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This study presents a new tool for the visualization and analysis of three-dimensional (3-D) cardiac single-photon emission computed tomography (SPECT). The first step consisted of computing the 3-D pseudo-skeleton of a binarized myocardium and, using the skeleton points, to design a bullet model (half ellipsoid prolonged by a cylinder). Afterwards, this model was used to drive the warping of the 3-D myocardium, initially egg-shaped, into a thick, flat disc using the thin-plate splines as deformation method. Hence, instead of achieving several rotations of the initial egg-shaped volume to have an idea on the myocardial outer face (epicardial) only, the whole myocardium is seen by looking either on top of the disc-shaped transformed myocardium (epicardial surface) or underneath for the inner face (endocardial). This new shape permitted us to localize any type of defect and to evaluate its extent and depth just by a single glance. A detailed analysis, achieved after stripping away this shape in about 10 layers, allowed us to evaluate the defect extent layer by layer and to determine whether the defect involves the totality of the myocardium layers. Finally, its flattening following the ventricular long-axis led to a summed bull's eye.

Purpose: The aim was to investigate in patients receiving doxorubicin whether any alteration in myocardial oxidative metabolism or blood flow as assessed by positron emission tomography (PET) could be observed either after the first dose of the drug, or during its chronic administration., Methods: Six female non-heart-failure cancer patients treated with doxorubicin were included in a longitudinal study. Resting radionuclide cineangiography and PET scanning with carbon-11 acetate were performed the day before the initiation of doxorubicin treatment at a dosage of 50 mg/m2 every 3 weeks, and 3 weeks after the cumulative administration of 300 mg/m2 (chronic toxicity). In addition, PET was performed 24 h after the first administration of doxorubicin (evaluation of acute toxicity). Myocardial oxidative metabolism and blood flow were assessed by PET (acute and chronic toxicity), and left ventricular ejection fraction was measured by radionuclide angiography (chronic toxicity)., Results: Using PET for both acute and chronic toxicity evaluations, no significant effect of doxorubicin was observed either on the flux through the tricarboxylic acid (TCA) cycle or on myocardial blood flow. However, systolic left ventricular function showed a small but significant impairment after the administration of 300 mg/m2 of doxorubicin., Conclusions: Other hypotheses should be explored to better explain the predominant mechanisms of the cardiotoxicity of anthracyclines in humans.

Objective: To assess the blood flow supply offered to the myocardium by surgical revascularization using bilateral internal mammary (IMAs) and gastroepiploic (GEA) arteries., Methods: Two-year assessment by exercise thallium myocardial scintigraphy without medical treatment was performed in 122 patients (mean age 61 +/- 9 years) who underwent coronary artery bypass grafting (CABG) with exclusive use of IMAs and GEA. Usually, the right IMA was used to bypass the left anterior descending coronary artery, and the left IMA to bypass the diagonal and the marginal arteries as a sequential graft if required. The GEA was used to bypass the right coronary artery (RCA) in 50 patients and its posterior branches in 72 patients., Results: During maximal or submaximal exercise stress testing, 119 patients (98%) were asymptomatic and 26 patients (21%) exhibited moderate ischemic ECG modifications which were correlated (P < 0.01) with incomplete revascularization and with the use of GEA to bypass the RCA. A third of patients had moderate ischemic thallium defects on exercise reversible after redistribution (anterior, 10; lateral, 2; inferior, 28). Silent residual myocardial ischemia detected by thallium scintigraphy was correlated (P < 0.001) with ECG modifications and incomplete revascularization; and inferior thallium defects were more frequent when GEA bypassed the RCA (P < 0.05). However, 26% of patients had residual ischemia despite a complete revascularization, and in at least 18% of cases for GEA and 8% for right IMA, arterial graft blood flow was insufficient at maximum exercise level and caused silent residual myocardial ischemia detected by thallium scintigraphy., Conclusions: Myocardial revascularization using bilateral IMAs and GEA offers a satisfactory myocardial perfusion in the majority of cases; however silent residual myocardial ischemia was detected in a third of patients and was related to incomplete revascularization and to insufficient blood flow supply probably due to small diameter of the arterial grafts.

Objective: To assess the prognostic factors of myocardial recovery expected after coronary bypass surgery and the impact of surgical technique used, a prospective non-randomized study including a 1-year postoperative evaluation of left ventricular function was performed in patients with left ventricular dysfunction (left ventricular ejection fraction (LVEF) < 0.40)., Methods: From 1993 to 1996, 110 patients (mean age 61+/-11 years) were included in the study. The mean LVEF was 31+/-6%. All patients had preoperative radionuclide investigations based on the combination of stress/reinjection thallium single photon emission computed tomography (SPECT) and planar evaluation of LVEF; 88% of patients had reversible ischemic thallium defects. Two surgical technique were used: 53 patients received the left internal mammary artery with associated sequential vein graft, and 57 patients received only arterial grafts, internal mammary and gastroepiploic arteries. The mean number of distal anastomoses was 3.2+/-0.8 and 54% of patients had complete revascularization. At 1 year, all survivors had clinical evaluation and the same radionuclide investigations., Results: The early mortality was 2.7%. At 1 year, 100 patients were surviving; on average, NYHA class decreased 1.9+/-0.8 to 1.4+/-0.6 (P < 0.01) and CCS class from 2.8+/-0.6 to 1+/-0.3 (P < 0.01). The mean LVEF increase from 31+/-9 to 34+/-10% (P < 0.01) and the mean LV end-diastolic volume decreased from 317+/-112 to 285+/-108 ml (n.s.). The postoperative improvement in LV function was higher in patients in NYHA class 3 or 4 before surgery (P < 0.05), when associated sequential vein graft had been used (P < 0.01), and in patients with low preoperative LVEF (P < 0.01). The postoperative LVEF improvement observed was significantly correlated with the improvement in left ventricular end-diastolic (LVED) volume and the improvement in redistribution/reinjection thallium uptake. Multivariate analysis showed that the surgical technique used and the preoperative LVEF were independent prognostic factors of the postoperative myocardial function recovery, with a significant positive impact of the vein use., Conclusion: This study confirms the excellent clinical results of coronary artery bypass grafting (CABG) in patients with coronary artery disease and LV dysfunction; improvement in LV function can be documented objectively and is correlated with reperfusion of hibernating myocardium. However, the extended use of arterial grafts does not allow to achieve the significant myocardial recovery observed with the use of one internal mammary artery (IMA) and associated sequential vein graft; it seems to be related to the preoperative selection of patients, but a direct negative impact of arterial grafts was documented and leads to be cautious in patients with severe LV dysfunction.

Technetium-99m tetrofosmin is a new myocardial imaging agent with improved handling and kinetic characteristics. The purpose of this study was to compare the ability of planar and SPECT Tc-99m tetrofosmin imaging with Thallium-201 planar data to detect coronary artery disease and individual vessel lesions ( > 50% diameter stenosis). Seventy-two patients with definite or suspected coronary artery disease were included. Sixty-three had angiographic evidence of coronary artery disease, among whom 42 had had a previous myocardial infarction, while 21 had not. The total number of diseased arteries was 111. Patients underwent symptom-limited treadmill or bicycle exercise to similar endpoints. Thallium and tetrofosmin images were analysed separately by consensus reading. Interpretation was made for five standard anatomical regions (anterior, septal, inferior, lateral and apex), classified into four categories (normal, reversible, fixed and mixed defects). Sensitivity and specificity to detect coronary artery disease were 71% and 78% for Thallium-201 vs 68% and 78% for tetrofosmin by planar imaging, and 87% and 89% for tetrofosmin by SPECT. The improved sensitivity of SPECT was confirmed both in patients with and without previous myocardial infarction. The sensitivity to detect individual vessel lesions was improved by SPECT (59% tetrofosmin SPECT vs 50% thallium planar and 51% tetrofosmin planar). Individual vessel lesion detection by SPECT was 50% for the left anterior descending coronary artery, 42% for the left circumflex and 86% for the right coronary artery. This study confirms the value of technetium-99m tetrofosmin as a myocardial imaging agent. Improvements in diagnosis and in evaluating extent of disease can be expected from using SPECT.

Background: Our objective was to compare the sensitivity and specificity of tetrofosmin, a new 99mTc-labeled myocardial perfusion imaging agent for the detection of myocardial perfusion abnormalities, with those of 201Tl and coronary angiography. Our hypothesis was that same-day stress/rest tetrofosmin imaging could provide data comparable to those of 201Tl imaging. Myocardial perfusion imaging plays an important role for the evaluation of coronary artery disease. Newer 99mTc-labeled agents offer several advantages over 201Tl, the conventional myocardial perfusion imaging agent. Tetrofosmin is a new 99mTc-labeled agent with promising results in preliminary studies., Methods and Results: Two hundred fifty-two patients with suspected coronary artery disease were enrolled in 10 centers in the United States and Europe. All patients underwent exercise and rest myocardial perfusion imaging with 99mTc-tetrofosmin using two separate injections of the radiotracer 4 hours apart on the same day. Planar images were obtained in three standard views 15 to 60 minutes after radiotracer injection. Patients also underwent standard exercise and redistribution planar 201Tl imaging within 2 weeks of tetrofosmin imaging. In addition, 58 healthy subjects with low likelihood of coronary artery disease underwent exercise and rest tetrofosmin imaging. Coronary angiograms were available in 181 patients with suspected coronary artery disease. All radionuclide images were processed in the central core laboratory and interpreted blindly by a panel of four experienced readers. 201Tl images and tetrofosmin images were read separately. Discrepancies were resolved by consensus. The workload, peak heart rate, and double products were comparable during exercise for both imaging agents. Technically acceptable paired 201Tl and tetrofosmin images were available in 224 of 252 patients. Tetrofosmin images were generally of good quality, with low extracardiac activity, and easy to interpret. Patients were categorized as showing normal, ischemia, infarction, or mixture with each imaging modality. Precise concordance for each of these categories was 59.4% (kappa = 0.44; 95% CI, 0.35 to 0.53). When patients were categorized as normal or abnormal, the concordance was 80.4% (kappa = 0.55; 95% CI, 0.43 to 0.67). When each of five anatomic territories (septal, anterior, inferior, lateral, and apical) was categorized as normal versus abnormal, the concordance varied from 81% to 90%. When similar comparison was made for the specific category of abnormality, the concordance was 64% to 84%. When coronary angiography was used as the criterion, the sensitivity and positive and negative predictive accuracy of tetrofosmin and 201Tl were comparable. The normalcy rate of tetrofosmin images in the healthy subjects with low likelihood of coronary artery disease was 97%., Conclusions: 99mTc tetrofosmin is a new myocardial imaging agent with favorable imaging characteristics with results comparable to those of 201Tl.

Unlabelled: There is no evidence of myocardial redistribution after tetrofosmin injection, therefore, two separate injections are needed to differentiate scar from ischemia with this tracer. The injections can be given on the same day (one-day protocol) or on separate days (two-day protocol). As part of a Phase II clinical study, a one-day protocol was compared with a two-day protocol., Methods: Fifty-five patients with suspected coronary artery disease were studied according to the following protocol: on the first day at rest, anterior, left lateral, left anterior oblique 40 degrees and 70 degrees images were acquired 30 min after injection of 8 mCi of tetrofosmin for 5 min each. Two days later, exercise and rest images were acquired on the same day. At peak exercise, 8 mCi of tetrofosmin were injected and 30 min later the same four standard planar images were recorded as on Day one. Four hours after the exercise injection, 24 mCi of tetrofosmin were injected at rest and imaging was repeated 30 min later. Qualitative comparisons between the one- and two-day protocols were performed in 50 patients in whom all data were available following blinded evaluation of images by three readers., Results: All three readers reported identical results for the 26 patients. A difference in extent or location between the observers was found in seven patients, differences between normal and abnormal in eight patients, while discrepancies between ischemia and necrosis were noted in four patients. In five patients, an ischemic area was found according to the one-day protocol, but according to the data of the two-day protocol, this area was judged to be necrotic. One observer reported the opposite in one patient. These discrepancies between the reversibility of defects were restricted to the inferior wall. Comparison with 201Tl data showed no systematic pattern of variation., Conclusion: Tetrofosmin can be used in a one-day protocol. However, in planar imaging, the inferior wall should be reported with caution.

Unlabelled: Images recorded after intravenous administration of 99mTc-tetrofosmin were compared to those obtained with 201Tl in a series of 40 patients with angiographically documented coronary artery disease. These patients were part of a Phase II tetrofosmin study and presented anamnestic or laboratory evidence suggestive of ischemic heart disease., Methods: Thirty-seven patients had one or more coronary obstructions greater or equal to 70% of luminal diameter. Three patients studied after bypass surgery or angioplasty had patent grafts, absence of disease progression or no significant restenosis. Twenty-six patients had evidence of previous myocardial infarction. All images were processed into a common display format by a core laboratory. They were identified by code and read by concensus of four investigators. Each segment was classified as normal or abnormal and these readings were combined and categorized into normal, reversible, fixed or mixed regional defects., Results: There was good segmental correspondence between thallium and tetrofosmin (kappa values ranged from 0.43 to 1.00). The ability of thallium and tetrofosmin to recognize and localize myocardial infarction was excellent, since corresponding abnormalities were present in respectively 24 and 25 of the 26 patients with previous myocardial infarction. Abnormalities in noninfarcted territories were recognized with both tracers in 16 of 28 patients presenting with coronary lesions involving vessels unrelated to the infarct., Conclusion: In comparison to rest tetrofosmin, thallium redistribution shows more reversibility in areas with myocardial infarction but less reversibility in areas of myocardial ischemia. Current Phase II results suggest that tetrofosmin is a sensitive and reliable tracer for detecting myocardial infarction and ischemia. Results should be confirmed in a larger group of patients.

Background: Technetium 99m tetrofosmin is a new ethylene diphosphine ligand for myocardial perfusion imaging and has unique properties. We have compared stress-rest single-photon emission computed tomographic (SPECT) imaging with 99mTc tetrofosmin with same-day and separate-day rest imaging to detect myocardial perfusion defects., Methods and Results: Myocardial SPECT imaging was performed in 22 patients with coronary artery disease who had undergone planar thallium 201 imaging and coronary angiography. Single-day (stress-rest) and separate-day rest 99mTc tetrofosmin SPECT protocols were compared in the same patient. Images were assessed by a blinded panel to identify myocardial infarction, ischemia, or normal scans. Overall sensitivity for identification of patients with coronary artery disease was 86% (19/22) by both same-day stress-rest and separate-day rest protocols with 99mTc tetrofosmin (p = NS). Of a total of 396 segments studied, 107 abnormal segments were identified at exercise and 76 and 81 at the same-day and separate-day rest tests, respectively (p = NS). Same-day stress-rest and separate-day rest 99mTc tetrofosmin SPECT protocols were also useful for detecting individual coronary stenosis with a greater than 50% lesion: 80% of the left anterior descending, 93% of the right coronary, and 75% of the left circumflex coronary arteries were detected., Conclusion: Excellent images were obtained with 99mTc tetrofosmin during both stress and rest. 99mTc tetrofosmin imaging with the same-day stress-rest and separate-day rest imaging protocols have similar diagnostic sensitivities for detection of coronary heart disease.

In order to evaluate the clinical value of a new myocardial perfusion tracer, a series of 30 patients (25 male, 5 female, mean age 56 years) referred for thallium 201 stress/redistribution scintigraphy has been studied using stress/rest (n = 7) or rest/stress (n = 23) protocols with technetium 99m teboroxime (Cardiotec SQUIBB). In all cases coronary artery disease was known or highly probable, with a history of myocardial infarction in 18 cases. Medical treatment was not discontinued at the time of stress testing, and coronary angiography was available in 27 patients. Exercise tests for both tracers were carried out on a bicycle ergometer during the same day, and the levels of exercise achieved for the 201Tl study were very similar to those achieved for 99mTc-teboroxime. Studies performed in three planar projections were evaluated using a model with four territories: septal and anterior assumed to correspond to the left anterior descending artery, lateral and latero-posterior (left circonflex), inferior and posterior (right coronary artery) and apex. Classification of results was: normal, ischaemic, infarcted and infarcted with ischaemia. On comparison with the 201Tl results, agreement was found in 86% (37/43) of normal regions and in 82% (63/77) of abnormal regions. Relative to documented coronary artery lesions (27 patients), sensitivity and specificity of 201Tl and 99mTc-teboroxime for exact correspondence between arteries and territories were respectively: 201Tl: sensitivity 64%, specificity 60%; 99mTc-teboroxime: sensitivity 62%, specificity 77%.(ABSTRACT TRUNCATED AT 250 WORDS)

After blood pool labeling using technetium albumin, 32 scintigraphic projections are recorded by means of a rotating gamma-camera. An electrocardiographic multi-gating acquisition procedure selects the dynamic pictures during the cardiac cycle of the patient. The computer processing of this set of data and the reconstruction of multiple tomographic slices through the thorax allow a precise kinetic analysis of the cardiac walls.

Myocardial images with thallium 201 are recorded on a computer with the ECG tracing and the cardiac cycle divided into 16 consecutive images. The patients then recieve 99Tcm albumin for first pass and a subsequent ECG gated series for comparison with the myocardial studies. These images can be superimposed and allow the topographic relationships of thallium uptake and ventricular contractility as reflected by the blood pool, to be seen. Quantitative parameters such as ejection fraction and stroke volume are also obtained. Examples in clinical practice are given.

Dynamic tomographic images of the heart may be obtained by computerised treatment of a number of projections and planes recorded by a gamma camera rotating around a patient whose blood is labelled with radioactive technetium. This new technique of assessing cardiac function was tested in a group of 40 coronary patients and the results compared with standard contrast angiography. The following parameters were compared : LV volume, global and regional ejection fractions. The zones of interest were easily defined on the tomographic images and correction for background noise was negligible. Two different methods have been developed to measure volume. The first consists in counting the matrix units in three dimensions on serial planes through a given cavity. The second is based on the reconstruction of thick slices integrating all the ventricular radioactivity, the counting of which is calibrated with reference to an orthogonal plane. The correlations with angiography were excellent with both methods (R = 0,85 and 0,87 respectively). An equally good correlation was observed for ejection fraction (r = 0,85). A segmental model acceptable for both gamma line angiography, gamma tomography and contrast angiography comprises 6 segments : septal, apical, antero-lateral, postero-lateral, posterior, and inferior. The sensitivity and specificity of both isotopic methods of detection of major wall abnormalities (akinesia and dyskinesia) were assessed.(ABSTRACT TRUNCATED AT 250 WORDS)

PROLOG (PROgramming in LOGic) is the declarative programming language at the heart of the Japanese fifth-generation computer project. It is proposed that PROLOG is a suitable tool for symbolic image processing, once standard preprocessing has been done. In the present application, the problem of prediction of coronary anatomy from myocardial scintigrams is addressed. Uncertainty is dealt with by a combination of fuzzy-set theoretic and probabilistic reasoning. Heuristic classification rules are based on clinical experience and on a set of 247 myocardial scintigrams with their corresponding coronary angiograms.

Cardiac kinetics can be visualized in two ways after i.v. injection of radiopharmaceutics for labeling either the myocardium or the cardiac chambers. The simpler way is the acquisition of the data in analog mode, using a multiimaging device. Thanks to a short time constant for the image advance, the cardiac cycle is divided into 16 frames, the first being triggered by the R wave of the ECG. The data of a large number of synchronized cycles are integrated on a film. This permits an almost continuous way to follow the kinetics of the studied compartments along the cycle. Several views can be registered successively. This procedure yields separately immediate information on the morphology and dynamics of the myocardium, and chambers. To evaluate quantitatively various parameters of left ventricular function a data processor is connected to the gamma camera. Examples of the two types of data are shown and demonstrate that both are useful for appreciating the value of kinetics though they are not yet accurate enough to replace in every case contrast radiologic techniques. Nevertheless, the indications for these procedures are continuously growing, due to technical progresses and the noninvasive nature of the investigation.

Images of radioactive tracer uptake are mainly functional images since the tracer distribution may directly be related to the regional variations in function, such as myocardial perfusion in the case of thallium-201 single photon tomography. Combination of pictures obtained in different physiological conditions (stress-rest, for instance) enhance the functional aspects of these studies. For gated cardiac blood pool images, on the contrary, labelling of the circulating blood pool using technetium-99m provides morphological pictures of the heart chambers and function can only be derived from the dynamic analysis of the image sequence recorded at the successive phases of the cardiac cycle. The technique of 'thick slice' tomography preserves the relationship between count rates and local volumes of radioactive blood. Parametric imaging therefore applies to tomography as well as to plane projections. In the simplest case reconstruction of the extreme phases of the heart beat, end-diastole and end-systole may be sufficient. But to achieve more sophisticated functional analysis such as Fourier phase mapping, reconstruction of the whole cardiac cycle is necessary.

In addition to positron tomography, which involves the use of radioactive elements of physiological or pathological significance, there is another technic available, that of gamma emission tomography, which makes use of conventional tracer elements, and which therefore has important clinical applications which complete plane projection imaging. This method can be used both to investigate myocardial blood supply, using thallium 201 and to evaluate cardiac kinetics--of both the right and left ventricles--after labeling of the blood flow with technetium 99m.

In a group of 207 patients undergoing coronary angiography, myocardial scintigrams have been performed at rest (n = 95), after exercise testing (n = 50) or after dipyridamole vasodilation (n = 62). Pictures recorded in anterior and 45 degrees left anterior oblique projections have been analysed according to a model which divides each projection into 5 territories. Thallium uptake has been visually assessed using a three grade scale: 0 = normal uptake, + = sightly abnormal uptake, ++ = evident hypoactivity. With reference to angiography, sensitivity and specificity for prediction of coronary artery disease have been calculated in a classical way using three different criteria of positivity of increasing severity, and by a computerized method based on discriminant analysis. In the first case, sensitivity and specificity were highly dependent one on the other and, as could be expected, varied in opposite directions, a high sensitivity (89 to 100%) being only achieved by accepting a lack of specificity (33 to 57%). Discriminant analysis, on the contrary, provided for each type of protocol: rest, stress, dipyridamole and redistribution, a single optimized combination of sensitivity (74 to 87%) and specificity (92 to 100%). The corresponding point, when located on the receiver operating characteristics (ROC) diagram, demonstrated a clear improvement in diagnostic accuracy. The same method has been applied for discrimination, not only between normals and abnormals, but also between normals and patients with and without myocardial infarction (correct diagnosis in 50 to 68% of cases), and between normals and patients with single-, double- or triple-vessel disease (correct diagnosis in 17 to 65% of cases) with a high specificity (correct classification of normals in 86 to 100% of cases).

The standard deviation of the first harmonic Fourier phase histogram is an indicator of the contraction heterogeneity of the heart ventricles. This approach has been applied to analyse tomographic blood pool (99mTc) examinations in a group of 32 patients with angiographically verified mainly right (RV) but also left (LV) kinetic disorders in relation to severe ventricular arrhythmias and suspicion of arrhythmogenic right ventricular dysplasia (ARVD). The reference group consisted of ten patients with low probability of cardiac kinetic abnormalities. Thick tomographic slices including both ventricles have been reconstructed in the horizontal long axis orientation from a series of 32 gated projections recorded over a 360 degrees rotation. Separately for each ventricle the Fourier phase histograms have been computed and characterized by their standard deviations (PSD). Normal values (mean +/- standard deviation, LV = 11 degrees +/- 5 degrees, RV = 12 degrees +/- 5 degrees) were significantly lower (P less than 0.01 and P less than 0.001) than those measured in abnormal cases (LV = 19 degrees +/- 10 degrees and RV = 31 degrees +/- 17 degrees). Detailed analysis of the data supports the hypothesis of a primary RV disease in ARVD, with secondary LV extension. PSD seems to be a good predictor of an organic cardiac disease underlying ventricular arrhythmias and may be used for screening the patients.