| Discussion: |
Classically, the lesions of multiple sclerosis are periventricular, ovoid, and oriented perpendicularly to the ventricular surface. These are occasionally called Dawson fingers, after neuropathologist James Dawson, who identified the perivascular distribution of inflammatory cells and the resulting fingerlike appearance of affected veins and venules in MS brain tissues.
Inflammation and breakdown of the blood-brain barrier leads to hyperintensity on T2-weighted images, as seen here. The FLAIR technique dampens ventricular CSF signal, which brings out the contrast of the MS lesions.
In general, MRI is an essential and very sensitive tool in the diagnosis and management of MS. However, it is not a specific test for MS, as there are mimics of MS on MRI. These include: postviral encephalomyelitis, Lyme Disease, Behcet Syndrome, sarcoidosis, Sjogren's syndrome, progressive multifocal leukencephalopathy (PML), and others. Consequently, it is generally not advisable to make a firm diagnosis of MS on the basis of a single scan.