Detection of Acute Myocardial Infarction in Closed- Chest Dogs by Analysis of Regional Two-Dimensional Echocardiographic Gray-Level Distributions

• Published in: Circulation research Vol. 52; no. 1; pp. 36 - 44
• Main Authors: Skorton, David J, Melton, Hewlett E, Pandian, Natesa G, Nichols, Jim, Koyanagi, Samon, Marcus, Melvin L, Collins, Steve M, Kerber, Richard E
• Format: Journal Article
• Language: English
• Published: United States American Heart Association, Inc 01.01.1983
• Subjects: Animals; Dogs; Echocardiography - methods; Image Enhancement - methods; Mathematics; Myocardial Infarction - diagnosis; Myocardial Infarction - pathology
• ISSN: 0009-7330; 1524-4571
• DOI: 10.1161/01.res.52.1.36

We hypothesized that acute myocardial infarction could be detected in standard two-dimensional echocardiograms of closed-chest dogs by evaluating regional echo amplitude distribu-tions using computerized image analysis. We tested this hypothesis by performing standard, 2.4 MHz two-dimensional echoes before and 2 days after circumflex coronary occlusion in seven closed-chest dogs. Control and infarcted regions of interest were studied in digitized stop-frame images. Average gray level was calculated for each region of interest, and the shape of the gray-level distribution was analyzed by calculation of skewness and kurtosis and by qualitative features of shape. Average gray level increased significantly from the pre-to postocclusion images in the infarcted regions (16.7 ± 4.2 vs. 32.4 ± 4.4 units, P < 0.01), but not in the control regions (17.4 ± 4 vs. 22.3 ± 5.5., P = NS). Average gray level could not distinguish between infarcted and normal regions within the postocclusion images (36 ± 5.2 vs. 33.6 ± 5.8, P = NS). Three independent observers qualitatively evaluated histogram shape and correctly identified 7/7 MI regions (100% sensitivity) and 14/20 normal regions (70% specificity). Quantitatively, infarct regions exhibited a significant decrease in kurtosis (2.8 ± 0.9 to 0.44 ± 0.5, P < 0.01); the normal regions showed no significant change in kurtosis from pre-to postocclusion images (7.1 ± 4.0 vs. 5.2 ± 2.9, P = NS). Within postocclusion images, infarcted regions displayed a significantly lower kurtosis than did normal regions (0.27 ± .47 vs. 2.5 ± 1.0, P < .01).