Table 2.

A overview of different plaque components, their clinical significance, and preferred imaging modality

Plaque feature	Pathophysiological impact	Feature of plaque vulnerability	Preferred imaging modality	Reported in clinical practice
Type of plaque	See below for comments on specific components		CT	Yes
Fibrous cap	Thinning of the fibrous cap increases the risk of plaque rupture	++	MR	No
Calcifications	While overall considered a sign of a plaque stability, conversely the type and chemical composition of calcium in atheromatous plaques can potentially increase plaque vulnerability	(debated)	CT	Yes
Intraplaque hemorrhage	Most important imaging biomarker for plaque instability. It is independent of stenosis severity, associated with acute events, and also with an increased risk for ipsilateral future ischemic events in both symptomatic and asymptomatic subjects.	+++	MR	Yes
Plaque ulceration	Presence of ulcerations is associated with cerebrovascular events	++	CT	Yes
Lipid-rich necrotic core	An increased amount of intraplaque lipid is associated with elevated cerebrovascular risk.	++	MR	Yes
Maximum Wall thickness	Maximum plaque thickness (measured in mm) is a predictor of cerebral ischemic events	+	CT/MR	Research setting
Plaque volume	Larger volume is associated with increased vulnerability and occurrence of future cerebrovascular events	+	CT>MR	Research setting
Plaque neovascularisation	Denser vasa vasorum network is associated with symptomatic disease	+	CT/MR	Research setting
Plaque- and perivascular fat inflammation	Inflammation is associated with cerebrovascular events	+++	18F-FDG PET-CT / MR	Research setting
Plaque remodelling	Remodelling refers to cross-sectional vessel area changes in reaction to atherosclerotic changes. Inadequate outward (positive) eccentric remodelling is associated with symptomatic disease and increased ipsilateral cerebrovascular events.	++	CT/MR	Yes