Table 1:

Framework for diagnostic categorization of vessel wall MR imaging findings^a

VW-MR Imaging Category	Findings
Normal	Arterial wall is thin or imperceptible; no wall enhancement other than ± proximal intracranial internal carotid and vertebral arteries attributed to vasa vasorum
Intracranial atherosclerotic disease	Arterial wall is focally, eccentrically thickened; T2 prolongation ± enhancement immediately adjacent to the lumen and T2 shortening within the wall more peripherally; markers of disease activity include plaque enhancement and intraplaque hemorrhage
Arterial dissection	Arterial wall is eccentrically thickened; thickened wall has the signal characteristics of blood products; marker of disease activity is intramural signal characteristics of acute or subacute blood product
Vasculitis	Arterial wall is concentrically, homogeneously thickened and enhancing
Reversible cerebral vasoconstriction syndrome	Arterial wall is concentrically, homogeneously thickened with no (or mild) enhancement

^aAdapted from the consensus recommendations of the Vessel Wall Imaging Study Group of the American Society of Neuroradiology.⁹