A 35-year-old woman presents with an acute episode of right-sided weakness and blurred vision that partially resolved. MRI brain shows multiple ovoid T2-hyperintense lesions in the periventricular white matter oriented perpendicular to the lateral ventricles. On sagittal imaging, these lesions appear to extend along medullary veins. What is this pattern called and what is the most likely diagnosis?

• A Leukoaraiosis; small vessel disease
• B Dawson fingers; multiple sclerosis ✓
• C FLAIR halos; metastatic disease
• D Butterfly glioma; glioblastoma

Explanation

Dawson fingers are ovoid periventricular white matter lesions oriented perpendicular to the lateral ventricles and extending along the medullary veins, pathognomonic of multiple sclerosis on MRI. They reflect perivenular inflammation and demyelination. This pattern is best seen on sagittal FLAIR sequences. Leukoaraiosis refers to diffuse periventricular signal change seen in small vessel disease without discrete lesion orientation. A butterfly glioma involves the corpus callosum bilaterally. Metastases are typically at the gray-white matter junction and do not follow a perivenular orientation.

Reference: Grainger & Allison's Diagnostic Radiology, 7th ed.

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Written and medically reviewed by the StethoPrep medical team.