[Assessment of myocardial perfusion in systemic lupus erythematosus]. / Evaluation de la perfusion myocardique au cours du lupus érythémateux systémique.

INTRODUCTION: Cardiovascular disease is a major cause of morbidity and mortality in patients with systemic lupus erythematosus (SLE). Necropsy studies found a high incidence of myocardial and coronary injuries while clinical manifestations were observed in less than 10%. The purpose of this study was to evaluate myocardial perfusion in SLE patients. PATIENTS AND METHODS: The study was carried out in 153 patients with a definite diagnosis of SLE according to the revised criteria of the American College of Rheumatology. Ninety-four (61.4%) underwent 99mTc-tétrofosmine SPECT analysis at rest and after stress. RESULTS: The average disease duration was 11 years. Ninety-four patients (93 women and one man) with a mean age 37 years were assessed. Twelve had a past history of vascular event: six stroke, four angina pectoris and two myocardial infarctions. Cardiovascular risk factor included: high blood pressure (35.2%), dyslipidemia (62.3%), moderate hyperhomocysteinemia (55%), BMI greater than 25 (40%).The cumulative prednisone dose per patient was 45.5g. Myocardial perfusion stress scanning showed abnormal perfusion in 21 patients (22.3%). Among these, eight underwent coronary angiography which was normal in seven cases. One patient had a right coronary stenosis. Perfusion abnormalities were correlated with stroke (p<0.01) and coronary events (p<0.02). CONCLUSION: Myocardial perfusion scintigraphy can be a useful noninvasive method to identify subclinical myocardial involvement in systemic lupus erythematosus and patients at risk of later events.

Left ventricle automated detection method in gated isotopic ventriculography using fuzzy clustering.

A method that uses the fuzzy ISODATA clustering algorithm and Fourier analysis is proposed for automated detection of heart left ventricle contours. This operation is used for quantitative analysis of cardiac function. The computation begins by finding the phase image. The fuzzy ISODATA algorithm is first applied to this image to generate a number of clusters that correspond to the organ substructures (ventricles, atria). Second, the ventricles cluster is isolated and the intensities of its points are replaced by the corresponding ones from the original (end diastolic) frame. Finally, a reduced image representing the ventricular region is obtained and an additional clustering is performed to find the left ventricular boundary automatically. This algorithm is tested by application of 105 sets of 16 images each. These results are compared with the measurements obtained with two semi-automatic methods used, respectively, on the Philips and the Sopha Medical gamma cameras.

Cross-calibration of a fan-beam X-ray densitometer with a pencil-beam system.

This study describes the cross-calibration of two Hologic bone densitometers, one using a fan-beam X-ray source (QDR4500/A) and the other a pencil-beam source (QDR1000/W). The QDR4500/A allows spine and hip measurements to be made at three principal speeds. Results from two spine phantoms and 154 patients showed no significant difference in the absolute values or precision between speeds. The middle speed (taking 1 min to scan an adult lumbar spine) was used for the comparison between the instruments. The two densitometers were compared using two spine phantoms and 182 patients. In vivo measurements were made of all lumbar spine, hip, forearm and whole body sites. Regression lines, constrained to pass through the origin, were calculated. Slopes for total bone mineral density (BMD) for each scan type ranged between 0.994 and 1.029, the best value being found for forearm (1.000). Scatter graphs of the individual points were generated and showed results slightly worse than would be expected from repeat measurements on a single machine (79-88% fell within the expected 2 SD range). A trend for the QDR4500/A to overestimate BMD at low values and underestimate it at high values was seen in the femoral neck. The trend was more significant in the lumbar spine. There was an overestimate of total hip BMD throughout the range. Slopes of the regression lines for area and bone mineral content (BMC) were used to improve cross-calibration between the systems on a site-to-site basis, after which the results improved to a level consistent with repeat measurements on a single machine (81-94% within 2 SD). At present only global, rather than site-specific, correction factors can be employed for the spine and hip and no overall improvement in cross-calibration was possible. We conclude that although global correction factors allow adequate cross-calibration to be achieved, improvements could be made by the use of scan-site-specific factors.

Significance of solitary spine abnormalities on technetium-99m bone imaging.

Solitary abnormalities located within the spine from 75 bone images with Tc-99m MDP were reviewed. For the sake of convenience, patients were grouped in three classes of age: 15-50, 51-65, and 66-90 years. In 67 cases, the diagnosis was apparent from clinical studies, x-ray examinations, or biopsies. In eight cases, no diagnosis could be made. The maximum percentage of lesion sites were within the lumbar spine (45 cases). Metastatic lesions were the most common solitary abnormalities within the spine (29.3%). Osteoporosis was second (24%) with the maximum percentage in age group 66-99 years (83%) with a greater female predominance (67%).

Septal endocarditis, bone infection and severe leg ischemia detected in Tc-99m labelled monoclonal anti granulocyte scan

Patient 28 years old has continued to have a persistent fever (39.2°C), despite ten days treatment by specific antibiotics for bacterial endocarditis associated to a recent claudication of the right lower leg. The persistent fever has motivated a 99mTc-labelled monoclonal anti granulocyte scan which has showed an important uptake in the myocardial septum, and other infection locations in temporal bone and in right tibial arteries. Two days after, a nanocolloids-99mTc WBS showed no uptake in the heart area, a total absence of uptake of the nanocolloids in the bone marrow of right tibia b and cranial SPECT views confirmed the infectious site in the right temporal bone. New antibiotic strategy was adopted successfully associated with surgical amputation of the right lower leg.