Stress 201Tl Research Articles

Effects of nicardipine on chronic stable effort angina: a non-invasive assessment.

The effects of 60 mg/day nicardipine hydrochloride were evaluated in a 4-week single-blind study on 12 patients with chronic stable effort angina. All patients completed the treatment with few reports of adverse effects. Nicardipine hydrochloride was effective in reducing the incidence of anginal attacks and consumption of glyceryl trinitrate. Treadmill exercise time, angina onset time and the time to 1 mm ST-segment depression were increased. The extent of ST-segment depression was reduced at maximum comparable exercise, with a reduced rate-pressure product and, at maximum exercise, with an increased rate-pressure product. Myocardial stress 201Tl scintillography was carried out in eight of the patients and showed improved washout in antero-septal, infero-apical and postero-lateral segments. Echocardiographic measures of left ventricular function were enhanced because of reduction of afterload. Systemic vascular resistance and end-systolic stress were also decreased and a significant correlation was found between the increase in ejection fraction and reduction of systolic blood pressure. It is concluded that nicardipine hydrochloride is effective in the control of stable effort angina by reducing myocardial oxygen consumption and enhancing coronary blood flow thereby improving left ventricular function.

Exercise-induced precordial ST-segment depression in prior inferior myocardial infarction with single-vessel disease; with special reference to its mechanisms and distinction from multi-vessel disease

We investigated the mechanisms of exercise-induced precordial ST-segment depression on the electrocardiogram in prior inferior myocardial infarction with single-vessel disease and attempted to differentiate the ST-segment depression between single- and multi-vessel disease. Subjects included three groups: group Ia ( n = 11), inferior myocardial infarction with single-vessel disease that showed no precordial ST-segment depression; group Ib ( n = 7), inferior myocardial infarction with single-vessel disease accompanied by precordial ST-segment depression; and group II ( n = 10), inferior myocardial infarction with multi-vessel disease. The subjects underwent 12-lead exercise electrocardiography, stress Tl-201 myocardial imaging and stress radionuclide ventriculography. Exercise-induced precordial ST-segment depression observed in group Ib was associated with large infarction and infarction extending into the inferoseptal wall of the left ventricle on myocardial image. On stress ventriculography, worsening of the septal wall motion was more frequently observed in group Ib than in group Ia. Coronary arteriography revealed a higher rate of rich collateral vessels to the infarcted zone in group Ib than in group Ia. When we compared the diagnostic ability for detecting multi-vessel disease in prior inferior myocardial infarction, although sensitivity was not different among three tests, both exercise electrocardiography and radionuclide ventriculography had poor specificity and predictive value compared to stress Tl-201 myocardial imaging. Thus we concluded that exercise-induced precordial ST-segment depression observed in prior inferior myocardial infarction with single-vessel disease should reflect a peri-infarctional ischemia located in the inferoseptal wall of the left ventricle, and that stress Tl-201 myocardial imaging is the most accurate method for diagnosing multi-vessel disease in prior inferior myocardial infarction.

Clinical significance of dipyridamole Tl-201 emission computed tomography perfusion abnormality for evaluating pathophysiological and pathological aspects in hypertrophic cardiomyopathy.

A dipyridamole-induced Tl-201 perfusion abnormality was evaluated from its clinical features, echocardiography and myocardial histopathology in 39 patients with hypertrophic cardiomyopathy (HCM). From the findings of Tl-201 emission computed tomography (ECT), subjects were divided into three groups: group 1 (n = 16) which did not show a perfusion abnormality in the hypertrophic region; group 2 (n = 12) which showed a perfusion defect on the initial image with complete redistribution on the delayed image; and group 3 (n = 11) which showed a persistent perfusion defect--this group included most patients who revealed partial and/or incomplete redistribution. Echocardiography revealed that group 2 showed a marked asymmetrical septal hypertrophy and an incidental obstructive pattern, and that group 3 had a significantly dilated left ventricular diastolic dimension and a decreased percentage of fractional shortening. Group 3 also showed frequent ventricular tachycardia and a familial history of cardiomyopathy. As for the myocardial biopsy findings, group 3 had significantly advanced myocardial fibrosis, the percentage being 6.0 +/- 3.1% in group 1; 5.5 +/- 2.5% in group 2; and 11.9 +/- 3.4% in group 3. Thus, it was concluded that the persistent perfusion defect on dipyridamole stress Tl-201 ECT testing is an important finding corresponding to the advanced clinical and pathological aspects of HCM.

Evaluation of diseased coronary arterial branches by polar representations of thallium-201 rotational myocardial imaging.

The perfusion territories in polar representations of stress Tl-201 rotational myocardial imaging in patients with angina pectoris who had one diseased coronary segment were analyzed. The lesions proximal or distal to the first major septal perforator in left anterior descending arteries were detected by the presence or absence of defects at the base of the anterior septum. Right coronary artery lesions were detected by the presence of defects at the basal posterior septum, in contrast to the preservation of myocardial uptake at this portion in lesions of the left circumflex artery. The specific defect patterns were detected in cases with lesions at the first diagonal, obtuse marginal, and posterolateral branches. Recognition of these defects in the polar maps allows detailed detection of diseased coronary arterial branches.

Evaluation of 3 dimensional space and time filtering on ECG gated 201Tl myocardial images.

Stress 201Tl myocardial images were obtained using a standard ECG gated acquisition protocol for 10 min per view. These images were filtered using a three dimensional space and time filter. The effects of filtering were evaluated by sectorial analysis. Comparing raw and filtered dynamic images, quantification demonstrated that filtering did not produce artefacts. A conventional static image was also obtained as the sum of the series of unfiltered dynamic images. Comparison of raw static and filtered diastolic images indicated that the latter demonstrated myocardial abnormalities more clearly (P less than 0.01) in 33 patients. Improvement in the signal to noise ratio produced by filtering made cinematic display and visual analysis possible which was not feasible with raw gated images. Clinical evaluation is in progress.

Specific perfusion pattern in stress 201Tl myocardial scintigraphy of left main coronary artery disease.

The usefulness of stress 201Tl myocardial scintigraphy for identifying left main coronary artery disease was evaluated with data from 23 patients with 50% or more narrowing of the left main coronary artery and 56 patients with 75% or more narrowing of the major coronary arteries but without left main coronary artery involvement (no left main coronary artery disease). Quantitative evaluation of stress perfusion scintigrams in all five patients with narrowing of the left main coronary artery of 90% or more showed a characteristic perfusion pattern (left main pattern) of extensive homogeneous defect over the whole anterolateral segment and simultaneous defects in all radii of the high anteroseptal and high posterolateral segments. On the other hand, such a perfusion pattern was noted in only 1 of 18 patients with less than 90% stenosis of the left main coronary artery and in only 1 of 56 patients with no left main coronary artery disease.

Noninvasive quantification of the extent of jeopardized myocardium in patients with single-vessel coronary disease by stress thallium-201 single-photon emission computerized rotational tomography

In 22 patients with single-vessel coronary artery disease and no history of infarction, stress Tl-201 rotational tomography was used to quantify the extent of jeopardized myocardium. The vertical long- and short-axis tomograms were quantified by means of maximum-count circumferential profile analysis. The scintigraphic extent of jeopardized myocardium was expressed as the percentage of profile points falling 2.5 standard deviations below a previously established mean normal profile and was correlated to a quantitatively expressed angiographic extent of jeopardized myocardium. The extent of jeopardized myocardium varied from 1% to 55% by tomography and 8% to 50% by angiography and correlated with an r = 0.79 and a 10% standard error of the estimate. Defect intensity, reflecting the mean depth by which the abnormal points fell below the normal value of ≥10%, was 100% specific for a coronary stenosis of ≥70%. In conclusion, this study demonstrates that: (1) patients with single-vessel disease have highly variable extents of hypoperfused myocardium defined by Tl-201 tomography and coronary arteriography, (2) there is a fair relationship between angiographic jeopardy score and perfusion defects by Tl-201 tomography during exercise, and (3) Tl-201 tomography may be used to noninvasively determine the extent of hypoperfused myocardium in coronary artery disease.

Acute Effect of Ketanserin on the Leg Perfusion Assessed by Doppler Pressure Measurements and 201Tl Scintigraphy in Patients with Intermittent Claudication

Ketanserin, a serotonin2-receptor blocker, was administered intravenously (10 mg) to 10 patients suffering from unilateral intermittent claudication in a double-blind, placebo-controlled, cross-over design. The acute effect of the drug was studied by doppler systolic pressure (SP) measurements at arm and ankle at rest (10 min after injection) and after exercise, and by radioactive thallium (201Tl) stress scintigraphy of the legs. Resting ankle-arm SP ratio was significantly higher after ketanserin compared with placebo. This was due to a lowered systemic SP with unchanged ankle SP. This difference was not seen after exercise. In addition, the drug did not influence significantly the postexercise accumulation of thallium in the distal leg on the affected or healthy side, although the difference between these two became significantly larger in favour of the healthy leg. Thus, acute administration of ketanserin improves peripheral hemodynamics in claudicating patients at rest, but muscle exercise abolishes this response. A beneficial effect of ketanserin in intermittent claudication cannot be anticipated from these results.

Positive exercise thallium-201 test responses in patients with less than 50% maximal coronary stenosis: Angiographic and clinical predictors

The incidence and causes of abnormal thallium-201 (Tl-201) myocardial perfusion studies in the absence of significant coronary artery disease were examined. The study group consisted of 100 consecutive patients undergoing exercise Tl-201 testing and coronary angiography who were found to have maximal coronary artery diameter narrowing of less than 50%. Maximal coronary stenosis ranged from 0 to 40%. The independent and relative influences of patient clinical, exercise and angiographic data were assessed by logistic regression analysis. Significant predictors of a positive stress Tl-201 test result were: (1) percent maximal coronary stenosis (p < 0.0005), (2) propranolol use (p < 0.01), (3) interaction of propranolol use and percent maximal stenosis (p < 0.005), and (4) stress-induced chest pain (p = 0.05). No other patient variable had a significant influence. Positive Tl-201 test results were more common in patients with 21 to 40% maximal stenosis (59%) than in patients with 0 to 20% maximal stenosis (27%) (p < 0.01). Among patients with 21 to 40% stenosis, a positive test response was more common when 85 % of maximal predicted heart rate was achieved (75%) than when it was not (40%) (p < 0.05). Of 16 nonapical perfusion defects seen in patients with 21 to 40% maximal stenosis, 14 were in the territory that corresponded with such a coronary stenosis. Patients taking propranolol were more likely to have a positive Tl-201 test result (45%) than patients not taking propranolol (22%) (p < 0.05). Although patients with stress-induced chest pain more often had a positive Tl-201 test result than those without chest pain, this difference did not reach statistical significance. However, Tl-201 perfusion defects were more frequently seen when typical angina pectoris was elicited than when atypical chest pain developed (p < 0.05). The high frequency of Tl-201 defects associated with 21 to 40% stenoses and the close correlation of such defects with myocardial territory supplied by these stenoses suggests that such coronary lesions may have true hemodynamic impact, especially at high levels of stress. In addition, the high incidence of positive Tl-201 studies in patients taking propranolol suggests that an attempt be made to wean patients off β-blocker treatment before Tl-201 exercise testing.

Quantitative planar thallium-201 stress scintigraphy: A critical evaluation of the method

The results of quantitative analysis of planar thallium-201 stress scintigraphy are superior to those of visual analysis. The increased sensitivity for detection of coronary artery disease is associated with maintenance of specificity. Consequently, we believe that quantitative analysis is the state-of-the-art for planar 201Tl stress scintigraphy. We emphasize that for reliable and reproducible results, rigorous quality control and strict adherence to a standardized imaging protocol are necessary. An important feature is clarity of display of computer data. In our experience, the most important feature for making quantitative analysis reliable and accessible for a broader user market is simultaneous display of the lower limits of normal with processed patient data. This provides a simple visual impression of the degree and extent of abnormal 201Tl distribution and kinetics relative to the lower limit of normal.

Usefulness and limitation of stress 201TL myocardial single photon emission computed tomography (SPECT) for diagnosis of ischemic heart disease

運動負荷201Tl心筋SPECTの虚血性心疾患(IHD)診断における有用性と限界について, IHD 123例,対照15例を対象に検討した. SPECTはplanar法に比べIHD診断率(96%: 89%, p<0.01),個々の罹患冠動脈の検出率(左前下行枝84%: 68%, p<0.005,左回旋枝60%: 47%, NS,右冠動脈88%: 69%, p<0.01),多枝病変(左前下行枝+左回旋枝and/or右冠動脈)検出率(53%: 31%, p<0.025),三枝病変検出率(60%: 13%, p<0.005)を有意に向上させ,さらに,中隔と側壁のなす角度の心尖部へ向かつての開大と,広範な前壁側の欠損および内腔拡大所見により心室瘤の検出も可能とした(sensitivity 94%, specificity 84%).一方診断精度は梗塞例に比べ狭心症例で,一枝病変に比べ多枝病変で,狭窄の高度なものに比べ軽度なもので,後下壁梗塞,前壁+後下壁梗塞に比べ前壁梗塞で低下した.梗塞部位での一過性虚血(前壁梗塞36%,後下壁梗塞24%)と心室瘤(前壁梗塞21%,後下壁梗塞0)の存在は,梗塞例での多枝病変検出を困難とする因子と考えられた.以上より,運動負荷201Tl心筋SPECTはIHDの検出,個々の罹患冠動脈の検出,多枝病変の検出(特に後下壁梗塞,前壁+後下壁梗塞),三枝病変の検出,心室瘤の検出に有用な非侵襲的検査法であるが,前壁梗塞例,狭心症例における多枝病変検出には限界があると考えられた.

Clinical significance of the right ventricular free wall appearance on stress Tl-201 myocardial images in ischemic heart disease.

In order to evaluate the clinical significance of thallium (Tl)-201 myocardial imaging for diagnosing the right ventricular (RV) ischemia, we studied the relationship of right ventricular free wall (RVFW) appearance on myocardial images to coronary arteriographic findings. Patients were divided into 3 groups as follows: 1) normal control (NC) group (19 cases) without angiographically documented coronary artery disease; 2) non-RCA group (18 cases) with significant coronary artery lesion restricted to the left coronary artery (LCA); and 3) RCA group (36 cases) with significant right coronary artery (RCA) stenosis regardless of underlying LCA disease. After the patients had exercised up to 80-85% of the predicted maximal heart rate, immediate and 3-4 hour delayed myocardial images were obtained. As for presence or absence of the RV ischemia on images, the RVFW appearance in 30 degrees and 60 degrees left anterior oblique (LAO) views were assessed carefully. On the immediate images, all patients except one in the NC group and all except 3 in the non-RCA group demonstrated 'continuous visualization' of the RVFW in both views. In the RCA group, 6 showed 'non-visualization' and 11 'defective visualization' of the RVFW in 30 degrees LAO view. In 60 degrees LAO view, 6 presented 'non-visualization' and other 6 'defective visualization' of the RVFW. On the delayed images, although none of the patients in the groups NC and non-RCA demonstrated redistribution phenomenon of the RVFW, 4 patients in the RCA group showed redistribution of Tl-201 into the RVFW. Non- and defective visualization of the RVFW on the immediate images were related to the proximally located RCA lesion, previous history of inferior myocardial infarction and high grade RCA stenosis. Collateral vessels seemed to protect the RVFW against the development of exercise induced ischemia and affect the occurrence of redistribution of Tl-201 into the RVFW. In conclusion, stress Tl-201 myocardial imaging enables us to estimate the myocardial blood flow of the RV and is a useful non-invasive method in the evaluation of RV ischemia.

Stress 201Tl scintigraphy: Temporal redistribution studied by means of local-to-maximum uptake ratio

Stress 201Tl scintigraphy: Temporal redistribution studied by means of local-to-maximum uptake ratio

Thallium—201 Scintigraphy After Surgical Repair of Hemodynamically Significant Primary Coronary Artery Anomalies

Nine patients with hemodynamically significant congenital coronary artery anomalies underwent surgical repair at our institution during the period 1960 to 1979. Four received diagnoses of anomalous left coronary artery arising from the pulmonary artery, while five patients had coronary artery fistulae. Stress 201Tl scintigraphy was performed on these patients 0.5 to 18 years after surgical correction as a means of assessing the adequacy of myocardial perfusion. No perfusion defects were visualized on any of the thallium studies. The surgical procedure used did not appear to influence the results of 201Tl stress imaging. Thus, these nine patients with surgically corrected primary coronary artery anomalies had no evidence of ischemia as assessed by stress thallium scintigraphy. Serial preoperative and postoperative thallium studies are now indicated to determine the role of this procedure in the management of hemodynamically significant congenital coronary artery anomalies.

Effects of diltiazem in patients with ischemic heart disease Evaluation by exercise stress test and 201Tl myocardial scintigraphy

Effects of diltiazem in patients with ischemic heart disease Evaluation by exercise stress test and 201Tl myocardial scintigraphy

Thallium-201 peripheral perfusion scans: feasibility of single-dose, single-day, rest and stress study

The distribution and redistribution kinetics of thallium-201 in the lower extremities were investigated to determine the relationships among the rest, stress, and delayed-stress perfusion studies. The distribution of perfusion when the tracer was administered at rest was compared with that when administered during stress, and the distribution 5--6 hr after the stress injection. The distribution was evaluated qualitatively by scanning and quantitatively by point counting. In nine of 10 subjects without peripheral vascular disease, the 5--6 poststress redistribution pattern was unchanged from the stress pattern and was different from the rest pattern. However, in all patients with peripheral vascular disease, the delayed poststress perfusion distribution had greater similarity to the rest pattern and was substantially different from that noted immediately after stress. Using the time frame of this study, the stress and delayed-stress 201Tl perfusion study of the lower extremities cannot be used to represent true rest perfusion. However, because of the similarity of the delayed-stress to the true rest distribution in abnormals, it may be clinically useful in defining rest and stress alterations.

Bayesian analysis of stress thallium-201 scintigraphy.

The variation of the diagnostic value of stress Tl-201 scintigraphy with prevalence of coronary heart disease (CHD) in the population has been investigated using Bayesian reasoning. From scintigraphic and arteriographic data obtained in 100 consecutive patients presenting with chest pain, the sensitivity of stress Tl-201 scintigraphy for the detection of significant CHD was 90% and the specificity was 88%. From Bayes' Theorem, the posterior probability of having CHD for a given test result was calculated for prevalences of CHD ranging from 1% to 99%. The discriminant value of stress Tl-201 scintigraphy was best when the prevalence of CHD lay between 30% and 70% and maximum for a prevalence of 52%. Thus, stress Tl-201 scintigraphy would be an unsuitable diagnostic test where the prior probability of CHD is low, e.g., population screening programmes, and would add little where the clinical probability of having CHD is already high. However, where the prior probability of having CHD is intermediate stress Tl-201 scintigraphy may provide valuable diagnostic information.

Evaluation of the left ventricular performance in patients with ischemic heart disease using radionuclide angiocardiography.

Radionuclide angiocardiography was utilized for the measurement of left ventricular dynamics and the analysis of its segmental wall motion. Left ventricular performance was measured by the first pass method and gated equilibrium method in patients with ischemic heart disease. The left ventricular wall motion was also examined by the analysis of computer-drawn outlines of radioactivity counts of the left ventricular chamber. These measurements were well correlated with those obtained by invasive methods such as contrast cine-ventriculography and thermodilution method in the resting state. The patients with effort angina often showed an almost normal left ventricular performance and wall motion in the resting state without ischemic episodes. However, at the time when anginal attack was provoked with exercise testing, an asynergy and a reduced performance of left ventricle were observed. The extent and localization of this asynergy well corresponded with the defect of myocardial scintigrams determined by 201-Tl stress myocardial imaging. From above findings we conclude that the myocardial ischemia with asynergy is a cause of decreased left ventricular hemodynamics during anginal attack. Although further evaluation is necessary to know limitations and to avoid inaccuracy, these techniques were shown to have a significant usefullness in evaluating ischemic heart disease.

Clinical value of the thallium-201 stress test sensitivity and specificity in the detection of coronary artery disease

Rest and exercise thallium-201 scintigraphy ( 201Tl stress test), 90% submaximal treadmill exercise test (ECG stress test), and coronary angiography were performed on 49 patients with suspected coronary artery disease. When technically unsatisfactory and uninterpretable scintiphotos were excluded, the sensitivity (true positives/true positives + false negatives) of the 201Tl stress test in detecting coronary artery stenosis ≥70% was 81%. The sensitivity of the 201Tl stress test in detecting coronary artery stenosis ≥50% was 84&‰ However, when technically unsatisfactory and uninterpretable studies were considered as failures of the test to detect disease, the sensitivity of the 201Tl stress test in detecting coronary artery stenosis ≥50% was 71%. The sensitivity of the ECG stress test was 92% in detecting stenosis ≥70% and 85%. in detecting stenosis ≥50% when non-diagnostic tests were excluded. However, when 11 non-diagnostic ECG stress tests were considered as a failure of the test to detect disease, the sensitivity of the ECG stress test in detecting coronary artery stenosis ≥50% was 64%. The sensitivity of the combined stress test in detecting coronary artery stenosis ≥50% was high whether or not technically unsatisfactory and uninterpretable studies were (89%) or were not (94%) included in the analysis. The specificity (true negatives,/true negatives + false positives) for ≥50% coronary artery stenosis was 90% for the 201Tl stress test, 75% for the ECG stress test and 80% for the combined stress test. Combined ECG and 201Tl stress testing detects a number of patients with significant coronary artery disease missed by ECG stress testing alone, primarily in those cases where the ECG stress test is non-diagnostic.