Biomedical subjects
Publications and source records attributed to R Lisbona.
Hypertrophic pseudarthrosis was studied with Tc-99m MDP and Ga-67 citrate in 11 patients. Two of the 11 pseudarthroses were complicated by infection. A high concentration of both radiopharmaceuticals was obtained at all 11 sites and their distribution patterns were identical. It was therefore impossible to distinguish the infected from the noninfected pseudarthroses by using Ga-67.
Right ventricular infarction is not uncommon in patients with inferior myocardial infarcts. Phase and amplitude analysis of equilibrium gated cardiac blood pool studies is useful in documenting right ventricular damage complicating left ventricular infarction. In 15 of 37 patients with acute inferior infarction, right ventricular extension of the infarct was demonstrated by this approach, complementing the findings of infarct avid imaging with Tc-99m pyrophosphate (Tc-99m PYP).
Twenty-four symptomatic patients with symptoms of active Paget's disease of bone were evaluated, during the course of their therapy, a total of 71 times (24 baseline and 47 follow-up examinations) by serial alkaline phosphatase levels (AP), Tc-99m MDP bone scans, and radionuclide blood-flow studies. The flow study correlated with disease activity in all of the baseline studies and in at least 85% of the follow-up studies. In five patients (seven follow-up studies) the changes in local blood flow correctly anticipated the eventual rise or fall of AP. In comparison with the bone scan, the changes in blood flow preceded the bone-scan alterations or were more reliable indicators of disease activity in 12 of the 13 follow-up studies in which the results of the two examinations disagreed. We conclude that the radionuclide flow study provides useful additional clinical information in the management of Paget's disease.
An unusual case of extensive tumor embolism is reported on which the lung scan was instrumental in demonstrating the underlying pathophysiology. Pulmonary arteriography failed to demonstrate vessel occlusion and the need to perform this study with special care is re-emphasized. A brief review of the literature indicates that tumor embolism occurs much more frequently than is clinically suspected.
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Radiogallium imaging plays a growing role in the investigation of acute and chronic inflammatory diseases of the lung. We studied a series of patients undergoing radiation treatment for carcinoma of the breast to evaluate the usefulness of imaging with 67gallium citrate in the detection of early radiation changes in the pulmonary parenchyma. In a series of 12 patients there was no correlation between the clinical and radiographic manifestations of radiation pneumonitis and the gallium scan.
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A 28-year-old woman who complained of mild abdominal pain was found to have a large liver tumor. Angiography and needle biopsy established the diagnosis of hepatocellular adenoma. The tumor was felt to be unresectable because of its size, and no treatment was given other than withdrawal of oral contraceptives. Subsequent hepatic scintiscans documented compete resolution of the tumor over a 12-month period.
Nine patients with acute segmental renal infarction were examined by renal scanning and excretory urograms. The diagnosis of segmental infarction by intravenous urography is difficult. Radionuclide imaging is the preferred noninvasive method for demonstrating and sizing the renal infarct.
Blood pool imaging of the lower limbs with Tc-99m-erythrocytes demonstrates the deep venous channels of the leg. The radionuclide image of deep vein thrombosis, by this method, appears sufficiently distinctive to suggest that Tc-99m-erythrocyte venography may be a useful screening examination for deep vein patency.
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Budd-Chiari syndrome or hepatic vein occlusion may be related to oral contraceptive medication. A patient is presented in whom radionuclide liver imaging contributed to the diagnosis of the syndrome and to the management of the patient.
Although infarct-avid scanning is used to diagnose myocardial infarction, no distinction is made between two very different mechanisms of myocardial cell death. These are occlusion necrosis and reperfusion necrosis. The former is the major form of cell injury after a sustained occlusion of a coronary artery; the latter occurs immediately after reperfusion of ischemic myocardium. The present study examines whether the technetium pyrophosphate scan becomes positive more rapidly with one form of injury rather than the other. Myocardial damage was produced in dogs by either sustained coronary occlusion (Group I, 6 dogs) or reperfusion (Group II, 18 dogs). Infarct-avid myocardial scans obtained with technetium-99m pyrophosphate were positive in only one of six animals in Group I when isotope was injected 4.5 hours after sustained coronary occlusion. In contrast, 12 or 13 animals (Group IIa) with reperfusion necrosis had a positive scan when isotope was injected 3.5 hours after reperfusion. When isotope was injected only 30 minutes after the onset of reperfusion (Group IIb), only two of five scans were clearly positive. The results indicate that if the interval between myocardial injury and a positive scan is known, inference can be made concerning the predominant type of injury.
Radionuclide angiography is a valuable screening test for arteriovenous (AV) fistulas. Seven iatrogenic AV communications of the genitourinary system were initially diagnosed by radionuclide imaging, and untreated patients are being followed up by yearly nuclear examinations. Contrast arteriography is reserved for patients requiring interventional therapy and for symptomatic patients with a negative radionuclide study.
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Despite major technical advances in coronary bypass surgery and myocardial preservation, perioperative infarction remains a serious problem. The authors review the pathogenesis of the two different types of myocardial injury, occlusion necrosis and reperfusion necrosis. These two entities can be distinguished clinically by radioisotope scanning. Experimental studies have demonstrated that reperfusion necrosis can be prevented pharmacologically. Since the majority of perioperative infarcts are probably due to reperfusion, the importance of distinguishing between these two entities is evident.
Dilated biliary radicles demonstrated on 99mTc-dimethyl-acetanilide-imino-diacetic-acid (99mTc-IDA) imaging suggested biliary obstruction, and led to transhepatic cholangiography and endoscopic retrograde cholangiopancreatography. Both showed a biliary tree of normal diameter.
Ultrasound and 67Ga-citrate imaging were used simultaneously for the evaluation of 26 suspected cases of abdominal abscess. Scintiscanning and ultrasonography identified respectively 92% and 69% of the abscesses. Jointly, both modalities detected all 13 abscesses and we suggest an integrated approach in the evaluation of such cases.