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Biomedical subjects

U Noelpp

Publications and source records attributed to U Noelpp.

13 recordsLinked to original sources
PubMed1989

A standard protocol for the exchange of nuclear medicine image files.

In order to meet an increasing demand for a standard file format which would facilitate the exchange of image files from one computer to another, the protocol initiated by Report #10 of the American Association of Physicists in Medicine has been adopted. This protocol uses the concept of an ASCII file in which key-value pairs are used to describe the various parameters of the image file. Keys specific to nuclear medicine image files have been established and are published here. In addition, the latest version of the keys has been placed on a list server which is accessible by electronic mail. This will facilitate the development of conversion programs which will also be placed on the same list server as they become available.

Computer Systems↗
PubMed1989

Routine 18F-2-deoxy-2-fluoro-D-glucose (18F-FDG) myocardial tomography using a normal large field of view gamma-camera.

There is a recent need to study glucose metabolism of the heart in ischemic, as well as in "hibernating or stunned" myocardium, and compare it with that in perfusion studies. In non-positron emission tomography centers, positron imaging is possible with a standard Anger-type camera if proper collimation and adequate shielding of the camera crystal can be achieved. For the study with fast-decaying isotopes, seven-pinhole tomography (7PHT), a limited-angle method designed for transaxial tomography of the left ventricle using a nonrotating camera, is well suited, because projections are acquired simultaneously. Individual adjustment (patient supine) of the camera's view axis (CAx) with the left ventricular axis (LVAx) gives excellent results: sensitivity for CHD 82%, specificity 72% in a prospective 201TI study (48 patients, x-ray coronarography as reference). Good alignment of CAx with LVAx is also achieved with the patient prone in LAO in a hammock above the camera surface. In this setting additional lead shielding of the camera is possible using a table reinforced with 5 cm of lead with a central hole for the 7PH-collimator, which has a special lead inlay. This allows utilization of the 511 KeV emitter 18F-FDG, which with a half-life of 109 minutes, can be transported a reasonable distance from the production site. System sensitivity and resolution for 18F was found comparable to 201Tl, 99mTc, and 123I using a phantom. First clinical examinations after 201Tl stress/redistribution studies showed increased 18F-FDG uptake in ischemic heart segments, as well as in "hibernating" nonperfused or "stunned" myocardium.

Deoxy Sugars↗
PubMed1985

On the prognostic potential of the sequential 123-I-HDA-tomoscintigram after the first MI.

Seven-pinhole tomography (SPT) using 123-I-heptadecanoic acid (HDA) is highly sensitive in confirming, sizing and localizing myocardial infarcts (MIs). Its prognostic value, however, is unknown. Thirty-five consecutive patients coming for a routine SPT within 10 days after MI underwent a second examination approximately 20 weeks later. These examinations combined an early (5 min) and a late (30 min) SPT after administration of 4 mCi 123-I-HDA, as well as a first pass radiocardioangiography. Scars and infarcts without residual HDA catabolism were related to lesions which followed (from 5 min to 30 min) a cool-cool or cold-cold behaviour. Cool-warm lesions (due to low HDA uptake and prolonged washout) were considered ischaemic. This ischaemic behaviour could not be correlated to the later course of the illness: in those patients with higher initial ischaemic scores, the ejection fraction did not increase disproportionately nor was the size of the lesion significantly smaller in the later examination than in those patients with lower ischaemic scores. Only a slightly better reduction of the end-diastolic volume was found in the patients with initially predominantly ischaemic lesions. Thus, SPT with HDA seems to be of limited value for an early prognostic evaluation of patients with MI.

Coronary Disease↗
PubMed1983

Obstructive uropathy: frusemide test and analysis of renographic curve patterns.

49 patients with clinically proven uropathy and 14 others suffering from nephropathy underwent quantitative 131I-OIHA renography, combined with a frusemide provocation test. In significant obstruction, diuresis reaction was typically less than 5% (predictive value of a positive test 76%). The renographic curves, derived from the renal cortex and from the pyelon were diverging, with the pelvic curve showing a continuous rise (predictive value of a positive test for the curve pattern analysis 92%). Non-obstructive dilatation of the urinary system was characterized by a high diuresis index (greater than 15%) (predictive value 82%). The curve pattern was plateau-like before and showed a converging course of cortical and pelvic activity spontaneously, at least after diuresis provocation (predictive value 75%). Nephropathy alone could exceptionally mimick both significant obstruction and non-obstructive dilatation. Qualitative renographic curve analysis combined with diuresis provocation renders a higher diagnostic yield regarding the dynamic state of questionable uropathy than either test alone.

Adolescent↗
PubMed1979

[Estimation of lung water with 131I-antipyrine and 99mTc-HSA (author's transl)].

Extravascular lung water is estimated in vivo from indicator dilution curves of diffusible and non-diffusible tracers utilizing their different transit times as they pass the lung microvessels. 131I-antipyrine as the diffusible and 99mTc-HSA as the non-diffusible tracer were injected simultaneously, using a pneumatic injector. Indices for rELW/V and rELW/F were calculated using programs previously published, and gave numerical values for the presence and intensity of pulmonary interstitial oedema. Inaccuracies due to sequential inputs are avoided. 131I-antipyrine has a more convenient pulmonary interstitial oedema. Inaccuracies due to sequential inputs are avoided. 131I-antipyrine has a more convenient shelflife and can therefore serve for emergency and follow-up examinations. The results do not differ significantly form those with 123I-antipyrine, and the higher radiation burden is tolerable. A mobile set-up for bed-side measurements is described.

Antipyrine↗
PubMed1979

Hepatic handling of a gamma-emitting bile salt derivative, 123I-cholylglycylhistamine, in the dog.

The hepatic handling of the bile salt derivative 123I-cholylglycylhistamine has been compared with that of the physiologic bile salt taurocholate in boxer dogs equipped with a Thomas duodenal cannula. After intravenous injection of trace amounts, 123I-cholylglycylhistamine and 14C-taurocholate disappeared from plasma with nearly identical disappearance rate constants. Excellent scintiscans of the liver were obtained with the Anger camera after injection of 3 mCi of 123I-cholylglycylhistamine. Monitoring of radioactivity over a hepatic region of interest revealed rapid uptake of 123I-cholylglycylhistamine by the liver, which reached a maximum 5.7 +/- 0.4 min after injection. The biliary excretion rates of the compounds closely paralleled each other, reaching their maximum within 15 min after injection. Cumulative biliary excretion within 45 min was 58.5 +/- 2.9% and 61.4 +/- 5.0% of the dose for 123I-cholylglycylhistamine and 14C-taurocholate, respectively. Modification of the side chain and gamma-labelling of bile salts may provide scintigraphic agents for the study of the biliary system, which in the behaviour closely resemble the physiologic parent compounds.

Animals↗
PubMed1978

The bedside determination of extravascular lung water: a non-invasive double indicator technique using 123I-antipyrine, 113mIn-transferrin and external counting.

Using the formulae of Fazio and coworkers, we calculated the extravascular lung water per unit of blood volume (ELW/V) and per unit of blood flow (ELW/F) after intravenous injection of 113In-transferrin as the blood label, and 123I-antipyrine as the diffusible, i.e. water label. Time-activity curves were recorded over the right anterior upper chest wall using a mobile detector. The curves were digitalized and fitted to a gamma-variate using a GAMMA-11 computer. Area over height calculations gave the mean transit times (t). Sixteen control subjects, without evidence of cardiac or pulmonary disease, and 10 patients, with clinical and radiological evidence of left heart failure, were examined. In the control group ELW/V was 0.37 plus or minus 0.17 and ELW/F 3.39 plus or minus 1.56 (mean plus or minus 1 SD). In the patients ELW/V was 0.71 plus or minus 0.26 and ELW/F 13.10 plus or minus 5.67. The difference between both ELW/V and ELW/F for the control group and the patient group is statistically significant. Our values for ELW/V both in patients and control subjects are very similar to those obtained by Fazio and coworkers using H2 15O. However, our values for ELW/F differed from those of Fazio; this could be partly due to dependence of this parameter on the cardiac output.

Aged↗
PubMed1977

[Characterization of gastric emptying by determination of transit time].

Gastric emptying of a solid test meal labelled with 99mTc-sulphur colloid has been studied in 18 healthy men using a gamma camera with on-line computer. Mean transit time (MTT) was determined by fitting the time-activity histogram to a gamma variate, and the half-time of emptying (T1/2) was calculated by exponential fitting of the down-slope of the C(t) curve. Mean transit times showed a smaller coefficient of variance than T1/2, and this difference was statistically significant (p less than 0.005). This result suggests that MTT may be a more suitable parameter for definition of normal values and for the separation of normal from pathological patterns of emptying.

Adult↗
PubMed1977

Mean transit time of solid test meals in gastric emptying.

Gastric emptying of a test meal labelled with 99Tcm-sulphur colloid has been studied in 9 healthy volunteers using a gamma-camera with on-line computer. Mean transit time (MTT) was determined by fitting the time-activity histogram to a gamma-variate, and the half-time of emptying (T1/2) was calculated by exponential fitting of the down-slope of the time-activity curve. MTT showed a smaller coefficient of variance than T1/2. This result suggests that MTT may be a more suitable parameter for definition of normal values and for the separation of normal from pathological patterns of emptying.

Adult↗
PubMed1977

[Trend scintigraphy].

Focal changes in activity concentration for given time function. The increase per time interval is calculated for each pixel and arranged into a result matrix. Areas with increasing activity are displayed in a "positive trend scintigramm", those with decreasing activity in a "negative trend scintigram", using a gray scale of color format. Statistical fluctuations are suppressed using this method; the data smoothing over the chosen time period and the fact that several individual pictures are included in the calculations provide displays with increased informational content as compared to serial imaging methods. The clinical interpretation of localized changes in activity concentration during a specific time interval is facilitated. The method is simple, can be adapted to different camera and computer systems, and requires no additional examination procedures on the patient.

Adult↗
PubMed1976

[Dependence of regional lung function on posture: radiospirometric findings in health].

Ten healthy volunteers were examined radiospirometrically using 133Xenon in physiologic saline i.v. and with 133Xenon gas inhalation. The measurements were done using a gamma camera (Nuclear Chicago, Pho/Gamma III) in the PA projection in both sitting and supine positions. For evaluation, each lung was divided into three regions: upper, middle, and lower fields. Using a computer (DEC, GAMMA 11), the minute exhalation value, the perfusion and ventilation indices, and the ventilation/perfusion quotient were calculated. In the upright position the ventilation and perfusion indices increase from cranial to caudal. In the horizontal position the regional lung functions tend to equalize. The vital capacity is larger in the vertical position than in the horizontal position, particularly in the right lung. The values are shown in tabular form.

Adult↗