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PubMed1994

Dobutamine echocardiography and resting-redistribution thallium-201 scintigraphy predicts recovery of hibernating myocardium after coronary revascularization.

The value of dobutamine echocardiography and resting thallium-201 scintigraphy to predict reversal of regional left ventricular wall motion dysfunction after revascularization in patients with chronic coronary artery disease was assessed. Improvement in wall motion during dobutamine echocardiography and normal or mildly decreased uptake on thallium-201 scanning are strong predictors of reversible left ventricular dysfunction. Dobutamine echocardiography and resting thallium-201 scanning are simple and safe methods of assessing hibernating myocardium.

Angioplasty, Balloon, Coronary↗
PubMed1995

Four- versus 6-minute infusion protocol for adenosine thallium-201 single photon emission computed tomography imaging.

Intravenous adenosine infusion results in immediate maximal coronary arteriolar vasodilatation. Side effects occur in most patients who receive adenosine. For these reasons, a shorter infusion for pharmacologic stress thallium-201 testing may improve patient tolerability without compromising diagnostic accuracy. In a retrospective, unblinded evaluation, we compared side effects and accuracy of a standard 6-minute adenosine infusion single photon emission computed tomography (SPECT) study with a 4-minute protocol in 730 and 621 patients, respectively. Adenosine was infused at 140 micrograms/kg/minute in both groups; thallium-201 was injected at the 3-minute mark of the 4-minute protocol and at the 4-minute mark of the 6-minute protocol. Angiographic follow-up (mean 8 days) after thallium-201 testing was available in 233 (32%) of the patients in the 6-minute protocol and in 174 (28%) of the patients in the 4-minute protocol (p not significant (NS). Side effects occurred in 90% of the patients in the 6-minute protocol and in 91% of the patients in the 4-minute protocol (p = NS). Premature termination of the infusion was required in 4% of the patients in the 6-minute protocol and 2% of the patients in the 4-minute protocol (p = 0.02). Second- or third-degree atrioventricular block was noted in 4.5% and 3.0% of the 6- and 4-minute groups, respectively (p = NS). The duration of symptoms averaged 2.9 +/- 4.4 minutes in the patients in the 6-min protocol and 2.1 +/- 1.6 minutes in the patients in the 4-minute protocol (p < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Adenosine↗
PubMed1995

Incremental value of exercise electrocardiography and thallium-201 testing in men and women for the presence and extent of coronary artery disease.

Our goal was to assess the incremental value of exercise testing in men and women for the diagnosis and extent of coronary artery disease. With data from one center, incremental logistic algorithms were developed and evaluated in a separate set of 865 patients from four centers. Variables included were pretest (age, sex, symptoms, diabetes, smoking, and cholesterol concentration); exercise electrocardiogram (ECG) (ST-segment depression [millimeters], ST-segment slope, peak heart rate, and change in systolic blood pressure); and thallium-201 scintigram (defect presence, reversibility, and intensity of hypoperfusion). End points were coronary disease presence (50% diameter stenosis) and extent (multivessel disease). Accuracy and incremental value were assessed by receiver operating characteristic (ROC) curve analysis. Incremental ROC curve areas for disease presence were pretest 0.75 +/- 0.02, post-exercise ECG 0.82 +/- 0.01, and post-thallium scintigram 0.85 +/- 0.01 and for disease extent were pretest 0.71 +/- 0.02, post-exercise ECG 0.76 +/- 0.02, and post-thallium scintigram 0.78 +/- 0.02 (p < 0.005 for all increments). Incremental increases in accuracy were similar for men and women. We conclude that when multivariable algorithms derived from one center were applied to a separate group, there was a significant incremental increase in accuracy associated with exercise testing for the presence and extent of coronary disease. This increase in accuracy was similar for men and women.

Adult↗
PubMed1978

Prevalence of right ventricular involvement in inferior wall infarction assessed with myocardial imaging with thallium-201 and technetium-99m pyrophosphate.

To assess the prevalence and clinical relevance of right ventricular involvement in acute inferior wall infarction, 78 consecutive patients with the latter condition were studied with thallium-201 and technethium-99m pyrophosphate myocardial imaging. Right ventricular involvement was determined from superimposition of the 45 degree left anterior oblique thallium-201 and technetium-99m pyrophosphate images. All 78 patients shoed thallium-201 defects. Sixty-four patients had positive pyrophosphate scans, and 24 of these (37.5 percent) showed right ventricular involvement. None of the patients with right ventricular involvement in this consecutive series showed the classic signs of severe right ventricular failure, although subclinicalright ventricular dysfunction may have been present. There was no significant difference in the incidence of cardiogenic shock between the groups with and without right ventricular involvement. It is concluded that right ventricular involvement in acute inferior wall infarction is relatively frequent but not necessarily associated with severe right-sided pump failure. In patients with acute inferior wall infarction and severe pump failure, dual imaging provides a simple nonivasive method of identifying the subgroup of patients with right ventricular involvement who may benefit from volume loading.

Adult↗
PubMed1979

Idiopathic hypertrophic subaortic stenosis: evaluation of anginal symptoms with thallium-201 myocardial imaging.

The evaluation of angina pectoris in patients with idiopathic hypertrophic subaortic stenosis is difficult in those in the age group prone to coronary artery disease. Ten patients with angina pectoris, normal coronary angiograms and idiopathic hypertrophic subaortic stenosis were studied with thallium-201 myocardial imaging performed in conjunction with submaximal treadmill exercise testing. The resting electrocardiogram demonstrated left ventricular hypertrophy with S-T segment abnormalities in seven patients, thereby vitiating the further increase in S-T segment abnormalities that developed in these patients during exercise or in the postexercise period. Of the three patients with a normal resting electrocardiogram, one had significant exercise-induced S-T segment depression. Thallium-201 myocardial imaging revealed no significant perfusion defects in 9 of the 10 patients (90 percent). In one patient with severe left ventricular hypertrophy significant perfusion defects developed after exercise that were not present at rest. Stress thallium-201 myocardial perfusion imaging is a useful noninvasive technique that assists in ruling out the presence of significant coronary artery disease in patients with idiopathic hypertrophic subaortic stenosis.

Adolescent↗
PubMed1980

Thallium-201 versus technetium-99m pyrophosphate myocardial imaging in detection and evaluation of patients with acute myocardial infarction.

Thallium-201 myocardial imaging is of value in the early detection and evaluation of patients with suspected acute infarction. The extent of a thallium defect in an initial myocardial image may have important prognostic value. Tomographic imaging techniques hold promise for increased diagnostic sensitivity and more accurate quantitation of both infarcted and residual viable myocardium. Thallium imaging may have a special value in characterizing patients with cardiogenic shock and in detecting patients at risk for subsequent infarction or death or death or both, before hospital discharge. Approximately 95 percent of patients with transmural or nontransmural myocardial infarction can be detected with technetium-99m pyrophosphate myocardial imaging if the imaging is performed 24 to 72 hours after the onset of symptoms. Pyrophosphate imaging has been useful in localizing the site and determining the extent of acute myocardial infarction. The "doughnut" pattern is associated with a relatively large incidence of subsequent congestive heart failure and death. However, the clinical utility of this information is limited because it is usually not available when it is most needed, on admission to the coronary care unit. Pyrophosphate imaging may have an important role in the evaluation of patients during the early follow-up period after hospital discharge from an episode of acute infarction. The finding of a persistently positive pyrophosphate image suggests a poor prognosis and is associated with a relatively large incidence of subsequent myocardial infarction and death.

Acute Disease↗
PubMed1982

Serial right ventricle thallium-201 imaging after exercise: relation to anatomy of the right coronary artery.

The relation of the appearance of the right ventricle on serium thallium-201 myocardial imaging to coronary artery anatomy was examined in 88 consecutive patients undergoing exercise thallium-201 testing and coronary angiography for the evaluation of chest pain. Transient defects in the right ventricle were found in 8 patients. All had high grade (greater than or equal to 90%) stenosis of the proximal right coronary artery. Nonvisualization of right ventricular (RV) activity occurred in 10 patients. Nine of the 10 (90%) had significant (greater than or equal to 50% stenosis) disease of the proximal right coronary artery and 7 (70%) had high grade stenosis. The right ventricle appeared normal in 70 patients. Twenty-nine (41%) of these patients had significant proximal right coronary artery disease. Right ventricular appearance was not affected by the presence or absence of disease of the left anterior descending or left circumflex artery or by the appearance of the left ventricle. Thus, with serial RV thallium-201 myocardial imaging after exercise, we found that (1) RV transient defects suggest the presence of high grade proximal right coronary artery stenosis, (2) non-visualization of RV activity also predicts significant proximal right coronary disease, and (3) the right ventricle frequently appears normal despite proximal right coronary artery disease and therefore this finding does not exclude such disease.

Aged↗
PubMed1984

Detection and quantification of previous myocardial infarction by exercise-redistribution tomographic thallium-201 scintigraphy.

Although myocardial perfusion scintigraphy at rest accurately diagnoses myocardial infarction (MI), the prevalence and size of previous MI is overestimated by exercise-redistribution thallium-201 studies. A new, quantitative approach to the analysis of tomographic thallium-201 scintigrams was developed in order to determine whether the presence and extent of MI could be determined. Sixty patients undergoing cardiac catheterization for chest pain syndromes, including 28 with previous MI, were studied by exercise and 3-hour delayed thallium-201 scintigraphy, with use of the 7-pinhole tomographic technique. Circumferential profiles of the postexercise and 3-hour radiotracer distribution were generated from apical, midventricular and basal left ventricular slices. The 3-hour profile fell below normal limits in 24 of 28 patients (86%) with remote MI, but was also abnormal in 9 of 22 patients (41%) with coronary disease but no MI. All missed MIs were either inferior or subendocardial and were associated with normal ejection fractions. To distinguish between MI and slowly resolving ischemic defects, a quantitative approach was used. MI area was calculated as the area in which the 3-hour profile fell below the 3-hour normal limits, and a redistribution area in the MI zone was determined as the area between the postexercise and 3-hour profiles in the region where the 3-hour profile was abnormal. The MI area was 1,000 +/- 980 units in patients with MI, vs 79 +/- 120 units in patients without MI (p less than 0.001), whereas the redistribution area was higher in patients without MI (1,240 +/- 810 vs 430 +/- 400 units, p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1984

Recognition of regional hypertrophy in hypertrophic cardiomyopathy using thallium-201 emission-computed tomography: comparison with two-dimensional echocardiography.

The configuration of the hypertrophied myocardium was evaluated by thallium-201 emission-computed tomography and 2-dimensional (2-D) sector scan in 10 patients with obstructive hypertrophic cardiomyopathy (HC), 10 with nonobstructive HC with giant negative T waves and 10 with concentric left ventricular (LV) hypertrophy. Thallium-201 myocardial imaging was reconstructed into multiple 12-mm-thick slices in 3 planes. The thickness ratio of the ventricular septum and the LV posterior wall in the short-axis plane and the ratio of the ventricular septum and the apical wall in the long-axis plane were analyzed. In the patients with obstructive HC the ventricular septal wall thickness index was increased, and the ratio of septal to posterior wall thickness index (1.45 +/- 0.23) was greater than that in the patients with nonobstructive HC with giant negative T waves or in those with concentric LV hypertrophy (1.03 +/- 0.20 and 0.98 +/- 0.11, respectively; p less than 0.01 for each). In the patients with nonobstructive HC with giant negative T waves, increased apical wall thickness with apical cavity obliteration was characteristic, and the ratio of ventricular septal to apical wall thickness index (0.66 +/- 0.14) was less than that in the patients with obstructive HC or in those with concentric LV hypertrophy (1.46 +/- 0.38 and 1.04 +/- 0.09, respectively; p less than 0.001 for each). In contrast, technically satisfactory 2-D sector scanning (83%) demonstrated various configurations of the hypertrophied ventricularseptum, but could not detect apical hypertrophy in 4 of the 10 patients with nonobstructive HC with giant negative T waves whose LV cineangiograms demonstrated apical hypertrophy. Thus, thallium-201 emission-computed tomography is useful in evaluating the characteristics of LV hypertrophy and assists 2-D sector scan, especially in patients with apical hypertrophy in HC.

Adult↗
PubMed1988

Usefulness of exercise electrocardiography and thallium scintigraphy in unstable angina pectoris in predicting the extent and severity of coronary artery disease.

The safety and efficacy of exercise electrocardiography and thallium scintigraphy early in the course of unstable angina pectoris were assessed 4.6 +/- 1.6 days after admission in 67 patients with unstable angina that stabilized after medical therapy. Coronary arteriography was performed in all patients 5.4 +/- 2.4 days after admission. There was no difference in clinical, exercise or scintigraphic variables between patients with stenoses less than 50% and patients with 1-vessel coronary artery disease (CAD) defined as a diameter stenosis greater than or equal to 50%. Patients with 3-vessel CAD had a significantly shorter exercise duration than patients with less than 50%-diameter narrowing (5.5 +/- 2.2 vs 8.3 +/- 3.3 minutes, respectively), lower exercise heart rate (119 +/- 20 vs 149 +/- 22 beats/min) and systolic blood pressure (156 +/- 29 vs 166 +/- 33 mm Hg), more frequent chest pain (76 vs 20%) and more pronounced ST depression (-1.48 +/- 1.37 vs -0.33 +/- 0.72 mm). In addition, thallium defect size on exercise was greater in the patients with 2-vessel CAD (159 +/- 132 degrees) and 3-vessel CAD (255 +/- 132 degrees) than in patients with no CAD (28 +/- 319 degrees) or 1-vessel CAD (73 +/- 78 degrees), p greater than or equal to 0.05. Multiple regression analysis demonstrated that thallium defect size was the best predictor of extent of CAD, with exercise heart rate and presence of chest pain during exercise also predictive of extent of CAD.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1988

A comparative study of thallium-201 single-photon emission computed tomography and electrocardiography in Duchenne and other types of muscular dystrophy.

Single-photon emission computed tomography (SPECT) using thallium-201 was compared with 12-lead electrocardiography (ECG) in patients with Duchenne (29), facioscapulohumeral (7), limb-girdle (6) and myotonic (5) dystrophies, by dividing the left ventricular (LV) wall into 5 segments. SPECT showed thallium defects (37 patients, mostly in the posteroapical wall), malrotation (23), apical aneurysm (5) and dilatation (7). ECG showed abnormal QRS (36 patients), particularly as a posterolateral pattern (13). Both methods of assessment were normal in only 7 patients. The Duchenne type frequently showed both a thallium defect (particularly in the posteroapical wall) and an abnormal QRS (predominantly in the posterolateral wall); the 3 other types showed abnormalities over the 5 LV wall segments in both tests. The percent of agreement between the 2 tests was 64, 66, 70, 72 and 72 for the lateral, apical, anteroseptal, posterior and inferior walls, respectively. The 2 tests were discordant in 31% of the LV wall, with SPECT (+) but ECG (-) in 21% (mostly in the apicoinferior wall) and SPECT (-) but ECG (+) in 10% (mostly in the lateral wall). Some patients showed large SPECT hypoperfusion despite minimal electrocardiographic changes. ECG thus appeared to underestimate LV fibrosis and to reflect posteroapical rather than posterolateral dystrophy in its posterolateral QRS pattern. In this disease, extensive SPECT hypoperfusion was also shown, irrespective of clinical subtype and skeletal involvement.

Cardiomyopathies↗
PubMed1989

Effect of the degree of effort on the sensitivity of the exercise thallium-201 stress test in symptomatic coronary artery disease.

The sensitivity of ST-segment depression on the electrocardiogram during exercise is influenced by the level of effort. Whether such is the case with thallium-201 imaging (initial defect or redistribution) has not been established. Accordingly, the prevalence of these parameters was evaluated in 288 patients (age 59 +/- 10 years, 88% men) with coronary artery disease who underwent both exercise thallium-201 imaging and coronary angiography within 3 months of each other: 159 had a prior myocardial infarction, 72 had 1-vessel, and 216 had multivessel disease. The degree of effort was evaluated by 3 criteria: (1) percentage of maximal predicted heart rate (less than or equal to 65, greater than 65 to 85, greater than 85%); (2) workload during exercise (less than or equal to 4, greater than 4 to 8, greater than 8 METs); and (3) duration of exercise (less than or equal to 3, greater than 3 to 6, greater than 6 minutes). The prevalence of defects on initial images was higher than both redistribution on delayed images and ST-segment depression on the electrocardiogram (p less than 0.01). The overall prevalence of initial defects remained the same for all levels of effort and was not influenced by the presence or absence of a prior infarction. However, it decreased in patients with 1-vessel disease who exercised to higher workloads. The prevalence of redistribution on delayed thallium-201 images was higher than that of ST-segment depression on the electrocardiogram (p less than 0.01), except at higher levels of effort where they were similar.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1989

A simplified approach for evaluating multiple test outcomes and multiple disease states in relation to the exercise thallium-201 stress test in suspected coronary artery disease.

This study describes a simplified approach for the interpretation of electrocardiographic and thallium-201 imaging data derived from the same patient during exercise. The 383 patients in this study had also undergone selective coronary arteriography within 3 months of the exercise test. This matrix approach allows for multiple test outcomes (both tests positive, both negative, 1 test positive and 1 negative) and multiple disease states (no coronary artery disease vs 1-vessel vs multivessel coronary artery disease). Because this approach analyzes the results of 2 test outcomes simultaneously rather than serially, it also negates the lack of test independence, if such an effect is present. It is also demonstrated that ST-segment depression on the electrocardiogram and defects on initial thallium-201 images provide conditionally independent information regarding the presence of coronary artery disease in patients without prior myocardial infarction. In contrast, ST-segment depression on the electrocardiogram and redistribution on the delayed thallium-201 images may not provide totally independent information regarding the presence of exercise-induced ischemia in patients with or without myocardial infarction.

Aged↗
PubMed1990

Decreased coronary vasodilatory capacity in hypertrophic cardiomyopathy determined by split-dose thallium-dipyridamole myocardial scintigraphy.

Split-dose thallium-dipyridamole myocardial scintigraphy was performed in patients with nonobstructive hypertrophic cardiomyopathy (HC) who had angiographically normal coronary arteries. The dipyridamole-induced increases in thallium-201 uptake, calculated to evaluate coronary vasodilatory capacity, were significantly lower in 30 patients with HC than in 13 control subjects (177 +/- 58 vs 281 +/- 46%) and the reductions were observed in both the septal and lateral segments. The reductions of the septal segment in HC patients were significantly greater than those in 10 hypertensive patients with comparable degrees of septal hypertrophy. Of patients with HC, 16 had increases in thallium uptake well below the normal range. Compared with those having normal increases, these patients had significantly lower exercise duration (11 vs 15 minutes), with 33% having ST depression develop at a workload less than or equal to 80 watts. These data indicate that approximately one-half of patients with HC have impaired coronary vasodilatory capacity that could be an important pathophysiologic abnormality of HC resulting in the development of myocardial ischemia and the impairment of cardiac performance during exercise.

Adolescent↗
PubMed1990

Quantitative exercise thallium-201 rotational tomography for evaluation of patients with prior myocardial infarction.

The utility of stress-redistribution thallium-201 myocardial perfusion single-photon emission computed tomography (SPECT) in patients with a prior single myocardial infarction was studied in 66 patients who were tested by both SPECT and coronary angiography. SPECT was quantified by comparing the patients' circumferential count profiles to a previously established normal data base and by plotting the results onto a polar coordinate map that localized defects to the 3 major coronary artery territories. The pattern of reversibility of the quantitatively detected defects was assessed by consensus visual analysis. SPECT thallium-201 detected myocardial infarction in 62 of 66 patients (sensitivity = 94%). Sixty-five percent of the infarct zones showed some reversibility at 4-hour imaging which corresponded with angiographic evidence of flow to the infarct zones in 95.5% of cases. Late (18 to 24 hours) imaging, done in 26 patients, showed complete or partial reversibility of 29% of infarct zone segments which were nonreversible on 4-hour images. To improve specificity for detection of disease in coronary arteries supplying the non-infarct territories, new quantitative criteria were developed that took into consideration contiguity of defects with the infarct zone. Accuracy for detection of patients with multivessel coronary disease by quantitative thallium-201 SPECT was 86%, which was significantly higher than those of the clinical response to exercise (48%), the exercise electrocardiographic response (56%) or their combination (65%).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

Value of thallium-201 reinjection after delayed SPECT imaging for predicting reversible ischemia after coronary artery bypass grafting.

The reinjection of a small dose (40 MBq) of thallium-201 after stress and delayed imaging often shows new redistribution in the regions with persistent defect. To assess whether these segments may represent reversible ischemia, reinjection thallium-201 single-photon emission computed tomography (SPECT) was performed after stress and 3-hour delayed imaging in 24 patients before coronary artery bypass grafting (CABG). The left ventricular myocardium was divided into 5 myocardial segments and regional wall motion was scored on a scale from 0 (normal) to 4 (dyskinesia). Thallium-201 findings were compared with improvement in regional perfusion and wall motion 1 to 2 months after CABG. The reinjection imaging identified new redistribution in 15 of 32 persistent defects (47%) on the 3-hour delayed images. In the study of stress and delayed SPECT imaging, the improvement in perfusion was observed in 34 of 43 segments (79%) exhibiting redistribution and 15 of 32 (47%) segments without redistribution (p less than 0.01). The reinjection SPECT identified new redistribution in 12 of the 15 improved segments that were not detected on the delayed images. Similarly, the improvement in wall motion was observed in 23 of 31 segments (74%) exhibiting redistribution and 14 of 30 segments (47%) without redistribution on the delayed images (p less than 0.05). The reinjection identified new redistribution in 10 of the 14 improved segments that were undetected on the delayed images. The predictive values for improvement in perfusion and wall motion by the reinjection imaging were significantly higher (92 and 89%) than those by the delayed imaging (69 and 62%, respectively, p less than 0.05 each).(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1990

Reverse redistribution of thallium-201 detected by SPECT imaging after dipyridamole in angina pectoris.

Reverse redistribution refers to a thallium-201 perfusion defect that develops or becomes more evident on delayed imaging compared with the initial image immediately after stress. To determine the diagnostic importance of reverse redistribution after intravenous dipyridamole, thallium-201 single photon emission computed tomography and quantitative coronary arteriography were performed in 90 men with angina pectoris. Of the 250 myocardial segments analyzed, reverse redistribution was present in 17 (7%). Minimal coronary cross-sectional area in proximal vessel segments was less than or equal to 2.0 mm2 more often in regions with transient perfusion abnormalities than in regions with reverse redistribution (66 vs 29%, p less than 0.05). Compared with regions exhibiting transient perfusion abnormalities, regions with reverse redistribution had larger proximal arterial diameters (1.9 +/- 1.1 vs 1.3 +/- 1.1 mm, p less than 0.001) and cross-sectional areas (3.9 +/- 3.1 vs 2.2 +/- 2.6 mm2, p less than 0.001). Coronary artery dimensions and relative stenosis severity did not differ between those regions with normal perfusion and those with reverse redistribution. Reverse redistribution detected by thallium-201 single photon emission computed tomographic imaging after dipyridamole is uncommon, appears to occur as frequently in normal subjects as in patients undergoing coronary arteriography and does not indicate the presence of severe coronary artery disease.

Adult↗
PubMed1990

Detection of human collateral circulation by vasodilation-thallium-201 tomography.

Coronary arteriolar vasodilation may provoke redistribution of flow to collateral-dependent jeopardized myocardium. To assess the physiologic significance of collaterals, 80 consecutive post-infarction patients (age 58 +/- 8 years) underwent vasodilation-redistribution thallium-201 tomographic imaging after administration of 0.56 mg of intravenous dipyridamole/kg body weight. Circumferential profile analysis of thallium-201 uptake and redistribution in representative left ventricular tomograms provided quantitative assessment of transient and fixed defects and separation between periinfarctional and distant inducible hypoperfusion. Tomographic perfusion data were correlated to wall motion and collateral circulation between distinct anatomic perfusion territories. Patients were grouped according to presence (59%) or absence (41%) of angiographically visible collateral channels to jeopardized myocardium. In the presence of collaterals, distant reversible defects were larger than in absence of collaterals (p less than 0.05); the extent of combined periinfarctional and distant redistribution was also larger in collateralized patients (p less than 0.025), whereas the size of the persistent perfusion defect was similar in both groups. By prospective analysis the tomographic perfusion pattern of combined periinfarctional and distant redistribution revealed a sensitivity of 85% and a specificity of 78% for the detection of significant collateral circulation in this group of patients. Thus, using the exhausted flow reserve as a diagnostic tool, vasodilation-thallium-201 tomography has the potential to identify and quantitate collateralized myocardium in post-infarction patients and may guide diagnostic and therapeutic decision-making.

Cardiac Catheterization↗