Seizure. Follow-up of brain lesion. New daily persistent headache. The poorly defined increased T2 signal lesion involving the mesial right temporal lobe (both the amygdala and the hippocampus) has improved since the previous examination. Both the bulkiness of this tissue and the degree of T2 signal abnormality have diminished, particularly within the amygdala, with some reexpansion of the right temporal horn. Minimal enhancement within this lesion seen on the prior examination has resolved.However, there are 2 new small foci of contrast enhancement: one situated in the anteromedial aspect of the right temporal lobe (see image 123 series 1101) and one in the right subinsular region (see image 175 series 1101). Both lesions correlate with focal T2 hyperintensity which also was not present previously. Neither lesion is associated with diffusion restriction. On single voxel MR spectroscopy (TE 35 ms), there is a decreased NAA peak within the right mesial temporal lobe lesion, with no significant change in the other major metabolites when comparison is made to the contralateral normal side. Single voxel spectroscopy was also performed of the right subinsular lesion which shows minimal if any elevation of the choline peak relative to the contralateral side and an otherwise normal pattern.There is new diffuse increased sulcal contrast enhancement, most pronounced in the right cerebral sulci, best visualized on the postcontrast FLAIR sequences (see series 1601). These findings probably reflect a combination of hyperemia and increased sulcal vascular permeability.The remainder of the brain is free of significant abnormalities. The dural venous sinuses and major intracranial arterial flow voids are preserved. There is a small retention cyst in the right maxillary sinus. There is mild right ethmoid mucosal thickening.
1.Compared to the previous examination of November 2015, the abnormal signal and mild expansion involving the mesial right temporal lobe have improved, and a small focus of enhancement seen previously within this lesion has resolved. MR spectroscopy of this lesion shows no evidence of a high-grade proliferative process, but rather, is suggestive of parenchymal injury and some neuronal loss.2.However, two new foci of T2-hyperintensity and contrast enhancement have developed in the anterior medial right temporal lobe and right subinsular region. MR spectroscopy of the subinsular lesion shows minimal if any choline elevation with an otherwise normal pattern which is nonspecific.3.New diffuse, predominantly right supratentorial sulcal contrast enhancement is probably reflective of hyperemia and increased regional vascular permeability suggesting the presence of an inflammatory process. 4.While a neoplastic process cannot be entirely excluded, the combination of improved mesial temporal signal abnormality and edema with development of new foci of contrast enhancement as well as signs of diffuse supratentorial hyperemia are more in favor of an inflammatory process. An encephalitic process should be considered including autoimmune or limbic encephalitis. In particular, anti-NMDA receptor encephalitis has been shown to present similarly.