Table 1. Summary of carotid vulnerable plaque components.

Plaque feature	MR appearance	Clinical significance
Lipid-rich necrotic core	1. T2 hypointense	1. Increasing LRNC is associated with the development of new ulceration, FC rupture, and increasing plaque burden
	2. Lack of contrast enhancement on CE-T1W images	2. Increasing LRNC is associated with fatal and nonfatal myocardial infarction, ischemic stroke, hospitalization for ACS, and need for revascularization
Fibrous cap	Intact:	1. Thin/ruptured FC is associated with higher risk of future stroke/TIA
	1. Enhancing band adjacent to dark lumen	2. Thin/ruptured FC is also associated with fatal and nonfatal myocardial infarction, ischemic stroke, hospitalization for ACS, and need for revascularization
	2. Smooth luminal surface on TOF and CE-T1W
	Thin:
	1. Loss of enhancing band
	2. Persistent smooth luminal surface
	Ruptured:
	1. Disrupted, dark band on CE-T1W
	2. Irregular luminal surface
Intraplaque hemorrhage	1. High signal on all T1W sequences including MPRAGE, TOF, and FSE	1. Presence of IPH is a predictor of future ipsilateral stroke
	2. Typically within LRNC, but may be seen adjacent to calcifications	2. IPH is associated with plaque progression, with new IPH suggesting transition from stable to unstable plaque
		3. Presence of IPH is a predictor of stroke in patients status post TIA

CE-T1W, contrast-enhanced T1 weighted image; LRNC, lipid-rich necrotic core; ACS, acute coronary syndrome; TOF, time-of-flight MR angiography; IPH, intraplaque hemorrhage.