In vivo quantitative measurement of intact fibrous cap and lipid-rich necrotic core size in atherosclerotic carotid plaque: comparison of high-resolution, contrast-enhanced magnetic resonance imaging and histology.
BACKGROUND
Previous studies with contrast-enhanced magnetic resonance imaging (CEMRI) have shown that the fibrous cap (FC) in atherosclerotic carotid plaques enhances with gadolinium-based contrast agents. Conversely, the lipid-rich necrotic core (LR-NC), lacking both vasculature and matrix, shows no or only slight enhancement. The goal of this study was to assess whether CEMRI can be used to accurately measure the dimensions of the intact FC and LR-NC.


RESULTS
Twenty-one patients scheduled for carotid endarterectomy were imaged with a 1.5-T scanner. Precontrast images and CEMRI were obtained. One hundred eight locations with an intact FC were matched between MRI and the excised histology specimens. Quantitative measurements of FC length along the lumen circumference, FC area, and LR-NC area were collected from CEMRI images and histology sections. Blinded comparison of corresponding MR images and histology slices showed moderate to good correlation for length (r=0.73, P<0.001) and area (r=0.80, P<0.001) of the intact FC. The mean percentage LR-NC areas (LR-NC area/wall area) measured by CEMRI and histology were 30.1% and 32.7%, respectively, and were strongly correlated across locations (r=0.87, P<0.001).


CONCLUSIONS
In vivo high-resolution CEMRI is capable of quantitatively measuring the dimensions of the intact FC and LR-NC. These new parameters may be useful to evaluate plaque vulnerability and provide continuous variables for characterizing the intact FC and LR-NC in progression and regression studies.
Cai
Jianming
J
Department of Radiology, University of Washington, Seattle, WA, USA.
Hatsukami
Thomas S
TS
Ferguson
Marina S
MS
Kerwin
William S
WS
Saam
Tobias
T
Chu
Baocheng
B
Takaya
Norihide
N
Polissar
Nayak L
NL
Yuan
Chun
C
D000368:Aged; D000369:Aged, 80 and over; D050197:Atherosclerosis / Q000473:pathology*; D002340:Carotid Artery Diseases / Q000473:pathology*; D003287:Contrast Media; D005260:Female; D005682:Gadolinium; D006652:Histological Techniques; D006801:Humans; D008055:Lipids; D008279:Magnetic Resonance Imaging / Q000379:methods* / Q000592:standards; D008297:Male; D008875:Middle Aged; D009336:Necrosis; D015203:Reproducibility of Results
D003287:Contrast Media; D008055:Lipids; D005682:Gadolinium