Detection of acute myocardial infarction in closed-chest dogs by analysis of regional two-dimensional echocardiographic gray-level distributions.

Abstract

SUMMARY. We hypothesized that acute myocardial infarction could be detected in standard twodimensional echocardiograms of closed-chest dogs by evaluating regional echo amplitude distributions 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 closedchest 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). We conclude that acute myocardial infarction may be detected in closed-chest dogs by analyzing regional echo amplitude data from standard twodimensional echocardiograms (Circ Res 52: 36-44, 1983)

Ultrasonic tissue characterization of infarcted myocardium by scanning acoustic microscopy

“…The level at the interface between degenerated myocar-84 Ultrasound in Medicine and Biology Volume 23, Number 1, 1997 dium and fibrosis is calculated as -26.9 dB and is the greatest value among those considered in this study. The clinical echocardiography literature shows that strong echoes are observed at the area of scar in myocardial infarction (Parisi et al 1982;Scorton et al 1983 ) . The dB level of reflected power at the interface between fibrosis and the other tissue elements may be proposed as one of the origin of the strong echo in the myocardial scar.…”

“…Wall-motion abnormalities, during and after myocardial infarction, can be detected by M-mode echocardiography or by centerline analysis of the two-dimensional echocardiogram (Hikichi and Tanaka 198 la;Moinihan et al 1980;Parisi et al 1980). Ultrasonic tissue characterization of myocardium is also under development (Lattanzi et al 1991(Lattanzi et al , 1992Miller et al 1985;Milunski et al 1989;Mimbs et al 1977;Picano et al 1990Picano et al , 1993Scorton et al 1983). The need to evaluate local myocardial function has increased in proportion to the progress of interven- (Ellis et al 1995;Hannan et al 1994).…”

“…The need to evaluate local myocardial function has increased in proportion to the progress of interven- (Ellis et al 1995;Hannan et al 1994). Tissue characterization studies have been reported, e.g., the detection of the cyclic variation of ultrasonic backscatter (Barzilai et al 1990;Miller et al 1985;Milunski et al 1989; Mimbs et al 1977;Vered et al 1989), the analysis of the gray scale level of echography (Chandrasekaran et al 1989;Parisi et al 1982;Scorton et al 1983); and the analysis of echo intensity by changing the echo sensitivity (Hikichi et al 1981b;Tanaka et al 1977Tanaka et al , 1985. The results of these investigations suggest that the acoustic properties of infarcted myocardium can be different from the normal state.…”

Cardiogenic hypertension in maturing dogs.

“…In particular, echocardiographic estimates of stroke volume (SV) have been shown to correlate closely with dye dilution technique measurements. 10 ' u Hence, left ventricular end-diastolic volume (LVEDV) and end-systolic volume (LVESV) were calculated, from which SV was deduced (SV = LVEDV -LVESV). CO (SV x HR) and ejection fraction (SV/LVEDV x 100) were then derived.…”

Ultrasonic myocardial textural parameters and midwall left ventricular mechanics in essential arterial hypertension

“…Several studies have pointed out that, despite a normal or supernormal conventional fractional shortening, the midwall left ventricular mechanic is impaired. 3,4 Moreover, a quantitative analysis of the 'texture' of the echocardiographic images, 5,6 represents a useful approach which allows the use of the ultrasound myocardial tissue characterisation (quantitative texture analysis) in this and in other 7 fields of interest. Previously our studies have shown that several myocardial textural videodensitometric parameters are impaired in essential hypertensive patients.…”