Quantification of leg muscle perfusion using thallium-201 single photon emission computed tomography.

The purpose of this study is to quantify leg muscle perfusion with 201Tl single photon emission computed tomography (SPECT). Six normal controls and 21 patients with peripheral arterial disease underwent this examination. Thallium-201 leg SPECT of both stress and redistribution was performed using a dual-headed digital gamma camera. Each slice of transverse images was normalized with pixels and whole-body counts. In normal controls, the activity of posterior tibial muscle components was significantly higher than that of anterior tibial muscle components (p less than 0.001). In 14 components, where patients had insignificant lesions, profile curves were normal in 10 (71%). In 62 components, where patients had arteriographically significant lesions, stress profile curves were abnormal in 57 (92%) compared with normal controls. Approximately, in half (28/62) components which had significant lesions, profile curves showed redistribution after 3 hr compared with normal redistribution curves. In three patients who underwent successful bypass graftings, the activity of each muscle component returned to a normal range.

Myocardial SPECT and left ventricular performance study using a single Tc-99m teboroxime injection. Comparison with thallium-201 myocardial SPECT.

Myocardial SPECT using teboroxime was compared to thallium SPECT in 26 patients undergoing cardiac catheterization. Agreement between thallium SPECT and teboroxime SPECT for the identification of myocardial segments was 209/235 (89%). A significant correlation was found in 15 patients between the left ventricular ejection fraction by teboroxime first-pass study and the ejection fraction by contrast ventriculography. In nine patients with myocardial infarction and/or multivessel coronary artery disease, the ejection fraction revealed a mean decrease from 0.52 at rest to 0.46 at exercise. Teboroxime makes it possible to perform an exercise first-pass study of left ventricular ejection fraction followed by myocardial perfusion imaging.

[Evaluation of infantile ventricular tachycardia by 201Tl myocardial SPECT].

201Tl myocardial SPECT findings in infantile ventricular tachycardia (VT) were examined. The subjects were 4 cases of infantile VT subjected exercise-loading 201Tl scintigraphy in 1990. These cases (3 males and 1 female) were aged 11-14 years, being persistent and non-persistent type VT (2 cases each). Echocardiography revealed no abnormal findings in these 4 cases. Exercise-loading was performed by means of sitting ergometer. ECG revealed sinus arrhythmia except for one case which throughout its course of treatment, had already been presenting ventricular extrasystole from before the exercise-loading. Myocardial SPECT revealed persistent defects (anteroseptal wall defects in three case). The above suggests that 201Tl myocardial SPECT enables us to search for etiology of VT, prognosis and the like.

[Evaluation of the left ventricular myocardial infarction by Tc-99m cardiac pool SPECT and TI-201 myocardial SPECT--diagnoses in the inferior wall of the left ventricle and septum in the vicinity of the base of the heart].

Thallium-201 myocardial single photon emission computed tomography (myocardial SPECT) has been believed likely to miss lesions or false lesions in the inferior wall of the left ventricle and septum in the vicinity of the basis of the heart. In 35 patients having undergone both coronary arterio-angiography and contrast left ventriculography, technetium-99m cardiac pool SPECT synchronized with electrocardiography (cardiac pool SPECT) and myocardial SPECT were performed simultaneously. Both cinematographic and phase techniques were used for the cardiac pool SPECT. Visual and Bull's eye techniques were used for the myocardial SPECT. The rate of correct diagnoses made by myocardial SPECT was compared by site with that by cardiac pool SPECT. With the inferior wall of the left ventricle of diagnoses made by cinematographic and phase techniques of cardiac pool SPECT, 97.0% each was correct. The rates of accurate diagnoses made by visual and Bull's eye techniques of myocardial SPECT were 97.0 and 93.9%, respectively. The rate at which at least one of the SPECT methods was correct was 97.1%. With the septum, the corresponding rates of accurate diagnoses were 97.1, 94.3, 90.0, and 90.9%, with rate of 94.3% at least one of these two methods made correct diagnoses. In conclusion, for diagnosing infarcts of the septal wall of the basis, the cardiac pool SPECT is more accurate than myocardial SPECT.

Effect of diltiazem hydrochloride in essential hypertension.

A number of studies have shown short term hemodynamic and symptomatic improvement in patients with essential hypertension under treatment with diltiazem. The long-term efficacy of the oral calcium antagonist, diltiazem, remain to be established in patient studies. We evaluated this drug in 70 patients with WHO classification 1-3 hypertension. Diltiazem was tested alone in 25 patients, in combination with diuretics in 14 patients and other drugs in 31 patients with essential hypertension. The fall in blood pressure after oral diltiazem was maximum with 24 weeks and then the fall continued steadily with significant improvement as judged by subjective patients impression in each group. The efficacy ratio of diltiazem was 57.1% in remarkably effective cases, 22.9% in effective, 10% in moderately effective and 10% in not effective cases. And this efficacy ratio was most prominent in other drugs concomitant group, followed by the diltiazem monotherapy group and in the diuretic concomitant use group. We concluded the oral calcium antagonist, diltiazem, is effective in patients with essential hypertension, providing significant blood pressure and symptomatic benefit with long-term treatment.

Comparison of thallium-201 and technetium-99m teboroxime myocardial single photon emission tomography with coronary arteriography.

Myocardial single photon emission tomography (SPET) using technetium-99m teboroxime (teboroxime) was studied and the results compared with those of thallium-201(thallium) SPET and coronary arteriography in 19 patients. Resting teboroxime SPET was performed initially. Two hours later, exercise teboroxime SPET was performed. Exercise ergometer tests for both teboroxime and thallium were carried out in a supine position. The levels of exercise achieved for both tests were similar. Agreement for the identification of myocardial segments between thallium SPET and teboroxime SPET was 147/171(86%) (NS). When a significant stenosis was defined as greater than or equal to 75% or greater than or equal to 50%, agreement between two radiopharmaceuticals for the detection of diseased vessels was 89% (NS, k = 0.601) or 88% (NS, k = 0.713), respectively. In only 2/19 cases were inferior and posterior segments (3/171) difficult to interpret in teboroxime SPET due to hepatic activity. Thus, teboroxime SPET with a short data acquisition time resulted in a rapid completion for each study and had a good correlation with thallium SPET.