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We have previously shown in studies of experimental animals that myocardium exhibits a cardiac cycle-dependent variation of integrated backscatter that reflects regional myocardial contractile performance and that is blunted promptly after arterial occlusion and recovers after reperfusion. To define the clinical utility of ultrasonic tissue characterization with integrated backscatter for detection of acute myocardial infarction and reperfusion, 21 patients (14 men and seven women) were studied in the cardiac care unit within the first 24 hours (mean time, 11.3 hours; range, 3.5-23.8 hours) after the onset of symptoms indicative of acute myocardial infarction with conventional two-dimensional and M-mode echocardiography and with analysis of integrated backscatter. The magnitude of cyclic variation of integrated backscatter was measured from several sites within acute infarct regions and normal regions remote from the infarct zone for each patient. The average magnitude of cyclic variation among all patients (n=21) was 4.8±0.5 dB in normal regions compared with 0.8±0.3 dB in infarct regions (p<0.05) within the first 24 hours after the onset of symptoms. Among the patients who had two studies, 15 (mean, 7.1 days; range, 2-31 days for second study) underwent coronary arteriography to define vessel patency. In patients with vessels with documented patency (n = 10), the magnitude of cyclic variation in infarct regions increased over time from 1.3±0.6 to 2.5±0.5 dB from the initial to final study (p<0.05). Patients with occluded infarct-related arteries (n=5) exhibited no significant recovery of cyclic variation (0.3±0.3-0.6+0.3 dB

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To determine whether quantitative ultrasound tissue characterization differentiates normal myocardial regions from segments of remote infarction, 32 consecutive patients with a diagnosis of previous myocardial infarction were evaluated. Images were obtained in real time with a modified two-dimensional ultrasound system capable of providing continuous signals in proportion to the logarithm of integrated backscatter along each A line. In 15 patients, adequate parasternal long-axis images that delineated both normal and infarct segments were obtained with standard time-gain compensation. Image data were analyzed to yield both magnitude and delay (electrocardiographic R wave to nadir normalized for the QT interval) of the cyclic variation of backscatter. Cyclic variation was present in 55 of 56 normal myocardial sites, averaging (mean +/- SEM) 3.2 +/- 0.2 dB in magnitude and exhibiting a mean normalized delay of 0.87 +/- 0.03. The magnitude of cyclic variation in infarct segments was significantly reduced to 1.1 +/- 0.2 dB (42 sites), and the delay was markedly increased to 1.47 +/- 0.12 (21 sites) (p less than 0.0001 for both). In 20 of 42 infarct sites, no cyclic variation was detectable. Thus, ultrasound tissue characterization quantitatively differentiated infarct segments from normal myocardium in patients with remote myocardial infarction.

tion of the pituitary activity by estrogenic substance extends to other pituitary hormones. Thus, in cases of climacteric thyrotoxicosis, Hoet and Gessler (4) were able to effect a reduction in the basal metabolic rate from around plus 50 to norrnal by injections of large amounts of estrogenic substance. It is probable that the thyrotoxicosis in these cases was due to increased production of thyrotropic hormone.The effect of injections of estrogenic substance in diabetic conditions has been tested both experimentally and clinically. Barnes, Regan and Nelson (5) and Nelson and Overholser (6) improved the sugar tolerance and definitely prolonged life in depancreatized dogs (5) and monkeys (6) by estrin injections. Attempts also have been made to influence human diabetes. In 1928 Rathery and Rudolf (7) and Carnot, Terris and Caroli (8) claimed to have produced improvement in diabetic women by injections of estrin. The doses employed were so minute, however, (10 units) that it is unlikely that the changes which occurred were due to the influence of this small amount of estrogenic substance. Mazer, Meranze and Israel (9) have come to the conclusion that the blood sugar level of normal women remains unaffected by injections of large doses of estrogenic substance, but that the blood and urine of diabetic women who are subjected to similar treatment will show an appreciable decrease in the sugar content. These workers give little detailed information concerning their 3 patients except for the fact that the maximum fall observed in the fasting blood sugar values was 60 mgm. per 100 cc. Jones and MacGregor (10) injected 10 non-diabetic women past the menopause with large doses of estrin without any effect on the blood sugar. In 1936 Collens, SloBodkin, Rosenbliett and Boas ( 11 ) gave 7 diabetic patients injections of estrogenic substance and came to the conclusion that this procedure had 715