knee MRI anatomy ligaments ACL PCL MCL

knee MRI meniscus tear pathology

knee MRI ACL tear PCL tear collateral ligament injury

ls -la /home/daytona/workspace/ && mkdir -p /home/daytona/workspace/mri-knee-ppt

cat > /home/daytona/workspace/mri-knee-ppt/create_mri_knee_ppt.js << 'EOF' const pptxgen = require('pptxgenjs'); const pptx = new pptxgen(); pptx.layout = 'LAYOUT_WIDE'; pptx.author = 'Orris'; pptx.subject = 'MRI Knee Anatomy, Ligaments and Pathology'; pptx.title = 'MRI Knee: Anatomy, Ligaments and Pathology'; pptx.company = 'Educational'; pptx.lang = 'en-US'; authorNote = { color: '666666', fontSize: 10, italic: true }; const titleStyle = { fontFace: 'Calibri', bold: true, color: 'FFFFFF' }; const bodyStyle = { fontFace: 'Calibri', color: '1F2937', fontSize: 18 }; function addHeader(slide, title) { slide.addShape(pptx.ShapeType.rect, { x: 0, y: 0, w: 13.33, h: 0.9, fill: { color: '0F4C81' }, line: { color: '0F4C81' } }); slide.addText(title, { x: 0.4, y: 0.2, w: 12.5, h: 0.5, ...titleStyle, fontSize: 24 }); } function addFooter(slide, text) { slide.addShape(pptx.ShapeType.line, { x: 0.3, y: 7.15, w: 12.7, h: 0, line: { color: 'D1D5DB', pt: 1 } }); slide.addText(text, { x: 0.4, y: 7.18, w: 12.5, h: 0.25, ...authorNote, align: 'left' }); } let slide = pptx.addSlide(); slide.background = { color: 'F8FAFC' }; addHeader(slide, 'MRI Knee: Anatomy, Ligaments and Pathology'); slide.addText('Comprehensive review of knee MRI anatomy, ligament assessment, and common pathologies', { x: 0.7, y: 1.3, w: 12, h: 0.8, fontFace: 'Calibri', fontSize: 26, bold: true, color: '0F172A', align: 'center' }); slide.addText('Topics: compartment anatomy, cruciate/collateral ligaments, meniscal and ligament tears, marrow and soft-tissue findings', { x: 0.9, y: 2.2, w: 11.6, h: 0.9, fontFace: 'Calibri', fontSize: 18, color: '334155', align: 'center' }); slide.addImage({ path: 'https://cdn.orris.care/cdss_images/4c736f35d04ddd5393a7cb4e6ca7f5319e6698c4df603426402b218adf322d25.png', x: 4.1, y: 3.2, w: 5.1, h: 3.2 }); addFooter(slide, 'Sources: Grainger & Allison\'s Diagnostic Radiology; Imaging Anatomy Text and Atlas; Rockwood and Green\'s Fractures in Adults'); slide = pptx.addSlide(); slide.background = { color: 'FFFFFF' }; addHeader(slide, 'Normal Knee MRI Anatomy'); slide.addText([ { text: '• Three compartments: medial tibiofemoral, lateral tibiofemoral, patellofemoral\n', options: { bullet: { indent: 18 } } }, { text: '• Joint capsule encloses menisci and cruciate ligaments\n', options: { bullet: { indent: 18 } } }, { text: '• Collateral ligaments are extra-articular (except popliteus intra-articular segment)\n', options: { bullet: { indent: 18 } } }, { text: '• MRI is the imaging modality of choice for internal derangement', options: { bullet: { indent: 18 } } }, ], { x: 0.6, y: 1.2, w: 6.4, h: 3.2, ...bodyStyle, paraSpaceAfterPt: 10 }); slide.addImage({ path: 'https://cdn.orris.care/cdss_images/f75962bad7e55db8bdd2fcfb7f33c0362b7c2418340144923a4563d365f08b86.png', x: 7.2, y: 1.4, w: 5.5, h: 5.4 }); addFooter(slide, 'Grainger & Allison\'s Diagnostic Radiology, p. 992; Imaging Anatomy Text and Atlas Vol 3, p. 776'); slide = pptx.addSlide(); slide.background = { color: 'FFFFFF' }; addHeader(slide, 'Cruciate Ligaments on MRI'); slide.addText([ { text: 'ACL\n', options: { bold: true } }, { text: '• Runs from posteromedial lateral femoral condyle to anterior tibial intercondylar region\n', options: { bullet: { indent: 18 } } }, { text: '• Seen as low-signal linear band, generally parallel to intercondylar roof\n', options: { bullet: { indent: 18 } } }, { text: '• Functional bundles: anteromedial and posterolateral\n\n', options: { bullet: { indent: 18 } } }, { text: 'PCL\n', options: { bold: true } }, { text: '• Thick low-signal structure in posterior intercondylar notch\n', options: { bullet: { indent: 18 } } }, { text: '• Key stabilizer against posterior tibial translation', options: { bullet: { indent: 18 } } }, ], { x: 0.6, y: 1.2, w: 6.4, h: 5.5, ...bodyStyle, fontSize: 16, paraSpaceAfterPt: 8 }); slide.addImage({ path: 'https://cdn.orris.care/cdss_images/2a57ad697f78083bab4f42cb6c25160f815abc3d490b6eba3d76cf23d9def90e.png', x: 7.2, y: 1.2, w: 2.6, h: 2.7 }); slide.addImage({ path: 'https://cdn.orris.care/cdss_images/893e6b321da770d28c3561366dc84388703daaced8eb4ff1de1ba16d23062eea.png', x: 10.0, y: 1.2, w: 2.8, h: 2.7 }); slide.addImage({ path: 'https://cdn.orris.care/cdss_images/f449889eb1ec6d63568b6ed347f158496eb609c60f0afc9e8de3e5e774436672.png', x: 7.2, y: 4.1, w: 5.6, h: 2.7 }); addFooter(slide, 'Imaging Anatomy Text and Atlas Vol 3, p. 776-777'); slide = pptx.addSlide(); slide.background = { color: 'FFFFFF' }; addHeader(slide, 'Collateral Ligaments and Corner Anatomy'); slide.addText([ { text: 'Medial side (MCL/PMC):\n', options: { bold: true } }, { text: '• Superficial MCL, deep MCL, posterior oblique ligament\n', options: { bullet: { indent: 18 } } }, { text: '• Posteromedial corner includes semimembranosus expansions and capsule\n\n', options: { bullet: { indent: 18 } } }, { text: 'Lateral side (LCL/PLC):\n', options: { bold: true } }, { text: '• Fibular collateral ligament (LCL), popliteus tendon, popliteofibular ligament\n', options: { bullet: { indent: 18 } } }, { text: '• PLC injuries are frequently associated with cruciate tears', options: { bullet: { indent: 18 } } }, ], { x: 0.6, y: 1.2, w: 6.4, h: 5.2, ...bodyStyle, fontSize: 16, paraSpaceAfterPt: 8 }); slide.addImage({ path: 'https://cdn.orris.care/cdss_images/bfddd510eae00abb4dd986e9ac91a2cdb69de543c1af456675c04061222f596f.png', x: 7.3, y: 1.3, w: 5.4, h: 2.5 }); slide.addImage({ path: 'https://cdn.orris.care/cdss_images/ad32eeb36aed3dd50626151cba4e56c57cbb6e9ab670f93e6aa14378a63b0fd5.png', x: 7.3, y: 4.0, w: 5.4, h: 2.5 }); addFooter(slide, 'Rockwood and Green\'s Fractures in Adults 10th ed, p. 3048, 3052'); slide = pptx.addSlide(); slide.background = { color: 'FFFFFF' }; addHeader(slide, 'Meniscal Pathology on MRI'); slide.addText([ { text: 'MRI criteria for tear:\n', options: { bold: true } }, { text: '• Intra-meniscal high signal extending to articular surface\n', options: { bullet: { indent: 18 } } }, { text: '• Morphologies: horizontal, longitudinal, radial, complex\n\n', options: { bullet: { indent: 18 } } }, { text: 'Important tear patterns:\n', options: { bold: true } }, { text: '• Bucket-handle tear with displaced fragment\n', options: { bullet: { indent: 18 } } }, { text: '• Ghost meniscus sign in complete radial tear\n', options: { bullet: { indent: 18 } } }, { text: '• Double PCL sign in displaced bucket-handle tear', options: { bullet: { indent: 18 } } }, ], { x: 0.6, y: 1.2, w: 6.3, h: 5.3, ...bodyStyle, fontSize: 16, paraSpaceAfterPt: 8 }); slide.addImage({ path: 'https://cdn.orris.care/cdss_images/f81127e9d685493f142fb3c90ca1061d7b38f620bd60e4e12348728832040531.png', x: 7.2, y: 1.2, w: 2.6, h: 2.4 }); slide.addImage({ path: 'https://cdn.orris.care/cdss_images/1e94c37965e38ef83e7207cab5ff68d7779d7613b43dac14ff93ea690a3231eb.png', x: 10.0, y: 1.2, w: 2.6, h: 2.4 }); slide.addImage({ path: 'https://cdn.orris.care/cdss_images/292d0646b428caf3cc4e81dffe5960e429af0637e037b5033fcf019f37ddc754.png', x: 7.2, y: 3.8, w: 2.6, h: 2.4 }); slide.addImage({ path: 'https://cdn.orris.care/cdss_images/079c6a1a8a6fe85e95007a39f8d8722a009061347cc4558a590b24d7a914fa1f.png', x: 10.0, y: 3.8, w: 2.6, h: 2.4 }); addFooter(slide, 'Grainger & Allison\'s Diagnostic Radiology, p. 993-994'); slide = pptx.addSlide(); slide.background = { color: 'FFFFFF' }; addHeader(slide, 'Cruciate and Collateral Ligament Injuries'); slide.addText([ { text: 'ACL injury:\n', options: { bold: true } }, { text: '• Complete tear: fiber discontinuity, high signal, laxity\n', options: { bullet: { indent: 18 } } }, { text: '• Secondary signs: kissing contusions, anterior tibial translation, PCL buckling\n\n', options: { bullet: { indent: 18 } } }, { text: 'PCL injury:\n', options: { bold: true } }, { text: '• Thickened high-signal or discontinuous fibers in acute tears\n\n', options: { bullet: { indent: 18 } } }, { text: 'MCL/LCL injury:\n', options: { bold: true } }, { text: '• Periligament edema, fiber disruption, avulsion fragments in high-grade injury', options: { bullet: { indent: 18 } } }, ], { x: 0.6, y: 1.2, w: 6.2, h: 5.5, ...bodyStyle, fontSize: 15, paraSpaceAfterPt: 8 }); slide.addImage({ path: 'https://cdn.orris.care/cdss_images/pmc_clinical_VQA_95e6c46182771523b7bfa203adefd4618a34bc8a7039de046de047d2164dff1a.jpg', x: 7.1, y: 1.3, w: 2.7, h: 2.4 }); slide.addImage({ path: 'https://cdn.orris.care/cdss_images/pmc_clinical_VQA_dbea8e2b2496283fe4f18ae1f1bddc21a8de8bd0e199947e7c804abf328be81b.jpg', x: 10.0, y: 1.3, w: 2.7, h: 2.4 }); slide.addImage({ path: 'https://cdn.orris.care/cdss_images/pmc_clinical_VQA_2de25f1eccd12d644b5cde97b2254b753112dd8e85e9c0fa0fb9fe6a4571c01c.jpg', x: 8.55, y: 4.0, w: 2.9, h: 2.4 }); addFooter(slide, 'Grainger & Allison\'s Diagnostic Radiology, p. 994-995; supplemental clinical MRI examples'); slide = pptx.addSlide(); slide.background = { color: 'FFFFFF' }; addHeader(slide, 'Bone Marrow and Associated Findings'); slide.addText([ { text: 'Common associated MRI findings in traumatic knee injury:\n', options: { bold: true } }, { text: '• Bone marrow edema/contusions (especially lateral femoral condyle and posterolateral tibial plateau)\n', options: { bullet: { indent: 18 } } }, { text: '• Joint effusion and synovitis\n', options: { bullet: { indent: 18 } } }, { text: '• Osteochondral defects or subchondral insufficiency changes\n', options: { bullet: { indent: 18 } } }, { text: '• Bursitis and popliteal cysts as secondary pain generators', options: { bullet: { indent: 18 } } }, ], { x: 0.6, y: 1.3, w: 6.5, h: 4.8, ...bodyStyle, fontSize: 16, paraSpaceAfterPt: 8 }); slide.addImage({ path: 'https://cdn.orris.care/cdss_images/fec8c067bb10a12a6753c530f3dc463a151d20d53aef80a67b9ba8c5b06bff94.png', x: 7.5, y: 1.7, w: 5.0, h: 4.5 }); addFooter(slide, 'Grainger & Allison\'s Diagnostic Radiology, p. 998'); slide = pptx.addSlide(); slide.background = { color: 'F8FAFC' }; addHeader(slide, 'MRI Knee Reporting Checklist'); slide.addText([ { text: '1. Technical quality and key sequences\n', options: { bullet: { indent: 18 } } }, { text: '2. Alignment, fractures, marrow edema pattern\n', options: { bullet: { indent: 18 } } }, { text: '3. Menisci: roots, body, horns, tear type/displacement\n', options: { bullet: { indent: 18 } } }, { text: '4. Ligaments: ACL, PCL, MCL complex, LCL/PLC complex\n', options: { bullet: { indent: 18 } } }, { text: '5. Cartilage, osteochondral lesions, loose bodies\n', options: { bullet: { indent: 18 } } }, { text: '6. Extensor mechanism, tendons, bursae, cysts\n', options: { bullet: { indent: 18 } } }, { text: '7. Final impression with clinically actionable priorities', options: { bullet: { indent: 18 } } }, ], { x: 1.0, y: 1.3, w: 11.4, h: 5.2, ...bodyStyle, fontSize: 20, paraSpaceAfterPt: 14 }); addFooter(slide, 'Structured approach improves diagnostic consistency and surgical planning communication.'); pptx.writeFile({ fileName: '/home/daytona/workspace/mri-knee-ppt/MRI_Knee_Anatomy_Ligaments_Pathology.pptx' }); EOF node /home/daytona/workspace/mri-knee-ppt/create_mri_knee_ppt.js

ultrasound imaging physics image quality artifacts radiology educational review

~/

mkdir -p "/tmp/workspace/ultrasound-q1-notes" && cat > "/tmp/workspace/ultrasound-q1-notes/create_pdf.py" <<'PY' from reportlab.lib.pagesizes import A4 from reportlab.lib import colors from reportlab.lib.styles import getSampleStyleSheet, ParagraphStyle from reportlab.lib.enums import TA_CENTER, TA_JUSTIFY from reportlab.lib.units import cm from reportlab.platypus import SimpleDocTemplate, Paragraph, Spacer, PageBreak, Table, TableStyle, KeepTogether, Flowable from reportlab.pdfbase.ttfonts import TTFont from reportlab.pdfbase import pdfmetrics from reportlab.lib.colors import HexColor OUT='/tmp/workspace/ultrasound-q1-notes/Q1_Ultrasound_Physics_Image_Quality_Artefacts.pdf' navy=HexColor('#123B5D'); blue=HexColor('#176B87'); teal=HexColor('#2B8C8D'); pale=HexColor('#EAF3F7'); ink=HexColor('#1D2939'); grey=HexColor('#5B6573') styles=getSampleStyleSheet() styles.add(ParagraphStyle(name='TitleX', parent=styles['Title'], fontName='Helvetica-Bold', fontSize=20, leading=25, textColor=navy, alignment=TA_CENTER, spaceAfter=7)) styles.add(ParagraphStyle(name='SubX', parent=styles['Normal'], fontName='Helvetica', fontSize=10, leading=14, textColor=grey, alignment=TA_CENTER, spaceAfter=12)) styles.add(ParagraphStyle(name='H1X', parent=styles['Heading1'], fontName='Helvetica-Bold', fontSize=14, leading=18, textColor=navy, spaceBefore=12, spaceAfter=6)) styles.add(ParagraphStyle(name='H2X', parent=styles['Heading2'], fontName='Helvetica-Bold', fontSize=11, leading=14, textColor=blue, spaceBefore=8, spaceAfter=4)) styles.add(ParagraphStyle(name='BodyX', parent=styles['BodyText'], fontName='Helvetica', fontSize=9.25, leading=13, alignment=TA_JUSTIFY, textColor=ink, spaceAfter=5)) styles.add(ParagraphStyle(name='BulletX', parent=styles['BodyText'], fontName='Helvetica', fontSize=9.15, leading=12.5, leftIndent=14, firstLineIndent=-9, textColor=ink, spaceAfter=3)) styles.add(ParagraphStyle(name='SmallX', parent=styles['BodyText'], fontName='Helvetica', fontSize=8, leading=10, textColor=grey, spaceAfter=3)) def p(t, s='BodyX'): return Paragraph(t, styles[s]) def bullet(t): return p('• '+t,'BulletX') class BeamDiagram(Flowable): def __init__(self,w=460,h=150): Flowable.__init__(self); self.width=w; self.height=h def draw(self): c=self.canv; w=self.width; h=self.height c.setStrokeColor(navy); c.setFillColor(pale); c.roundRect(5,92,92,38,6,stroke=1,fill=1) c.setFillColor(navy); c.setFont('Helvetica-Bold',9); c.drawCentredString(51,113,'TRANSDUCER') c.setFont('Helvetica',7); c.drawCentredString(51,101,'PZT crystal') c.setStrokeColor(blue); c.setLineWidth(1.4) for yy in [100,108,116,124]: c.line(98,yy,230,75+(yy-100)*1.4) c.setFillColor(blue); c.setFont('Helvetica',8); c.drawString(117,132,'short pulse') c.setStrokeColor(teal); c.setFillColor(HexColor('#D9F0EE')); c.roundRect(230,47,165,66,6,stroke=1,fill=1) c.setFillColor(teal); c.setFont('Helvetica-Bold',9); c.drawCentredString(312,88,'TISSUE INTERFACE') c.setFont('Helvetica',8); c.setFillColor(ink); c.drawCentredString(312,73,'different acoustic impedance') c.setStrokeColor(navy); c.setLineWidth(1.3) for yy in [70,80,90]: c.line(230,yy,105,40+(yy-70)*0.55) c.setFillColor(navy); c.setFont('Helvetica',8); c.drawString(115,44,'returning echoes') c.setFillColor(grey); c.setFont('Helvetica',8); c.drawString(10,15,'Image depth is calculated from round-trip time assuming c = 1540 m/s; brightness reflects echo amplitude.') def footer(canvas, doc): canvas.saveState(); canvas.setStrokeColor(HexColor('#C8D3DC')); canvas.line(1.7*cm,1.25*cm,19.3*cm,1.25*cm) canvas.setFont('Helvetica',8); canvas.setFillColor(grey) canvas.drawString(1.7*cm,0.85*cm,'Radiodiagnosis Internal Examination | Q1: Ultrasound Physics') canvas.drawRightString(19.3*cm,0.85*cm,f'Page {doc.page}') canvas.restoreState() doc=SimpleDocTemplate(OUT,pagesize=A4,rightMargin=1.7*cm,leftMargin=1.7*cm,topMargin=1.35*cm,bottomMargin=1.55*cm) story=[] story += [p('QUESTION 1: ULTRASOUND IMAGING','TitleX'),p('Physical principles, determinants of image quality, common artefacts, their causes and minimisation | Structured 20-mark answer','SubX')] story += [p('<b>Question:</b> Describe the physical principles of ultrasound imaging. Discuss factors affecting image quality, common artefacts, their causes and methods of minimising them.','BodyX')] story += [p('Suggested answer structure: 6 marks physics + 6 marks image quality + 6 marks artefacts + 2 marks conclusion/clinical optimisation.','SmallX')] story.append(Spacer(1,4)); story.append(BeamDiagram()); story.append(Spacer(1,5)) story += [p('1. Physical principles of diagnostic ultrasound','H1X'),p('<b>Definition.</b> Diagnostic ultrasound uses high-frequency mechanical sound waves, usually about 2-15 MHz, which are above the audible range. It is not ionising electromagnetic radiation. The scanner transmits short pulses and constructs an image from returning echoes.','BodyX')] story += [p('1.1 Transducer and piezoelectric effect','H2X'),bullet('<b>Piezoelectric crystals</b> in the transducer convert electrical energy to mechanical vibration, creating ultrasound pulses. Returning echoes deform the crystals and are converted back into electrical signals.'),bullet('A backing/damping material shortens the pulse. A short spatial pulse length improves <b>axial resolution</b>. Matching layers improve transfer of energy into the patient; an acoustic lens and electronic phasing help focus the beam.'),bullet('The system alternates rapidly between transmit and receive modes. Pulse repetition frequency determines the maximum imaging depth and is limited by the need to wait for echoes to return.')] story += [p('1.2 Wave parameters and propagation','H2X'),bullet('Frequency (f), wavelength (λ), and propagation speed (c) are related by <b>c = fλ</b>. The assumed mean speed in soft tissue is <b>1540 m/s</b>.'),bullet('Higher frequency gives a shorter wavelength and better spatial resolution, but is attenuated more, reducing penetration. Lower frequency improves penetration at the cost of detail.'),bullet('For pulse-echo imaging, depth is estimated from <b>depth = c × time / 2</b>, since measured time is for the outward and return journey.')] story += [p('1.3 Acoustic impedance and tissue interactions','H2X'),bullet('Acoustic impedance <b>Z = ρc</b>, where ρ is tissue density and c is sound velocity. An impedance mismatch at an interface produces reflection; the larger the mismatch, the stronger the echo.'),bullet('<b>Reflection:</b> basis of anatomic B-mode imaging. Specular interfaces reflect best when the beam is perpendicular. Oblique incidence produces weak return and apparent dropout.'),bullet('<b>Scattering:</b> occurs from small/rough structures, including red blood cells; it returns low-amplitude echoes in many directions and is the physical basis of Doppler imaging.'),bullet('<b>Refraction:</b> beam changes direction when it crosses an oblique boundary between media with different sound speeds. It may cause lateral displacement or duplication.'),bullet('<b>Attenuation:</b> progressive loss of intensity from absorption, scattering and reflection. It increases with path length and frequency, limiting penetration. The scanner uses time-gain compensation (TGC) to compensate for depth-related loss.')] story += [p('1.4 Image formation and display','H2X'),bullet('In <b>B-mode</b>, echo amplitude is represented as pixel brightness, producing real-time greyscale sectional images. Strong echoes are hyperechoic; fluid with few internal reflectors is anechoic.'),bullet('The scanner assumes a straight path, one reflection per pulse, return of echoes from the central beam, constant sound speed, and predictable attenuation. Artefacts occur when one or more assumptions fail.'),bullet('<b>Doppler</b> uses the frequency shift caused by motion of scatterers, mainly red cells. The Doppler shift is proportional to transmitted frequency and velocity, and proportional to cos θ; velocity estimation is most accurate when the insonation angle is ≤60°.')] story.append(PageBreak()) story += [p('2. Factors affecting ultrasound image quality','H1X'),p('Image quality means adequate penetration, spatial and contrast resolution, temporal resolution, low noise and correct anatomic localisation. Optimisation must balance these competing requirements.','BodyX')] rows=[['Factor','Effect on image','Practical optimisation'],['Frequency','High f: ↑ resolution, ↓ penetration','Use high-frequency linear probe for superficial structures; low-frequency curvilinear/phased probe for deep abdomen.'],['Depth and field of view','Excess depth lowers frame rate and makes target small','Set depth just beyond region of interest; place target in central/focal part of display.'],['Focus / beam width','Narrow beam improves lateral resolution; resolution best at focal zone','Place one focal zone at or just below target. Avoid multiple focal zones if temporal resolution is important.'],['Gain / TGC','Too high: noise and false echoes. Too low: loss of genuine echoes','Set overall gain for appropriate brightness, then use TGC to achieve uniform brightness from near to far field.'],['Dynamic range','Wide range: more grey shades, lower contrast. Narrow range: greater contrast','Use wider range for parenchymal texture; narrower range for cystic-solid discrimination when appropriate.'],['Power output','Higher output may improve signal but increases bioeffect potential','Use ALARA: lowest output and shortest scan time compatible with diagnosis.'],['Patient and acoustic window','Obesity, bowel gas, bone and dressings reduce penetration','Reposition patient, use compression, intercostal/alternative window, lower frequency, adequate gel.'],['Motion / frame rate','Motion causes blur; low frame rate misses rapid motion','Shorten depth, narrow sector, reduce focal zones; ask breath-hold or use cine loop.']] t=Table([[p('<b>'+x+'</b>','SmallX') for x in rows[0]]] + [[p(c,'SmallX') for c in r] for r in rows[1:]],colWidths=[3.15*cm,6.0*cm,8.0*cm],repeatRows=1) t.setStyle(TableStyle([('BACKGROUND',(0,0),(-1,0),navy),('TEXTCOLOR',(0,0),(-1,0),colors.white),('VALIGN',(0,0),(-1,-1),'TOP'),('GRID',(0,0),(-1,-1),0.3,HexColor('#B9C8D3')),('BACKGROUND',(0,1),(-1,-1),HexColor('#F8FBFC')),('LEFTPADDING',(0,0),(-1,-1),5),('RIGHTPADDING',(0,0),(-1,-1),5),('TOPPADDING',(0,0),(-1,-1),4),('BOTTOMPADDING',(0,0),(-1,-1),4)])) story.append(t) story += [p('Key resolution terms','H2X'),bullet('<b>Axial resolution</b> distinguishes structures lying one behind the other along the beam. It is approximately half the spatial pulse length. Improve it with higher frequency and short pulses.'),bullet('<b>Lateral resolution</b> distinguishes side-by-side structures perpendicular to the beam. It is determined by beam width, therefore improves in the focal zone with focusing and a higher-frequency/wider aperture probe.'),bullet('<b>Elevational (slice-thickness) resolution</b> is determined by beam thickness. A thick slice may introduce partial-volume echoes into a cyst.'),bullet('<b>Contrast resolution</b> is the ability to distinguish small differences in echo amplitude. It is affected by dynamic range, gain, harmonic imaging, noise and attenuation.'),bullet('<b>Temporal resolution</b> is the ability to display moving structures accurately. It decreases as imaging depth, number of focal zones and line density increase.')] story.append(PageBreak()) story += [p('3. Common ultrasound artefacts: cause, appearance and minimisation','H1X'),p('Artefacts are structures or signal characteristics that do not faithfully represent the imaged anatomy. Some are useful diagnostic signs, but all should be recognised.','BodyX')] art=[['Artefact','Cause and appearance','Minimisation / use'],['Reverberation','Repeated reflections between two strong parallel reflectors. Multiple equally spaced echoes deepen with time; includes near-field clutter.','Change probe angle/position, reduce gain, use tissue harmonics or a different window.'],['Comet-tail / ring-down','Subtype of reverberation. Comet-tail: closely spaced short tapering echoes. Ring-down: continuous echogenic trail from resonating gas bubbles.','Often diagnostic: comet-tail with metal/cholesterol crystals; ring-down strongly supports gas. Modify angle/frequency if obscuring target.'],['Acoustic shadowing','Marked attenuation/reflection by calcification, bone, gas or metal creates a dark distal band.','Change window/angle; lower frequency for penetration. Diagnostic behind gallstones, calcification and bone.'],['Posterior enhancement','Low attenuation through fluid leads to increased distal brightness behind cyst, bladder or vessel.','Recognise as a fluid sign; adjust TGC rather than misdiagnosing distal tissue as abnormal.'],['Mirror image','Strong reflector such as diaphragm causes a duplicated structure beyond it at increased apparent depth.','Scan in orthogonal plane/change angle. Recognise typical location across diaphragm.'],['Refraction / edge shadow','Beam bends at oblique speed boundary, producing lateral displacement, duplication, or dark edges of rounded structures.','Use a more perpendicular beam, alternate window or lower frequency; confirm in another plane.'],['Side-lobe / grating-lobe','Off-axis energy receives echoes but system assigns them to main beam, creating spurious internal echoes in cysts.','Use tissue harmonic imaging, change angle, reduce gain; modern probes reduce this with apodisation.'],['Beam-width / slice-thickness','Finite beam width or thickness includes adjacent tissues; echoes displayed as if from centre, creating pseudo-debris in cyst.','Move focal zone to target, use harmonic imaging, scan in multiple planes.'],['Speed-displacement','Actual sound speed differs from assumed 1540 m/s, causing erroneous depth or shape.','Recognise at fat/soft-tissue interfaces; assess in another plane; cannot be fully corrected by routine controls.'],['Range ambiguity','Echo from a previous pulse returns after next pulse and is displayed too superficially, usually at great depth.','Reduce PRF/increase listening time by reducing imaging depth; use a different probe/frequency.'],['Doppler aliasing','Doppler shift exceeds Nyquist limit (PRF/2), causing colour wrap or spectral waveform wrap.','Increase PRF/scale, shift baseline, reduce transmit frequency, use a shallower window, or use continuous-wave Doppler.']] t2=Table([[p('<b>'+x+'</b>','SmallX') for x in art[0]]] + [[p(c,'SmallX') for c in r] for r in art[1:]],colWidths=[3.0*cm,8.15*cm,6.0*cm],repeatRows=1) t2.setStyle(TableStyle([('BACKGROUND',(0,0),(-1,0),navy),('TEXTCOLOR',(0,0),(-1,0),colors.white),('VALIGN',(0,0),(-1,-1),'TOP'),('GRID',(0,0),(-1,-1),0.25,HexColor('#B9C8D3')),('ROWBACKGROUNDS',(0,1),(-1,-1),[HexColor('#F8FBFC'),colors.white]),('LEFTPADDING',(0,0),(-1,-1),4),('RIGHTPADDING',(0,0),(-1,-1),4),('TOPPADDING',(0,0),(-1,-1),3),('BOTTOMPADDING',(0,0),(-1,-1),3)])) story.append(t2) story += [p('4. Practical conclusion','H1X'),p('Diagnostic ultrasound depends on the pulse-echo principle: echoes generated at tissue interfaces are converted to a greyscale image using assumptions about sound speed, beam path and echo return. Optimal scanning selects the appropriate transducer and frequency, positions the focal zone at the region of interest, sets appropriate depth, gain and TGC, and uses the best acoustic window. Recognition of artefacts prevents false-positive findings and can itself provide diagnostic information, for example posterior shadowing from a calculus, enhancement behind fluid, and ring-down from gas.','BodyX')] story += [p('Reference books used','H1X'),p('• Grainger & Allison’s Diagnostic Radiology: A Textbook of Medical Imaging, 7th ed. General principles of imaging and ultrasound sections.<br/>• Textbook of Clinical Echocardiography, 7th ed, Chapter 1: ultrasound physics and imaging artefacts, pp. 17-25.<br/>• Miller’s Anesthesia, 10th ed, Principles of Ultrasound: physical assumptions of ultrasound image formation.<br/>• Murray & Nadel’s Textbook of Respiratory Medicine, Ultrasound Physics section: frequency, penetration and resolution.','SmallX')] doc.build(story,onFirstPage=footer,onLaterPages=footer) print(OUT) PY python "/tmp/workspace/ultrasound-q1-notes/create_pdf.py" && ls -lh "/tmp/workspace/ultrasound-q1-notes/Q1_Ultrasound_Physics_Image_Quality_Artefacts.pdf"