Which sequence is the most illustrative in order to distinguish a fibroblastic meningioma from an angioblastic one?
The T2 weighted Spin-Echo sequence is the one that allow to distinguish between different patterns of meningiomas. In this particular case, a fibroblastic meningioma is mainly hypointense to the cerebral cortex, while an angioblastic one is hyperintense to the cerebral cortex.
Why is the signal so different between the SWI and the contrast enhanced SWI?
This is an aspect we are currently evaluating, but we found evidence in the literature that assume that hyperintensity in SWI C+ means EEB damage, while and an hypointense brink can be indicative of neovascularization.
FLAIR and TSE-T2w axial and coronal images show compression of frontal horns and midline 7 millimeters left shift caused by double extra-axial masses.
The first one (LL axis 7,5 centimeters, CC axis 5,5 centimeters, AP axis 5,5 centimeters) develops bilaterally from anterior falx in median anterior frontal region; it appears slightly hyperintense in T2 weighted images, hysointense to the sorrounding cerebral parenchyma in FLAIR images and contains a calcific component well depicted by SWI images; CBF and CBV maps and values show focal hyperperfusion, confirmed by the colorimetrics pASL maps. This finding is thereby a match for a fibroblastic meningioma.
The second one (LL axis 5 centimeters, CC axis 4,8 centimeters, AP axis 5,7 centimeters) shows marked hyperintensity in T2w and FLAIR images, poor calcific component in SWI images, wide right dural fronto-parietal attachment with patchy enhancement and dural tail in Gd-T1w images, strong neovascularization and high values of CBV and CBF in DSCpMR and in the colorimetric pASL maps. These findings suggested a diagnosis of angioblastic meningioma.
TOF-MRA shows antero-posterior and dislocation of both ACAs and pericallosal arteries.