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Biomedical subjects

U Büll

Publications and source records attributed to U Büll.

At least 145 records · Page 8Linked to original sources
PubMed1980

[Evaluation of renal transplant function by 99mTc-DTPA dynamic imaging (author's transl)].

In 60 patients with a kidney transplant 86 perfusion studies with 99mTc-DTPA were performed during the early postoperative period. Correlative data and clinical differentiation were obtained by isotope nephrograms, laboratory values and clinical presentation. In addition to evaluation of scintiphotos, time-activity curves were derived from the transplant and evaluated quantitatively, obtaining a perfusion ratio by a computer program. A ratio of greater than 0.80 was found to be normal. In 20 patients with acute rejection, the ratio was decreased. In 13 patients with acute tubular necrosis, the perfusion ratio was between 0.39 and 0.65, decreasing further during an added rejection crisis. Follow-up examinations confirmed rejection through a decrease of the perfusion ratio (mean difference 0.44; p less than 0.025). In 9 cases, successful rejection therapy was documented by an increase (mean difference 0.29; p less than 0.005). In addition to quantitative evaluation, visual analysis revealed acute occlusion of the renal artery, renal infarction, urinoma, ureteral stenosis or necrosis. Quantitative scintigraphy with 99mTc-DTPA broadened the methods of describing kidney transplant function. Its quantitative evaluation enables the definition of acute rejection and its differentiation from acute tubular necrosis combined with acute rejection in the early postoperative period. Since the method recognizes morphological alterations as well, it usefully complements isotope nephrography.

Acute Kidney Injury↗
PubMed1980

[Assessment of left ventricular performance by single crystal gamma camera and first pass radionuclide angiography (author's transl)].

Employment of a single crystal gamma camera in first pass radionuclide angiography yields essential parameters of left ventricular performance. These are: global ejection fraction, end-diastolic, end-systolic and stroke volumes, regional wall motion and regional ejection fractions. Since the right anterior oblique (30 degree RAO) projection is used, results of this noninvasive method are comparable to findings from invasive contrast ventriculography. A critical evaluation of the comparative results (correlation r = 0.84 to 0.97 in global ejection fraction; r = 0.87 to 0.95 in end-diastolic volume; agreement in segmental wall motion analysis of 72 to 90%) justifies the use of a single crystal gamma camera in first pass radionuclide angiocardiography. At elevated heart rates, e.g. during exercise, the single crystal system yields information of limited value as compared with that of the multiple crystal system. As compared to other methods (e.g. equilibrium methods), short examination times (30 s) of first pass are advantageous. First pass radionuclide angiocardiography may directly precede equilibrium examinations. Within this sequence, it may be used to assess right ventricular function and lung circulation.

Angiography↗
PubMed1980

[The determination of the ejection fraction of the left ventricle by the first passage of an indicator bolus. Comparison of two curve-fitting algorithms (author's transl)].

In 28 studies of the first left ventricular bolus passage, the end-systolic and end-diastolic phase were determined in the left ventricular time activity curve (4 msec per frame) by simply smoothing this curve 25 times. Comparing this method with a highly sophisticated curve-fitting algorithm (Sinusoidial Approximation), a very high correlation (r = 0.95) was found of the resulting ejection fractions. Thus, the two methods can be regarded as equivalent. In comparison with the ejection fractions evaluated by cineventriculoangiographic studies, a good correlation (r = 0.85) was obtained as well. To generate end-systolic and end-diastolic frames the two frames containing the highest left ventricular radioactivity were designated as end-diastolic, and the two frames containing the lowest radioactivity as end-systolic, for each heart cycle. This criterion was found to be very efficient although the temporal resolution was 8 msec per image. Furthermore, mean filling- and ejection-times of the left ventricle were derived from the extensively smoothed time activity curve. Those parameters seemed not to be of great clinical value. By employment of fast computing procedures, the evaluation time of a first passage (including image and curve generation) could be reduced to less than 10 min. Accuracy remained constant so that this method was introduced into our clinical routine diagnostics.

Cardiac Output↗
PubMed1979

[Validity of scintigraphic and endocrinological methods in classifying autonomous adenomas of the thyroid (author's transl)].

The validity of various scintigraphic and endocrinological methods was assessed in order to classify confirmed autonomous adenomas (AA) and to differentiate AA from euthyroid and hyperthyroid goitres. Methods used included: Measurement of 131J-uptake 6, 24 and 48 hours after 131J-application, before and after suppression by T3, thyroid scanning, count-rate measurement in the AA and the paranodular tissue, and determination of T4. All patients received 131J-therapy (40,000 rads). In 8 out of 30 scintigraphically compensated autonomous adenomas (CAA) there was no TSH response to TRH. 12 cases showed a subnormal TSH response and 10 patients had a normal TSH response. T4-values were increased in only 2 cases. Out of 73 decompensated autonomous adenomas (DAA), 66 cases (90%) had no TSH response and 7 cases showed only a subnormal response. In 48% of DAA T4-levels turned out to be in the hyperthyroid range. Both, scintigraphic and endocrinological tests were found to agree in most cases of DAA. However, the diagnosis of CAA could only be proved on the basis of a scintigraphically confirmed suppressive effect of T3 on the paranodular tissue. Thus, in the individual case, separation of CAA from DAA turned out to be impossible using the results of TRH-test alone.

Adenoma↗
PubMed1979

[Results of employing single crystal gammacamera and minicomputer in the first tracer passage to determine left-ventricular ejection fraction and wall motion (author's transl)].

Single crystal gammacamera and minicomputer were employed in 71 patients to determine left-ventricular ejection fraction (EF) (17 mCi 99mTc-HSA; 30 degrees RAO projection) by means of the first tracer passage. In 30 out of these patients, ventricular wall motion could be analyzed additionally because later on the gammacamera was equipped with a converging collimator. Comparison with cineventriculographically determined EF values revealed a good correlation (r = 0.91), not depending on left-ventricular wall motion pattern. Hereby, with first transit, high EFs were computed somewhat lower and low EFs were found somewhat higher. This non-limiting discrepancy is closely related to the influence of paracardiac "background"-radioactivity. Comparative analysis of segmental wall motion demonstrated agreement in 83% of the 90 segments examined. Therefore, it can be confirmed that performance of the first tracer passage for a evaluating segmental wall motion must not mandatorily be done with a multicrystal camera.

Adult↗
PubMed1979

[Multi-parameter evaluation of cerebral perfusion curves in cerebrovascular diseases results of computer-assisted radionuclide angiography (author's transl)].

The validity of computer-assisted radionuclide angiography was assessed in 189 patients with cerebrovascular disease including TIA (transient ischemic attack), PRIND (prolonged reversible ischemic neurological deficit), completed stroke and a-v. angioma. Time-activity curves were derived from regions of interest established over the right as well as the left side vascular supply territories of both middle and anterior cerebral arteries. Employing Fortran programs, parameters (right to left) A (ratio of maximal count rates), B (ratio of mean count rates) and C (relative perfusion efficiency) were computed. In patients with completed stroke, C revealed 85% and combined evaluation of A and C, 93% correct positive findings as compared with clinical and/or angiographic findings. In patients with asymptomatic stenoses, TIA and PRIND, C revealed an overall sensitivity of 83%, but was correct positive in unilateral extra- and intracranial vascular abnormalities in 96%. Out of seven a-v. angioma, five were diagnosed correctly by parameter C. These high success rates indicate the usefulness of computer-assisted radionuclide angiography (CARNA) supplementary to visual evaluation in patients suspected of having stenoses or occlusion of the major extra- or intracranial cerebral arteries.

Adolescent↗
PubMed1979

[Automatic recognition of hemisphere-borderlines in cerebral radionuclide angiography (author's transl)].

The diagnostic value of brain perfusion studies with radionuclides is based upon the careful determination of intracerebral vascular supply areas in sequential scintigraphic frames. This paper describes an automatic algorithm to determine cerebral hemisphere-borderlines (Regions of Interest). In 134 randomized brain perfusion studies, regions of interest were set by three techniques: automatically by a computer program at the beginning of the venous phase, automatically by using all images derived from the total bolus passage (40 sec.), and manual marking with a light pen at the beginning of the venous phase. A good correlation of these different techniques was obtained (r = 0.87). Furthermore, we found the bilateral perfusion index independent within a wide range, from the size of the marked regions and the quality of the injected indicator bolus. Time saving and lesser carefulness, concomitant with higher precision and reliability, in addition to the standardisation of the marking technique increase the diagnostic value of cerebral radionuclide angiography.

Brain↗
PubMed1978

Computerized tomography and nuclear imaging of the liver: a comparative study in 83 cases.

This study was performed to comparatively assess the diagnostic accuracy of computerized tomography (CT) and nuclear liver-scanning in detecting and defining circumscript and diffuse liver diseases in 83 patients. Presence or absence of liver diseases was assessed based on the results of invasive diagnostic procedures such as biopsy, laparoscopy, laparotomy, and/or autopsy. The percentage of true negative diagnoses was 94% for CT and 91% for static gamma-imaging (n = 33). With a rate of 94% true positive diagnoses, CT proved to be superior to gamma imaging with radiocolloids (81% true positives) in diagnosing circumscript liver diseases (n = 31). In addition. CT was superior to nuclear imaging regarding discrimination of number and size of space-occupying lesions within the liver. In contrast to nuclear screening, CT scans were pathognomonic to some circumscript liver diseases such as cysts, metastases, and perhaps echinococciasis. This was also true for obstructive jaundice. Nuclear imaging, because it reflects a sort of liver function, was superior with cirrhosis, whereas CT showed only alterations in the size and shape of the liver and spleen.

Abscess↗
PubMed1978

[The role of cerebral serial scintigraphy within the noninvasive diagnosis of cerebral diseases (author's transl)].

Based on findings obtained from 442 patients with various cerebral diseases by comparative evaluation of cerebral serial scintigraphy (cSS) and cranial axial compouted transmission tomography (T-CAT), a scheme is introduced which illustrates reasonable employment of cSS in combination with T-CAT in patients presumed to have (a) "intracranial tumor", (b) "cerebrovascular disease" or (c) "unspecific symptoms". Concerning group (a), T-CAT should primarily be employed; as to groups (b) and (c), cSS is recommended to be the first study.

Brain Neoplasms↗
PubMed1978

[Validity of hepato-biliary functional scintigraphy using 99mTc-diethyl-IDA (author's transl)].

99mTc-DAIDA is superior to other cholotropic radiopharmaceuticals. As radiochromatographic examinations with various systems showed, it is secreted by the hepatocytes into the bile as an unchanged anion. In a study of hepato-gastroenterologically selected patients (n = 45) values for liver function parameters such as Tmax' T/2, time of appearance in gall-bladder and duodenum were in the group of patients without any hepato-biliary disease (x +/- S.D.): 15.5, +/- 5.2 min, 30.8 +/- 8.2 min, 13.5 +/- 6.1 min, and 22.0 +/- 10.8 min. The clearance determined after comparison of different defining regions and types of calculation in this group was 323.8 +/- 145.8 ml/min x 1.73 m2 (x +/- S.D.); the renal excretion competitive with the hepato-biliary elimination amounted within 51 min p.i. to 5.15% of the injected activity. The values of the several time-parameters as well as the participation of the kidneys in the 99mTc-DAIDA excretion increased substantially in patients with intrahepatic jaundice, but only slightly in the group of other liver cell diseases. It was not possible to determine the various liver function values in patients with extrahepatic jaundice. Because of their large spread within the different groups these parameters were without diagnostic relevance in the individual case. The hepato-biliary sequential scintigraphy with 99mTc-DAIDA appears to find its main use in morphologic diagnostics.

Biliary Tract Diseases↗