Evaluation of multicontrast MRI including fat suppression and inversion recovery spin echo for identification of intra-plaque hemorrhage and lipid core in human carotid plaque using the mahalanobis distance measure

• Published in: Magnetic resonance in medicine 2012-06, Vol.67 (6), p.1764-1775
• Main Authors: te Boekhorst, Bernard C., van 't Klooster, Ronald, Bovens, Sandra M., van de Kolk, Kees W., Cramer, Maarten J., van Oosterhout, Matthijs F., Doevendans, Pieter. A., van der Geest, Rob J., Pasterkamp, Gerard, van Echteld, Cees J.
• Format: Article
• Language: English
• Subjects: Adipose Tissue - pathology; Algorithms; Carotid Stenosis - complications; Carotid Stenosis - metabolism; Carotid Stenosis - pathology; Hemorrhage - complications; Hemorrhage - metabolism; Hemorrhage - pathology; Humans; Image Enhancement - methods; Image Interpretation, Computer-Assisted - methods; intra-plaque hemorrhage; lipid core; Lipid Metabolism; Magnetic Resonance Imaging - methods; MRI; Reproducibility of Results; rupture prone plaque; Sensitivity and Specificity; Spin Labels
• ISSN: 0740-3194; 1522-2594
• DOI: 10.1002/mrm.23191

Intra‐plaque hemorrhage (IPH) and lipid core, characteristics of rupture prone carotid plaques, are often visualized in vivo with MRI using T1 weighted gradient and spin echo, respectively. Increasing magnetic field strength may help to identify IPH and lipid core better. As a proof of concept, automatic segmentation of plaque components was performed with the Mahalanobis distance (MD) measure derived from image contrast from multicontrast MR images including inversion recovery spin echo and T1 weighted gradient echo with fat suppression. After MRI of nine formaldehyde‐fixated autopsy specimens, the MDs and Euclidean Distances between plaque component intensities were calculated for each MR weighting. The distances from the carotid bifurcation and the size and shape of calcification spots were used as landmarks for coregistration of MRI and histology. MD between collagen/cell‐rich area and IPH was largest with inversion recovery spin echo (4.2/9.3, respectively), between collagen/cell‐rich area/foam cells and lipid core with T1 weighted gradient echo with fat suppression (26.9/38.2/4.6, respectively). The accuracy of detection of IPH, cell‐rich area, and collagen increased when the MD classifier was used compared with the Euclidean Distance classifier. The enhanced conspicuity of lipid core and IPH in human carotid artery plaque, using ex vivo T1 weighted gradient echo with fat suppression and inversion recovery spin echo MRI and MD classifiers, demands further in vivo evaluation in patients. Magn Reson Med, 2011. © 2011 Wiley Periodicals, Inc.