Quantitative evaluation of carotid plaque composition by in vivo MRI.
OBJECTIVE
This study evaluates the ability of MRI to quantify all major carotid atherosclerotic plaque components in vivo.


RESULTS
Thirty-one subjects scheduled for carotid endarterectomy were imaged with a 1.5T scanner using time-of-flight-, T1-, proton density-, and T2-weighted images. A total of 214 MR imaging locations were matched to corresponding histology sections. For MRI and histology, area measurements of the major plaque components such as lipid-rich/necrotic core (LR/NC), calcification, loose matrix, and dense (fibrous) tissue were recorded as percentages of the total wall area. Intraclass correlation coefficients (ICCs) were computed to determine intrareader and inter-reader reproducibility. MRI measurements of plaque composition were statistically equivalent to those of histology for the LR/NC (23.7 versus 20.3%; P=0.1), loose matrix (5.1 versus 6.3%; P=0.1), and dense (fibrous) tissue (66.3% versus 64%; P=0.4). Calcification differed significantly when measured as a percentage of wall area (9.4 versus 5%; P<0.001). Intrareader and inter-reader reproducibility was good to excellent for all tissue components, with ICCs ranging from 0.73 to 0.95.


CONCLUSIONS
MRI-based tissue quantification is accurate and reproducible. This application can be used in therapeutic clinical trials and in prospective longitudinal studies to examine carotid atherosclerotic plaque progression and regression.
Saam
T
T
Department of Radiology, University of Washington, Seattle, Wash, USA.
Ferguson
M S
MS
Yarnykh
V L
VL
Takaya
N
N
Xu
D
D
Polissar
N L
NL
Hatsukami
T S
TS
Yuan
C
C
D000368:Aged; D002340:Carotid Artery Diseases / Q000473:pathology*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity