On MRI, a 45-year-old woman has multiple periventricular ovoid T2/FLAIR hyperintense lesions perpendicular to the ventricles, involving the corpus callosum ('Dawson fingers'), with some lesions showing central vein sign on susceptibility-weighted imaging (SWI). Which diagnosis do these features support?
- A Cerebral small vessel disease (lacunar infarcts)
- B Neurosarcoidosis — leptomeningeal enhancement pattern
- C Multiple sclerosis (MS) — perivenular demyelinating plaques ✓
- D CNS vasculitis — cortical/subcortical infarcts
Explanation
Multiple sclerosis (MS) produces demyelinating plaques that develop around perivenous inflammation. On MRI, the cardinal features are periventricular lesions oriented perpendicular to the ventricular surface — 'Dawson fingers' on sagittal FLAIR — and involvement of the callosalseptal interface (undersurface of the corpus callosum). The central vein sign on SWI (a central vein visible within each T2 lesion) is a highly specific imaging biomarker for MS, present in >80% of MS lesions vs. <20% of vascular lesions. Lacunar infarcts are round, small, in the basal ganglia, without perpendicular orientation. Vasculitis produces cortical/watershed infarcts.
Reference: Grainger & Allison's Diagnostic Radiology, 7th ed.
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Written and medically reviewed by the StethoPrep medical team.