Guy Bisson

Massive Hydrothorax Compacting Peritoneal Dialysis: Isotopic Investigation (peritoneopleural Scintigraphy)

Massive hydrothorax occurring during continuous ambulatory peritoneal dialysis is a rare complication that may appear at any time during the course of the treatment. Most of the time, it is right-sided and is more frequent in female patients. A case is presented that was investigated by peritoneopleural scintigraphy. A rapid accumulation of the radiopharmaceutical over the right hemithorax was observed. To explain that finding, a macroscopic diaphragmatic defect was suspected. Different therapeutic approaches are presented.

Myocardial technetium 99m-labeled sestamibi single-photon emission computed tomographic imaging in the detection of coronary artery disease: Comparison between early (15 minutes) and delayed (60 minutes) imaging

BackgroundPrevious studies have demonstrated that there is a “partial” myocardial redistribution of99mTc-labeled sestamibi (MIBI) between 1 and 3 hours after intravenous injection at stress. The purpose of this prospective study was to compare MIBI single-photon emission computed tomographic (SPECT) imaging performed 15 and 60 minutes after the injection at stress in the detection of coronary artery disease.Methods and resultsThirty-five patients with coronary artery disease (26 underwent coronary angiography and 23 had a positive201Tl study result) were included in this study. SPECT imaging started 15 minutes after the injection of 25 to 30 mCi MIBI at peak stress (180-degree arc, 32 angles, 25 sec/view, and high-resolution collimator). Patients underwent reimaging at 60 minutes according to the same protocol and with the same gamma camera. A rest study was obtained 75 minutes after the injection of MIBI (25 to 30 mCi) at rest, 48 hours later. Images (divided for a total of 19 segments per patient) were interpreted by two blinded observers for patient diagnosis and segmental comparison. The patient diagnosis was the same for the two protocols: normal = 3, ischemia = 27, and scar = 5. The segmental agreement (k = 0.90) was 632/665 (95.0%). The imaging performed at 15 minutes detected normal, ischemia, and scar in 413, 189, and 63 segments, respectively, whereas the imaging performed at 60 minutes detected 422, 180, and 63 segments, respectively (difference not significant). The early and delayed images were placed side by side for subjective comparison of the extent of the defect. Early imaging showed slightly larger defects in six patients, equal defects in 24 patients, and slightly smaller defects in five patients. Ischemic/normal wall ratios were 0.67 ±0.16 at 15 minutes and 0.68 ±0.15 at 60 minutes.ConclusionsThere is no clinically significant difference between SPECT imaging performed at 15 minutes or 60 minutes after the injection of MIBI at stress. Furthermore, this study showed that it is feasible to obtain good-quality MIBI images even 15 minutes after the injection at stress.

Imaging the pneumoconioses: a multidisciplinary approach.

The initial early reaction of pulmonary tissue to inorganic dust inhalation is a fibrosing macrophagic alveolitis. This initial pulmonary lesion can be detected by an enhanced gallium 67 pulmonary uptake and analyses of bronchoalveolar lavage. These two techniques can document not only the increased proliferation of macrophages, but also the activation of macrophages to produce excessive amounts of fibronectin and other factors of fibroblastic growth implicated in the pathogenesis of the pneumoconioses. Of equal clinical interest is the development of computed tomography, which has permitted better characterization of the early stages of fibrosis in the pneumoconioses. These refinements in disease recognition will contribute to the earlier detection of pneumoconioses before they become incapacitating. Newer therapeutic methods are also under investigation that could permit inactivation of either the dust itself or the pulmonary macrophage. The coupling of these new diagnostic and therapeutic developments will bring in a new era in occupational pulmonary medicine.

Safety of dipyridamole testing in patients with cerebrovascular disease

Abstract Severe undiagnosed coronary artery disease is a major cause of morbidity and mortality in patients with carotid stenoses. 22,23 Our study demonstrates that dipyridamole testing carries a very low risk of neurologic complications in patients with cerebrovascular disease.

Gallium-67 citrate accumulation in a mycotic popliteal artery aneurysm

A 31-year-old man with bacterial endocarditis developed a mycotic popliteal aneurysm which presented clinically like an acute osteomyelitis. Bone and Ga-67 scanning played a major role in disclosing this unsuspected lesion. Various isotopic techniques proposed for the detection of mycotic aneurysm are reviewed. The potential usefulness of Ga-67 imaging in patients at risk of developing such lesions is discussed.

Tl-201 chloride bone marrow uptake in a patient with minor thalassemia.

A 67-year-old man underwent TI-201 chloride dipyridamole myocardial perfusion imaging before surgery for laryngeal carcinoma. He had minor thalassemia and mild microcytic anemia. After a standard stress-redistribution session, images were obtained with a resting injection of TI-201 to evaluate a fixed deficit in the anterior wall. Post-dipyridamole images revealed faint bone marrow uptake in the sternum and vertebrae. This uptake is more prominent on the redistribution and rest scintigrams. Posterior chest and pelvis images were obtained after the resting injection to demonstrate the bone uptake better. Increased metabolic activity in the bine marrow could explain this unusual finding