Tc-99m-DTPA aerosol and radioactive gases compared as adjuncts to perfusion scintigraphy in patients with suspected pulmonary embolism.

To evaluate the clinical utility of improved methods for radioaerosol inhalation imaging, we obtained preperfusion radioaerosol images in 107 patients (mean age = 62 years), who were referred for evaluation of suspected pulmonary embolism (PE). For each patient, we compared six-view aerosol images with accompanying perfusion scans and chest radiographs and with Xenon-133 (Xe-133) or Krypton-81m (Kr-81m) studies. Four observers at four different institutions independently evaluated aerosol-perfusion and gas-perfusion pairs, classifying the probability of PE as low, high, or indeterminate.

Chromaticity coordinates of frequency-limited functions.

We compute the gamut of coordinates in the Commission Internationale de l'Eclairage chromaticity diagram that correspond to positive frequency-limited functions having only three degrees of freedom (a trichromatic system). The results suggest that practical colors are either suitably frequency limited to be represented by three samples or have suitably frequency-limited metamers.

Problems in noninvasive imaging of pulmonary embolism.

The V/Q scintigram is the mainstay of pulmonary embolism diagnosis, but there are limitations, such as the need for sophisticated interpretation, the production of indeterminate readings, and the lack of specificity. The authors discuss these problems and the emerging techniques that may be more of a help to the radiologist faced with diagnosing pulmonary embolism.

Trichromacy, opponent colours coding and optimum colour information transmission in the retina.

This paper presents a systematic analysis of the role of opponent type processing in colour vision and the relation between opponent type colour transformations and the initial three colour mechanisms. It is shown that efficient information transmission is achieved by a transformation of the initial three colour mechanisms into an achromatic and two opponent chromatic channels. The derivation of the transformation is dependent solely on criteria from information theory.

Serial radionuclide assessment of doxorubicin cardiotoxicity in cancer patients with abnormal baseline resting left ventricular performance.

While previous studies have demonstrated that sequential radionuclide angiocardiography allows identification of patients at risk for development of congestive heart failure and prediction of the appropriate time for safe discontinuation of doxorubicin, these studies were based predominantly on patients with normal baseline left ventricular performance. This study addresses the use of doxorubicin in patients with abnormal left ventricular ejection fraction (less than 55%) prior to drug administration. Of 337 patients referred for evaluation of left ventricular performance prior to doxorubicin therapy during a 36-month period, 45 (13%) had abnormal baseline left ventricular performance determined by first-pass radionuclide angiocardiography.

Platelet kinetics and biodistribution in canine endotoxemia.

Kinetics and magnitudes of changes in Indium-labeled platelet biodistribution were studied in dogs given E. coli endotoxin. Marked, reversible, dose-dependent shifts of platelets from blood to lung and apparently irreversible shifts to liver were demonstrated.

Tomographic gallium-67 citrate scanning. Useful new surveillance for metastatic melanoma.

Conventional gallium scans are not useful to evaluate patients with metastatic melanoma. We evaluated a new method of tomographic gallium imaging. One hundred fourteen tomographic scans were obtained in a prospective surveillance study of 67 patients over a 3-year period.

Perfusion of nonventilated lung: failure of hypoxic vasoconstriction?

Alveolar hypoxia is a well established cause of regional vasoconstriction such that nonventilated segments are not perfused. The paradoxical situation of retained perfusion of nonventilated lung has seldom been discussed. Three clinical examples are illustrated.

The technetium-99m-sulfur colloid angiogram in suspected gastrointestinal bleeding.

Dynamic radionuclide angiography (5-sec. images) with technetium-99m-sulfur colloid proved to be helpful in 5 patients who presented with gastrointestinal bleeding. In 2, intermittently bleeding hypervascular lesions were seen on dynamic but not on static images; in 2 others, the dynamic images demonstrated hypervascular lesions better than the static scans; and in 1, the radionuclide angiogram localized colonic bleeding more accurately because of rapid peristalsis of extravasated tracer.

Tomographic gallium-67 citrate scanning: useful new surveillance for metastatic melanoma.

Conventional gallium scans are not useful to evaluate patients with metastatic melanoma. We evaluated a new method of tomographic gallium imaging. One hundred fourteen tomographic scans were obtained in a prospective surveillance study of 67 patients over a 3-year period.

Improvement in cardiac performance by oral long-acting theophylline in chronic obstructive pulmonary disease.

Although oral theophylline is a widely used bronchodilator in chronic obstructive pulmonary disease (COPD), its effects upon cardiac performance have not been fully established. The effect of slow release oral theophylline upon right ventricular and left ventricular ejection fraction was evaluated using first-pass quantitative radionuclide angiocardiography in 15 patients with COPD. After 72 hours of therapy, oral theophylline significantly increased right ventricular ejection fraction (42% to 48%, p less than 0.

1982 George Simon Memorial Fellowship Award. Experimental studies with 111indium-labeled platelets in pulmonary embolism.

The effects of several potential modifiers on the detection of experimental pulmonary emboli by indium-111-labeled autologous platelets were studied. Contrast material did not affect embolus visualization; heparin prevented it, but its effect was not irreversible. The addition of exogenous thrombin to the experimental thrombus was not necessary for successful detection of the resulting emboli.

Scintigraphic perfusion patterns in patients with diffuse lung disease.

Perfusion scintigrams of 55 patients with radiographic evidence of diffuse lung disease were reviewed. Thirty-nine had acute and/or chronic changes caused by congestive heart failure, and 16 had diffuse reticulonodular disease. A normal or near-normal perfusion pattern was seen in 40/55 (73%), and this finding was equally common in the two groups.

The stripe sign: a new sign for diagnosis of nonembolic defects on pulmonary perfusion scintigraphy.

A total of 47 patients who underwent both lung ventilation-perfusion scintigraphy and pulmonary arteriography were evaluated for presence on the scintigram of perfusion defects that did not extend to the lung edge, leaving a peripheral parenchymal stripe (PPS) of perfused lung between the defect and the adjacent pleural surface. Scans were scored both with and without regard for the PPS according to probability of pulmonary embolism; these predictions were then compared with the official lung scan report given initially to the referring physician. Predictions were then verified by pulmonary arteriography.

Radionuclide assessment of left ventricular function in patients requiring intraoperative balloon pump assistance.

Twenty-three surviving patients who were weaned from cardiopulmonary bypass with intraaortic balloon pump assistance returned for follow-up radionuclide left ventricular (LV) function and thallium 201 perfusion studies at a mean of 23 +/- 3 months following operation. It was found tat despite profound intraoperative myocardial depression requiring intraaortic balloon assistance, 13 patients had no change (within 10%) in the resting LV ejection fraction compared with the preoperative measurement. Among all 23 patients, there was no difference between mean (+/- standard error of the mean) preoperative and postoperative resting LV ejection fraction (48 +/- 4 vs 46 +/- 4%, p = not significant [NS]).

Effect of antiarrhythmic drugs on In-111-labeled leukocytes: chemotaxis and adherence to nylon wool.

The influence of lidocaine (L) and procainamide (P) on the chemotactic ability and adherence to nylon wool of In-111-labeled human polymorphonuclear leukocytes (PMNs) was investigated. At the normal therapeutic levels of L (0.022 mM whole blood) or P (0.

Imaging the inflammatory response to acute myocardial infarction in man using indium-111-labeled autologous platelets.

The feasibility of imaging the inflammatory response to acute transmural myocardial infarction in man using biologically active indium-111 (111In)-labeled autologous leukocytes was assessed in 36 patients. Indium-111 leukocytes (approximately 500 microCi) were injected i.v.

Indium-111-labeled human platelets: improved method, efficacy, and evaluation.

An improved method for labeling human platelets with In-111 oxine is described. The method used modified Tyrode's solution (MTS) as a labeling medium and allowed 86 +/- 7% incorporation of In-111 into platelets, which upon stimulation with ADP aggregated 66 +/- 15% of control platelets. This compared favorably with the 5% radioactivity uptake in plasma and the 36 and 55% aggregability of platelets labeled in saline and citrated saline, respectively.

Current aspects of nuclear imaging in clinical oncology.

This presentation will focus on the recent developments in nuclear medicine that relate to diagnosis and staging in the cancer patient. The commercial availability of new Agar cameras as well as longitudinal tomographic scanning devices has improved gallium imaging significantly. This has enhanced tumor detection and resulted in better use of gallium scanning in the cancer patient.

A miniature cadmium telluride detector module for continuous monitoring of left-ventricular function.

The authors describe a miniature cadmium telluride (CdTe) detector module for continuous monitoring of ventricular function using an equilibrium radionuclide blood-pool label. The detector and collimator are small, light, and suitable for direct attachment to the chest wall. Clinical studies in 18 patients using a prototype system demonstrated reasonably good correlation with left-ventricular ejection fractions (LVEF) determined by first-pass studies performed with a multicrystal scintillation camera (r = 0.

Beat-to-beat left ventricular performance assessed from the equilibrium cardiac blood pool using a computerized nuclear probe.

The feasibility, accuracy and reproducibility of continuous beat-to-beat evaluation of left ventricular performance with a computerized nonimaging scintillation probe was assessed in 71 patients. This portable instrument has enough sensitivity to generate a real-time relative left ventricular volume curve using the labeled equilibrium blood pool without electrocardiographic gating. The probe was positioned at the left ventricular and background regions of interest using a systematic series of computerized algorithms and operator routines that were developed and standardized during the initial phase of this study.