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Biomedical subjects

W Burchert

Publications and source records attributed to W Burchert.

41 records · Page 3Linked to original sources
PubMed1990

[A comparison of two algorithms for determining renal whole body clearance following simultaneous acquisition with a partially shielded whole-body counter and a gamma camera].

The influence of instrumentation, algorithm, and the time of blood sampling on whole-body renal clearance as defined by effective renal plasma flow (ERPF) was investigated. The study involved simultaneous sampling with a partially shielded whole-body counter (WBC) and a gamma camera to assess ERPF. The results obtained using two different analysis algorithms for each modality are compared. Although ERPF as determined by the Oberhausen technique was significantly higher than that obtained using an algorithm developed by the authors, for each algorithm there was no significant difference between the WBC and gamma camera-derived values within the range of 100 to 800 ml/min. Furthermore, positioning of the ROI was not critical for gamma camera-derived ERPF (SD less than 1% for multiple crescentic ROIs and approximately 4% for multiple rectangular ROIs). However, the time of blood sampling did appear more important since the average ERPF derived from the 10- and 20-min samples compared with that from the 15- and 25-min samples differed significantly for both analysis algorithms. The methodology which we have validated provides a more precise tool for further investigations of the influence of medication, posture, and exercise stress on renal function.

Algorithms↗
PubMed1990

[Clinical and magnetic resonance imaging follow-ups of children after dilatation of aortic isthmus stenosis (CoA)].

Aortic aneurysm and stenosis are the most severe post-interventional complications after angioplasty of CoA and require regular follow-up. Twenty children (4 2/12-13 11/12 years old) underwent MRI within 3 months to 5 7/12 years after dilatation. All children were in a good state of health and showed no signs of heart failure. Three patients suffered from arterial hypertension; seven children showed hypertension on exertion. In six children, a resting gradient (minimal 20 mm Hg, maximal 40 mm Hg) between the upper and lower extremities could be measured. Four children showed pathological changes of the ascending aorta, three had a moderate ectasia, one had severe dilatation of more than 5 cm in diameter. In three cases, a circumscript aneurysm of the descending aorta was found. In many cases, there were mild changes in the aortic wall in the region of dilatation. In 12 children, there was a moderate spindly dilatation distal to the aortic isthmus, which, however, could be seen in the pre-dilatation angiography. After dilatation of CoA, several patients continue to have hypertension and pathological changes of the thoracic aorta. With regard to adequate therapy, regular controls are necessary. Besides routine examinations, MRI is an effective non invasive imaging method for the initial investigation and short-time follow-up evaluation of CoA.

Adolescent↗
PubMed1989

Screening for pheochromocytoma in the MEN 2 syndrome.

Twenty-two patients with the multiple endocrine neoplasia type 2 (MEN 2) syndrome were screened for pheochromocytoma since it is a major cause of morbidity in MEN 2 families. Clinical symptoms, biochemical parameters, ultrasound, computed tomography or magnetic resonance imaging, and meta-iodo-benzylguanidine (MIBG) scintigraphy were evaluated for detection of adrenal tumors. Clinical symptoms and plasma or urine catecholamines appeared to be nonspecific, whereas MIBG scintigraphy was highly specific and the most sensitive parameter. Patients older than age 30 should be scintigraphically screened at least once despite the radiation exposure. Demonstration of only slight uptake is not an indication for surgery but rather for careful follow-up.

3-Iodobenzylguanidine↗