ABSTRACT
A computerized procedure has been developed for the generation, graphic presentation and quantitative evaluation of circumferential profiles of thallium-201 myocardial perfusion. The computer data are first filtered using a two-dimensional fast Fourier transform. The optimum criteria for evaluating the profiles of the left anterior oblique (LAO) view have been empirically determined for both rest and stress. The sensitivity of 89 percent and specificity of 75 percent compare well with the results of other methods and are free of the variables of visual interpretation.
Subject(s)
Coronary Circulation , Diagnosis, Computer-Assisted , Heart Diseases/diagnostic imaging , Coronary Disease/diagnostic imaging , Humans , Myocardial Infarction/diagnostic imaging , Perfusion , Physical Exertion , Radionuclide Imaging , RestABSTRACT
A comparison is made of relative organ-to-plasma T1-201 uptake in rats at rest and after exercise (2 h swimming). Organs were obtained 1/2 or 3 h after T1-201 injection. Under the four experimental conditions, the largest uptake was found in kidneys, heart and adrenal glands. The post-exercise to rest ratio of myocardial uptake is in agreement with clinical data reported in the literature. Two extensive tissues, skeletal muscle and fat, showed a remarkable increase of T1-201 uptake at 3 h as compared to 1/2 h in both rested and post-exercised animals. During the same time interval there was a temporal "washout" of T1-201 from heart (both at rest and after exercise) and kidney (after exercise only). The findings do not support the view of a delayed myocardial uptake phase of T1-201 during which T1-201 would be reintroduced into the blood from other body organs.
Subject(s)
Physical Exertion , Thallium/metabolism , Animals , Male , Radioisotopes , Rats , Thallium/blood , Tissue DistributionABSTRACT
The kinetics and distribution of TI-201 in isolated myocardial tissue of rats injected i.v. with this radionuclide are compared at rest and after exercise (2 hr of forced swimming). At 1/2 and 3 hr after injection, a myocardial segment was obtained and subjected to continuous washout with the radioactivity remaining in the tissue recorded each 10 sec for 1 hr. Altogether there were four groups of ten animals each. A three-compartment model (extracellular, main intracellular, and subcellular) was found to describe adequately the kinetics of TI-201. In the groups studied 1/2 hr after TI-201 injection the most dramatic effect of exercise was a translocation of TI-201 into the subcellular compartment. The change was also present but less marked in samples from exercised rats obtained 3 hr after TI-201 injection, which suggests a transition to the resting stage. The findings suggest the possibility of structural subcellular differences in myocardial uptake for TI-201 in clinical images visualized after exercise and at rest.
Subject(s)
Myocardium/metabolism , Physical Exertion , Thallium/metabolism , Animals , Cytoplasm/metabolism , Extracellular Space , Heart/diagnostic imaging , Injections, Intravenous , Kinetics , Mitochondria/metabolism , Myocardium/ultrastructure , Radioisotopes , Radionuclide Imaging , Rats , Rest , Thallium/administration & dosageABSTRACT
In healthy volunteers, the effects of intravenously administered glucagon on small intestinal function was investigated. Bolus doses resulting in plasma glucagon concentrations of greater than 800 pg/ml (5 min after injection) abolished jejunal contractions for 4.4 +/- 0.4 (SEM) min after a latency period of 49 +/- 4 sec. During continuous intravenous glucagon infusion, jejunal dilatation and increase in mean transit time (MTT) occurred at plasma levels greater than 720 pg/ml, while inhibition of water and electrolyte absorption was observed only with plasma glucagon concentrations of 1760 +/- 114 pg/ml. Under these conditions, the propulsion of fasting intestinal contents was slowed without change in flow rate. The observed effects cannot be attributed to the simultaneously occurring rise in plasma insulin and glucose concentrations. Short-term increases in circulating glucagon concentration inhibit intestinal tone, contractions, and propulsion with only a minor effect on water and electrolyte absorption limited to a narrow concentration range of plasma glucagon. Neither effect occurs at glucagon levels likely to occur under physiologic concentrations. The latency period preceding the abolition of jejunal contractions suggests that glucagon does not act directly on intestinal smooth muscle cells.
Subject(s)
Gastrointestinal Motility/drug effects , Glucagon , Jejunum/physiology , Adult , Blood Glucose/metabolism , Glucagon/blood , Humans , Insulin/blood , Jejunum/drug effects , Male , Middle Aged , Muscle Contraction/drug effects , PerfusionABSTRACT
Two cases of urinary extravasation with ureteral obstruction demonstrated by the radionuclide studies are reported. The value of radionuclide studies in patients with renal transplantation has been reported previously, but studies in patients without transplantation have rarely been described in the literature. Ureteral obstruction may cause urinary extravasation, which may be demonstrated by radiouclide studies even when radiologic studies are inconclusive. In one case, urinary extravasation was detected in the sitting position but not in the supine position. Renal imaging should probably be performed not only with multiple projections but also in different positions.
Subject(s)
Ureteral Obstruction/diagnostic imaging , Ureteral Obstruction/physiopathology , Urine , Adult , Female , Humans , Middle Aged , Radionuclide Imaging , Technetium Tc 99m PentetateABSTRACT
Proper orientation of the B-mode ultrasonic aspiration transducer is important for accurate imaging during aspiration biopsy. The transducer extension axis must be perpendicular to the plane of the scanning arm for accurate representation of reflector locations. Single pass scans without compound angulation of the transducer are recommended when perpendicularity is not absolute. A simple adaptor to maintain perpendicularity is described.
Subject(s)
Biopsy, Needle/instrumentation , Transducers , Ultrasonics/instrumentation , Humans , Kidney/pathology , Models, StructuralABSTRACT
Methods have been developed for on-line computer enhancement of a scintillation camera's myocardial images and for a graphical presentation showing relative thallium-201 activity in the myocardium. Enhancement uses fast Fourier transform techniques. The methods have been applied to multiple images obtained after stress and 4--5 hr rest. Patients with myocardial infarction and/or transient ischemia were evaluated and typical examples are presented.
Subject(s)
Heart/diagnostic imaging , Radioisotopes , Thallium , Computers , Coronary Disease/diagnostic imaging , Fourier Analysis , Humans , Myocardial Infarction/diagnostic imaging , Perfusion , Physical Exertion , Radiographic Image Enhancement/methods , Radionuclide ImagingSubject(s)
Heart/diagnostic imaging , Physical Exertion , Radioisotopes , Thallium , Animals , Computers , In Vitro Techniques , Kinetics , Male , Models, Biological , Myocardium/metabolism , Radionuclide Imaging , Rats , Thallium/metabolism , Tissue DistributionABSTRACT
In B-mode ultrasound abdominal studies, vascular structures may be confused with other tissues. A pulsed Doppler unit was coupled to a B-mode scanner by attaching the Doppler transducer to the B-mode transducer. A standardization procedure was designed to assure that the ultrasound beams from the 2 transducers were properly aligned, and that the Doppler focusing was accurate. The Doppler signal may be obtained from any point in the B-mode image in order to differentiate vascular structure from other tissue types.
Subject(s)
Ultrasonics , Abdomen/anatomy & histology , Doppler Effect , Humans , Transducers , Ultrasonics/instrumentation , UltrasonographyABSTRACT
Minicomputer methods were developed to enhance lesions in scintillation camera images. This study was directed towards improving the diagnostic quality of liver images. A PDP-12 digital computer was interfaced to a Pho/Gamma HP III scintillation camera and programmed to carry out two-dimensional frequency-domain analysis and processing as an on-line operation. A two-dimensional frequency spectrum is produced. An interactive program allows the operator to construct graphically a frequency-domain filter and apply it to the data matrix. The filter is optimized using the image of a known phantom and then applied unchanged to the clincial liver image. An inverse Fourier transform produces an enhances image in the spatial domain. Significant enhancement of both phantom and liver images has been obtained.
Subject(s)
Diagnosis, Computer-Assisted , Radionuclide Imaging/instrumentation , Humans , Liver Diseases/diagnosisABSTRACT
Jugular venous reflux was observed in six routine cerebral radionuclide angiograms. Repeat studies during a Valsalva maneuver failed to reproduce the reflux. In one case the reflux appeared to be related to the arm position; but in the other five cases, the cause remains unknown. Such reflux may be mistaken for superior vena cava syndrome or asymmetric carotid blood flow.
Subject(s)
Jugular Veins , Radionuclide Imaging , Cerebral Angiography , Humans , Technetium , Valsalva Maneuver , Vascular Diseases/diagnosisABSTRACT
An edge defect in the superior area of the left lobe is difficult to evaluate on the liver image. Eighty normal liver-heart images showed no focal separation between liver and heart images. Four cases with suspicious edge defects in the superior area of the left lobe were also studied with liver-heart imaging. One case was well demonstrated to be due to right ventricular compression of the liver without focal separation of the liver-heart images. Three cases showed focal separation of the liver-heart images. One defect was diagnosed as amebic abscess and showed enlargement on the followup images. The other two cases were proven to have liver metastasis. Liver-heart imaging is a reliable technique in evaluating a suspicious defect in the superior area of the left lobe of the liver.
