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Biomedical subjects

H S Hecht

Publications and source records attributed to H S Hecht.

46 records · Page 3Linked to original sources
PubMed1981

Biplanar cardiac blood-pool tomography.

Dynamic transverse axial wall tomograms of the left ventricle (LV) are reconstructed by a new technique from anterior and LAO views acquired with a conventional scintillation camera imaging the distribution of in-vivo Tc-99m-labeled red blood cells. By confining reconstruction to the singular contiguous uniform concentration of activity in the LV, the requisite angular samplings for a given level of accuracy are substantially reduced in this restricted form of emission computed tomography (ECT). Static phantom studies using a series of volumes having various cross-sectional dimensions demonstrate tomographic edge reconstruction with less than or equal to 12% rms radial error. The dynamic cardiac ECT is demonstrated in a series of representative patient studies by reconstruction of wall tomograms in the end-diastolic and end-systolic phases of the 28-frame cardiac cycle. In contrast to the conventional dual multiframe projection views, the motion tomograms derived from the reconstructions clearly show the complete three-dimensional perspective of wall displacement.

Heart↗
PubMed1978

Left-ventricular ejection fraction and segmental wall motion by peripheral first-pass radionuclide angiography.

A computerized edge-detection method was developed to obtain radionuclide ventriculograms for analysis of left-ventricular ejection fraction and segmental wall motion from first-pass studies following i.v. injection of radionuclide. The accuracy of this technique was examined in 21 patients undergoing cardiac catheterization. Tc-99m DTPA was injected into an antecubital vein, with data acquisition in the 30 degrees RAO projection by a gamma scintillation camera interfaced to a computer. A computerized profile analysis was used to determine objectively the edge of the left-ventricular blood pool. Time-activity curves were generated, and the ejection fraction was calculated from sequential end-diastolic and end-systolic count rates. The values for ejection fraction correlated well with those obtained by single-plane contrast ventriculography (r = 0.95). End-diastolic and end-systolic images were reconstructed from the time-activity curve. To analyze segmental wall motion, the left-ventricular outline was divided into five segments and the motion of each segment was graded qualitatively from 1 to 5. Seventy-five of 105 segments had the same grade as the wall motion determined by contrast angiography, and 102 of 105 were within one grade. (P less than 0.001). These findings demonstrate the accuracy of this improved technique for objective, rapid, and noninvasive determination of left-ventricular function.

Adult↗
PubMed1975

Role of the coronary collateral circulation in the preservation of left ventricular function.

An angiographic assessment of the coronary arteries, the presence and quality of arterial collateralization and segmental left ventricular (LV) wall motion indicated that (a) in the presence of total or subtotal obstruction of a coronary artery, there was a significantly higher incidence of normal motion (p less than 0.001) if the segment of LV wall was supplied by good rather than poor collaterals, and (b) normal wall motion with good arterial collateralization was not associated with abnormal Q waves. It is concluded that a positive correlation exists between the quality of collateral filling and the preservation of LV wall motion in the area supplied.

Cardiac Output↗
PubMedDate not supplied

Supine bicycle stress echocardiography: peak exercise imaging is superior to postexercise imaging.

The abilities of peak exercise (PEAK) stress echocardiography versus postexercise (POST) stress echocardiography to detect coronary artery disease were evaluated in 136 consecutive patients undergoing supine bicycle stress echocardiography and coronary arteriography: 42 (31%) had normal coronary vessels, 38 (28%) had single-vessel disease, 34 (25%) had double-vessel disease, and 22 (16%) had triple-vessel disease. The results were as follows: (1) For detection of disease in the group of patients, sensitivity of PEAK versus POST was 94% versus 83% (p < 0.01) and specificity was 88% versus 90%. (2) For detection of disease in specific vessels, sensitivity of PEAK versus POST was 90% versus 72% (p < 0.0001) and specificity was 89% versus 92%. (3) For evaluation of the three major coronary arteries, sensitivity of PEAK versus POST was 96% versus 85% (p < 0.05) for the left anterior descending artery, 90% versus 65% (p < 0.01) for the right coronary artery, and 79% versus 60% (p < 0.05) for the left circumflex coronary artery. There were no differences in specificity. (4) The percent diameter stenosis of vessels normalizing from PEAK to POST versus vessels abnormal at PEAK and POST was 80.6% +/- 16% versus 85.9% +/- 14%, p = 0.07. There were no differences in exercise parameters between patients with and without resolution from PEAK to POST. (5) PEAK versus POST accuracy for identification of patients with multivessel disease was 93% versus 68% (p < 0.001). We conclude that stress echocardiography performed during peak exercise is superior to postexercise stress echocardiography.

Coronary Angiography↗
PubMedDate not supplied

Supine bicycle stress echocardiography versus tomographic thallium-201 exercise imaging for the detection of coronary artery disease.

To compare the accuracy of supine bicycle stress echocardiography (SBSE), a new technique for evaluating coronary disease during peak exercise, with tomographic thallium-201 exercise imaging (SPECT), 71 patients were evaluated by SBSE, SPECT, and coronary arteriography. Twenty patients had normal coronary vessels; 22 had single-vessel, 14 had double-vessel, and 15 had triple-vessel disease. There were no differences in sensitivity (90% vs 92%), specificity (80% vs 65%), and accuracy (87% vs 85%) between SBSE and SPECT for the group of 71 patients. The results were similar in patients with and without prior myocardial infarction and with single-, double-, or triple-vessel disease. There were no differences between SBSE and SPECT for disease detection for the group of 213 individual vessels in sensitivity (88% vs 80%), specificity (87% vs 84%), and accuracy (88% vs 82%), but SBSE was more sensitive for the left anterior descending artery (97% vs 82%, p < 0.005) and for arteries involved in triple-vessel disease (93% vs 69%, p < 0.01) and more specific for the right coronary artery (88% vs 66%, p < 0.01). Supine bicycle exercise was associated with significantly lower maximal heart rates than treadmill exercise but with significantly higher systolic and diastolic blood pressures. There were no differences in heart rate x systolic blood pressure. We conclude that SBSE and SPECT are equally reliable for coronary disease detection in patients and for evaluation of disease in specific arteries with the exception of SBSE's higher sensitivity for the left anterior descending artery and arteries involved in triple-vessel disease and higher specificity for the right coronary artery.

Coronary Disease↗