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At least 19 recordsLinked to original sources
PubMed1979

Detection of a false left ventricular aneurysm by first-pass radionuclide ventriculography.

A false left ventricular aneurysm complicating an inferior myocardial infarction was successfully identified by computerized first-pass radionuclide ventriculography using a multicrystal gamma camera. The aneurysmal chamber exhibited paradoxical systolic expansion, a pattern of contraction confirmed by contrast cineangiography. Because of the propensity of false aneurysms to rupture, early noninvasive firm diagnosis is desirable and may be accomplished by first-pass radionuclide angiography.

Cineangiography↗
PubMed1992

Changes in septal regional ejection fraction early and late following coronary artery bypass grafting in patients without postoperative myocardial infarction.

Changes in regional ejection fraction (rEF) of the interventricular septum following coronary artery bypass graft (CABG) surgery were examined using first-pass radionuclide ventriculography (RNVG) in patients without objective evidence of postoperative myocardial infarction (MI). One hundred and one patients had pre- (mean 6.3 days) and early postoperative (mean 8.7 days) RNVGs, and 60 of these patients had follow-up studies at 14-39 months (mean 27 months) postsurgery. Early post-CABG, mean rEF in the proximal septum was unchanged from the preoperative value (35.3%), with almost equal numbers of patients showing increased (n = 36), unchanged (n = 33) or decreased (n = 32) rEFs. In the distal septum, mean rEF increased from 47.1 to 50.7%, with more than twice as many patients having increased (n = 44) as decreased (n = 20) rEF. At late follow-up, proximal septum rEF in individual patients tended to revert to the presurgery baseline, with 72% (13/18) of regions with early decrease improved and 61% (14/23) of those with early improvement decreased. In the distal septum, rEF was less than early post-CABG in 76% (19/25) of patients with early improvement, while being improved in 27% (3/11) of those with early decrease in rEF. In the absence of MI, changes in rEF in the proximal septum early post-CABG tend to resolve over time. While global changes in cardiac systolic motion are the probable cause of many new post-CABG septal abnormalities, persistent septal dysfunction probably reflects effects of permanent damage as a result of the operative procedure.

Adult↗
PubMed1992

Left ventricular volume calculation using a count-based ratio method applied to first-pass radionuclide angiography.

Most count-based radionuclide methods for calculating left ventricular volume rely on measurement of radioactivity in a peripheral blood sample and a measurement of ventricle to collimator distance. We have developed a method which requires neither a blood sample nor a distance measurement and which is applicable to first-pass radionuclide angiography. The parameters used to calculate volume are the area of pixel, the total counts in the left ventricle and the maximum pixel count. The equation was used to calculate the volumes in 50 patients who had both resting first-pass radionuclide angiography (25 patients with a single crystal and 25 patients with a multicrystal camera) and contrast ventriculography on the same day. Correlation coefficients for end-diastolic and end-systolic volumes showed r ranging 0.93-0.98 and standard error of estimate ranging 23-35 ml for end-diastolic volume (14%-17% of mean end-diastolic volume) and 16-23 ml for end-systolic volume (18%-21% of mean end-systolic volume). Image processing software for extracting the needed values is generally available on most commercial nuclear medicine imaging systems and the additional time for the calculations is short. Although the theory is based on multiple assumptions, the volume calculation appears to be reasonably accurate and clinically applicable.

Adult↗
PubMed1992

Reliability of first-pass radionuclide determination of cardiac output in the upright position at rest and during exercise.

The reliability of non-invasive determination of cardiac output using first-pass radionuclide cardiography at rest and during exercise in the upright position was evaluated in 20 patients with coronary artery disease. Cardiac output values ranged from 2.97 to 5.99 l/min at rest and from 5.08 to 10.82 l/min during exercise. Cardiac output results obtained by the radionuclide method were compared with those derived from the thermodilution technique performed simultaneously. The mean difference between the two techniques was 0.02 l/min at rest and -0.34 l/min during exercise; the limits of agreement (mean +/- 1.96 SD) were -1.29 to 1.33 l/min and -1.97 to 1.29 l/min, respectively, indicating an acceptable level of agreement. A high reproducibility of the radionuclide technique was found, with a mean difference between determinations by two observers of 0.03 l/min at rest and 0.21 l/min during exercise, the corresponding limits of agreement being -0.75 to 0.81 l/min and -0.79 to 1.21 l/min, respectively. With the aid of a variance component analysis of two determinations by each of four observers, 95% confidence intervals of +/- 10% at rest and +/- 12% during exercise were computed for the radionuclide cardiac output measurements. The observer variation was most pronounced for the part of the cardiac output determination related to measurement of left ventricular equilibrium activity during exercise. First-pass radionuclide cardiography is a reliable method for determination of cardiac output in cardiac patients at rest and during exercise in the upright position.

Aged↗
PubMed1992

Improvement in the efficacy of exercise first-pass radionuclide angiocardiography in detecting coronary artery disease and the effect of patient age.

The most widely used criterion of normality during exercise radionuclide angiocardiography (a five EF units increase in left ventricular ejection fraction from rest to exercise) has been established in young, healthy volunteers resulting in a relatively low specificity when applied to older, less fit patients or in women. In a group of 57 patients ranging in age from 22 to 79 years with a low likelihood of coronary artery disease, the age of the patient was the only independent variable predicting left ventricular ejection fraction change during exercise. The efficacy of a new age-based criterion for the diagnosis of coronary artery disease was then evaluated in 115 patients with chest pain undergoing both exercise first-pass radionuclide angiocardiography and coronary arteriography. Compared to the classic five EF unit criterion, the age-based criterion had a higher specificity (73.2% vs 34.1% P less than 0.001) without significant loss in sensitivity (85.1% vs 92.6%; P = NS).

Adult↗
PubMed1992

Evaluation of myocardial viability with technetium-99m hexakis-2-methoxyisobutyl isonitrile and iodine-123 phenylpentadecanoic acid and single photon emission tomography.

The detection of viable myocardium in infarcted regions, i.e. hibernating myocardium, is a major goal in clinical cardiology today. We applied combined planar and single photon emission tomography (SPET) to the non-invasive estimation of the left ventricular ejection fraction (LVEF), myocardial blood flow and free fatty acid uptake in the heart. Of the 31 patients with coronary artery disease, 25 (81%) had had a previous myocardial infarction. All patients had at least one persistent perfusion defect on the stress-rest technetium-99m hexakis-2-methoxyisobutyl isonitrile (Sestamibi) study, and the results revealed 57/124 (46%) persistent perfusion defects. As a part of the perfusion study, the LVEF was measured at rest using the first-pass 99mTc-Sestamibi injection, and the mean LVEF was 47% +/- 9% (mean +/- 1 standard deviation). Iodine-123 phenylpentadecanoic acid (123I-pPPA) imaging at rest was performed within 2 weeks from the perfusion study. Then 6-mm transaxial, sagittal and coronal slices of the perfusion and 123I-pPPA studies were reconstructed. The bull's eye displays of the coronal slices were visually surveyed and divided into 4 quadrants: anterior, lateral, posterior and septal. The following image score was used: 0 = fixed defect, 1 = partial uptake and 2 = normal uptake. Moreover an index of metabolic reserve (MR) was calculated by dividing the bull's eye of the 123I-pPPA study by the bull's eye of resting 99mTc-Sestamibi, and its maximum value was normalized to 100%.(ABSTRACT TRUNCATED AT 250 WORDS)

Fatty Acids↗
PubMed1992

Right ventricular performance in arterial hypertension.

To investigate right ventricular function, 24 patients with arterial hypertension and five normotensive controls underwent equilibrium radionuclide ventriculography with simultaneous right heart catheterization. In normal subjects, left ventricular ejection fraction was 57 +/- 2% at rest and 71 +/- 5% on effort, and right ventricular ejection fraction (RVEF) averaged 51 +/- 5% at rest and 65 +/- 2% during exercise. Pulmonary vessel resistance (PVR) was 56 +/- 37 dyn.s.cm-5 at rest and 46 +/- 10 dyn.s.cm-5 on effort. Hypertensive patients were divided into three groups according to their left ventricular function: group 1 (n = 10) had normal left ventricular ejection fraction (LVEF) at rest and on effort (57 +/- 9%; 65 +/- 6%), in this group, right ventricular systolic reserve was reduced (RVEF 52 +/- 7% at rest, ns; RVEF 57 +/- 7% on effort, P less than 0.01 compared to controls). Pulmonary vessel resistance during exercise averaged 78 +/- 24 dyn.s.cm-5, which was significantly higher compared to controls (P less than 0.01). In group 2, left ventricular contractions were normal at rest (60 +/- 6%, ns) but deteriorated during exercise to 56 +/- 8% (P less than 0.001, compared to controls). These patients also showed a lack of right ventricular augmentation at ejection fraction (54 +/- 8% at rest, ns; 56 +/- 8% under exercise, P less than 0.05). PVR was significantly enhanced during exercise (88 +/- 40 dyn.s.cm-5, P less than 0.05 compared to controls).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

Difference in the residual left ventricular pump function between anterior and inferior myocardial infarctions.

To evaluate the left ventricular regional ejection fraction (EF) of noninfarcted area in relation to the left ventricular end-diastolic volume (EDV) in patients with recent myocardial infarction (MI), 75 patients with Q-wave MI (anterior: 51 patients; inferior; 24 patients) were studied. The regional EF of noninfarcted area was obtained by radionuclide angiocardiography 4 weeks after the onset of MI and was used to estimate the left ventricular regional function of the noninfarcted area. Peak creatine kinase and QRS scores were not significantly different between anterior and inferior MI in each left ventricular EDV (EDV < or = 100, 101-139 and > or = 140 ml). Global EF and regional EF of noninfarcted area in anterior MI with left ventricular EDV > or = 140 ml was significantly lower than in those with EDV < or = 139 ml (p < 0.01), whereas there were no significant differences in global EF and regional EF of noninfarcted area in the three groups of left ventricular EDV in inferior MI. Thus, the effect of left ventricular EDV on regional EF of noninfarcted area and on the total cardiac performance was more important in anterior than in inferior MI, because a similar degree of left ventricular dilatation resulted in more severe derangements after anterior MI.

Adult↗
PubMed1992

Dynamic process between the clotting and the lytic activities on intracardiac thrombi--its relationship with systemic embolization.

To clarify the relationship between clotting and lytic activities of intracardiac thrombi, and to elucidate whether this could be used to evaluate the embolic risk the ratio of indium-111 radioactivity accumulated on thrombi to that in the blood pool using dual-tracer technique %IE as a parameter of the clotting activity, and D-dimer, which is a fibrin specific degradation product, as a parameter of lytic activity were measured in 37 patients with intracardiac thrombi. Fifteen of the 37 patients had past histories of arterial embolization. The values of D-dimer correlated significantly with those of %IE (r = 0.758, p less than 0.01), e.g., the higher the values of D-dimer the higher the values of %IE. 37 patients were divided into 2 groups using the regression line for the D-dimer and %IE domains. Eleven patients above the regression line had thrombosis in excess of fibrinolysis but the remaining 26 patients under the regression line had fibrinolysis in excess of thrombosis. The incidence of past embolic episodes was 82% (9/11) in patients with thrombosis in excess of fibrinolysis but 23% (6/26) in patients with fibrinolysis in excess of thrombosis. These results demonstrated that intracardiac thrombi were under the dynamic process between the clotting and the lytic activities and moreover patients with intracardiac thrombi and thrombosis in excess of fibrinolysis had a substantial risk of arterial embolization.

Aged↗
PubMedDate not supplied

Thermodilution measures of right ventricular ejection fraction and volumes in heart transplant recipients: a comparison with radionuclide angiography.

A reliable, convenient measure of right ventricular ejection fraction may be a useful adjunct to evaluate cardiac allograft rejection. The purpose of this investigation was to compare two measures of right ventricular ejection fraction: (1) radionuclide angiography with the first-pass technique and (2) thermodilution with a balloon flotation catheter. The study was performed in 26 heart transplant recipients; hemodynamics, thermodilution cardiac output, and right ventricular ejection fraction were measured. First pass radionuclide angiography was performed either simultaneously (n = 11) or within 4 hours (n = 15) of the thermodilution study. Mean thermodilution right ventricular ejection fraction was 39% +/- 8%, and radionuclide angiography ejection fraction was 47% +/- 9%, which represents a highly significant difference (p < 0.001) in techniques. Linear regression showed no correlation between the two techniques (r = 0.3; p = NS). No differences in results were observed in those studied simultaneously versus less than 4 hours. We conclude that the thermodilution technique underestimates right ventricular ejection fraction in heart transplant recipients and that its usefulness as a tool to screen for systolic dysfunction related to rejection is limited.

Cardiac Catheterization↗
PubMed1992

Role of the septal leaflet in tricuspid valve closure. Consideration for treatment of complete atrioventricular canal.

A septal leaflet of the tricuspid valve is thought to work differently from other anterior and posterior leaflets. We studied its role in valve closure in dogs by means of a dynamic area meter. During the control state, the tricuspid valve orifice area increased twice in diastole coincidentally with either atrial systole or rapid ventricular filling. We observed several findings after the septal leaflet resection: (1) two peak area patterns of the tricuspid valve orifice in diastole, (2) no elevation of right atrial pressure on ventricular systole (there was no V wave), (3) no tricuspid valve regurgitation on right ventriculography. These findings suggest that a complete valve closure occurred without the septal leaflet in regular sinus rhythm. An elevation of the right ventricular pressure produced by pulmonary artery stenosis without septal leaflet, however, easily caused tricuspid valve regurgitation in contrast to the same pressure of the right ventricle with the normal tricuspid valve. The right ventricular pacing caused severe valve regurgitation without the septal leaflet. Results indicate that in the repair of the complete atrioventricular canal defect and other tricuspid valve lesions, the septal leaflet of the tricuspid valve rarely requires attention. An atrioventricular block should be avoided, however, because electrical cardiac pacing on the right ventricle causes severe valve regurgitation without the septal leaflet.

Animals↗
PubMed1992

[The right ventricle and tachyarrhythmias. The structural-functional characteristics studied by radionuclide ventriculography].

Radionuclide ventriculography was used to evaluate the functional structural parameters of the right ventricle systole and diastole in 100 patients with paroxysmal tachyarrhythmia without signs of cardiac insufficiency (42 with cardiac fibrillation, 35--supraventricular tachycardia, 23--with ventricular arrhythmia). Results indicate that radionuclide ventriculography allows to evaluate objectively the functional state of the right ventricle in patients with paroxysmal tachycardia, detect early signs of deterioration of its hemodynamic productivity and contractile capacity in patients refractory to treatment of cardiac arrhythmias.

Adolescent↗
PubMed1992

[Right ventricular volume determination by continuous 81mKr infusion and 99mTc blood pool imaging].

Our newly developed radionuclide method for the calculation of right ventricular (RV) volume was examined in this study. Using a semi-geometric count-based method, volume can be measured by the following equation: Cv = Cm/(L/d). V = (Ct/Cv) x d3 = (Ct/Cm) x L x d2. (V = volume, Cv = voxel count, Cm = the maximum count of a container, Ct = the total count of the container, L = maximum length of the image of the container obtained from a direction perpendicular to the direction where the count data were collected, and d = pixel size.) A phantom study was performed by setting a cylindrical container in a system which circulated 5 liters of water per minute. 81mKr solution was infused continuously into the container, and images of the container were collected for one minute. Cm and Ct were obtained and, because the container was cylindrical, the maximum width of the image of the container was measured as L. The volume of the container was calculated using the above equation. The container's true volume and the volume measured by this method showed a good correlation with r = 0.997 (n = 13, p < 0.001). This theorem was applied to RV images obtained in the 30 degree right anterior oblique position by continuous infusion of the 81mKr solution. Multiple gated acquisition was performed and RV end-diastolic maximum counts and total counts were obtained. The RV maximum width was measured as L on the end-diastolic cardiac pool image with 99mTc-D-HSA collected in the 40 degree left anterior oblique position.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1979

Validity of left-ventricular ejection fractions measured at rest and peak exercise by equilibrium radionuclide angiography using short acquisition times.

To validate ejection fraction (EF) calculations from 5 and 2 minutes of multiple-gated equilibrium radionuclide angiographic data and to establish its utility during alterations in cardiac performance, we studied 38 patients with chest pain suggestive of coronary artery disease. Twenty-four patients underwent contrast ventriculography (CV) as well as first-pass (FP) and equilibrium (EQ) radionuclide angiography at rest, and 14 additional patients had both radionuclide tests performed at rest as well as during peak supine bicycle exercise. The resting 5-min acquisition ejection fractions were compared between each method and the following correlations were generated: r = .92, n = 24 (CV-EQ), r = .92, n = 24 (CV-FP), and r = .95, n = 38 (FP-EQ). The variability of EQ-EF calculations between two independent observers was less than 2%; the mean absolute difference between two sequential 2-min acquisitions and the 5-min recordings was -.1 +/- 1.6%, and the reproducibility of sequential 2-min ejection fractions was excellent (r = .98). EQ and FP ejection fractions at symptom-limited exercise correlated well (r = .96, n = 14). We conclude that equilibrium radionuclide angiography is a valid method to measure EF both at rest as well as during peak exercise even when 2-min acquisition periods are used.

Adult↗
PubMed1992

Analysis of left ventricular function from gated first-pass and multiple gated equilibrium acquisitions.

99mTechnetium-sestamibi is a new myocardial perfusion imaging agent that offers significant physical advantages over 201thallium for myocardial perfusion imaging. One of these advantages is that it can be used in the assessment of ventricular function by means of first-pass radionuclide angiography (FPRNA), acquired during the injection of the tracer. In this study we compared gated list mode first-pass acquisition with 99mTc-sestamibi (FP-MIBI) to multiple gated equilibrium radionuclide ventriculography (MUGA) with 99mTc-labelled red blood cells for the determination of global left ventricular ejection fraction (LVEF). The study population consisted of 20 patients (mean age 54 years) who were submitted to stress-rest perfusion imaging. Resting FPRNA was performed using 99mTc-sestamibi and the reference data were acquired within a week with the MUGA technique. A linear correlation between FP LVEF and MUGA LVEF gave an r = 0.974 (p < 0.01). Diastolic and systolic timing and velocity parameters had lower correlations between these two methods. We conclude that global LVEF can be precisely measured with 99mTc-sestamibi when compared to usually employed MUGA technique with 99mTc-labelled red blood cells.

Cardiac Output↗
PubMed1978

Left-ventricular ejection fraction and segmental wall motion by peripheral first-pass radionuclide angiography.

A computerized edge-detection method was developed to obtain radionuclide ventriculograms for analysis of left-ventricular ejection fraction and segmental wall motion from first-pass studies following i.v. injection of radionuclide. The accuracy of this technique was examined in 21 patients undergoing cardiac catheterization. Tc-99m DTPA was injected into an antecubital vein, with data acquisition in the 30 degrees RAO projection by a gamma scintillation camera interfaced to a computer. A computerized profile analysis was used to determine objectively the edge of the left-ventricular blood pool. Time-activity curves were generated, and the ejection fraction was calculated from sequential end-diastolic and end-systolic count rates. The values for ejection fraction correlated well with those obtained by single-plane contrast ventriculography (r = 0.95). End-diastolic and end-systolic images were reconstructed from the time-activity curve. To analyze segmental wall motion, the left-ventricular outline was divided into five segments and the motion of each segment was graded qualitatively from 1 to 5. Seventy-five of 105 segments had the same grade as the wall motion determined by contrast angiography, and 102 of 105 were within one grade. (P less than 0.001). These findings demonstrate the accuracy of this improved technique for objective, rapid, and noninvasive determination of left-ventricular function.

Adult↗
PubMed1992

Presurgical identification of hibernating myocardium by combined use of technetium-99m hexakis 2-methoxyisobutylisonitrile single photon emission tomography and fluorine-18 fluoro-2-deoxy-D-glucose positron emission tomography in patients with coronary artery disease.

We tested the possibility of identifying areas of hibernating myocardium by the combined assessment of perfusion and metabolism using single photon emission tomography (SPET) with technetium-99m hexakis 2-methoxyisobutylisonitrile (99mTc-MIBI) and positron emission tomography (PET) with fluorine-18 fluoro-2-deoxy-D-glucose (18F-FDG). Segmental wall motion, perfusion and 18F-FDG uptake were scored in 5 segments in 14 patients with coronary artery disease (CAD), for a total number of 70 segments. Each subject underwent the following studies prior to and following coronary artery bypass grafting (CABG): first-pass radionuclide angiography, electrocardiography gated planar perfusion scintigraphy and SPET perfusion scintigraphy with 99mTc-MIBI and, after 16 h fasting, 18F-FDG/PET metabolic scintigraphy. Wall motion impairment was either decreased or completely reversed by CABG in 95% of the asynergic segments which exhibited 18F-FDG uptake, whereas it was unmodified in 80% of the asynergic segments with no 18F-FDG uptake. A stepwise multiple logistic analysis was carried out on the asynergic segments to estimate the postoperative probability of wall motion improvement on the basis of the preoperative regional perfusion and metabolic scores. The segments with the highest probability (96%) of functional recovery from preoperative asynergy after revascularization were those with a marked 18F-FDG uptake prior to CABG. High probabilities of functional recovery were also estimated for the segments presenting with moderate and low 18F-FDG uptake (92% and 79%, respectively). A low probability of functional recovery (13%) was estimated in the segments with no 18F-FDG uptake.(ABSTRACT TRUNCATED AT 250 WORDS)

Coronary Artery Bypass↗