Noninvasive evaluation of regional myocardial perfusion in 112 patients using a mobile scintillation camera and intravenous nitrogen-13 labeled ammonia

The short half-life positron emitter 13N, as labeled ammonia (13NH4+), was evaluated as a myocardial imaging agent. Regional myocardial uptake of 13NH4 correlated with the distribution of labeled microspheres in experimental myocardial infarction. Using intravenous 13NH4+, myocardial scintigraphy was performed in 85 cardiac patients and 27 normal subjects. Ninety-five scintigrams were suitable for analysis. Eighteen of 24 normal subjects had homogeneous myocardial images; six had inhomogeneous images attributable to early technical problems. Perfusion defects were observed in the scintigrams of 82% (57/65) of patients with coronary artery disease, being most common in patients with myocardial infarction (27/28). Six sequential studies showed changes in perfusion consistent with the clinical course of each patient. Scintigraphic abnormalities were also observed in 4/6 patients with valvular heart disease. 13NH4+ myocardial scintigraphy is a valid and sensitive method of assessing regional myocardial perfusion and is especially useful for sequential imaging at short intervals.     

Estimation of shunt flow in coronary-pulmonary fistula by lung perfusion scintigraphy with technetium-99m macroaggregated albumin

The shunt flow from the coronary artery to pulmonary arteries was evaluated in 6 patients with coronary-pulmonary fistula by lung perfusion scintigraphy with technetium-99m macroaggregated albumin. In 2 patients, whose degree of visualization of pulmonary arteries by coronary angiography was relatively high, lung perfusion scintigrams demonstrated the defects at the distal of coronary-pulmonary fistulas.     

Scintigraphic diagnosis of coronary artery disease: myocardial bull's-eye images contain the important information

The bull's-eye image, also called polar map image, has been developed as an important display for the visual and quantitative analysis of myocardial perfusion scintigrams. Quantitative analysis can be performed for example by comparing areas in the bull's-eye image with normal limits or by processing it using artificial neural networks. The usefulness of such methods is highly dependent on the information content of the bull's-eye image. The purpose of this study was to investigate whether there is more diagnostically important information in a set consisting of the myocardial bull's-eye image plus tomographic slice image than in the bull's-eye image alone. A population of 135 patients who had undergone both myocardial scintigraphy and coronary angiography, with no more than 3 months elapsing between the two examinations, was studied retrospectively. Four experienced observers independently classified visually all scintigrams regarding the presence/absence of coronary artery disease in two vascular territories using a four-grade scale. The observers classified the scintigrams once viewing bull's-eye images only, and once viewing tomographic slices and bull's-eye images. Coronary angiography was used as gold standard. The classifications were evaluated using the areas under the receiver operating characteristics (ROC) curves. The classifications based on bull's-eye images only were slightly more accurate than those based on tomographic slices and bull's-eye images in one of the two vascular territories (ROC areas of 0.66 vs. 0.64). The opposite relationship was found in the other vascular territory (0.78 vs. 0.81). None of the differences was statistically significant. In conclusion, the diagnostically important information for the diagnosis of coronary artery disease by myocardial perfusion scintigraphy is present in the bull's-eye image.     

Are the results of thallium scintigraphy and coronary angiography equivalent? An evaluation of thallium scintigraphies performed at Vestfold Central Hospital

The value of exercise-redistribution thallium-201 perfusion scintigraphy (SPECT; single photon emission computed tomography) in the diagnosis of coronary artery disease was evaluated in 23 patients (one patient tested twice) who were subsequently submitted to coronary angiography. Reversible perfusion defects indicating myocardial ischemia were found in 22 patients, of whom 18 had angiographically significant coronary artery stenoses. Two patients had negative thallium scans, one had a normal angiogram and one had single vessel disease. Thus 18 of 19 patients with angiographically verified coronary heart disease had a positive thallium scan. The majority of patients with left main stenosis and triple vessel disease had scintigraphic evidence of double or triple vessel disease. The scintigraphic method identified the correct anatomical localization in 73% of the angiographically verified coronary artery stenoses. In conclusion, a positive exercise-redistribution thallium scan had a high predictive value in the diagnosis of coronary artery disease, whereas its value in estimating the number and localization of stenoses was more limited.     

Left main coronary artery compression during primary pulmonary hypertension

Primary pulmonary hypertension (PPH) is often associated with angina-like chest pain, the mechanism of which is controversial. A 37-year-old woman with severe PPH and angina had transient ischemic ECG changes and reversible anterior perfusion defect on 201thallium scintigraphy. Coronary angiography revealed severe stenosis of the left main coronary artery (LMCA) and otherwise normal vessels. After heart-lung transplantation, examination of the explanted heart showed normal coronary arteries. Compression of the LMCA by the dilated pulmonary artery trunk was responsible for myocardial ischemia. This mechanism should be considered in patients with PPH and angina and might contribute to the high sudden death rate.     

Improved outcome after coronary bypass surgery in patients with ischemic cardiomyopathy and residual myocardial viability

BACKGROUND: Although residual myocardial viability in patients with coronary artery disease and extensive regional asynergy is associated with improved ventricular function after coronary bypass surgery, the relationship between viability and clinical outcome after surgery is unclear. We hypothesized that patients with poor ventricular function and predominantly viable myocardium have a better outcome after bypass surgery compared with those with less viability. METHODS AND RESULTS: Seventy patients with multivessel coronary artery disease and left ventricular ejection fractions < 40% who underwent preoperative quantitative 201Tl scintigraphy before coronary bypass surgery were analyzed retrospectively. 201Tl scintigrams were reviewed blindly, and each segment was assigned a score based on defect magnitude. Segmental viability scores were summed and divided by the number of segments visualized to determine a viability index. The viability index was significantly related to 3-year survival free of cardiac event (cardiac death or heart transplant) after bypass surgery (P=.011) and was independent of age, ejection fraction, and number of diseased coronary vessels. Patients with greater viability (group 1; viability index > 0.67; n=33) were similar to patients with less viability (group 2; viability index < or = 0.67; n=37) with respect to age, comorbidities, and extent of coronary artery disease. There were 6 cardiac deaths and no heart transplants in group 1 patients and 15 cardiac deaths and two transplants in group 2 patients. Survival free of cardiac death or transplantation was significantly better in group 1 patients on Kaplan-Meier analysis (P=.018). CONCLUSIONS: We conclude that resting 201Tl scintigraphy may be useful in preoperative risk stratification for identification of patients more likely to benefit from surgical revascularization.     

Effect of gallopamil on myocardial microperfusion in patients with stable effort angina: a randomized, cross-over, double-blind, placebo-controlled trial

We evaluated the efficacy and safety of daily administration of gallopamil 150 mg/day and its effects on myocardial perfusion in a medium-term, randomized, double-blind, cross-over, placebo-controlled trial. We studied 19 patients (17 males and 2 females; mean age 57 +/- 6.8 years) with stable effort angina, angiographically documented coronary artery disease and reversible perfusion defects during exercise thallium-201 myocardial scintigraphy of at least one segment of the left ventricle. After 2 weeks of a single-blind placebo run-in period, during which each patient underwent at least 2 exercise tests and a 48-hour Holter ECG recording, all patients were treated with either placebo or gallopamil 50 mg t.i.d. for 28 days. At the end of this period, patients crossed over to the alternate regimen. This phase was double blind. After treatment with placebo or gallopamil, patients underwent exercise tests, 24-hour Holter ECG recording and thallium-201 myocardial scintigraphy. Weekly angina frequency and trinitroglycerin (TNT) consumption and safety were also evaluated. No patients dropped out of the study because of major side effects. The number of total ischemic and symptomatic events recorded at 24-hour ECG monitoring, weekly angina frequency and TNT consumption were significantly reduced during gallopamil treatment. After gallopamil administration, exercise duration significantly increased (run-in: 419 +/- 116 s, placebo: 420 +/- 118 s, gallopamil: 511 +/- 144 s; p < 0.05), and ST segment depression was significantly reduced (run-in: -1.3 +/- 0.3 mm, placebo: -1.3 +/- 0.3 mm, gallopamil: -0.94 +/- 0.68 mm; p < 0.01), while heart rate, systolic blood pressure and rate-pressure product were unchanged at rest, at submaximal and at peak exercise. Qualitative and quantitative evaluation of myocardial perfusion and the myocardial uptake percentage of thallium-201 in ischemic zones were significantly improved by gallopamil treatment. These findings demonstrate that gallopamil can improve myocardial perfusion and reduce myocardial oxygen consumption.     

Enhanced detection of proximal right coronary artery stenosis with the additional analysis of right ventricular thallium-201 uptake in stress scintigrams

The value of right ventricular thallium-201 analysis in detecting proximal right coronary artery stenosis in exercise myocardial scintigraphy was analyzed in 52 patients, 27 with and 25 without proximal right coronary artery stenosis. For the detection of proximal right coronary artery stenosis, the sensitivity and specificity of thallium scintigraphic analysis were 59 and 88% for a right ventricular abnormality, 67 and 68% for a left ventricular inferior wall abnormality, and 93 and 56% for an abnormality of either. When both right and left ventricular thallium images were abnormal, all 9 patients had proximal right coronary artery stenoses, and when both were normal, 26 of 28 patients had a normal proximal right coronary artery. The sensitivity and specificity of blood pool scintigraphic variables during exercise (right ventricular ejection fraction and left ventricular inferior wall motion) were not significantly different for detection of proximal right coronary artery stenosis. Thus, the additional analysis of the right ventricle on thallium-201 stress scintigrams can improve the detection of proximal right coronary artery stenosis. When both right ventricular and left ventricular thallium scintigrams are abnormal (or normal), the ability to predict the presence (or absence) of proximal right coronary artery stenosis is very high.     

Pathophysiologic studies of the pulmonary and coronary circulations in man

Studies of the pulmonary circulation in normal man, performed with external radiation detectors, have shown that pulmonary blood volume is about 10% of total blood volume. Pulmonary blood volume was unchanged in patients with acute or chronic left atrial hypertension and in normal persons during expansion of total blood volume in spite of marked increases in pulmonary vascular pressures. However, pulmonary blood volume was greatly increased in patients with polycythemia rubra vera and a large total blood volume and in patients with a left to right shunt but normal pulmonary intravascular pressure. Studies of regional myocardial perfusion with injection of xenon-133 solution into the left coronary artery revealed localized areas of ischemia distal to stenotic lesions even when the patient was at rest. During angina produced by pacing, more severe ischemia occurred, thus suggesting that functional factors reduce local perfusion below resting levels. In patients with "variant" angina, intravenous injection of thallium-201 chloride during spontaneous attacks has revealed large cold areas in myocardial scintigrams not present under control conditions, thus suggesting severe transmural reduction of perfusion in heart muscle corresponding to S-T segment elevation in the electrocardiogram.     

Noninvasive myocardial imaging with potassium-43 and rubidium-81 in patients with left bundle branch block

Noninvasive myocardial imaging with potassium-43 and rubidium-81 has been used successfully to identify areas of infarction and exercise-induced ischemia as regions of decreased radioactivity. The image defects observed are believed to be due to a decreased radionuclide uptake in regions of myocardial scar or to heterogeneous myocardial accumulation of tracer as a result of regional ischemia. Of 27 patients with left bundle branch block studied with noninvasive imaging at rest and during exercise, 25 manifested at rest reduced radioactivity in the region of the interventricular septum. This pattern is similar to that seen in patients with anteroseptal myocardial infarction. Sixteen of the 27 patients underwent diagnostic coronary arteriography and left ventriculography. Only five of these patients had evidence of either previous infarction or significant obstructive coronary artery disease as assessed with clinical or angiographic criteria, or both. Although the image defect was routinely demonstrated at rest in patients with left bundle branch block, this defect was generally normalized or less distinct with exercise in patients with no anatomic heart disease. In contrast, a larger, more distinct or new image defect with exercise correctly identified the presence of significant obstructive coronary artery disease in patients with left bundle branch block. In the clinical application of noninvasive myocardial imaging, these image defects observed at rest can lead to the false pasitive radionuclide interpretation of anteroseptal myocardial infarction.     

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OBJECTIVE: To evaluate the clinical usefulness of cardiac SPECT in the detection of coronary artery disease, and the relation with the site, number and severity of the angiographic lesions. METHOD: We studied 216 patients; with myocardial perfusion imaging with SPECT (T1-201 and/or Tc-99 Sestamibi) and coronary angiogram. We defined the localization of myocardial perfusion defects (anterior, inferior, septal, lateral or apex), and their correlation with coronary angiogram, based on the location, number and severity of coronary angiographic lesions. We considered significative coronary stenosis obstructions of 60% or more. RESULTS: Of the 216 patients studied, 181 (83.8%) were male and 35 (16.2%) female. Age ranged between 30 and 82 years; 143 males and 23 females had a previous myocardial infarction. The SPECT sensitivity for diagnosing ischemia of one, two and three vessel disease was 94%, 96% and 100%. The sensitivity for diagnosing disease in specific vascular territories was 91.6% for LAD 100% for RCA, 92.8% for CX and 100% for left main. CONCLUSIONS: Myocardial perfusion imaging with SPECT has high sensitivity for diagnosing coronary artery disease. The sensitivity and specificity were more accurate in proximal anterior descending artery disease, left main and three-vessel coronary artery disease. We found correlation in the site, number and severity of the angiographic lesions and in myocardial perfusion defects.     

Contribution of MRI in the evaluation of ischemic heart diseases

The high spatial and temporal resolution of MRI provides accurate identification of left ventricular endocardial and epicardial contours. Cine-MRI allows reliable and reproducible measurements of end-systolic and end-diastolic volumes, ejection fraction and left ventricular mass. These measurements are not based on any geometrical hypothesis and so remain valid in presence of ventricular deformation as observed after myocardial infarctions. The value of cine-MRI has been demonstrated in ischaemic heart disease for the study of regional left ventricular function, by analysis of left ventricular segmental function and systolic thickening of the myocardial walls. Cine-MRI may also be performed during pharmacological stress. In coronary patients without ventricular dysfunction at rest, stress cine-MRI enables detection of segmental wall motion abnormalities or reduction of systolic thickening in potentially ischaemic territories. Cine-MRI may contribute to be study of myocardial viability. Regional myocardial perfusion may also be assessed using the rapid sequences of imaging and contrast agents opacifying the intravascular compartment. In coronary patient, underperfused regions may there by be detected. The most rapid imaging techniques enable visualisation of the proximal segments of the coronary arteries and the measurement of blood velocity in the coronary arteries and the calculation of coronary reserve. Simultaneous analysis under basal conditions and after pharmacological stress of global and segmental left ventricular function and of myocardial perfusion, associated with the possibility of imaging the proximal coronary arteries and of measuring the velocity of coronary flow, makes MRI a complete non-invasive method of evaluating patients with ischaemic heart disease.     

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A semi-quantitative right coronary artery score (RCA score) was derived from the ratio of the number of the major left ventricular branches of the right coronary artery to the total of the right coronary and left circumflex arteries, to stratify the extent of perfusion in patients with right coronary artery dominance. Thirty-seven patients with one-vessel coronary disease involving a dominant right coronary artery proximal to the left ventricular branches were selected for study. Thallium scintigraphy was performed after right intracoronary injection in 11 patients, and 26 patients underwent conventional stress thallium scintigraphy (24 exercise thallium and two dipyridamole thallium scintigraphy). Thallium scores of perfusion region size after right intracoronary thallium injection and perfusion defect size in stress thallium studies were quantitated from planar thallium images. Both the RCA score and the regional thallium scores spanned over a wide range. The RCA score (range 0.23-0.85) correlated best with the posterior (70 degrees left anterior oblique view) plus lateral segment (40 degrees left anterior oblique view) thallium score (r = 0.88 and 0.53 for intracoronary and stress thallium studies respectively). It also correlated with the summed thallium scores in the posterior, lateral, apical and inferior segments (r = 0.73 and 0.54 respectively) but not with thallium scores in the apex or inferior segment alone. The proposed RCA score quantitates the variable posterolateral perfusion territory of the right coronary artery, and could stratify the area of myocardium at risk from coronary stenosis in the majority of patients with right coronary dominance.     

Selection of patients for cardiac evaluation before peripheral vascular operations

PURPOSE: This study evaluated the value of preoperative cardiac screening with dipyridamole thallium scintigraphy and radionuclide ventriculography in vascular surgery patients. METHODS: From July 1, 1989, to Dec. 31, 1991, we routinely (irrespective of the patient's cardiac history or symptomatology) performed dipyridamole thallium scintigraphy (DTS) and radionuclide ventriculography (RVG) in 394 patients being considered for an elective vascular operation. Patients with reversible defects on DTS underwent coronary arteriography. RESULTS: DTS results were normal in 146 patients (37%), showed a fixed defect in 75 (19%), and showed a reversible defect in 173 (44%). Patients with and without a history of angina or myocardial infarction had identical rates of reversible defects. Normal left ventricular function (> 50%) was noted in 76% of the patients; 17% had moderate dysfunction (35% to 50%) and 7% had a low ejection fraction (< 35%). The finding of severe coronary artery disease led to cardiac revascularization in 17 patients who had no prior history of cardiac disease and in 13 patients with a history of angina or myocardial infarction. Two deaths and nine major complications were associated with coronary arteriography and cardiac revascularization. Vascular procedures (144 aortic, 53 carotid, 146 infrainguinal) were ultimately performed in 343 patients, with a mortality rate of 1.7% (3.5% aortic, 0% carotid, and 0.7% infrainguinal bypass). The nonfatal perioperative myocardial infarction rate was 2.0%. We monitored all 394 patients for cardiovascular events, with a mean follow-up of 40 months. Patients who underwent cardiac revascularization had a 4-year survival rate of 75%, which was similar to those with a normal DTS. Late cardiac events were significantly more frequent in patients who had either a reversible DTS or RVG < 35%. CONCLUSIONS: Routine cardiac screening of vascular surgery patients had similar impact on patients irrespective of their prior history or current symptoms suggesting coronary artery disease. Routine screening did not result in substantial benefit. Screening studies such as DTS or RVG may be most useful as part of an overall risk versus benefit assessment in patients without active symptoms of coronary artery disease who have less compelling indications for vascular intervention (claudication, moderate-sized aortic aneurysms, or asymptomatic carotid disease).     

Myocardial perfusion scintigraphy to evaluate patients after coronary stent implantation

Coronary stent implantation is an increasingly accepted revascularization method. The 20%-30% restenosis rate during the first 6 mo requires a close follow-up of the patients. Since there is very little data available defining the role of perfusion scintigraphy in the management of this population, the aim of this study was to assess the diagnostic performance of stress myocardial perfusion imaging for detecting restenosis in patients after coronary stent implantation. METHODS: In 82 patients, 93 rest or stress SPECT studies were performed using 201Tl and 99mTc-hexakis-2-methoxyisobutyl isonitrile to evaluate 99 vascular territories with implanted coronary stents. The average interval between the stent implantation and the scintigraphic study was 210.5 +/- 129.6 days. The scintiscans were visually evaluated. A stress-induced perfusion defect with reversibility at rest was used as the criterion for stent restenosis. RESULTS: Coronary angiography revealed a stenosis of > 50% diameter in the region of the stent in 19 arteries, while in 80 arteries there was no evidence of restenosis angiographically. With perfusion scintigraphy, 15/19 vascular territories with restenosed stents showed stress-induced perfusion abnormalities (sensitivity = 79%), while 62/80 territories without restenosis did not (specificity = 78%). In territories without a myocardial infarction (n = 48), sensitivity and specificity values were 8/8 (100%) and 36/44 (82%), and in territories with a myocardial infarction (n = 47) 7/11 (64%) and 26/36 (72%), respectively. Side branch stenosis was fairly frequent in patients without stent restenosis but with a reversible perfusion pattern on their scintiscan (8/18); however, these stenoses were induced infrequently by the stents (3 cases). CONCLUSION: Using the criterion of defect reversibility, stress perfusion SPECT can accurately detect restenoses of coronary artery stents. This method is most accurate for evaluating patients without a previous myocardial infarction in the stented vascular territory.     

Thallium-201 myocardial SPECT in Bland-White-Garland syndrome: two adult patients with inferoposterior perfusion defect

A myocardial 201TI SPECT examination was conducted both prior to and following surgery of two adult patients with an anomalous left coronary artery originating from the pulmonary artery (Bland-White-Garland syndrome). In this syndrome, the anterior wall is usually affected first. Preoperative examination demonstrated an inferoposterior perfusion defect. In both patients, the right coronary artery was markedly dilated, and a significant left-to-right shunt formation was observed. Both patients were diagnosed as possibly having coronary steal syndrome. A prolonged inadequate blood supply to the right coronary region may cause inferoposterior cardiomyopathy. In the postoperative examination, myocardial perfusion markedly improved in one patient whose preoperative SPECT showed redistribution in a delayed scan. Thallium-201 SPECT was therefore found to be useful in assessing both the preoperative and postoperative myocardial perfusion.     

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Emergent cardiac catheterization was performed on a 70-year-old female patient who was admitted for further evaluation of acute myocardial infarction. Coronary angiography didn't reveal any significant stenotic lesion, but levogram showed extensively abnormal contractility around the center of the apex region. On the second hospital day, 99mTc-PYP/201TlCl dual SPECT gave findings similar to those found in acute myocardial infarction, but myocardium--released enzyme stayed within the normal range. Two weeks after, 201TlCl myocardial scintigraphy showed disappearance of the perfusion defect, and normal contractility was observed on the levogram of the chronic phase. Since this case was clinically denied to be myocardial infarction, it was considered a typical case of stunned myocardium which showed prolonged left ventricular abnormal contractility with transient myocardial ischemia. This is a case suggestive for estimations of myocardial reversibility in patients with myocardial perfusion and metabolic disorder in dual SPECT.     

Evaluation of coronary flow velocity dynamics and flow reserve in patients with Kawasaki disease by means of a Doppler guide wire

OBJECTIVES: To assess the pathophysiologic effects of the coronary sequelae of Kawasaki disease on coronary hemodynamic variables, we regionally evaluated the flow velocity dynamics and flow reserve in coronary vessels with lesions using an intracoronary Doppler flow guide wire. BACKGROUND: The pathophysiologic effects of the coronary sequelae of Kawasaki disease on coronary hemodynamic variables have not been completely clarified, and we previously reported some discrepancies between coronary angiographic findings and exercise stress tests in Kawasaki disease. METHODS: Doppler phasic coronary flow velocity was determined using an 0.018-in. (0.046-cm) intracoronary Doppler flow guide wire at rest and during the adenosine triphosphate-induced hyperemic response in 95 patients (75 male, 20 female, mean age 9.8+/-6.2 years) with Kawasaki disease. RESULTS: In 25 patients with coronary aneurysms in 29 vessels, the average peak velocity and diastolic to systolic velocity ratio were significantly (p < 0.05) decreased in the moderate-sized and large-sized aneurysms. Significantly lower values in coronary flow reserve (CFR) were noted in 3 of 10 vessels with moderate aneurysms and in 4 of 7 vessels with large aneurysms. A significant positive correlation (y = 0.53x + 14.6, r2 = 0.91) was observed between the percent diameter stenosis evaluated by angiography and that calculated from the flow velocity measurement. However, the percent diameter stenosis calculated from the flow velocity measurement was underestimated compared with that determined by angiography in the stenotic lesions of intermediate severity. A reduced CFR was noted in five of seven vessels with intermediate stenosis ranging from 50% to 75%, and also in three vessels with mild stenosis ranging from 30% to 40%. A reduced CFR was also observed in six of the eight angiographically normal vessels associated with the area of reduced perfusion on exercise thallium-201 myocardial scintigraphy. CONCLUSIONS: Abnormalities in flow dynamics and a reduction in flow reserve were revealed in coronary aneurysms of intermediate to large size and in stenotic lesions, even of mild to intermediate severity, in patients with Kawasaki disease. Abnormalities in the coronary microcirculation, as well as epicardial lesions, contribute to the pathophysiologic responses in Kawasaki disease.     

Diagnostic value of myocardial thallium stress scintigraphy in the detection of coronary artery disease in patients undergoing chronic hemodialysis

Atherosclerotic heart disease is the leading cause of death in patients with end stage renal disease, but its non invasive detection remains difficult because of a low efficacy of exercise testing. The aim of the study was to evaluate diagnostic accuracy of thallium myocardial imaging after dipyridamole combined with exercise. Forty two chronic dialysis patients (34 men, 8 women) aged 55 +/- 11 years (range: 36 to 75) without symptom of angina nor myocardial infarction were studied. In each patient, an echocardiography, a myocardial scintigraphy with dipyridamole combined with symptom-limited exercise, and coronarography were performed. A coronary heart disease was diagnosed by coronarography in 10 patients (4.5 and 1 respectively with 1, 2 and 3 vessels diseased). Echocardiography detected a left ventricular hypertrophy (LVH) in 26 patients and a regional asynergia in 14 patients. A positive scintigraphy was present in 11 patients. Three false-positive and 2 false-negative on scintigraphy were noted. Sensibility, specificity, positive predictive value and negative predictive value were respectively evaluated at 80, 73, 73 and 93%. All the five patients with either false-positive or false-negative scintigraphy exhibited a LVH. CONCLUSION. In chronic dialysis patients, coronary heart disease may be detected by thallium myocardial imaging after dipyridamole combined with exercise.     

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We compared the results of visual and quantitative evaluation of imaging of myocardial perfusion with 201Tl-SPECT and 13NH3-PET in the 7 non-myocardial infarction (non-MI) and 42 myocardial infarction (MI) patients. On the 201Tl-SPECT and 13NH3-PET imaging, the degree of accumulation of each radioisotope (RI) was visually classified into four grades of defect score. The percentage of uptake was also quantitatively evaluated. RESULTS: In the 7 non-MI patients, NH3% uptake in the lateral wall was significantly lower than in the septum, and in the lateral wall NH3% uptake was significantly lower than Tl% uptake. For the 42 MI patients, segmental defect scores (DS) on 201Tl-SPECT were compared with those on 13NH3-PET, and a high degree of concordance in DS was found for all territories of the left ventricle, antero-septum MI and inferior MI territories. Average Tl% uptake/NH3% uptake was near 1, a highly positive correlation was found between Tl% uptake and NH3% uptake in all territories of the left ventricle and antero-septum MI territories, and Tl% uptake/NH3% uptake was larger than 1, but, a significant positive correlation existed between Tl% uptake and NH3% uptake in the territory with inferior MI. CONCLUSION: These findings indicate that results of 201Tl-SPECT imaging were similar to those of 13NH3-PET in evaluation of myocardial perfusion in the antero-septum and inferior. However, a difference in distribution was observed between 201TlCl and 13NH3 in the lateral wall, indicating that particular attention should be paid to the results of imaging of myocardial perfusion in the lateral wall.