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Leukocytes labeled with technetium-99m hexamethylpropyleneamine oxime (HMPAO) were used in 100 patients: 32 with suspected inflammatory bowel disease, 17 with fever of unknown origin, 21 with suspected abdominal sepsis, 20 with suspected bone sepsis, seven with bronchiectasis, and three with recent myocardial infarction. The distribution of activity in patients subsequently shown not to have inflammatory bowel disease was similar to that previously described for indium-111-labeled leukocytes. However, in this study, activity was also seen in the kidneys and bladder and occasionally the gallbladder on both early (1-3 hours) and late (24 hours) views, and in the colon in late views. Migration of Tc-99m-labeled granulocytes was seen in inflammatory disease as early as 30 minutes after injection, while normal bowel activity was not seen before 4 hours. The sensitivity of Tc99m-labeled leukocytes in the detection of inflammation was 100%, the specificity was 95%.

OBJECTIVE.Regional ventilation and perfusion were studied in patients with idiopathic pulmonary fibrosis (cryptogenic fibrosing alveolitis) to seek an explanation for the mismatched ventilation/perfusionseen on scintigrams, which may suggest pulmonary embolic disease. SUBJECTS

The application of 111In-oxine to platelet labeling has contributed to the understanding of platelet kinetics along three lines: 1. It allows the measurement of new parameters of splenic function, such as the intrasplenic platelet transit time, which has shed new light on the physiology of splenic blood cell handling. 2. It facilitates the measurement of platelet life span in conditions, such as ITP, in which 51Cr may undergo undesirable elution from the platelet as a result of platelet-antibody interaction. 3. It allows the determination of the fate of platelets, that is, the site of platelet destruction in conditions in which reduced platelet life span is associated with abnormal platelet consumption, as a result of either premature destruction of "abnormal" platelets by the RE system, or the consumption (or destruction) of normal platelets after their interaction with an abnormal vasculature. Future research using 111In platelets may yield further valuable information on the control as well as the significance of intrasplenic platelet pooling, on the role of platelets in the development of chronic vascular lesions, and on the sites of platelet destruction in ITP. With regard to the latter, methods will have to be developed for harvesting sufficient platelets representative of the total circulating platelet population from severely thrombocytopenic patients for autologous platelet labeling. This would avoid the use of homologous platelets, which is likely to be responsible for some of the contradictory data relating to the use of radiolabeled platelet studies for the prediction of the response of patients with ITP to splenectomy.

To determine the effect of the heart on regional ventilation, Krypton-81m (81mKr) tomographic (SPECT) ventilation scans were recorded in seven patients with cardiomegaly and four normal subjects in the supine and prone positions. All patients had a cardiothoracic ratio of greater than 0.50 and clear lung fields radiographically. Using standard gamma camera tomographic reconstruction techniques, images of transaxial slices were obtained during a 360 degree rotation around the thorax of the subject breathing the radioactive gas 81mKr. The transaxial images, acquired over 10 min were aligned in each posture at the level of the cardiac apex, mid-heart, and aortic arch and were matched in relation to a radioactive marker on the chest wall and to anatomic landmarks. A horizontal line (gravity independent and parallel to the couch) was drawn on the transaxial section through the dorsal regions of the right and left lung. Counts per resolution element (12 to 15 mm) were plotted along this line and the ratios of the peak values in right and left lung compared. These ratios represent differences in regional ventilation per unit lung volume. In controls the mean left-to-right (L/R) peak count ratio varied from 0.91 to 1.00 at the three levels (range: 0.76 to 1.04); there were no significant differences between supine and prone. In patients with cardiomegaly the mean (+/- SEM) L/R peak count ratio at cardiac apex, mid-heart, and aortic arch was 0.46 (+/- 0.08), 0.55 (+/- 0.07), and 0.89 (+/- 0.08) when supine and 1.04 (+/- 0.07), 1.05 (+/- 0.05), and 1.08 (+/- 0.07) when prone, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)