Table 2.

Criteria for plaque assessment for reproducibility assessment

Not assessable

Too much artifact to adequately assess the arterial wall Congenitally hypoplastic artery that is too small to assess

No plaque

Wall thickening and enhancement on post-contrast T 1 VISTA not seen or appears within the lumen on T 1 pre-contrast, PD and/or TOF MRA No wall abnormality or stenosis Wall abnormality that does not appear to follow expected contours of the wall, i.e. spoke-like projection or extends linearly away from wall (likely due to CSF artifact or parenchyma TOF MRA shows luminal narrowing but no narrowing on IVW

Possible plaque

Wall thickening on pre- and post-contrast T 1 VISTA without stenosis/irregularity on TOF MRA Circumferential enhancement and/or wall thickening without stenosis involving proximal intradural vertebral artery and internal carotid artery (possibly vasa vasorum) Stenosis on TOF MRA and IVW without appreciable wall thickening For cavernous ICA, appreciable wall thickening on pre-contrast T 1 VISTA with similar lumen diameter on all sequences, without visualization of wall thickening or differentiation of the wall from surrounding cavernous sinus on post-contrast T 1 VISTA

Definite plaque

Stenosis or irregularity on luminal imaging with wall thickening on T 1 pre- and post-contrast VISTA Equivalent lumen diameter on MRA, pre and post contrast T 1 VISTA with stenosis or irregularity with wall thickening on pre- and post-contrast T 1 VISTA that shows differential signal from the surrounding cavernous sinus

CSF, cerebrospinal fluid; IVW, intracranial vessel wall; MRA, MR angiography; TOF, time of flight; VISTA, volume isotropic turbo spin echo acquisition.