Myocardial scintigraphy with technetium 99m pyrophosphate]

The pyrophosphate of Tc99m attaches itself to ischaemic myocardial cells, and therefore makes it possible to obtain a scintigram of necrotic or necrosing myocardium. In a series of 65 cases the scintigram was positive in every case in which there had been a recent transmural infarct (17 cases). The results showed greater variation in the other ischaemic conditions involving the myocardium (limited infarcts or simple angina). The progress as a function of time was stuided in a series of fairly recent and older infarcts. The limitations and future prospects of this investigations are discussed.     

Detection of unstable angina by 99m technetium pyrophosphate myocardial scintigraphy.

99mTechnetium stannous pyrophosphate has been shown to accumulate in acutely infarcted myocardium. To determine if the isotope is also taken up by severely ischemic, but not necrotic myocardium, we performed myocardial scintigraphic studies in 17 patients with chest pains. Seven of the patients satisfied conventional clinical, electrographic, and laboratory criteria for the diagnosis of unstable angina and showed no electrocardiographic or enzymatic evidence of myocardial necrosis. Five of these seven patients with unstable angina demonstrated abnormal localized patterns, and one showed a borderline picture. Myocardial scintiscans were normal in all of a control group of ten patients with stable angina. Thus, scanning with 99mtechnetium stannous pyrophosphate is shown to be of value in the objective demonstration of myocardial abnormality in unstable angina.     

Clinical and prognostic value of myocardial scintigraphy using technetium Tc 99m pyrophosphate in patients with unstable stenocardia]

The clinical and predictive value of 99mTc pyrophosphate myocardial scintigraphy was studied in 164 patients with various clinical courses of unstable angina pectoris. Some patients with the unstable anginal syndrome proceeding with prolonged pain attacks were shown to have irreversible myocardial lesions detectable by 99mTc pyrophosphate myocardial scintigraphy. However, the study indicated that the presence of small myocardial necrotic foci in this case was of insignificant predictive value.     

Echography and scintigraphy using technetium 99m pyrophosphate in the diagnosis of cardiac amyloidosis

The diagnosis of amyloid cardiomyopathy was only based, until the last few years, on the results of invasive techniques. It seems presently that the combined contribution of cardiac sonography and scintigraphy using technetium 99m pyrophosphate, makes, most of the time, this diagnosis possible without need for additional examinations. This notion is illustrated by a typical case-report and data from the literature. Demonstration on the cardiac sonogram of a thickening of the walls-while the context and especially the electrocardiogram are not in favor of a left ventricular hypertrophy--associated with a very particular "hyperechoing" aspect and an abnormal fixation on the scintigram, may be considered specific of this disease.     

Noninvasive quantitation of myocardial infarction with technetium 99m pyrophosphate.

We sought to quantitate infarct size using radioactive imaging techniques. Infarcts were created in closed chest dogs. Using a scintillation camera interfaced to a computer, infarct images were made in the anterior, left lateral, LAO, and RAO projections, 48 hours after infarction and 75 to 90 min following the intravenous injection of 15 mCi of Technetium 99m pyrophosphate (Tc-PYP). Images were computer enhanced and area was calibrated with a radioactive grid source of known dimensions. Image radioactivity was normalized for decay and dose corrected for body weight. Animals were sacrificed two hours following the injection Tc-PYP. Postmortem images were also computer enhanced and calibrated. Gross infarct area and weight were estimated and transmural biopsies were evaluated for Tc-PYP activity and analyzed for creatine phosphokinase (CPK) content. Contiguous biopsies were pathologically analyzed and graded. There was a negative correlation between tissue Tc-PYP activity and CPK content (r=0.89). Pathologic severity worsened with increased Tc-PYP activity and diminished CPK content. There was a good correlation between gross infarct area and image infarct area, both in vivo (r     

Early noninvasive detection of reperfusion and infarct by intravenous technetium 99m pyrophosphate scintigraphy following thrombolysis

To determine whether technetium-99-pyrophosphate accumulation immediately after intravenous thrombolysis can serve as a marker of reperfusion and infarct size, 17 patients with acute myocardial infarction were studied. Immediately after thrombolysis 10 mCi of technetium-99m pyrophosphate were injected intravenously. Coronary and left ventricular angiography were then performed in all patients, revealing patent coronary arteries in 13 patients. In all patients, 0.3 and 0.5 mCi of thallium-201 were injected into the right and left coronary artery, respectively, followed by planar scintigraphy. 6 patients with patent coronary arteries and a large thallium-201 defect had massive (more than one third of the cardiac silhouette) pyrophosphate accumulation (group A), whereas 7 patients with a small or no thallium-201 defect in the presence of a patent infarct artery had either focal or no pyrophosphate accumulation (group B). In contrast, 4 patients with an occluded infarct artery showed no acute pyrophosphate uptake despite a large thallium-201 defect (group C). Emission computed tomography confirmed the planar scintigraphic data in group A patients and revealed small thallium-201 defects and focal pyrophosphate accumulation in group B patients with negative planar scintigrams. Global and regional ejection fractions in the infarct area, measured from the acute and follow-up left ventricular angiograms, were higher in group A than in group B and C patients. It is concluded that early intravenous technetium-99m pyrophosphate scintigraphy in patients with acute myocardial infarction undergoing intravenous thrombolysis may serve as an indicator of reperfusion and infarct size.     

Right ventricular myocardial infarction diagnosed by 99 m technetium pyrophosphate scintigraphy: clinical course and follow-up

Out of 178 consecutive patients with acute inferior wall myocardialinfarction submitted to technetium-99 m pyrophosphate scintigraphy,49 (27.5%) were found to have concomitant right ventricularinfarction. Gated blood pool scans showed right ventricularabnormalities in 21 out of 26 patients who were submitted tothis investigation (right ventricular asynergy: 16 cases; rightventricular dilatation: eight cases; decreased right ventricularejection fraction: 16 cases). Complications were common in the acute stage. Shock was notedin 19 cases (eight related to bradycardia, three related torelative hypovolaemia and eight instances of true cardiogenicshock). Atrial fibrillation (seven patients), ventricular fibrillation(eight patients) and severe atrioventricular conduction disorders(13 patients) were also frequent. In spite of this, the in-hospitalmortality was low: three deaths occurred (6.1%), one from heartfailure, two others from posterior septal rupture. All patients were followed up for one year or more. Six additionaldeaths were noted (three from left cardiac failure, two fromrecurrent anterior wall infarction and one from massive pulmonaryembolism). Clinical assessment, haemodynamic measurements andgated blood pool scans showed significant improvement of rightventricular function with return to normal in those cases withsmall right ventricular infarcts as judged from technetium-99m pyrophosphate scintigraphy. In spite of the complications seen in the initial period, patientswith a right ventricular infarction have a good overall prognosisand the long-term outcome, primarily determined by the left-sidedlesions, is often favourable.     

Technetium-99m stannous pyrophosphate myocardial scintigraphy after cardiopulmonary resuscitation with cardioversion.

Thirty consecutive patients underwent technetium-99m stannous pyrophosphate myocardial scintigraphy 48--72 hours after successful cardiopulmonary resuscitation and direct current cardioversion. Five patients with transmural myocardial infarctions by ECG and enzyme determinations were correctly identified by scintigraphy. Myocardial scans were positive in five of nine patients with nontransmural infarction. Of 16 patients without evidence of myocardial infarction, only two (13%) had false-positive myocardial scans. The overall accuracy of imaging in this series was 80%. We conclude that false-positive scans after cardiopulmonary resuscitation with electrical cardioversion are infrequent, and do not significantly detract from the value of myocardial scintigraphy in the diagnosis of myocardial infarction.     

Utility of technetium Tc 99m pyrophosphate bone scanning in cardiac amyloidosis

Thirty-four patients with amyloidosis proved by biopsy specimen were studied using technetium Tc 99m pyrophosphate scintigraphy to assess its utility in the diagnosis of amyloid heart involvement. Of 14 patients studied retrospectively, only three had intense uptake judged to be diagnostic of cardiac amyloidosis. In a prospective analysis of 20 patients with amyloidosis, all of whom had evidence of cardiac involvement by two-dimensional echocardiography, 17 had abnormal scans. Fourteen of the 17 scans had only 1+ or 2+ uptake, a finding that also was present in 15 of the 20 control patients (without amyloid heart disease). Only three of the 20 patients with cardiac amyloidosis had intense uptake that was considered unequivocal and diagnostic of amyloidosis. Of the five patients with biopsy specimen proof of endomyocardial amyloidosis, only one had intense uptake and one had no uptake. When intense uptake of technetium Tc 99m pyrophosphate is found in the heart of a patient, amyloidosis is highly likely. The technique, however, is not sufficiently sensitive to warrant routine screening of patients with amyloidosis or cardiomyopathies. Cross-sectional echocardiography is superior to pyrophosphate scintigraphy for recognition of cardiac amyloidosis.     

False-positive technetium 99m depreotide scintigraphy resulting from round atelectasis

The authors report two cases of round atelectasis that showed increased accumulation of technetium (Tc) 99m depreotide on planar and single photon emission computed tomographic scintigraphy. It should be considered that round atelectasis is a potential nonmalignant cause for positive 99mTc depreotide scintigraphy.     

Assessment of diagnostic value of technetium-99m pyrophosphate myocardial scintigraphy in 80 patients with possible acute myocardial infarction.

The diagnostic value of technetium-99m-pyrophosphate (Tc-pyrophosphate) myocardial scintigraphy was determined in 80 consecutive patients who had been admitted to the coronary care unit in order to rule out an acute myocardial infarction. Scintigraphic findings obtained within 5 days of admission were correlated with the final cardiac diagnosis determined for each patient. Significant myocardial uptake of Tc-pyrophosphate (positive scans) occurred in 13 of 22 patients (59%) who had enzyme and/or electrocardiographic proven acute myocardial infarct: 3 out of 5 with transmural myocardial infarct, 9 of 16 with nontransmural myocardial infarct, and 1 patient with left bundle-branch block. Of 58 patients who showed no evidence of acute myocardial infarction, positive scans occurred in 14 of 33 patients who had unstable angina pectoris (42%), 0 of 6 who had congestive heart failure, 6 of 9 who had other acute cardiac syndromes, and in 0 of 10 who had noncardiac chest pain. In the patients with unstable angina pectoris positive scans could not be predicted on the basis of the history, electrocardiographic findings or the arteriographically determined severity of the coronary artery disease. Blood levels of Tc-99m activity measured in 21 cardiac patients and in 6 volunteers did not correlate with the uptake intensity of Tc-pyrophosphate. These findings suggest caution in the use of this imaging method for the diagnosis of acute myocardial infarct in patients admitted with 'rule out myocardial infarction'.