.0*cm, 4.0*cm, 8.3*cm])
    wf_t.setStyle(TableStyle([
        ('BACKGROUND', (0,0), (-1,0), C_GREEN),
        ('TEXTCOLOR',  (0,0), (-1,0), C_WHITE),
        ('FONTNAME',   (0,0), (-1,0), 'Helvetica-Bold'),
        ('FONTSIZE',   (0,0), (-1,-1), 7.5),
        ('ROWBACKGROUNDS', (0,1), (-1,-1),
         [colors.HexColor('#EAFAF1'), colors.HexColor('#FDFEFE')]*4),
        ('GRID',       (0,0), (-1,-1), 0.4, C_MID_GRAY),
        ('VALIGN',     (0,0), (-1,-1), 'TOP'),
        ('TOPPADDING', (0,0), (-1,-1), 4),
        ('BOTTOMPADDING', (0,0), (-1,-1), 4),
        ('FONTNAME',   (0,1), (0,-1), 'Helvetica-Bold'),
        ('TEXTCOLOR',  (0,1), (0,-1), C_GREEN),
        ('ALIGN',      (0,1), (0,-1), 'CENTER'),
    ]))
    story.append(wf_t)
    story.append(Spacer(1, 0.3*cm))

    # FLAIR vascular sign note
    story.append(Paragraph(
        "<b>FLAIR Vascular Sign:</b> Hyperintense signal within an artery on FLAIR (not DWI) "
        "indicates slow/absent flow distal to an occlusion — a marker of perfusion failure "
        "even before infarction is visible. On SWI, a thrombosed vessel shows as a markedly "
        "hypointense 'blooming' serpiginous structure — the <b>susceptibility vessel sign</b>.",
        callout_style))

    story.append(Spacer(1, 0.3*cm))

    # Sources
    story.append(HRFlowable(width=avail_w, thickness=0.5, color=C_MID_GRAY))
    story.append(Spacer(1, 0.15*cm))
    story.append(Paragraph(
        "<b>Sources:</b> Adams and Victor's Principles of Neurology 12th Ed.  |  "
        "Bradley and Daroff's Neurology in Clinical Practice  |  "
        "Grainger & Allison's Diagnostic Radiology  |  "
        "Neuroanatomy through Clinical Cases 3rd Ed.  |  Goldman-Cecil Medicine  |  "
        "Orris Medical Library",
        note_style))

    # ── Page number footer ────────────────────────────────────────────────────
    def add_page_number(canvas, doc):
        canvas.saveState()
        canvas.setFont("Helvetica", 8)
        canvas.setFillColor(C_MID_GRAY)
        canvas.drawCentredString(PAGE_W/2, 1.2*cm,
            f"Brain CT & MRI Reference Guide  |  Page {doc.page}")
        canvas.setFillColor(C_LIGHTBLUE)
        canvas.rect(2*cm, 1.0*cm, PAGE_W-4*cm, 0.05*cm, fill=1, stroke=0)
        canvas.restoreState()

    doc.build(story, onFirstPage=add_page_number, onLaterPages=add_page_number)
    print(f"PDF saved to: {output_path}")


if __name__ == "__main__":
    build_pdf("/home/daytona/workspace/brain-imaging-guide/Brain_CT_MRI_Reference_Guide.pdf")

Successfully replaced 1 instance(s) of the string in '/home/daytona/workspace/brain-imaging-guide/build_pdf.py'

Successfully replaced 1 instance(s) of the string in '/home/daytona/workspace/brain-imaging-guide/build_pdf.py'

Successfully replaced 1 instance(s) of the string in '/home/daytona/workspace/brain-imaging-guide/build_pdf.py'

#!/usr/bin/env python3
"""
Brain CT & MRI Reference Guide - Version 2
Includes REAL textbook images alongside explanatory diagrams.
"""

from reportlab.lib.pagesizes import A4
from reportlab.lib import colors
from reportlab.lib.styles import getSampleStyleSheet, ParagraphStyle
from reportlab.lib.units import cm, mm
from reportlab.platypus import (
    SimpleDocTemplate, Paragraph, Spacer, Table, TableStyle,
    HRFlowable, PageBreak, Image as RLImage, KeepTogether
)
from reportlab.platypus.flowables import Flowable
from reportlab.lib.enums import TA_CENTER, TA_LEFT, TA_JUSTIFY, TA_RIGHT
import os, math

IMG_DIR = "/home/daytona/workspace/brain-imaging-guide/images"
OUT_PATH = "/home/daytona/workspace/brain-imaging-guide/Brain_CT_MRI_Reference_Guide_v2.pdf"

# ── Colors ────────────────────────────────────────────────────────────────────
C_NAVY      = colors.HexColor('#0D1B2A')
C_BLUE      = colors.HexColor('#1B4F72')
C_LIGHTBLUE = colors.HexColor('#2E86AB')
C_TEAL      = colors.HexColor('#17A589')
C_RED       = colors.HexColor('#C0392B')
C_ORANGE    = colors.HexColor('#E67E22')
C_GREEN     = colors.HexColor('#1E8449')
C_PURPLE    = colors.HexColor('#7D3C98')
C_DARK_GRAY = colors.HexColor('#2C3E50')
C_MID_GRAY  = colors.HexColor('#7F8C8D')
C_LIGHT_GRAY= colors.HexColor('#ECF0F1')
C_WHITE     = colors.white
C_BLACK     = colors.black
C_CREAM     = colors.HexColor('#FDFEFE')

PAGE_W, PAGE_H = A4
AVAIL_W = PAGE_W - 4*cm

# ── Styles ─────────────────────────────────────────────────────────────────────
styles = getSampleStyleSheet()

def make_style(name, **kw):
    return ParagraphStyle(name, **kw)

TITLE_S  = make_style('T1', fontName='Helvetica-Bold', fontSize=18, leading=22,
                       textColor=C_WHITE, alignment=TA_CENTER)
HEAD_S   = make_style('H1', fontName='Helvetica-Bold', fontSize=13, leading=16,
                       textColor=C_WHITE, alignment=TA_LEFT)
H2_S     = make_style('H2', fontName='Helvetica-Bold', fontSize=10.5, leading=13,
                       textColor=C_NAVY, spaceAfter=3, spaceBefore=6)
BODY_S   = make_style('BD', fontName='Helvetica', fontSize=8.5, leading=12,
                       textColor=C_DARK_GRAY, spaceAfter=4, alignment=TA_JUSTIFY)
CAPTION_S= make_style('CP', fontName='Helvetica-Oblique', fontSize=7.5, leading=10,
                       textColor=C_MID_GRAY, spaceAfter=4, alignment=TA_CENTER)
LABEL_S  = make_style('LB', fontName='Helvetica-Bold', fontSize=8, leading=10,
                       textColor=C_NAVY, spaceAfter=2)
NOTE_S   = make_style('NT', fontName='Helvetica-Oblique', fontSize=7.5, leading=10,
                       textColor=C_MID_GRAY, spaceAfter=3)
CALLOUT_S= make_style('CO', fontName='Helvetica-Bold', fontSize=8.5, leading=12,
                       textColor=C_NAVY, spaceAfter=4,
                       backColor=colors.HexColor('#EBF5FB'),
                       borderPad=5)
WARN_S   = make_style('WN', fontName='Helvetica-Bold', fontSize=8.5, leading=12,
                       textColor=colors.HexColor('#7B241C'), spaceAfter=4,
                       backColor=colors.HexColor('#FDEDEC'),
                       borderPad=5)

# ── Helper: section banner ────────────────────────────────────────────────────
class Banner(Flowable):
    def __init__(self, title, subtitle="", bg=C_BLUE, w=None, h=None):
        Flowable.__init__(self)
        self.title    = title
        self.subtitle = subtitle
        self.bg       = bg
        self.w        = w or AVAIL_W
        self.h        = h or (1.5*cm if subtitle else 1.1*cm)

    def wrap(self, aw, ah):
        return self.w, self.h

    def draw(self):
        c = self.canv
        c.setFillColor(self.bg)
        c.roundRect(0, 0, self.w, self.h, 6, fill=1, stroke=0)
        c.setFillColor(C_WHITE)
        c.setFont("Helvetica-Bold", 13)
        c.drawString(0.4*cm, self.h - 0.58*cm, self.title)
        if self.subtitle:
            c.setFont("Helvetica", 8.5)
            c.setFillColor(colors.HexColor('#AED6F1'))
            c.drawString(0.4*cm, 0.22*cm, self.subtitle)

# ── Helper: image with border + caption ──────────────────────────────────────
def img_block(path, width, caption, label_color=C_NAVY):
    """Returns a list of flowables: bordered image + caption paragraph."""
    items = []
    if os.path.exists(path):
        img = RLImage(path, width=width)
        img.hAlign = 'CENTER'
        items.append(img)
    if caption:
        items.append(Paragraph(caption, CAPTION_S))
    return items

def img_table(rows):
    """
    rows: list of lists of flowables (table cells)
    Creates a centered table of images with spacing.
    """
    col_w = AVAIL_W / max(len(r) for r in rows)
    flat  = []
    for row in rows:
        flat.append(row)
    t = Table(flat, colWidths=[col_w]*len(flat[0]) if flat else [AVAIL_W])
    t.setStyle(TableStyle([
        ('VALIGN',      (0,0), (-1,-1), 'TOP'),
        ('ALIGN',       (0,0), (-1,-1), 'CENTER'),
        ('TOPPADDING',  (0,0), (-1,-1), 4),
        ('BOTTOMPADDING',(0,0),(-1,-1), 4),
        ('LEFTPADDING', (0,0), (-1,-1), 3),
        ('RIGHTPADDING',(0,0), (-1,-1), 3),
    ]))
    return t

# ── Helper: CT timeline diagram ───────────────────────────────────────────────
class CTTimelineBar(Flowable):
    def __init__(self, w=None, h=3.8*cm):
        Flowable.__init__(self)
        self.w = w or AVAIL_W
        self.h = h

    def wrap(self, aw, ah): return self.w, self.h

    def draw(self):
        c   = self.canv
        w, h = self.w, self.h
        phases = [("Hyperacute\n0-6 hrs",0.18),("Acute\n6-24 hrs",0.18),
                  ("Subacute\n1-7 days",0.22),("Late Sub\n1-3 wks",0.22),("Chronic\n>3 wks",0.20)]
        hem_shade = [0.94, 0.92, 0.55, 0.45, 0.28]
        inf_shade = [0.58, 0.42, 0.33, 0.40, 0.22]
        hem_lbl = ["BRIGHT\nHyperdense","BRIGHT\nHyperdense","ISODENSE\n(can miss!)","ISODENSE\n→Hypodense","HYPODENSE"]
        inf_lbl = ["NORMAL\nor Subtle","HYPODENSE\nGW blur","CLEARLY\nHypodense","FOGGING\nEffect","ENCEPHALO-\nMALACIA"]

        hdr_h = h*0.28; row_h = h*0.34
        y_hem = h - hdr_h - row_h
        y_inf = h - hdr_h - 2*row_h

        x = 0.0
        for i,(ph,frac) in enumerate(phases):
            bw = w*frac
            bg = C_LIGHT_GRAY if i%2==0 else colors.HexColor('#D5D8DC')
            c.setFillColor(bg); c.setStrokeColor(C_DARK_GRAY); c.setLineWidth(0.4)
            c.rect(x, h-hdr_h, bw, hdr_h, fill=1, stroke=1)
            c.setFillColor(C_DARK_GRAY); c.setFont("Helvetica-Bold",7)
            for li,ln in enumerate(ph.split('\n')):
                c.drawCentredString(x+bw/2, h-0.2*cm-li*0.28*cm, ln)

            sh = hem_shade[i]
            c.setFillColor(colors.Color(sh,sh,sh)); c.setStrokeColor(C_DARK_GRAY); c.setLineWidth(0.4)
            c.rect(x, y_hem, bw, row_h, fill=1, stroke=1)
            tc = C_DARK_GRAY if sh>0.6 else C_WHITE
            c.setFillColor(tc); c.setFont("Helvetica-Bold",6.5)
            for li,ln in enumerate(hem_lbl[i].split('\n')):
                c.drawCentredString(x+bw/2, y_hem+row_h-0.22*cm-li*0.26*cm, ln)

            si = inf_shade[i]
            c.setFillColor(colors.Color(si,si,si)); c.setStrokeColor(C_DARK_GRAY); c.setLineWidth(0.4)
            c.rect(x, y_inf, bw, row_h, fill=1, stroke=1)
            tc2 = C_DARK_GRAY if si>0.6 else C_WHITE
            c.setFillColor(tc2); c.setFont("Helvetica-Bold",6.5)
            for li,ln in enumerate(inf_lbl[i].split('\n')):
                c.drawCentredString(x+bw/2, y_inf+row_h-0.22*cm-li*0.26*cm, ln)
            x += bw

        c.setFillColor(C_RED); c.setFont("Helvetica-Bold",8)
        c.drawRightString(-0.1*cm, y_hem+row_h*0.4, "BLEED")
        c.setFillColor(C_BLUE)
        c.drawRightString(-0.1*cm, y_inf+row_h*0.4, "INFARCT")

# ── Helper: MRI hemorrhage signal grid ────────────────────────────────────────
class MRIHemGrid(Flowable):
    def __init__(self, w=None, h=5.5*cm):
        Flowable.__init__(self)
        self.w = w or AVAIL_W
        self.h = h

    def wrap(self, aw, ah): return self.w, self.h

    def draw(self):
        c   = self.canv
        w, h = self.w, self.h
        phases=["Hyperacute\n0-6h\nOxyHb","Acute\n1-3d\nDeoxyHb",
                "Early Sub\n3-7d\nIntracel\nMetHb","Late Sub\n7-30d\nExtracel\nMetHb","Chronic\n>14d\nHemosiderin"]
        seqs=["T1","T2","SWI"]
        sigs={"T1":[0.5,0.5,1.0,1.0,0.15],"T2":[0.85,0.05,0.1,0.9,0.0],"SWI":[0.25,0.02,0.03,0.1,0.0]}
        lbls={"T1":["Iso\n(Gray)","Iso\n(Gray)","BRIGHT\n(White)","BRIGHT\n(White)","Hypo\n(Dark)"],
              "T2":["Bright\nLt Gray","DARK\nBlack","DARK\nBlack","BRIGHT\nWhite","BLACK"],
              "SWI":["Dark","VERY\nDARK","VERY\nDARK","Dark","BLACK\n'Blooms'"]}

        hw = 1.3*cm; col_w = (w-hw)/len(phases)
        hdr_h = h*0.22; row_h = (h-hdr_h)/(len(seqs)+0.2)

        # Corner
        c.setFillColor(C_PURPLE); c.setStrokeColor(C_DARK_GRAY); c.setLineWidth(0.4)
        c.rect(0, h-hdr_h, hw, hdr_h, fill=1, stroke=1)
        c.setFillColor(C_WHITE); c.setFont("Helvetica-Bold",7)
        c.drawCentredString(hw/2, h-hdr_h/2-0.1*cm, "SEQ")

        # Phase headers
        x = hw
        for i,ph in enumerate(phases):
            bg = colors.HexColor('#F9EBF8') if i%2==0 else colors.HexColor('#E8DAEF')
            c.setFillColor(bg); c.setStrokeColor(C_DARK_GRAY); c.setLineWidth(0.4)
            c.rect(x, h-hdr_h, col_w, hdr_h, fill=1, stroke=1)
            c.setFillColor(C_PURPLE); c.setFont("Helvetica-Bold",6)
            lns=ph.split('\n')
            for li,ln in enumerate(lns):
                c.drawCentredString(x+col_w/2, h-0.15*cm-li*0.22*cm, ln)
            x += col_w

        # Rows
        for si,seq in enumerate(seqs):
            y = h - hdr_h - (si+1)*row_h
            c.setFillColor(C_PURPLE); c.setStrokeColor(C_DARK_GRAY); c.setLineWidth(0.4)
            c.rect(0, y, hw, row_h, fill=1, stroke=1)
            c.setFillColor(C_WHITE); c.setFont("Helvetica-Bold",8)
            c.drawCentredString(hw/2, y+row_h/2-0.1*cm, seq)
            x = hw
            for pi in range(len(phases)):
                sg = sigs[seq][pi]
                c.setFillColor(colors.Color(sg,sg,sg)); c.setStrokeColor(C_DARK_GRAY); c.setLineWidth(0.3)
                c.rect(x, y, col_w, row_h, fill=1, stroke=1)
                tc = C_WHITE if sg<0.5 else C_DARK_GRAY
                c.setFillColor(tc); c.setFont("Helvetica-Bold",6.5)
                lns2=lbls[seq][pi].split('\n')
                for li,ln in enumerate(lns2):
                    c.drawCentredString(x+col_w/2, y+row_h-0.18*cm-li*0.24*cm, ln)
                x += col_w

# ── Helper: MRI infarct signal grid ──────────────────────────────────────────
class MRIInfarctGrid(Flowable):
    def __init__(self, w=None, h=4.5*cm):
        Flowable.__init__(self)
        self.w = w or AVAIL_W
        self.h = h

    def wrap(self, aw, ah): return self.w, self.h

    def draw(self):
        c   = self.canv
        w, h = self.w, self.h
        phases=["Hyperacute\n0-6h","Acute\n6h-5d","Subacute\n5-14d","Late Sub\n2-3wk","Chronic\n>3wks"]
        seqs=["DWI","ADC","FLAIR"]
        sigs={"DWI":[0.95,0.95,0.80,0.65,0.1],"ADC":[0.05,0.05,0.15,0.55,0.88],"FLAIR":[0.30,0.82,0.88,0.85,0.82]}
        lbls={"DWI":["BRIGHT★","BRIGHT★","Bright\n(fading)","Fading\nshine","DARK"],"ADC":["DARK★","DARK★","→Pseudo\nnorm","Pseudo-\nnormal","BRIGHT"],"FLAIR":["Normal\nor subtle","BRIGHT","BRIGHT\n+Swelling","Bright","Bright\nGliosis"]}

        hw = 1.3*cm; col_w = (w-hw)/len(phases)
        hdr_h = h*0.24; row_h = (h-hdr_h)/(len(seqs)+0.2)

        c.setFillColor(C_TEAL); c.setStrokeColor(C_DARK_GRAY); c.setLineWidth(0.4)
        c.rect(0, h-hdr_h, hw, hdr_h, fill=1, stroke=1)
        c.setFillColor(C_WHITE); c.setFont("Helvetica-Bold",7)
        c.drawCentredString(hw/2, h-hdr_h/2-0.1*cm, "SEQ")

        x = hw
        for i,ph in enumerate(phases):
            bg = colors.HexColor('#E8F8F5') if i%2==0 else colors.HexColor('#D1F2EB')
            c.setFillColor(bg); c.setStrokeColor(C_DARK_GRAY); c.setLineWidth(0.4)
            c.rect(x, h-hdr_h, col_w, hdr_h, fill=1, stroke=1)
            c.setFillColor(C_TEAL); c.setFont("Helvetica-Bold",6.5)
            for li,ln in enumerate(ph.split('\n')):
                c.drawCentredString(x+col_w/2, h-0.18*cm-li*0.27*cm, ln)
            x += col_w

        for si,seq in enumerate(seqs):
            y = h - hdr_h - (si+1)*row_h
            c.setFillColor(C_TEAL); c.setStrokeColor(C_DARK_GRAY); c.setLineWidth(0.4)
            c.rect(0, y, hw, row_h, fill=1, stroke=1)
            c.setFillColor(C_WHITE); c.setFont("Helvetica-Bold",8)
            c.drawCentredString(hw/2, y+row_h/2-0.1*cm, seq)
            x = hw
            for pi in range(len(phases)):
                sg = sigs[seq][pi]
                c.setFillColor(colors.Color(sg,sg,sg)); c.setStrokeColor(C_DARK_GRAY); c.setLineWidth(0.3)
                c.rect(x, y, col_w, row_h, fill=1, stroke=1)
                tc = C_WHITE if sg<0.5 else C_DARK_GRAY
                c.setFillColor(tc); c.setFont("Helvetica-Bold",6.5)
                lns2=lbls[seq][pi].split('\n')
                for li,ln in enumerate(lns2):
                    c.drawCentredString(x+col_w/2, y+row_h-0.18*cm-li*0.24*cm, ln)
                x += col_w

        c.setFillColor(C_DARK_GRAY); c.setFont("Helvetica-Oblique",7)
        c.drawString(0, -0.3*cm, "★ DWI bright + ADC dark = TRUE restricted diffusion = ACUTE INFARCT (gold standard diagnosis)")

# ── HU Scale Bar ──────────────────────────────────────────────────────────────
class HUBar(Flowable):
    def __init__(self, w=None, h=1.8*cm):
        Flowable.__init__(self)
        self.w = w or AVAIL_W
        self.h = h
    def wrap(self, aw, ah): return self.w, self.h
    def draw(self):
        c = self.canv; w,h = self.w,self.h
        bx=1.0*cm; bw=w-2.0*cm; by=h*0.45; bh=0.55*cm
        n=150
        for i in range(n):
            s=i/n; c.setFillColor(colors.Color(s,s,s))
            c.rect(bx+s*bw, by, bw/n+0.5, bh, fill=1, stroke=0)
        c.setStrokeColor(C_DARK_GRAY); c.setLineWidth(0.5)
        c.rect(bx, by, bw, bh, fill=0, stroke=1)
        tks=[(0.0,"-1000\nAir"),(0.14,"0\nCSF"),(0.30,"~35\nBrain"),(0.52,"~70\nBlood"),(0.72,"~130\nCalc."),(1.0,">400\nBone")]
        for f,lbl in tks:
            tx=bx+f*bw
            c.setStrokeColor(C_DARK_GRAY); c.setLineWidth(0.5); c.line(tx,by-0.05*cm,tx,by-0.22*cm)
            c.setFillColor(C_DARK_GRAY); c.setFont("Helvetica",6.5)
            for li,ln in enumerate(lbl.split('\n')):
                c.drawCentredString(tx, by-0.3*cm-li*0.18*cm, ln)
        c.setFillColor(C_RED); c.setFont("Helvetica-Bold",7)
        c.drawCentredString(bx+0.52*bw, by+bh+0.15*cm, "BLOOD ~60-80 HU (BRIGHT)")
        c.setFillColor(C_BLUE)
        c.drawCentredString(bx+0.22*bw, by+bh+0.15*cm, "INFARCT <30 HU (DARK)")


# ══════════════════════════════════════════════════════════════════════════════
# BUILD PDF
# ══════════════════════════════════════════════════════════════════════════════
def build():
    doc = SimpleDocTemplate(OUT_PATH, pagesize=A4,
        leftMargin=2*cm, rightMargin=2*cm, topMargin=2*cm, bottomMargin=2*cm,
        title="Brain CT & MRI: Bleed vs Infarct - Visual Reference Guide",
        author="Orris Medical Reference")

    story = []

    # ── COVER ──────────────────────────────────────────────────────────────────
    class Cover(Flowable):
        def __init__(self):
            Flowable.__init__(self)
            self.w = AVAIL_W; self.h = 24*cm
        def wrap(self,aw,ah): return self.w,self.h
        def draw(self):
            c=self.canv; w,h=self.w,self.h
            c.setFillColor(C_NAVY); c.rect(0,h*0.42,w,h*0.58,fill=1,stroke=0)
            c.setFillColor(C_BLUE); c.rect(0,h*0.28,w,h*0.14,fill=1,stroke=0)
            c.setFillColor(colors.HexColor('#1A5276')); c.rect(0,0,w,h*0.28,fill=1,stroke=0)
            c.setFillColor(C_WHITE); c.setFont("Helvetica-Bold",24)
            c.drawCentredString(w/2,h*0.82,"BRAIN CT & MRI")
            c.setFont("Helvetica-Bold",17)
            c.drawCentredString(w/2,h*0.74,"VISUAL READING GUIDE")
            c.setFont("Helvetica",13); c.setFillColor(colors.HexColor('#AED6F1'))
            c.drawCentredString(w/2,h*0.66,"Hemorrhage  •  Infarction  •  Timeline")
            c.drawCentredString(w/2,h*0.61,"Acute  |  Subacute  |  Chronic")
            # Brain icon
            bx=w/2; by=h*0.43; br=2.0*cm
            c.setFillColor(colors.HexColor('#1A1A2E'))
            c.circle(bx,by,br*1.18,fill=1,stroke=0)
            c.setFillColor(colors.HexColor('#7F8C8D'))
            c.circle(bx,by,br,fill=1,stroke=0)
            c.setFillColor(colors.HexColor('#111111'))
            c.ellipse(bx-0.3*cm,by-0.1*cm,bx+0.3*cm,by+0.38*cm,fill=1,stroke=0)
            c.setFillColor(colors.HexColor('#F5F5F5'))
            c.circle(bx+0.65*cm,by+0.35*cm,0.4*cm,fill=1,stroke=0)
            c.setFillColor(colors.HexColor('#505050'))
            c.circle(bx-0.6*cm,by+0.2*cm,0.35*cm,fill=1,stroke=0)
            c.setFillColor(C_WHITE); c.setFont("Helvetica-Bold",7)
            c.drawCentredString(bx+0.65*cm,by+0.15*cm,"BLEED")
            c.drawCentredString(bx-0.6*cm,by+0.02*cm,"INFARCT")
            # Bottom text
            c.setFillColor(C_WHITE); c.setFont("Helvetica-Bold",11)
            c.drawCentredString(w/2,h*0.22,"Real Textbook Images + Explanatory Diagrams")
            c.setFont("Helvetica",9); c.setFillColor(colors.HexColor('#AED6F1'))
            c.drawCentredString(w/2,h*0.16,"CT Density  |  MRI Sequences  |  DWI/ADC  |  SWI  |  Hemorrhage Types")
            c.setFont("Helvetica-Oblique",8.5); c.setFillColor(colors.HexColor('#85C1E9'))
            c.drawCentredString(w/2,h*0.1,"Sources: Adams & Victor's Neurology  •  Bradley & Daroff  •  Grainger & Allison")
            c.setFont("Helvetica",7); c.setFillColor(colors.HexColor('#5D6D7E'))
            c.drawCentredString(w/2,h*0.03,"Orris Medical Reference  |  For educational purposes only")

    story.append(Cover())
    story.append(PageBreak())

    # ── PAGE 1: CT BASICS + HU SCALE ──────────────────────────────────────────
    story.append(Banner("1.  NON-CONTRAST CT BRAIN BASICS",
        "First-line investigation for ALL stroke and head injury presentations", bg=C_NAVY))
    story.append(Spacer(1,0.3*cm))

    story.append(Paragraph("Hounsfield Unit (HU) Density Scale", H2_S))
    story.append(Paragraph(
        "Every CT pixel has a Hounsfield Unit (HU) value. Brain tissue is ~25-40 HU (gray). "
        "<b>Blood clots are denser (~60-80 HU) and appear BRIGHT WHITE (hyperdense). "
        "Infarcted brain loses fluid balance and appears DARK (hypodense, &lt;30 HU).</b> "
        "This single principle lets you differentiate bleed from infarct at a glance.", BODY_S))
    story.append(HUBar(w=AVAIL_W, h=1.9*cm))
    story.append(Spacer(1,0.4*cm))

    story.append(Paragraph("CT Window Settings", H2_S))
    wt = Table([
        ["Window","Width (WW)","Level (WL)","Use For"],
        ["Brain window","~80","~35","Parenchyma, hemorrhage, edema"],
        ["Bone window","~2000","~300","Skull fractures"],
        ["Stroke window","~35","~35","Early subtle ischemia - widens gray/white contrast"],
        ["Subdural window","~200","~60","Subdural hematoma detection"],
    ], colWidths=[3.5*cm,2.3*cm,2.3*cm,7.9*cm])
    wt.setStyle(TableStyle([
        ('BACKGROUND',(0,0),(-1,0),C_BLUE),('TEXTCOLOR',(0,0),(-1,0),C_WHITE),
        ('FONTNAME',(0,0),(-1,0),'Helvetica-Bold'),('FONTSIZE',(0,0),(-1,-1),8),
        ('ROWBACKGROUNDS',(0,1),(-1,-1),[C_CREAM,C_LIGHT_GRAY]),
        ('GRID',(0,0),(-1,-1),0.4,C_MID_GRAY),('VALIGN',(0,0),(-1,-1),'MIDDLE'),
        ('TOPPADDING',(0,0),(-1,-1),3),('BOTTOMPADDING',(0,0),(-1,-1),3),
    ]))
    story.append(wt)
    story.append(Spacer(1,0.4*cm))

    # ── REAL IMAGE: SAH + CT skull fracture ────────────────────────────────────
    story.append(Paragraph("Real CT Example: Skull Fracture + Subarachnoid Hemorrhage", H2_S))
    story.append(Paragraph(
        "Below: axial CT scans showing bone window (fracture), brain window (hyperdense SAH in sulci), "
        "and FLAIR MRI confirming subarachnoid blood as hyperintense signal in the cortical sulci.",BODY_S))

    ipath = os.path.join(IMG_DIR, "img_skull_fracture_sah_ct.png")
    if os.path.exists(ipath):
        img = RLImage(ipath, width=AVAIL_W, height=5.5*cm)
        img.hAlign = 'CENTER'
        story.append(img)
    story.append(Paragraph(
        "Fig. A: Bone window - right temporal fracture (arrow). "
        "Fig. B: Brain window - hyperdense contusion + SAH in sulci (arrowheads). "
        "Fig. C: FLAIR MRI - hyperintense subarachnoid blood in sulci.  "
        "[Bradley & Daroff's Neurology in Clinical Practice]", CAPTION_S))
    story.append(Spacer(1,0.2*cm))

    story.append(Paragraph(
        "<b>Key early CT signs of ischemic stroke:</b> "
        "(1) Loss of gray-white differentiation at basal ganglia/insular cortex.  "
        "(2) <b>Insular ribbon sign</b> — blurring of the insular cortex (MCA territory).  "
        "(3) <b>Sulcal effacement</b> — swollen gyri obliterate normal sulci.  "
        "(4) <b>Hyperdense vessel sign</b> — bright MCA/basilar = acute thrombus.  "
        "(5) <b>One-third MCA rule</b> — >1/3 MCA hypodense = contraindication to tPA.", BODY_S))

    story.append(PageBreak())

    # ── PAGE 2: CT TIMELINE ────────────────────────────────────────────────────
    story.append(Banner("2.  CT TIMELINE — HEMORRHAGE vs. INFARCT",
        "How CT density changes over time for each pathology", bg=C_RED))
    story.append(Spacer(1,0.3*cm))

    story.append(CTTimelineBar(w=AVAIL_W, h=3.8*cm))
    story.append(Spacer(1,0.5*cm))

    # ── REAL IMAGE: Subacute & chronic infarct on CT+MRI ──────────────────────
    story.append(Paragraph("Real Images: Subacute & Chronic Infarct Progression", H2_S))
    story.append(Paragraph(
        "The panels below show progressive CT and MRI changes of an infarct as it matures: "
        "CT becomes progressively more hypodense (darker) with volume loss and ventricular dilation; "
        "MRI shows increasing T2/FLAIR hyperintensity and ultimately encephalomalacia.", BODY_S))

    ipath2 = os.path.join(IMG_DIR, "img_subacute_chronic_infarct.png")
    if os.path.exists(ipath2):
        img2 = RLImage(ipath2, width=AVAIL_W, height=5.5*cm)
        img2.hAlign = 'CENTER'
        story.append(img2)
    story.append(Paragraph(
        "Subacute and chronic infarct: CT (A,B) shows progressive hypodensity and volume loss; "
        "MRI T2/FLAIR (C,D) shows progressive hyperintensity; chronic stage (E) = encephalomalacia "
        "approaching CSF signal. [Grainger & Allison's Diagnostic Radiology]", CAPTION_S))

    story.append(Spacer(1,0.3*cm))

    ct_detail = [
        ["Phase","Time","HEMORRHAGE on CT","INFARCT on CT"],
        ["Hyperacute","0-6 hrs","HYPERDENSE (white)\n~60-80 HU, immediate","Normal CT or sulcal effacement only"],
        ["Acute","6-24 hrs","HYPERDENSE\nPeripheral edema halo","Definite HYPODENSE territory\nGray-white differentiation lost"],
        ["Early Sub","1-7 days","Hyperdense → ISODENSE\nMass effect increasing","CLEARLY HYPODENSE\nMass effect peaks day 3-5"],
        ["Late Sub","1-3 wks","ISODENSE — easy to miss!\nCheck for displaced cortex","FOGGING EFFECT\nMay look falsely normal"],
        ["Chronic",">3 wks","HYPODENSE (dark)\nMay calcify; subdural = crescent","ENCEPHALOMALACIA\nEx-vacuo ventricular dilation"],
    ]
    ctdt = Table(ct_detail, colWidths=[2.5*cm,1.8*cm,7.0*cm,4.7*cm])
    ctdt.setStyle(TableStyle([
        ('BACKGROUND',(0,0),(-1,0),C_DARK_GRAY),('TEXTCOLOR',(0,0),(-1,0),C_WHITE),
        ('FONTNAME',(0,0),(-1,0),'Helvetica-Bold'),('FONTSIZE',(0,0),(-1,-1),7.5),
        ('BACKGROUND',(2,1),(2,-1),colors.HexColor('#FEF9E7')),
        ('BACKGROUND',(3,1),(3,-1),colors.HexColor('#EBF5FB')),
        ('ROWBACKGROUNDS',(0,1),(1,-1),[colors.HexColor('#FDEBD0'),colors.HexColor('#FEF9E7')]),
        ('GRID',(0,0),(-1,-1),0.4,C_MID_GRAY),('VALIGN',(0,0),(-1,-1),'TOP'),
        ('TOPPADDING',(0,0),(-1,-1),3),('BOTTOMPADDING',(0,0),(-1,-1),3),
    ]))
    story.append(ctdt)
    story.append(Spacer(1,0.15*cm))
    story.append(Paragraph(
        "<b>Pitfall:</b> At 7-14 days a subdural hematoma becomes ISODENSE with brain and can "
        "be completely invisible on CT without contrast. Clues: displaced cortex, asymmetric sulci, "
        "midline shift without visible hyperdensity.", WARN_S))

    story.append(PageBreak())

    # ── PAGE 3: HEMORRHAGE TYPES ───────────────────────────────────────────────
    story.append(Banner("3.  TYPES OF INTRACRANIAL HEMORRHAGE",
        "Location determines shape, etiology, and clinical presentation", bg=C_RED))
    story.append(Spacer(1,0.3*cm))

    story.append(Paragraph("Real CT + MRI: Acute Subdural Hematoma", H2_S))
    story.append(Paragraph(
        "Acute SDH is typically hyperdense (white) on CT - the classic crescent shape "
        "follows the brain surface and crosses suture lines. On MRI, acute SDH is "
        "ISOINTENSE on T1 (hard to see) but HYPERINTENSE on T2 - explaining why T2 is "
        "crucial for acute SDH detection.", BODY_S))

    ipath3 = os.path.join(IMG_DIR, "img_acute_subdural_mri.png")
    if os.path.exists(ipath3):
        img3 = RLImage(ipath3, width=AVAIL_W*0.75, height=4.5*cm)
        img3.hAlign = 'CENTER'
        story.append(img3)
    story.append(Paragraph(
        "Acute Subdural Hematoma on MRI. A: T1 - subdural collection over left temporal lobe "
        "is isointense to brain (arrowheads) - nearly invisible! B: T2 - the same collection is "
        "now clearly HYPERINTENSE (bright). [Bradley & Daroff's Neurology in Clinical Practice]", CAPTION_S))

    story.append(Spacer(1,0.3*cm))

    hem_types = [
        ["Type","CT Shape","Location","Typical Cause","Key Features"],
        ["EDH\n(Epidural)","BICONVEX\n(lens-shaped)\nDoes NOT cross\nsutures","Between skull\n& dura","Middle meningeal\nartery (temporal\nfracture)","Lucid interval;\ntemporal fracture;\narterial speed"],
        ["SDH\n(Subdural)","CRESCENT\n(concave inner)\nCrosses sutures\nfreely","Between dura\n& brain","Bridging veins\n(shear force)","Elderly; falls;\nanticoag use;\n venous bleeder"],
        ["SAH","Fills sulci &\nbasal cisterns;\n'star' pattern","Subarachnoid\nspace","Berry aneurysm;\nAVM; trauma","Thunderclap HA;\nFisher grade;\nCSF xanthochromia"],
        ["ICH\n(Parenchymal)","Round/oval;\nwell defined","Basal ganglia;\nthalamus; pons;\ncerebellum","HTN (deep);\nAmyloid\nangiopathy\n(cortical)","Location predicts\ncause: deep=HTN;\ncortical=amyloid"],
    ]
    htt = Table(hem_types, colWidths=[1.9*cm,2.8*cm,2.6*cm,3.2*cm,5.5*cm])
    htt.setStyle(TableStyle([
        ('BACKGROUND',(0,0),(-1,0),C_RED),('TEXTCOLOR',(0,0),(-1,0),C_WHITE),
        ('FONTNAME',(0,0),(-1,0),'Helvetica-Bold'),('FONTSIZE',(0,0),(-1,-1),7.5),
        ('ROWBACKGROUNDS',(0,1),(-1,-1),[colors.HexColor('#FDEDEC'),colors.HexColor('#FEF9E7'),
         colors.HexColor('#FEF5E7'),colors.HexColor('#FDFEFE')]),
        ('GRID',(0,0),(-1,-1),0.4,C_MID_GRAY),('VALIGN',(0,0),(-1,-1),'TOP'),
        ('TOPPADDING',(0,0),(-1,-1),3),('BOTTOMPADDING',(0,0),(-1,-1),3),
        ('FONTNAME',(0,1),(0,-1),'Helvetica-Bold'),('TEXTCOLOR',(0,1),(0,-1),C_RED),
    ]))
    story.append(htt)
    story.append(PageBreak())

    # ── PAGE 4: MRI SEQUENCES ──────────────────────────────────────────────────
    story.append(Banner("4.  MRI SEQUENCES — WHAT EACH SHOWS",
        "Understand each sequence before reading an MRI", bg=C_TEAL))
    story.append(Spacer(1,0.3*cm))

    mri_seq = [
        ["Sequence","Bright (hyperintense)","Dark (hypointense)","Best For"],
        ["T1","Fat, methemoglobin (subacute blood),\ngadolinium, protein-rich fluid","CSF, water, edema,\ndeoxyhemoglobin","Anatomy; subacute\nblood; contrast enhancement"],
        ["T2","CSF, water, edema, gliosis,\nlate subacute blood (extracel MetHb)","Acute blood (deoxy),\nhemosiderin, calcium","Infarcts, edema,\ntumors, inflammation"],
        ["FLAIR","Edema, gliosis, subarachnoid blood,\nperiventricular lesions","CSF (suppressed = BLACK)","SAH; periventricular MS;\ninfarct staging (DWI-FLAIR mismatch)"],
        ["DWI ★","ACUTE INFARCT (restricted diffusion)\nAbscess, epidermoid","Chronic lesions, blood\n(after several days)","ACUTE STROKE DIAGNOSIS\nPositive from 5 minutes!"],
        ["ADC ★","Vasogenic edema, chronic gliosis,\nfree diffusion","ACUTE INFARCT (dark = true\nrestriction), abscess","Confirm true restriction;\nexclude T2 shine-through"],
        ["SWI/GRE","Nothing significant","ALL blood products ('blooms')\ncalcification, iron, veins","Microhemorrhages;\nvenous thrombosis; amyloid"],
    ]
    msqt = Table(mri_seq, colWidths=[2.0*cm,4.8*cm,3.8*cm,5.4*cm])
    msqt.setStyle(TableStyle([
        ('BACKGROUND',(0,0),(-1,0),C_TEAL),('TEXTCOLOR',(0,0),(-1,0),C_WHITE),
        ('FONTNAME',(0,0),(-1,0),'Helvetica-Bold'),('FONTSIZE',(0,0),(-1,-1),7.5),
        ('ROWBACKGROUNDS',(0,1),(-1,-1),[colors.HexColor('#E8F8F5'),C_CREAM]*5),
        ('GRID',(0,0),(-1,-1),0.4,C_MID_GRAY),('VALIGN',(0,0),(-1,-1),'TOP'),
        ('TOPPADDING',(0,0),(-1,-1),3),('BOTTOMPADDING',(0,0),(-1,-1),3),
        ('FONTNAME',(0,4),(0,5),'Helvetica-Bold'),('TEXTCOLOR',(0,4),(0,5),C_TEAL),
    ]))
    story.append(msqt)
    story.append(Spacer(1,0.3*cm))

    # ── REAL IMAGE: Acute MCA infarct DWI + ADC ────────────────────────────────
    story.append(Paragraph("Real MRI: Acute MCA Infarct — DWI vs ADC", H2_S))
    story.append(Paragraph(
        "The DWI-ADC pair is the single most important MRI finding in stroke. "
        "<b>DWI bright + ADC dark = restricted diffusion = acute infarction confirmed.</b> "
        "This is positive within minutes of onset — far earlier than CT.", BODY_S))

    ipath4 = os.path.join(IMG_DIR, "img_acute_mca_infarct_dwi.png")
    if os.path.exists(ipath4):
        img4 = RLImage(ipath4, width=AVAIL_W*0.85, height=5.0*cm)
        img4.hAlign = 'CENTER'
        story.append(img4)
    story.append(Paragraph(
        "Acute left MCA infarct. A: DWI — large BRIGHT hyperintense territory with sulcal effacement "
        "and midline shift. B: ADC map — corresponding DARK hypointensity confirming restricted "
        "diffusion = irreversible infarction. [Bradley & Daroff's Neurology in Clinical Practice]", CAPTION_S))

    story.append(Spacer(1,0.25*cm))
    story.append(Paragraph(
        "<b>DWI-ADC Rule:</b><br/>"
        "• DWI BRIGHT + ADC DARK = TRUE restricted diffusion = ACUTE INFARCT ✓<br/>"
        "• DWI BRIGHT + ADC normal/bright = T2 shine-through = NOT acute infarct<br/>"
        "• DWI DARK + ADC BRIGHT = chronic gliosis / encephalomalacia", CALLOUT_S))

    story.append(PageBreak())

    # ── PAGE 5: ACUTE STROKE CT + MRI COMPARISON ──────────────────────────────
    story.append(Banner("5.  ACUTE STROKE: CT vs. MRI — REAL IMAGES",
        "Why MRI (DWI) is superior to CT in the first 6 hours", bg=C_LIGHTBLUE))
    story.append(Spacer(1,0.3*cm))

    story.append(Paragraph("Real Images: Acute MCA Infarct on CT AND MRI", H2_S))
    story.append(Paragraph(
        "This case shows the same left MCA territory infarct imaged at 7 hours after onset. "
        "CT already shows subtle hypodensity in the frontal operculum and insula (A). "
        "T2/FLAIR shows hyperintensity and gyral swelling (B, C). "
        "But the FULL extent — including basal ganglia involvement — is ONLY clearly "
        "visible on DWI (D) and its ADC map (E). This is why DWI is the gold standard.", BODY_S))

    ipath5 = os.path.join(IMG_DIR, "img_acute_stroke_ct_mri.png")
    if os.path.exists(ipath5):
        img5 = RLImage(ipath5, width=AVAIL_W, height=5.2*cm)
        img5.hAlign = 'CENTER'
        story.append(img5)
    story.append(Paragraph(
        "Acute left MCA infarct at 7 hours. A: CT — low attenuation in left frontal operculum/insula (subtle). "
        "B,C: T2/FLAIR — hyperintensity + gyral swelling (more than CT shows). D: DWI — full territory bright "
        "including basal ganglia. E: ADC — corresponding dark hypointensity confirms restriction. "
        "[Grainger & Allison's Diagnostic Radiology]", CAPTION_S))

    story.append(Spacer(1,0.3*cm))
    story.append(Paragraph("DWI-FLAIR Mismatch — The Wake-Up Stroke Rule", H2_S))
    story.append(Paragraph(
        "In patients who wake up with a stroke (unknown onset time), MRI can estimate "
        "whether the infarct is within the treatment window. "
        "<b>DWI bright but FLAIR normal/subtle = infarct is likely &lt;4.5 hours old = can give tPA.</b> "
        "If both DWI and FLAIR are bright = infarct is likely &gt;4.5-6 hours.", BODY_S))

    ipath6 = os.path.join(IMG_DIR, "img_wake_up_stroke_dwi_flair.png")
    if os.path.exists(ipath6):
        img6 = RLImage(ipath6, width=AVAIL_W, height=5.5*cm)
        img6.hAlign = 'CENTER'
        story.append(img6)
    story.append(Paragraph(
        "Wake-up strokes. Top row (A-D): Large DWI infarct + clear FLAIR signal + no perfusion mismatch "
        "→ beyond treatment window. Bottom row (E-G): Small DWI infarct in left insula + minimal FLAIR "
        "signal (within 4.5h window) + large CT perfusion mismatch → treated with tPA. "
        "[Grainger & Allison's Diagnostic Radiology]", CAPTION_S))

    story.append(PageBreak())

    # ── PAGE 6: MRI HEMORRHAGE TIMELINE ───────────────────────────────────────
    story.append(Banner("6.  MRI HEMORRHAGE SIGNAL TIMELINE",
        "Signal evolves as hemoglobin changes form — know each stage", bg=C_PURPLE))
    story.append(Spacer(1,0.3*cm))

    story.append(MRIHemGrid(w=AVAIL_W, h=5.5*cm))
    story.append(Spacer(1,0.5*cm))

    # ── REAL IMAGES: Acute parenchymal hemorrhage ──────────────────────────────
    story.append(Paragraph("Real MRI: Acute Parenchymal Hemorrhage (T1 + T2)", H2_S))
    story.append(Paragraph(
        "In ACUTE hemorrhage (deoxyhemoglobin stage, days 1-3): T1 shows the hematoma as "
        "ISOINTENSE (gray — hard to see!). T2 shows it as STRIKINGLY HYPOINTENSE (dark/black) "
        "due to deoxyhemoglobin's paramagnetic effect. Surrounding edema is hyperintense on T2.", BODY_S))

    ipath7 = os.path.join(IMG_DIR, "img_acute_parenchymal_hemorrhage.png")
    if os.path.exists(ipath7):
        img7 = RLImage(ipath7, width=AVAIL_W, height=6.0*cm)
        img7.hAlign = 'CENTER'
        story.append(img7)
    story.append(Paragraph(
        "Two cases of acute parenchymal hemorrhage. A,B: Large acute left basal ganglia hemorrhage — "
        "T1 (A) shows faint hypointensity; T2 (B) shows STRIKING DARK hypointensity with bright surrounding "
        "edema + mass effect. C,D: More advanced stage — T1 (C) center turning bright (intracellular MetHb "
        "developing, arrowheads); T2 (D) still dark. Note ventricular hemorrhage (arrows) = poor prognosis. "
        "[Bradley & Daroff's Neurology in Clinical Practice]", CAPTION_S))

    story.append(PageBreak())

    # ── PAGE 7: SUBACUTE + CHRONIC HEMORRHAGE ─────────────────────────────────
    story.append(Banner("7.  SUBACUTE & CHRONIC HEMORRHAGE ON MRI",
        "Methemoglobin and hemosiderin — the characteristic MRI signatures", bg=C_PURPLE))
    story.append(Spacer(1,0.3*cm))

    story.append(Paragraph("Real MRI: Late Subacute Hemorrhage (Extracellular MetHb)", H2_S))
    story.append(Paragraph(
        "In the LATE SUBACUTE stage (7-30+ days), RBCs lyse and methemoglobin spills "
        "into the extracellular space. This is the classic 'bright on T1 AND bright on T2' stage. "
        "A dark hemosiderin rim beginning to form at the periphery on T2 is an early sign of transition "
        "to the chronic phase.", BODY_S))

    # Side-by-side: T1 and T2 of late subacute
    ip_t1 = os.path.join(IMG_DIR, "img_late_subacute_hemorrhage_t1.png")
    ip_t2 = os.path.join(IMG_DIR, "img_late_subacute_hemorrhage_t2.png")
    row_imgs = []
    cell1 = []
    cell2 = []
    if os.path.exists(ip_t1):
        i_t1 = RLImage(ip_t1, width=AVAIL_W*0.48, height=4.8*cm)
        i_t1.hAlign='CENTER'
        cell1 = [i_t1, Paragraph("T1: BRIGHT (hyperintense)\nHomogeneous white signal\n= Extracellular MetHb", CAPTION_S)]
    if os.path.exists(ip_t2):
        i_t2 = RLImage(ip_t2, width=AVAIL_W*0.48, height=4.8*cm)
        i_t2.hAlign='CENTER'
        cell2 = [i_t2, Paragraph("T2: BRIGHT (hyperintense)\nAlso white signal\n+ dark hemosiderin rim (arrowheads)", CAPTION_S)]
    if cell1 and cell2:
        t = Table([[cell1, cell2]], colWidths=[AVAIL_W*0.5, AVAIL_W*0.5])
        t.setStyle(TableStyle([('VALIGN',(0,0),(-1,-1),'TOP'),('ALIGN',(0,0),(-1,-1),'CENTER'),
                                ('TOPPADDING',(0,0),(-1,-1),2),('BOTTOMPADDING',(0,0),(-1,-1),2)]))
        story.append(t)
    story.append(Paragraph(
        "Late Subacute Hematoma in right corona radiata — T1 (left) AND T2 (right) both show "
        "BRIGHT homogeneous signal = extracellular methemoglobin. Note early dark hemosiderin "
        "rim on T2 (arrowheads) signaling transition to chronic phase. "
        "[Bradley & Daroff's Neurology in Clinical Practice]", CAPTION_S))

    story.append(Spacer(1,0.3*cm))

    story.append(Paragraph("Real MRI: Chronic Hemorrhage — Hemosiderin Ring", H2_S))
    story.append(Paragraph(
        "In CHRONIC hemorrhage (&gt;4 weeks), macrophages phagocytose the blood products and "
        "deposit hemosiderin and ferritin. This creates a characteristic DARK RIM on T2 and GRE/SWI. "
        "The center forms a CSF-like cavity. The dark rim NEVER disappears — it permanently "
        "marks the site of prior hemorrhage.", BODY_S))

    ip_c1 = os.path.join(IMG_DIR, "img_chronic_hemorrhage_t2.png")
    ip_c2 = os.path.join(IMG_DIR, "img_chronic_hemorrhage_gre.png")
    cell3=[]; cell4=[]
    if os.path.exists(ip_c1):
        ic1 = RLImage(ip_c1, width=AVAIL_W*0.48, height=4.5*cm); ic1.hAlign='CENTER'
        cell3=[ic1, Paragraph("T2: Slit-like CSF cavity (bright center)\n+ DARK hemosiderin rim (arrowheads)", CAPTION_S)]
    if os.path.exists(ip_c2):
        ic2 = RLImage(ip_c2, width=AVAIL_W*0.48, height=4.5*cm); ic2.hAlign='CENTER'
        cell4=[ic2, Paragraph("GRE (T2*): Markedly DARK hemosiderin\ndeposition — 'blooming' effect\n(more prominent than on T2)", CAPTION_S)]
    if cell3 and cell4:
        t2 = Table([[cell3, cell4]], colWidths=[AVAIL_W*0.5, AVAIL_W*0.5])
        t2.setStyle(TableStyle([('VALIGN',(0,0),(-1,-1),'TOP'),('ALIGN',(0,0),(-1,-1),'CENTER'),
                                 ('TOPPADDING',(0,0),(-1,-1),2),('BOTTOMPADDING',(0,0),(-1,-1),2)]))
        story.append(t2)
    story.append(Paragraph(
        "Chronic parietal lobe hemorrhage. T2 (left): slitlike cavity with CSF-bright center + "
        "dark hemosiderin rim (arrowheads). GRE (right): markedly hypointense hemosiderin with "
        "'blooming' artifact — GRE/SWI is MORE sensitive than T2 for blood products. "
        "[Bradley & Daroff's Neurology in Clinical Practice]", CAPTION_S))

    story.append(PageBreak())

    # ── PAGE 8: MRI INFARCT TIMELINE + HAEMORRHAGIC TRANSFORMATION ────────────
    story.append(Banner("8.  MRI INFARCT TIMELINE + HAEMORRHAGIC TRANSFORMATION",
        "Evolution of ischemic infarct and the complication of hemorrhagic conversion", bg=C_TEAL))
    story.append(Spacer(1,0.3*cm))

    story.append(MRIInfarctGrid(w=AVAIL_W, h=4.5*cm))
    story.append(Spacer(1,0.45*cm))

    story.append(Paragraph("Real MRI: Haemorrhagic Transformation of Infarct", H2_S))
    story.append(Paragraph(
        "Haemorrhagic transformation (HT) occurs in up to 80% of infarcts on MRI. "
        "It is more common in large infarcts, cardioembolic strokes, after thrombolysis, "
        "and in diabetics. CT shows hyperdense blood within the infarct. "
        "SWI is exquisitely sensitive — it detects blood products as strikingly dark 'blooming' "
        "even when CT shows only subtle hyperdensity.", BODY_S))

    ipath8 = os.path.join(IMG_DIR, "img_haemorrhagic_transformation.png")
    if os.path.exists(ipath8):
        img8 = RLImage(ipath8, width=AVAIL_W, height=5.5*cm)
        img8.hAlign='CENTER'
        story.append(img8)
    story.append(Paragraph(
        "Haemorrhagic Transformation. A: DWI shows large right MCA territory infarct. B: Follow-up "
        "CT at 60 hours — acute haemorrhage (hyperdense) within the infarct + midline shift. "
        "C: Separate case — large left MCA infarct. D: SWI shows markedly dark 'blooming' blood "
        "products in the basal ganglia (white arrows) — barely visible on CT (C). "
        "[Grainger & Allison's Diagnostic Radiology]", CAPTION_S))

    story.append(Spacer(1,0.3*cm))

    mri_inf_detail = [
        ["Phase","Time","DWI","ADC","T2/FLAIR","Clinical Action"],
        ["Hyperacute","0-6 hrs","BRIGHT ★\n(5 min+)","DARK ★","Normal/subtle","DWI+ADC− = confirmed infarct\nStart tPA workup immediately"],
        ["Acute","6h-5d","BRIGHT ★","DARK ★","BRIGHT\n+mass effect","Full DWI extent = treatment target\nMass effect may mimic tumor"],
        ["Subacute","5-14d","Fading\n(T2 shine-through)","PSEUDO-\nNORMAL\n~day7-10","BRIGHT\n+gyral enhance","ADC trap! Still bright on T2/FLAIR.\nCheck for haemorrhagic transformation"],
        ["Chronic",">3wks","DARK","BRIGHT\n(free)","BRIGHT\n(gliosis)","Encephalomalacia.\nEx-vacuo ventricular enlargement"],
    ]
    midt = Table(mri_inf_detail, colWidths=[2.2*cm,1.8*cm,2.0*cm,2.0*cm,2.5*cm,5.5*cm])
    midt.setStyle(TableStyle([
        ('BACKGROUND',(0,0),(-1,0),C_TEAL),('TEXTCOLOR',(0,0),(-1,0),C_WHITE),
        ('FONTNAME',(0,0),(-1,0),'Helvetica-Bold'),('FONTSIZE',(0,0),(-1,-1),7.5),
        ('ROWBACKGROUNDS',(0,1),(-1,-1),[colors.HexColor('#E8F8F5'),C_CREAM]*4),
        ('BACKGROUND',(2,1),(3,2),colors.HexColor('#F5F5F5')),
        ('BACKGROUND',(3,1),(3,2),colors.HexColor('#222222')),('TEXTCOLOR',(3,1),(3,2),C_WHITE),
        ('GRID',(0,0),(-1,-1),0.4,C_MID_GRAY),('VALIGN',(0,0),(-1,-1),'TOP'),
        ('TOPPADDING',(0,0),(-1,-1),3),('BOTTOMPADDING',(0,0),(-1,-1),3),
    ]))
    story.append(midt)

    story.append(PageBreak())

    # ── PAGE 9: MASTER COMPARISON + WORKFLOW ──────────────────────────────────
    story.append(Banner("9.  MASTER QUICK-REFERENCE + EMERGENCY WORKFLOW",
        "Summary comparison and step-by-step imaging algorithm", bg=C_NAVY))
    story.append(Spacer(1,0.3*cm))

    master = [
        ["Feature","HEMORRHAGE","INFARCT"],
        ["CT (acute)","HYPERDENSE (bright white)\n~60-80 HU","HYPODENSE (dark)\n<30 HU after 6 hrs"],
        ["CT visibility","Immediately visible","Subtle <6 hrs; clear >6 hrs"],
        ["CT shape","Round/oval, well-defined","Wedge, follows vascular territory"],
        ["Location","Deep (HTN): BG, thalamus, pons\nCortical: amyloid angiopathy","Cortex+subcortex; arterial territory"],
        ["MRI T1","Iso → Iso → BRIGHT → BRIGHT → Dark","Normal → Hypointense"],
        ["MRI T2","Bright → DARK → DARK → BRIGHT → BLACK","Normal → BRIGHT (permanent gliosis)"],
        ["MRI DWI","Dark (blood suppresses DWI)","BRIGHT ★ from 5 minutes onset"],
        ["MRI ADC","Variable (not useful for blood)","DARK ★ (confirmed restriction)"],
        ["SWI/GRE","BLACK 'blooms' — all stages","Negative (unless haemorrhagic Tx)"],
        ["Mass effect","Yes, immediate + edema halo","Peaks day 3-5 in large infarcts"],
        ["Chronic","Hypodense cavity; hemosiderin ring\n(permanent dark rim on MRI)","Encephalomalacia; ex-vacuo dilation"],
    ]
    mt = Table(master, colWidths=[3.5*cm,6.5*cm,6.0*cm])
    mt.setStyle(TableStyle([
        ('BACKGROUND',(0,0),(-1,0),C_NAVY),('TEXTCOLOR',(0,0),(-1,0),C_WHITE),
        ('FONTNAME',(0,0),(-1,0),'Helvetica-Bold'),('FONTSIZE',(0,0),(-1,-1),8),
        ('BACKGROUND',(1,1),(1,-1),colors.HexColor('#FDEDEC')),
        ('BACKGROUND',(2,1),(2,-1),colors.HexColor('#EBF5FB')),
        ('ROWBACKGROUNDS',(0,1),(0,-1),[C_LIGHT_GRAY,colors.HexColor('#D5D8DC')]*8),
        ('GRID',(0,0),(-1,-1),0.4,C_MID_GRAY),('VALIGN',(0,0),(-1,-1),'TOP'),
        ('TOPPADDING',(0,0),(-1,-1),3),('BOTTOMPADDING',(0,0),(-1,-1),3),
        ('FONTNAME',(0,1),(0,-1),'Helvetica-Bold'),
    ]))
    story.append(mt)
    story.append(Spacer(1,0.3*cm))

    story.append(Paragraph("Emergency Imaging Workflow", H2_S))
    wf = [
        ["Step","Modality","Question","Action"],
        ["1","NCCT Brain","Hemorrhage? Mass?","YES bleed → no tPA; manage per bleed type\nNO bleed → proceed to step 2"],
        ["2","CT Angiography\n(arch→skull)","Large Vessel\nOcclusion (LVO)?","LVO present → thrombectomy pathway\nLook for hyperdense vessel sign"],
        ["3","CT Perfusion\n(if available)","Penumbra vs core?\nSalvageable tissue?","Large mismatch → extended window thrombectomy\nSmall/no mismatch → conservative"],
        ["4","MRI DWI+ADC\n+FLAIR+SWI","Confirm infarct?\nAge? Microbleeds?","DWI+/ADC− = acute infarct confirmed\nDWI-FLAIR mismatch = <4.5h → tPA eligible\nSWI dark = haemorrhagic component"],
        ["5","MRA/CTA\nfollow-up","Recanalisation?","Assess response; plan secondary prevention"],
    ]
    wft = Table(wf, colWidths=[0.8*cm,3.0*cm,3.8*cm,8.4*cm])
    wft.setStyle(TableStyle([
        ('BACKGROUND',(0,0),(-1,0),C_GREEN),('TEXTCOLOR',(0,0),(-1,0),C_WHITE),
        ('FONTNAME',(0,0),(-1,0),'Helvetica-Bold'),('FONTSIZE',(0,0),(-1,-1),7.5),
        ('ROWBACKGROUNDS',(0,1),(-1,-1),[colors.HexColor('#EAFAF1'),C_CREAM]*4),
        ('GRID',(0,0),(-1,-1),0.4,C_MID_GRAY),('VALIGN',(0,0),(-1,-1),'TOP'),
        ('TOPPADDING',(0,0),(-1,-1),3),('BOTTOMPADDING',(0,0),(-1,-1),3),
        ('FONTNAME',(0,1),(0,-1),'Helvetica-Bold'),('TEXTCOLOR',(0,1),(0,-1),C_GREEN),
        ('ALIGN',(0,1),(0,-1),'CENTER'),
    ]))
    story.append(wft)
    story.append(Spacer(1,0.2*cm))

    story.append(HRFlowable(width=AVAIL_W, thickness=0.5, color=C_MID_GRAY))
    story.append(Paragraph(
        "<b>Sources:</b> Adams and Victor's Principles of Neurology 12th Ed.  |  "
        "Bradley and Daroff's Neurology in Clinical Practice  |  "
        "Grainger & Allison's Diagnostic Radiology  |  "
        "Neuroanatomy through Clinical Cases 3rd Ed.  |  "
        "Plum & Posner's Stupor & Coma  |  Goldman-Cecil Medicine", NOTE_S))

    # ── Footer ─────────────────────────────────────────────────────────────────
    def footer(canvas, doc):
        canvas.saveState()
        canvas.setFont("Helvetica", 8); canvas.setFillColor(C_MID_GRAY)
        canvas.drawCentredString(PAGE_W/2, 1.2*cm,
            f"Brain CT & MRI Visual Reference Guide  |  Page {doc.page}")
        canvas.setFillColor(C_LIGHTBLUE)
        canvas.rect(2*cm, 1.0*cm, PAGE_W-4*cm, 0.04*cm, fill=1, stroke=0)
        canvas.restoreState()

    doc.build(story, onFirstPage=footer, onLaterPages=footer)
    print(f"✓ PDF saved: {OUT_PATH}")
    import os as _os
    sz = _os.path.getsize(OUT_PATH)
    print(f"  Size: {sz/1024:.0f} KB  |  Path: {OUT_PATH}")

build()