Intracranial vessel wall lesions on MRI: anatomical and pathological issues

Vessel Wall Imaging (VWI) is a Magnetic Resonance (MR) technique whose employment is more and more frequent for investigating intracranial arterial diseases. This is mainly due to its potential to see beyond the arterial luminal stenosis giving information on the arterial walls. This promising role could help to distinguish among several causes of intracranial arteriopathies (atherosclerosis, vasculitis, Moyamoya, etc.) and to predict the instability of plaques and aneurysms.

In this review, the main technical issues and potential source of misinterpretation of VWI were analyzed and the data provided by the literature on pathological validation of these findings were critically proposed, in order to better define the limitations and the future potential of this method.

Only in isolated cases the main findings of VWI were validated against histopathology and in several diseases, there is not a pathological validation of the interpretation of abnormal findings of VWI technique.

The lack of a pathological substrate underlying wall contrast enhancement and wall thickening (two of the most characterizing aspects of this technique) makes difficult to rely only on this technique for drawing a conclusive diagnosis.