SUMMARY The clinical value of combining exertional ECG and postexertional thallium (201T1) scintigraphy was assessed in 160 patients (130 men and 30 women) suspected of having coronary artery disease (CAD) who underwent a coronary arteriography. Based on sex and history, the patients were subdivided in two groups with different prevalences of CAD: Group 1 (high prevalence of CAD = 90%) included 98 men with typical angina pectoris (AP) and group 2 (low prevalence of CAD = 18%) included 32 men and 30 women with atypical AP.Compared with the exertional ECG, myocardial scintigraphy was more sensitive (87% vs 74%) and more specific (89% vs 70%) for the diagnosis of CAD. The combination of the ECG and scintigraphic data was useful if both tests gave concordant results: 100% of true positives (n = 67) and 84% of true negatives (n = 43). In case of discordant results (n = 50), no firm diagnostic conclusion could be made due to the many false-positive (27%) and false-negative (25%) scintigrams.These results are easier to interpret when the prevalence of CAD is taken into account. According to Bayes' theorem, abnormal exercise results confirm CAD when the prevalence is high and normal results rule out CAD when the prevalence is low; also, a normal response to exercise has no predictive value when the prevalence is high. When the prevalence is low, an abnormal ECG or thallium has low predictive value but concordant abnormal responses are highly predictive for CAD (100% of true positives).EXERCISE myocardial perfusion scintigraphy with thallium-201 is useful for detecting myocardial ischemia due to coronary artery disease (CAD) and seems more reliable than the exertional ECG. '-5 In symptomatic patients, the characteristics of the complaints are important and, from a well-taken history, one can evaluate the likelihood of CAD.8 12 Several reports on exertional ECG have indicated that the diagnostic information provided by the test was largely determined by the prevalence of the disease within the population.9" [13][14][15][16][17] This study was undertaken to assess the diagnostic value of exercise thallium scintigraphy and its combination with exertional ECG; in order to analyze the influence of the prevalence of CAD, the patients were subdivided in groups according to the information provided by the history. The prevalence of CAD is almost 100% after an acute myocardial infarction, so patients with a history of infarction were excluded. Material One hundred sixty patients, 130 men and 30 women, suspected of CAD but without evidence of a previous myocardial infarction, were studied. They underwent a multistage maximal exercise test 1 to several days before the arteriographic study. These patients were studied because of the presence of chest pain. Before the exercise test, the patients were carefully questioned by the same physician. From the clinical history, the complaints were subjectively judged to be typical or atypical of angina pectoris (AP). As in a previous study,9 this judgment was based on the location, qualit...
As part of the staging of 38 patients with Hodgkin's disease seen over an 18-month period, we have used radioisotopic scanning of bone, as well as radiography and bone marrow biopsy, in an attempt to assess osseous and bone marrow involvement. Of the 38 patients, 14 were found to have skeletal involvement. In 11 this was histologically proved. In 8 patients, the radioisotopic scan first raised the suspicion of localized bone involvement, which was subsequently proved by bone marrow biopsy or by radiography. We believe that bone marrow involvement may at times be localized when patients with Hodgkin's disease are first staged and may precede local osseous involvement. If this is so, a reasonable approach to the search for bone marrow or osseous involvement would be to start with a bone scan and to follow this with a bone marrow biopsy from the suspicious area or a careful radiography of the same site; the latter is important if the site of increased uptake of the radionuclide is inaccessible to the biopsy needle.
We report the case of a family in which the mother died of hypertensive encephalopathy following the relapse of a phaeochromocytoma. Two of her children are still alive. Both children had malignant phaeochromocytomas that have been treated by surgery and 131I-MIBG. The first child presented with phaeochromocytoma of the right suprarenal gland at the age of 7 years. Surgery was performed. At the age of 14 years, he developed a tumour of the left suprarenal gland and two pulmonary metastases demonstrated by 131I-MIBG. The three tumours were removed, but new lesions occurred. The boy then was treated with 200 mCi (7,400 MBq) of 131I-MIBG given twice, and is now free of disease more than 2 years after treatment. His sister presented at the age of 12 years with phaeochromocytoma of the left suprarenal gland, the only lesion recognized by 131I-MIBG. The tumour was removed, but 5 months later, she developed phaeochromocytoma in the right suprarenal gland. She was treated with 200 mCi (7,400 MBq) of 131I-MIBG and surgery was performed 6 months later. Histology of the suprarenal gland could not demonstrate the persistence of phaeochromocytoma cells. The child is now free of disease more than 2 years after treatment.
In the human upright lung the downward increase in lung perfusion reverses in the lower third, thus giving rise to a zone of reduced basal perfusion (zone 4). The flow in zone 4 is regulated by the extra-alveolar vessels, the diameter of which is determined by lung volume, perivascular interstitial pressure, and vasomotor tone. To estimate the role of pulmonary vascular tone in the formation of zone 4, we infused nitroprusside (NTP), a potent pulmonary vasodilator, in six normal seated subjects. We measured their regional perfusion distribution using 133Xe in control conditions and at two dose levels of NTP (20.8 and 52.1 micrograms/min). Regional perfusion distribution was measured similarly and according to the same protocol in six subjects receiving only a placebo solution. In four of the six subjects receiving NTP, right-heart catheterization allowed simultaneous estimations of cardiac output and pulmonary arterial pressure to be made. NTP slightly decreased the perfusion of the nondependent parts of the lungs and markedly increased the perfusion of the lung bases, thus reducing the extent of zone 4. No changes were observed in the placebo experiments. Cardiac output and indices of ventilation and gas exchange did not change significantly. Peripheral and pulmonary arterial pressure fell slightly but significantly during NTP infusion. We attribute the observed changes in basal perfusion to the vasodilatory effects of NTP on the extra-alveolar vessels. Our findings thus support the hypothesis that in normal subjects zone 4 is partly created by the pulmonary vascular tone.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.