Single photon emission computed tomography in Alzheimer's disease. Abnormal iofetamine I 123 uptake reflects dementia severity.

To determine whether abnormalities in regional cerebral functional activity estimated by iofetamine hydrochloride I 123 and single photon emission computed tomography can be detected in mild or moderate as well as severe cases of Alzheimer's disease (AD), we performed iofetamine I 123-single photon emission computed tomography in 37 patients with probable AD (nine patients with mild, 18 patients with moderate, and ten patients with severe dementia) and nine age-matched control subjects. Iofetamine I 123 uptake was measured in right and left frontal, temporal, parietal, and occipital cortices. Mean (right and left) iofetamine I 123 activity was lowest in the parietal region of patients with AD and was significantly reduced in the other three regions compared with control subjects.

Simultaneous measurement of ventricular function and myocardial perfusion using the technetium-99m isonitriles.

To assess both ventricular function and myocardial perfusion, five normal volunteers, 19 patients with coronary artery disease, and two patients with cardiomyopathy and normal coronary arteries were injected with 20 mCi of Tc-99m isonitrile (either methoxyisobutyl isonitrile or carbomethoxyisopropyl isonitrile) at peak bicycle exercise and again at rest. A standard Tl-201 stress test was performed in all patients at the same level of exercise within one month of the isonitrile study. In all normal subjects, myocardial perfusion was normal at stress levels and the left ventricular ejection fraction increased 5% or more with exercise.

Pulmonary perfusion after rt-PA therapy for acute embolism: early improvement assessed with segmental perfusion scanning.

To determine if pulmonary perfusion was improved in acute pulmonary embolism after therapy with recombinant human tissue-type plasminogen activator (rt-PA), lung scans were obtained before and a mean of 22 hours after therapy in 19 patients. The posttherapy lung scans were compared with baseline, pretherapy scans with use of two semiquantitative methods--an anteroposterior view method, similar to that used in the Urokinase Pulmonary Embolism Trial, and a segmental method that emphasized pulmonary anatomy. There was an improvement in the defect score from 0.

Hexakis(carbomethoxyisopropylisonitrile) technetium(I), a new myocardial perfusion imaging agent: binding characteristics in cultured chick heart cells.

Cellular kinetics and binding characteristics of hexakis(carbomethoxyisopropylisonitrile) technetium(I) (Tc-CPI), a new cationic, highly lipophilic myocardial perfusion imaging agent, were evaluated in chick embryo heart cells grown in monolayer culture. Myocytes showed uptake of Tc-CPI to a plateau level with a half-time (t1/2) of 4.1 +/- 0.

Sequential hepatobiliary scintigraphy demonstrating apparent transient biliary obstruction.

A case of acute acalculous cholecystitis in which sequential hepatobiliary scintigraphy demonstrated apparent transient biliary obstruction is presented. An initial technetium-99m diisopropyliminodiacetic acid ([99mTc]DISIDA) study in a patient suspected of acute cholecystitis showed persistent hepatic activity, nonvisualization of the gallbladder, and minimal intestinal activity seen only at 24 hr. Following a second injection of [99mTc]DISIDA administered shortly after the 24-hr image from the first study, the gallbladder and bowel were both visualized within 75 min.

The utilization of technetium-99m CPI as a myocardial perfusion imaging agent in exercise studies.

Myocardial perfusion imaging with Tc-99m carbomethoxyisopropylisonitrile (CPI) was compared with Tl-201 imaging in 22 patients who were assessed for coronary artery disease. There was agreement between Tc-99m CPI and Tl-201 imaging for detecting segmental myocardial ischemia and fixed defects in 185/198 (93%) of left ventricular segments. There was also an excellent correlation between the two tracers for the detection of coronary artery disease (18/22 patients).

Comparison of nifedipine and isosorbide dinitrate when added to maximal propranolol therapy in stable angina pectoris.

A study was performed to compare isosorbide dinitrate and nifedipine as adjunctive therapy in 14 patients with coronary artery disease and stable angina pectoris taking maximal beta-blocking drugs. Drug titration phases ensured maximal therapy of propranolol, isosorbide or nifedipine. The combination of nifedipine and propranolol was more effective than the combination of isosorbide and propranolol in reducing angina and increasing exercise capacity (323 vs 416 seconds, p less than 0.

Cavernous hemangioma of the liver: detection with single-photon emission computed tomography.

The roles of single-photon emission computed tomography (SPECT) and planar imaging with technetium-99m-labeled red blood cells in the diagnosis of cavernous hemangioma of the liver were evaluated. The study group consisted of 26 consecutive patients referred for evaluation of liver lesions. A total of 23 cavernous hemangiomas were found, all of which showed decreased or normal flow and delayed uptake of the radiotracer.

Lymphoma: evaluation with Ga-67 SPECT.

To determine the value of gallium-67 single photon emission computed tomography (SPECT) in imaging patients with lymphoma, the authors compared Ga-67 planar images and SPECT images in 40 consecutive patients, using radiologic examinations and/or medical records to confirm the presence or absence of disease. Thirty-three patients had Hodgkin disease, and seven had non-Hodgkin lymphoma. Fifty-four examinations were performed.

Prevalence of hypertension in bus drivers.

This paper reports the results of a cross-sectional study conducted to evaluate the prevalence of hypertension in 1500 black and white male bus drivers from a large urban transit system in the US. Data for this study were compiled from the files of an occupational health clinic which conducts biennial medical examinations for drivers' license renewal. To test whether prevalence of hypertension was higher among bus drivers than among employed individuals in general, drivers were compared to three groups: individuals from both a national and local health survey and individuals undergoing baseline health examinations prior to employment as bus drivers.

Effect of antidepressant and narcoleptic drugs on N-isopropyl p-iodoamphetamine biodistribution in animals.

N-isopropyl p-iodoamphetamine (IMP) demonstrates a high affinity for lung and brain during the first pass following intravenous injection. Its high brain affinity has been used to advantage for cerebral perfusion imaging, but the effects of drugs on IMP distribution could affect its utility. In this study, we determined the effects of the tricyclic antidepressant imipramine and the MAO inhibitors deprenyl and phenelzine on the biodistribution of IMP.

Phenotypic diversity of murine B16 melanoma detected by anti-B16 monoclonal antibodies.

A panel of monoclonal antibodies (MoAbs), produced against the murine B16 melanoma, has been used to characterize its phenotypic diversity. Six MoAbs that did not bind to primary cultures of kidney, brain or liver, spleen cells, thymocytes, 3T3 fibroblasts, melanin, or transferrin receptors were selected for further evaluation. Five MoAbs, which recognized surface antigens expressed on parental B16 cells and the B16-F1, B16-F10, B16-F10 FLR, and B16-BL6 sublines, did not appear to cross-react with each other, suggesting that they identified antigenically distinct epitopes.

Cerebral perfusion imaging in Alzheimer's disease. Use of single photon emission computed tomography and iofetamine hydrochloride I 123.

We used single photon emission computed tomography (SPECT) to study 15 patients with Alzheimer's disease and nine controls. Iofetamine hydrochloride I 123 uptake data were recorded from the entire brain using a rotating gamma camera. Activity ratios were measured for the frontal, posterior parietal, posterior, medial, and lateral cortical temporal regions and striate cortex and were normalized by the activity in the cerebellum.

Continuous fiberoptic arterial oxygen tension measurements in dogs.

An experimental study using a new fiberoptic sensor for the continuous intraarterial measurement of oxygen tension is described. This "optode" sensor uses the phenomenon of fluorescence quenching to determine the oxygen tension of the surrounding medium. To assess the accuracy of this device, we anesthetized 4 dogs and monitored them continuously with arterial catheters and an intraarterial optode probe, and intermittently with arterial blood gas analysis.

Myocardial imaging with technetium-99m CPI: initial experience in the human.

The hexakis(isonitrile)technetium(I) analog [99mTc]carbomethoxyisopropyl isonitrile (CPI) has high myocardial uptake and rapid lung and liver clearance in most animal species. To evaluate [99mTc]CPI as a myocardial imaging agent in the human, we evaluated this tracer in three normals and in six patients with coronary artery disease (CAD). In normals, [99mTc]CPI cleared quickly from the lungs and accumulated in the liver and heart.

Quantitative radionuclide angiocardiography.

Quantitation of cardiac pump function using radionuclide angiocardiography provides objective information for the management of patients with heart disease. Left and right ventricular ejection fraction, stroke volume ratio, ejection rate, diastolic function, ventricular volume, parametric imaging, amplitude and phase analysis, and shunt quantification can be measured from the radionuclide angiocardiogram at rest, during exercise, and during pharmacologic interventions. This review describes these methods and discusses their reliability and their role in the clinical assessment of patients with cardiac disease.

Collimator selection for SPECT brain imaging: the advantage of high resolution.

We compared a prototype long-bore (LB) high-resolution collimator with a low-energy, general-purpose collimator (LEGP) using 99mTc and 123I. The LB collimator provided a 56% improvement in tomographic resolution (autocorrelation width) over the LEGP for 99mTc; for 123I, the gain was 79%, providing substantially improved contrast for small structures. The sensitivity of the LB collimator, however, is only 32% of that of the LEGP.

Caudate nucleus infarction demonstrated by N-isopropyl-p iodoamphetamine SPECT imaging using a rotating gamma camera.

N-isopropyl p-iodoamphetamine (I-123 IMP) was used in two patients with previous unilateral basal ganglia infarcts documented by CT of the head. Tomographic images obtained with a commercially available rotating gamma camera equipped with a long-bore collimator showed corresponding areas of decreased uptake in the head of the caudate nuclei. Detection of such small areas of decreased perfusion is possible using SPECT and I-123 radiolabeled IMP.

Mechanisms of pulsus paradoxus during resistive respiratory loading and asthma.

To determine the mechanisms of pulsus paradoxus during asthma, six subjects known to have cold air bronchial hyperreactivity were studied while in a quiescent phase of their disease. All were free of significant airway obstruction at the time of study. After placement of an esophageal balloon to estimate intrathoracic pressure, the subjects were assessed during quiet breathing, resistive airway loading and then during a stable period of airway obstruction induced by cold air.