Case 4

This is an MRI brain study, showing innumerable FLAIR hyperintense, ovoid or rounded white matter lesions with a generalized distribution throughout both cerebral hemispheres in a generalized, fairly symmetrical distribution. They are found in the subcortical, deep and periventricular white matter, corona radiata, internal and external capsules, and cerebellar hemispheres. The lesions are most concentrated at the calloso-septal interface, where they have an elliptical shape with an orientation perpendicular to the lateral ventricles. A few lesions demonstrate avid ring and open ring enhancement on the post-gadolinium series sequence.

These features are highly characteristic of multiple sclerosis; the enhancing lesions indicate active inflammation.

The differential diagnosis includes small vessel chronic ischemia with leukoariaosis- however, this would not enhance at all, and the lesion morphology and locations are atypical for this disease.