Search

Purpose: The authors wanted to identify those patients assessed by exercise SPECT in whom the quantification of lung Tl-201 uptake helps to evaluate disease prognosis., Methods: One hundred forty-nine patients (114 men, 35 women; 74 after myocardial infarction [MI]; mean age, 54 +/- 9 years) underwent exercise Tl-201 SPECT. The SPECT patterns were divided into normal (n = 45), fixed defects (n = 29), and inducible ischemia (n = 75). Anterior planar imaging was performed before SPECT acquisition to calculate the lung-to-heart ratio (L:H)., Results: During an average follow-up of 20 +/- 9 months, eight patients had died of cardiac causes and 13 patients experienced nonfatal MIs. Among the 45 patients with normal perfusion, no cardiac event was observed and the L:H ratio was not helpful for risk stratification. In 29 patients with fixed defects, four cardiac deaths occurred (all in patients with L:H ratios >0.5; annual event rate, 21.1% for L:H ratios >0.5 compared with 0% for L:H ratios <0.5; chi-square = 4.07, P < 0.05). Among the 75 patients with ischemia, 4 died and 13 had nonfatal MIs (annual event rate, 15.4% for L:H ratios >0.5 compared with 13% for L:H ratios <0.5; P = NS)., Conclusions: These findings suggest a benign prognosis in patients with normal SPECT (regardless of the L:H ratio). Conversely, all patients with ischemia are at high risk for future cardiac events. Quantification of the Tl-201 lung uptake seems to be valuable in evaluations of disease prognosis, especially in patients with fixed defects.

Objective: To assess the prognostic value of SPECT in patients with diabetes (DM) and without DM., Method: A total of 366 patients (104 women, 262 men) were examined by T1 +/- 201 or Tc-99m-MIBI SPECT of the myocardium. DM was recorded in 149 patients, 217 patients did not suffer from DM. The SPECT findings were classified as normal and abnormal perfusion (fixed or reversible perfusion defect). A serious cardiac event was defined as sudden cardiac death or non-fatal myocardial infarction. Also angina pectoris requiring revascularization was recorded., Results: During the average investigation period of 24 +/- 7 months we recorded in 147 patients with a normal load perfusion only one non-fatal myocardial infarction and the risk of a serious cardiac event was low: 0.3% per annum in the whole group. A significantly higher incidence of a severe cardiac event, 5.9% per year, was recorded in 219 patients with an abnormal finding on SPECT (10 deaths and 16 non-fatal myocardial infarctions, P < 0.01). On comparison of the frequency of serious cardiac events in groups of patients with and without DM no significant difference was found as regards normal load perfusion of the heart muscle (1.1% vs. 0%, P = NS) even in patients with an abnormal SPECT finding (5.8% vs. 6.1, P = NS)., Conclusion: SPECT myocardial perfusion makes it possible to stratify the risk in patients with DM similarly as proved previously in non-selected groups. Similarly as in patients without DM normal perfusion in diabetic patients predicts a benign prognosis.

Purpose: The authors assessed the prognostic value of stress myocardial perfusion tomographic imaging (SPECT) in patients with recurrent angina or inconclusive results of exercise electrocardiographic tests after successful percutaneous transluminal coronary angioplasty (PTCA)., Materials and Methods: After PTCA, 70 patients (54 men, 16 women; 41 after myocardial infarction; mean age, 56 +/- 9 years) underwent TI-201 or Tc-99m sestamibi SPECT studies. SPECT patterns were divided into normal (n = 25), fixed defects (n = 15), and reversible or combined fixed plus reversible defects (n = 30). A cardiac event was defined as either cardiac death, nonfatal myocardial infarction, or unstable angina requiring further revascularization., Results: During an average follow-up of 25 +/- 10 months, two patients had severe outcomes (one cardiac death and one nonfatal myocardial infarction), and revascularization was required in 13 patients. In patients with normal SPECT or fixed defects, the annual event rate was low (1.2%), with only one revascularization. In patients with reversible or combined defects, the annual event rate was significantly greater (22.4%; chi square = 17.32, P = 0.00003)., Conclusions: Normal perfusion or fixed defects predict a benign prognosis in patients after successful PTCA. The presence of stress-induced reversible defects appears to be the best predictor of future cardiac events.

The sensitivity and specificity of a myocardial perfusion single-photon emission tomography (SPECT) for the detection of the coronary artery disease (CAD) was investigated. As a gold standard the coronary angiography was used--the stenosis of the artery by 50% and more was considered as significant for CAD. After performing SPECT studies patients were examined by coronary angiography according to the attending physician's judgement. In the retrospectively created group of 123 subjects (94 males and 29 females, mean age 53 years, range 30-69 years) 55 patients underwent myocardial infarction (MI). The stress was performed using a bicycle ergometer or, in case of patient's inability, an intravenous dipyridamole infusion. Before december 1995 201T1 was used in all patients, after this date only in patients with prior MI with regard to the advantage of this radionuclide for the detection of the ischemic but viable myocardium. Other patients were administered 99mTc-tetrofosmin. In our group of patients we found the high sensitivity of myocardial SPECT of 94.5% 86 (from 91), specificity of 84.4% (27 from 32) corresponding to usually values and the high diagnostic accuracy of 91.9% (113 from 123). Specificity can be impaired by marked attentuation of gamma-rays by overlying soft-tissue structures such as the breast or diaphragm. The artificial imaging of the inferior wall due to the infradiaphragmatic structures represents the most serious problem-there were four false positive findings in our group; further ones in our 99mTc-tetrofosmin studies were avoided by the routine use of the prone position recommended in the literature. The validity of SPECT myocardial perfusion findings should be verified by coronary angiography; however, one must be aware of some questionable points inherent in this comparison.

The authors designed and constructed device simulating the activity of the heart, based on periodic filling and emptying two rubber blowers a radioactive solution by means of two pistons in cylinders operated by two specially shaped cams. The phantom enables to control the correctness of the method and a computer programme for evaluating parameters of heart activity (ejection fraction, end-diastolic volume, pulse volume etc.) in balanced ventriculography performed by a scintillation camera coupled with a computer. The performed measurements have shown a very good agreement of the evaluated parameters with those set at the phantom. The designed device is of an original construction and was granted the author's certificate No. 238,298.