On diffusion-weighted MRI (DWI), acute cerebral infarction appears as high signal. The corresponding apparent diffusion coefficient (ADC) map would show:
- A Low ADC (dark) in the infarcted zone confirming restricted diffusion ✓
- B High ADC (bright) in the infarcted zone
- C No change on ADC map (T2 shine-through artefact)
- D Variable ADC depending on patient age
Correct answer: A. Low ADC (dark) in the infarcted zone confirming restricted diffusion
Explanation
True restricted diffusion (as in cytotoxic oedema of acute stroke) shows high DWI signal AND correspondingly low ADC (dark). This confirms the high DWI signal is due to restricted water movement, not T2 shine-through. T2 shine-through occurs when a lesion is bright on DWI but ADC is elevated or normal, seen in subacute strokes. ADC map analysis is essential to distinguish true restriction from shine-through; stroke ADC appears dark within minutes of onset.
Reference: Grainger & Allison's Diagnostic Radiology, 7th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.