Male, 59 years old, with right MCA stroke, evaluate for penumbra. On perfusion imaging, markedly reduced relative cerebral blood volume and blood flow are seen corresponding to the area of restricted diffusion involving the right middle frontal gyrus, operculum and insula. The region of elevated time-to-peak and mean transit time is, however, significantly larger than the infarct core, encompassing a majority of the right MCA territory.FLAIR signal abnormality within the infarct core is not significantly changed in geographic extent. Scattered additional foci of white matter T2 hyperintensity are also unchanged. As before, there may be mild effacement of the right lateral ventricle, but no significant generalized mass effect is seen.On postcontrast images, there is prominence of sulcal vascularity throughout the right cerebral hemisphere possibly representing compensatory vasodilatation and/or collateralization. No pathologic enhancement is detected. A nodular enhancing structure within the left lateral ventricle is unchanged from 2010 likely representing a venous varix or venous aneurysm of doubtful clinical significance.
rCBV and rCBF mapping demonstrate findings compatible with completed infarction involving the right middle frontal gyrus, operculum and insula, corresponding very well with the area of restricted diffusion on prior MRI. MTT and TTP mapping, however, demonstrate a penumbra of compromised perfusion which is significantly larger than the infarct core, encompassing a majority of the right MCA territory.