Patient Details

Step-by-Step Assessment Approach

1. NCCT Brain — What to Look For

From the NCCT images, the posterior fossa slices and supratentorial cuts need careful review. Small cortical or posterior fossa infarcts can be missed on CT.

2. MRI DWI — Critical Sequence

• Positive finding: Focal bright (hyperintense) signal on DWI = restricted diffusion = acute infarct
• Confirm with ADC map: corresponding dark (hypointense) signal confirms true restriction (not T2 shine-through)
• From the DWI panel (left half of MRI film), there appear to be areas of hyperintensity in the posterior fossa / cerebellar region on lower cuts and supratentorial white matter on mid-level cuts — these are the key positive findings

3. FLAIR — DWI-FLAIR Mismatch Rule

• If DWI bright but FLAIR normal → infarct is < 4.5 hours old (thrombolysis window)
• If DWI bright AND FLAIR bright → infarct is > 4.5–6 hours (established)
• The FLAIR sequence (right half of MRI film, T2W FLAIR AXIAL labeled) should be compared slice-by-slice with DWI

4. T2W / GRE (FFE) Sequences

• T2W: Bright signal in infarct territory (may lag behind DWI in hyperacute phase)
• *GRE/FFE (T2)**: Look for blooming artifact = hemorrhagic transformation or microbleeds (dark spots)
  • From the GRE panel (third film, right side labeled T2W FFE/GRE), check for any dark foci

5. MR Angiography — Vessel Assessment

• Normal: Both carotid systems and vertebrobasilar system show well-opacified vessels with smooth tapering
• Positive findings to report:
  • Stenosis: Focal narrowing / signal dropout
  • Occlusion: Abrupt cutoff of vessel
  • Atherosclerotic irregularity: Irregular contour of vessel walls
  • Assess: ICAs, MCAs (M1/M2), ACAs, basilar artery, vertebral arteries, PCAs

How to Write the Positive Findings Report

Template

NCCT BRAIN:
- Hypo/isodense area noted in [location] suggestive of [acute/subacute] infarct
  / No significant hypodensity / No intracranial hemorrhage
- Hyperdense MCA sign: Present / Absent
- Midline shift: Present [X mm to left/right] / Absent
- Ventricles: Normal / Dilated / Effaced
- Posterior fossa: Normal / Hypodensity in [cerebellum/brainstem]

MRI BRAIN — STROKE PROTOCOL:

DWI/ADC:
- Focal area of restricted diffusion (DWI bright, ADC dark) noted in [location — e.g., 
  left MCA territory / right cerebellar hemisphere / right internal capsule]
  measuring approximately [X × Y cm], consistent with ACUTE INFARCT.

FLAIR:
- Corresponding FLAIR [hyperintensity / no signal change] at the above-described site,
  suggesting infarct age [>4.5 hrs if FLAIR positive / <4.5 hrs if FLAIR negative — 
  DWI-FLAIR mismatch].

T2W:
- [T2 hyperintensity / no signal change] in the infarcted territory.

GRE/T2*:
- No blooming artifact to suggest hemorrhagic transformation / microbleeds.
  [OR: Foci of blooming artifact noted in [location] — hemorrhagic transformation / 
  microbleeds cannot be excluded.]

MR ANGIOGRAPHY (Intracranial + Neck vessels):
- [Normal flow signal in bilateral ICAs, MCAs, ACAs, PCAs, vertebral arteries, 
  and basilar artery]
  [OR: Focal signal dropout / stenosis / occlusion noted at [location].]
- Carotid bifurcation: Normal / Atherosclerotic changes with [mild/moderate/severe] stenosis
- Vertebral arteries: Symmetrical / Dominant right/left / Hypoplastic [side]

IMPRESSION:
1. Acute ischemic infarct in [territory/location] — [size if measurable]
2. DWI-FLAIR mismatch [present/absent] — [thrombolysis window open/closed]
3. [MRA findings — occlusion/stenosis if present, or normal intracranial vasculature]
4. No intracranial hemorrhage / hemorrhagic transformation

Key Teaching Points for This Case

1. Stroke protocol MRI is far superior to CT for acute infarct detection — especially posterior fossa (where CT has bone artifact)
2. Always correlate DWI ↔ ADC ↔ FLAIR for confirmation and timing
3. MRA without contrast (Time of Flight) is sufficient to assess large vessel occlusion (LVO) — the key treatable target
4. Report territory (MCA/PCA/ACA/PICA/basilar), side, and approximate size
5. GRE/FFE is the sequence to exclude hemorrhage before thrombolysis decisions