Male, 37 years old, with left-sided numbness, burning lesion noted on outside MRI. An oval, T2 hyperintense and mildly diffusion restricting lesion is evident within the white matter adjacent to the posterior body and atrium of the right lateral ventricle. The lesion measures 29 x 23 mm on axial images and has not significantly changed in overall size. On postcontrast images, this lesion demonstrates incomplete ring enhancement with the open end of the ring oriented away from the ventricle. The pattern of enhancement is similar to that seen on the prior examination, though it is somewhat better defined on today's study.The lesion exerts only mild local mass effect. The right lateral ventricle is of smaller caliber than the left but this is felt to be due to anatomic variation rather than the lesion as this asymmetry involves the entire ventricle.Multiple additional small foci of T2 hyperintensity are seen elsewhere in the periventricular regions. These are most notable in the left periatrial white matter.No evidence of any intracranial hemorrhage or significant susceptibility artifact is seen. No abnormal extra-axial collections are detected. Parenchymal enhancement is otherwise unremarkable.Single and multi voxel spectroscopic assessment of the dominant right periventricular lesion shows mildly to moderately reduced NAA, and mildly elevated choline. Portions of the lesion show significant lipid resonances along with a smaller quantity of lactate. No unusual resonances are identified. Normal-appearing tissue immediately adjacent to the lesion shows normal spectra or only mild alterations of the expected metabolite patterns.On perfusion imaging, relative CBV is reduced over a majority of the dominant lesion with only small scattered areas of elevated relative CBV along the periphery of the lesion.
A lesion is redemonstrated in the periventricular white matter along the right lateral ventricle which shows little significant interval change. Lesion location and morphology, and particularly the incomplete ring pattern of enhancement, along with the presence of additional smaller white matter lesions on the left, are most suggestive of a demyelinating process.The MR spectroscopic pattern of this lesion, while nonspecific, is compatible with a significant inflammatory process such as demyelination. The pattern is not supportive of a high-grade neoplastic process, and no specific features of either bacterial or fungal infection are seen. Perfusion imaging is reassuring for a benign process as a majority of the lesion demonstrates reduced rCBV. Alternate diagnostic considerations, including low-grade neoplasm or infection, are considered less likely at this time.