Intra‐ and interreader reproducibility of magnetic resonance imaging for quantifying the lipid‐rich necrotic core is improved with gadolinium contrast enhancement

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.

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).

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.

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. J. Magn. Reson. Imaging 2006. © 2006 Wiley‐Liss, Inc.