The mass demonstrates mildly diminished cerebral blood flow on arterial spin labeling MR perfusion. The mass also demonstrates mildly diminished cerebral blood flow, decreased cerebral blood volume, and slightly prolonged mean transit time on dynamic
susceptibility contrast-enhanced perfusion imaging. There are no additional areas of altered cerebral perfusion in the brain.
Single voxel and multivoxel MR spectroscopy demonstrates decreased NAA within the lesion but no significant elevation of the choline to creatine ratio. An elevated myoinositol peak is evident at 3.6 ppm on the single voxel spectrum. In addition, there is
a small lactate peak at 1.3 ppm on the single voxel spectrum that inverts on the multivoxel spectrum suggestive of necrosis or anaerobic glycolysis.
2.2 cm x 1.5 cm right anterior frontal cortical and subcortical nonenhancing T2 hyperintense lesion with central FLAIR hyperintensity is stable compared to the April 2015 MRI. The mass demonstrates hypoperfusion and a normal choline to creatine ratio
indicative of hypometabolism and low cell turnover, respectively. In addition, MR spectroscopy suggests the presence of gliosis and anaerobic glycolysis such as can be seen with inflammation, necrosis, and cystic neoplasms. The differential diagnosis
remains the same and includes a low-grade glioma, atypical focal cortical dysplasia, and cystic encephalomalacia related to prior trauma or infection (such as neurocysticercosis).