Quantitative assessment of myocardial scar in delayed enhancement magnetic resonance imaging

• Published in: Journal of magnetic resonance imaging 2003-10, Vol.18 (4), p.434-441
• Main Authors: Setser, Randolph M., Bexell, Daniel G., O'Donnell, Thomas P., Stillman, Arthur E., Lieber, Michael L., Schoenhagen, Paul, White, Richard D.
• Format: Article
• Language: English
• Subjects: cardiac MRI; chronic ischemic heart disease; chronic myocardial infarction; delayed enhancement MRI; Humans; image processing; Image Processing, Computer-Assisted; Magnetic Resonance Imaging - methods; Middle Aged; Myocardial Infarction - pathology; Myocardial Ischemia - pathology; Myocardium - pathology; Observer Variation
• ISSN: 1053-1807; 1522-2586
• DOI: 10.1002/jmri.10391

Purpose To characterize the extent and distribution of left ventricular myocardial scar in delayed enhancement magnetic resonance imaging (MRI). Materials and Methods Delayed enhancement images from 18 patients were categorized into three groups based on myocardial scar appearance: discrete myocardial infarction (N = 10), diffuse fibrosis (N = 4), and circumferential endocardial scarring (N = 4). Images were segmented manually by two observers (twice by one observer) to identify nonviable myocardium. Scar was characterized by the following morphologic parameters: the relative area of nonviable myocardium (Percent Scar); a measure of scar cohesion (Patchiness); and the extent to which scar traversed the ventricle wall (Trans>50). Results The three scar parameters successfully discriminated between patient groups, although no one parameter was able to differentiate between all groups. The average bias between readers was approximately 3% for each parameter, and the average bias between repeated measurements was 1%. In addition, five patients exhibited regions of nonhyperenhanced nonviable myocardium that were expected to show hyperenhancement based upon their location within the infarct zone and appearance on cine images. Conclusion Quantitative characterization of myocardial scar showed good interobserver and intraobserver agreement. However, the appearance of nonhyperenhanced scar in chronic ischemia is problematic for segmentation of delayed enhancement images. J. Magn. Reson. Imaging 2003;18:434–441. © 2003 Wiley‐Liss, Inc.