Association between carotid plaque characteristics and subsequent ischemic cerebrovascular events: a prospective assessment with MRI--initial results.
OBJECTIVE
MRI is able to quantify carotid plaque size and composition with good accuracy and reproducibility and provides an opportunity to prospectively examine the relationship between plaque features and subsequent cerebrovascular events. We tested the hypothesis that the characteristics of carotid plaque, as assessed by MRI, are possible predictors of future ipsilateral cerebrovascular events.


METHODS
A total of 154 consecutive subjects who initially had an asymptomatic 50% to 79% carotid stenosis by ultrasound with > or =12 months of follow-up were included in this study. Multicontrast-weighted carotid MRIs were performed at baseline, and participants were followed clinically every 3 months to identify symptoms of cerebrovascular events.


RESULTS
Over a mean follow-up period of 38.2 months, 12 carotid cerebrovascular events occurred ipsilateral to the index carotid artery. Cox regression analysis demonstrated a significant association between baseline MRI identification of the following plaque characteristics and subsequent symptoms during follow-up: presence of a thin or ruptured fibrous cap (hazard ratio, 17.0; P< or =0.001), intraplaque hemorrhage (hazard ratio, 5.2; P=0.005), larger mean intraplaque hemorrhage area (hazard ratio for 10 mm2 increase, 2.6; P=0.006), larger maximum %lipid-rich/necrotic core (hazard ratio for 10% increase, 1.6; P=0.004), and larger maximum wall thickness (hazard ratio for a 1-mm increase, 1.6; P=0.008).


CONCLUSIONS
Among patients who initially had an asymptomatic 50% to 79% carotid stenosis, arteries with thinned or ruptured fibrous caps, intraplaque hemorrhage, larger maximum %lipid-rich/necrotic cores, and larger maximum wall thickness by MRI were associated with the occurrence of subsequent cerebrovascular events. Findings from this prospective study provide a basis for larger multicenter studies to assess the risk of plaque features for subsequent ischemic events.
Department of Radiology, University of Washington, Seattle, WA, USA.
Norihide
N
Takaya
Chun
C
Yuan
Baocheng
B
Chu
Tobias
T
Saam
Hunter
H
Underhill
Jianming
J
Cai
Nam
N
Tran
Nayak L
NL
Polissar
Carol
C
Isaac
Marina S
MS
Ferguson
Gwenn A
GA
Garden
Steven C
SC
Cramer
Kenneth R
KR
Maravilla
Beverly
B
Hashimoto
Thomas S
TS
Hatsukami
D000368:Aged; D000369:Aged, 80 and over; D002339:Carotid Arteries / Q000473:pathology; D016893:Carotid Stenosis / Q000175:diagnosis / Q000473:pathology*; D005260:Female; D006801:Humans; D007511:Ischemia / Q000473:pathology; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D016017:Odds Ratio; D016016:Proportional Hazards Models; D011446:Prospective Studies; D012044:Regression Analysis; D012307:Risk Factors; D013997:Time Factors; D016896:Treatment Outcome; D014465:Ultrasonics