Characterization of carotid plaque hemorrhage: a CT angiography and MR intraplaque hemorrhage study.
OBJECTIVE
The main objective of this study was to evaluate CT angiographic (CTA) features that are able to predict the presence of intraplaque hemorrhage (IPH) as defined by MR-IPH.


METHODS
One hundred sixty-seven consecutive patients (mean age 69 years, SD 12.8; 58 females) underwent both MR-IPH and CTA within 3 weeks. MR-IPH, the gold standard, was performed at 1.5 T using a neurovascular phased-array coil as a coronal T1-weighted 3-dimensional fat-suppressed acquisition. CTA was performed using a 4-slice or a 64-slice CT machine and evaluated, blinded to MR-IPH findings, for carotid stenosis, plaque density, and plaque ulceration. Plaque density was defined as the mean attenuation of plaque at the site of maximum stenosis and 2 sections above and below. Plaque ulceration was defined as outpouching of contrast into the plaque at least 2 mm deep on any single plane.


RESULTS
Prevalence of IPH increased at higher degrees of carotid stenosis. Mean CT plaque density was higher for plaques with MRI-defined IPH (47 Hounsfield units) compared with without IPH (43 Hounsfield units; P=0.02). However, significant overlap between distributions of plaque densities limited the value of mean plaque density for prediction of IPH. CTA plaque ulceration had high sensitivity (80.0% to 91.4%), specificity (93.0% to 92.3%), positive predictive value (72.0% to 71.8%), and negative predictive value (95.0% to 97.9%) for prediction of IPH. Interobserver agreement for presence/absence of CTA plaque ulceration was excellent (kappa=0.80).


CONCLUSIONS
CTA plaque ulceration, but not mean CTA plaque density, was useful for prediction of IPH as defined by the MR-IPH technique.
U-King-Im
Jean Marie
JM
Division of Neuroradiology, Department of Medical Imaging, Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada.
Fox
Allan J
AJ
Aviv
Richard I
RI
Howard
Peter
P
Yeung
Robert
R
Moody
Alan R
AR
Symons
Sean P
SP
D000368:Aged; D000369:Aged, 80 and over; D000792:Angiography; D002339:Carotid Arteries / Q000000981:diagnostic imaging*; D016893:Carotid Stenosis / Q000000981:diagnostic imaging*; D005260:Female; D006470:Hemorrhage / Q000000981:diagnostic imaging*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D012307:Risk Factors; D018709:Statistics, Nonparametric