Intra- and interreader reproducibility of magnetic resonance imaging for quantifying the lipid-rich necrotic core is improved with gadolinium contrast enhancement.
OBJECTIVE
To test the hypothesis that intra- and interreader reproducibility for measuring the lipid-rich necrotic core (LR-NC) size is significantly improved with gadolinium (Gd) contrast-enhanced magnetic resonance imaging (CEMRI) compared to non-CEMRI.


METHODS
Thirty-seven individuals with >50% carotid artery stenosis underwent carotid MRI at 1.5T (pre- and postcontrast T1-weighted (T1W), T2-weighted (T2W), proton density-weighted (PDW), and three-dimensional time-of-flight (TOF) sequences). Two independent readers measured the mean area of the LR-NC from the precontrast images only, followed by a second measurement using the additional postcontrast images. One reader repeated the measurements after an interval of five months. Intra- and interreader reproducibility was analyzed by means of the intraclass correlation coefficient (ICC), coefficient of variation (CV), and standard deviation (SD).


RESULTS
The CV decreased from 33.7% to 8.8% for intrareader measurements of the LR-NC, and from 33.5% to 17.6% for interreader measurements. The SD was significantly smaller with CEMRI than with non-CEMRI (P = 0.003 and P = 0.006, respectively). The ICC increased from 0.94 to 0.99 and from 0.85 to 0.93 for the intra- and interreader measurements, respectively.


CONCLUSIONS
Reader reproducibility for in vivo MRI quantification of LR-NC size is significantly improved by the addition of Gd contrast in individuals with >50% carotid stenosis.
Takaya
Norihide
N
Department of Radiology, University of Washington, Seattle, Washington, USA.
Cai
Jianming
J
Ferguson
Marina S
MS
Yarnykh
Vasily L
VL
Chu
Baocheng
B
Saam
Tobias
T
Polissar
Nayak L
NL
Sherwood
Jane
J
Cury
Ricardo C
RC
Anders
Robert J
RJ
Broschat
Kay O
KO
Hinton
Denise
D
Furie
Karen L
KL
Hatsukami
Thomas S
TS
Yuan
Chun
C
D001158:Arteries / Q000473:pathology; D016893:Carotid Stenosis / Q000473:pathology; D003287:Contrast Media / Q000494:pharmacology*; D005682:Gadolinium / Q000494:pharmacology*; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D008055:Lipids / Q000737:chemistry*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D009336:Necrosis; D015588:Observer Variation; D015203:Reproducibility of Results
D003287:Contrast Media; D008055:Lipids; D005682:Gadolinium