Biomedical subjects

W Müller-Schauenburg

Publications and source records attributed to W Müller-Schauenburg.

At least 19 recordsLinked to original sources

PubMed2001

Follow-up in neuroblastoma: comparison of metaiodobenzylguanidine and a chimeric anti-GD2 antibody for detection of tumor relapse and therapy response.

Early and correct diagnosis of local tumor recurrence, occurrence of metastases, and therapy response are essential in patients with neuroblastoma stage IV. The aim of the study was to evaluate the diagnostic value of metaiodobenzylguanidine (mIBG) and a chimeric GD2 antibody in the follow-up of patients with neuroblastoma. In a prospective study, mIBG (N = 31 scans) and immunoscintigraphy were compared with a chimeric antiganglioside antibody, ch14.18 (MAb) (N = 31 scans), labeled with technetium Tc 99m in the follow-up of 18 patients with stage IV neuroblastoma. The findings were compared with histologic findings, other imaging examinations, and clinical changes over the course of 4 to 6 years. For the diagnosis of local tumor recurrences, sensitivity was 80% for MAb and 70% for mIBG. Specificity was 93% for MAb and 72% for mIBG. The MAb was superior for the detection of skeletal metastases, with a sensitivity of 82% compared with 72% for mIBG. Specificity was 100% for both techniques. Also, for soft tissue/lymph node metastases, sensitivity for MAb was higher (50%) than for mIBG (31%). Specificity was 100% for each technique. In sequential studies, metastases were detected earlier with MAb (mean: 2.3 m for skeletal metastases, 3.6 m for soft tissue metastases) than with mIBG. After therapy, tumor uptake was visualized longer with mIBG (mean 6.3 m) than with MAb. The chimeric antibody ch14.18 is likely to be valuable for follow-up examinations and for assessment of therapy response because of earlier detection of new metastases.

3-Iodobenzylguanidine↗

PubMed2000

[Nuclear medicine diagnosis of the kidneys].

BACKGROUND: Renal studies have a long tradition in nuclear medicine and are available for routine use for more than 30 years. Their high clinical acceptance is mainly based upon the fact that they allow for quantitative evaluation of different functional parameters such as glomerular filtration, effective renal plasma flow, or postrenal transport. The used methods are validated by experimental as well as numerous clinical studies and are performed throughout the world in a highly standardized way. INDICATIONS: Indications are verification/exclusion of a disturbed renal function, detection or evaluation of renal artery stenosis, and differential diagnosis of urinary tract obstruction. Further diagnostic improvement might be achieved by use of positron emission tomography which has the potential for absolute quantification of physiological parameters such as renal blood flow in ml.min-1.100 g-1 tissue.

Glomerular Filtration Rate↗

PubMed1999

Quantification of Viable Myocardium in Multivessel Coronary Disease: Effects of the Redistribution Time after Reinjection Of Thallium-201 and Comparison with Postrevascularization Defect Size.

Reinjection of 201Tl is used for improved detection of viable myocardium. Prospectively the effect of the redistribution time after injection for the quantification of the definitive perfusion defect size in multivessel coronary heart disease and severely impaired left ventricular function was examined. Thirty patients were included preoperatively before CABG. The study was performed with 80-90 MBq 201Tl-Cl and reinjection (40-50 MBq). Imaging was performed after an exercise test and 3 hours afterwards. Thereafter, the reinjection dose was given and repeated studies were performed 10 minutes, 2 hours, and 20 hours later. Defect sizes were compared with the 3-hour rest-study without reinjection. Imaging studies were repeated postoperatively. The defect size was expressed as % of left ventricular total myocardium. Perfusion defect sizes were as follows: post-stress study (27%), 3 hour rest-study (17%), post-reinjection-10 min (12%), 2 hours (9%), and 20 hours (7%). Compared with the 3 hour rest-study, the perfusion defect was reduced only in 7/30 patients in the study immediately after reinjection. In the delayed studies, defect sizes were markedly smaller (p < 0.05) both in studies 2 hours and 20 hours after reinjection. In 15/30 patients there was a marked reduction of 50% of defect sizes in the study 2 hours post-reinjection vs the 3 hour rest-study. The residual defects at 2 hours after reinjection were identical to the postoperative defect sizes (10%). Further prolongation of the redistribution time to 20 horus caused an additional small reduction in defect size only in two patients compared with the 2-hour post-reinjection images (n.s.). Using a marker as 201Tl with redistribution characteristics, the redistribution time after reinjection is of utmost importance to correctly identify the definitive size of the perfusion defect vs viable myocardium in patients with multivessel disease. A delay of 2 hours for redistribution after the reinjection most correctly corresponds to the postop defect size; a longer redistribution time did not provide additional advantages.

Journal Article↗

PubMed1999

Allogenic bone graft viability after hip revision arthroplasty assessed by dynamic [18F]fluoride ion positron emission tomography.

The biological fate of allogenic bone grafts in the acetabular cavity and their metabolic activity after acetabular augmentation is uncertain but is most important for the stability of hip implants after hip revision arthroplasty. The aim of this study was to quantify regional bone metabolism after hip replacement operations. Dynamic [18F]fluoride ion positron emission tomography (PET) was used to investigate the metabolic activity of acetabular allogenic bone grafts and genuine bone, either 3-6 weeks (short-term group, n = 9) or 5 months to 9 years (long-term group, n = 10) after hip revision arthroplasty. Applying a three-compartment model, the fluoride influx constant was calculated from individually fitted rate constants (Knlf) and by Patlak graphical analysis (Kpat). The results were compared with genuine cancellous and cortical acetabular bone of contralateral hips without surgical trauma (n = 7). In genuine cortical bone, Knlf was significantly increased in short- (+140.9%) and long-term (+100.0%) groups compared with contralateral hips. Allogenic bone grafts were characterised by a significantly increased Knlf in the short-term group (+190.9%) compared with contralateral hips, but decreased almost to the baseline levels of contralateral hips (+45.5%) in the long-term. Values of Knlf cor-related with the rate constant K1 in genuine (r = 0.89, P<0.001) and allogenic bone regions (r = 0.79, P<0.001), indicating a coupling between bone blood flow and bone metabolism in genuine bone as well as allogenic bone grafts. Kpat values were highly correlated with Knlf measurements in all regions. In conclusion, [18F]fluoride ion PET revealed the presence of an increased host bone formation in allogenic bone grafts early after hip revision arthroplasty. In contrast to genuine cortical bone, allogenic bone graft metabolism decreased over time, possibly due to a reduced ability to respond to the same extent as genuine bone to elevated metabolic demands after surgery.

Aged↗

PubMed1996

Catecholamine secreting glomus tumor detected by iodine-123-MIBG scintigraphy.

We report the case of a 41-yr-old woman who presented with arterial hypertension and tinnitus in the right ear synchronous with pulse. She had previously undergone surgery for suspected pheochromocytoma without positive therapeutic effect. CT and MRI revealed a homogenous tumor with contrast enhancement in the right hypotympanon and foramen jugulare, and [123I]metaiodobenzylguanidine (MIBG) scintigraphy demonstrated strong tracer uptake in the same area. Selective venous sampling of catecholamines in the ipsilateral jugular vein confirmed the tumor to have originated from hormone production.

3-Iodobenzylguanidine↗

PubMed1996

Fluorine-18-FDG and iodine-131-iodide uptake in thyroid cancer.

UNLABELLED: We conducted a prospective study to define the sensitivity of 131I scintigraphy and 18FDG PET whole-body scanning in the detection of thyroid cancer and metastases. METHODS: Forty-one patients with differentiated thyroid carcinoma who underwent thyroidectomy and 131I elimination of the remaining thyroid were studied by 18FDG whole-body PET in 52 examinations and by 131I whole-body scanning. RESULTS: Combined 18FDG and 131I imaging resulted in a sensitivity of about 95%, with alternating uptake of 131I and 18FDG in the metastases: 131I trapping metastases with no 18FDG uptake and 18FDG trapping metastases with no 131I uptake. Five uptake types were differentiated. Alternating uptake was found in about 90% of the patients, which was nearly identical to the sensitivity of the combined 131I/18FDG investigation. In six patients with increasing human thyroglobulin levels, we found that 18FDG whole-body PET localized positive neck metastases of papillary thyroid carcinomas that were histologically confirmed after extirpation. CONCLUSION: Combination 18FDG and 131I whole-body imaging protocol enables detection of local recurrence or metastases on whole-body scans that are often not shown by other imaging methods. Biochemical grading of thyroid cancer may also be possible with this method: Tumors with remaining functional differentiation for hormone synthesis and iodine uptake have low glucose metabolism in more than 95%; tumors without this functional differentiation of 131I uptake show high, glucose metabolism. Fluorine-18-FDG uptake seems to be an indicator of poor functional differentiation, and possibly higher malignancy, in thyroid cancer.

Adenocarcinoma↗

PubMed1995

[18FDG whole-body PET in differentiated thyroid carcinoma. Flipflop in uptake patterns of 18FDG and 131I].

In 27 examinations of 24 patients with differentiated thyroid carcinoma an alternating pattern of metastases with either 131I- or FDG-uptake was found. In the follow-up of these patients this flip-flop pattern was seen in 89% (17/19) of patients with metastases and uptake of 131I or FDG as described here as uptake types 1 and 2 (type 1: FDG-positive and 131I-negative; type 2: FDG-negative and 131I-positive). In 4 patients a mixed type was observed (uptake type 3), i.e. a combination of metastases with uptake types 1 and 2 in the same patient. Metastases of papillary or follicular thyroid carcinoma without uptake of iodine have all been found to be FDG-positive in patients with an increase of thyroglobulin and with negative diagnostic results from other imaging modalities, and were histologically confirmed by surgery. False-negative or false-positive cases were not observed in this study. The FDG uptake showed an inverse proportionality to iodine uptake and to tumor differentiation. Increased glucose metabolism is a sign of higher malignancy.

Adenocarcinoma, Follicular↗

PubMed1994

Multiple system atrophy: natural history, MRI morphology, and dopamine receptor imaging with 123IBZM-SPECT.

Sixteen patients with a clinical diagnosis of probable multiple system atrophy (MSA) were examined clinically by MRI and by 123I-iodobenzamide single photon emission computed tomography (IBZM-SPECT). The clinical records of another 16 patients were also analysed retrospectively. On the basis of their clinical presentation, patients were subdivided into those with prominent parkinsonism (MSA-P, n = 11) and those with prominent cerebellar ataxia (MSA-C, n = 21). Autonomic symptoms were present in all patients and preceded the onset of motor symptoms in 63% of patients. Calculated median lifetime and the median time to become wheelchair bound after onset of disease were significantly shorter for MSA-P than for MSA-C (lifetime: 4.0 v 9.1 years; wheelchair: 3.1 vs 5.0 years) suggesting a better prognosis for cerebellar patients. A significant loss of striatal dopamine receptors (below 2 SD threshold) was detected by IBZM-SPECT in 63% of the patients (56% below 2.5 SD threshold). There was no difference between patients with MSA-C and those with MSA-P in the proportion with significant receptor loss and the extent of dopamine receptor loss. Planimetric MRI evaluation showed cerebellar and brainstem atrophy in both groups. Atrophy was more pronounced in patients with MSA-C than in those with MSA-P. Pontocerebellar hyperintensities and putaminal hypointensities on T2 weighted MRI were found in both groups. Pontocerebellar signal abnormalities were more pronounced in MSA-C than in MSA-P, whereas the rating scores for area but not for intensity of putaminal abnormalities were higher in MSA-P. MRI and IBZM-SPECT provide in vivo evidence for combined basal ganglia and pontocerebellar involvement in almost all patients in this series.

Adult↗

PubMed1994

[Perfusion of the left ventricular myocardium in patients with aortic valve diseases using single photon emission computerized tomography].

To determine resting myocardial perfusion in 30 patients with aortic valve disease (AVD) TI-201 emission computer tomography (ECT) studies and heart catheterization were performed. 16 patients had a predominant aortic regurgitation (AR); an aortic stenosis (AS) was found in 14 patients at catheterization. Perfusion defects were documented in 10 of 16 patients with AR, and in 5 of 14 patients with AS. Regional determination demonstrated in 10 of these 15 abnormal cases at least one of the perfusion defects in the postero-basal segment. In patients with aortic valve disease and normal myocardial perfusion scintigraphy, the ejection fraction (EF) was significantly higher (p < 0.05) as compared to the patients with abnormal TI-201 ECT (EF 65.2 +/- 15.0% vs. 58.9 +/- 15.1%). Additionally, in the 15 patients with abnormal TI-201 ECT, the left ventricular end-diastolic volume index (LVEDVI) and the left ventricular end-systolic volume index (LVESVI) were both increased (LVEDVI in AVD: 130.3 +/- 15.3 ml/m2 vs. 107.4 +/- 13.6 ml/m2, LVESVI in AVD: 61.9 +/- 14.6 ml/m2 vs. 48.0 +/- 9.8 ml/m2). In conclusion, left ventricular perfusion defects at rest can be detected by TI-201 ECT in many patients with aortic valve disease. Such myocardial perfusion defects indicate left ventricular enlargement and impaired left ventricular function, especially in patients with aortic regurgitation.

Adult↗

PubMed1994

Myocardial perfusion and left ventricular function early after successful PTCA in 1-vessel coronary artery disease.

Myocardial perfusion (201TI-ECT) and contractile function (99mTc-ventriculography) were studied during exercise and rest 3 to 6 days after PTCA in 20 patients (11 with stable and 9 with unstable angina pectoris). All patients had single vessel disease and no previous myocardial infarction. During exercise after PTCA the ejection fraction increased for 3 to 5% and no regional wall motion abnormalities, ST-segment depression or perfusion defects occurred (with exception in one patient with very early restenosis). Therefore, perfusion and wall motion were completely normalized at rest and during exercise within days after technically successful PTCA even in patients with previously unstable angina pectoris. Pathological stress test results after this time should thus be attributed to other causes e.g. early restenosis, multivessel disease, false positive tests) and are not due to the specific situation early after PTCA.

Adult↗

PubMed1993

Accurate local blood flow measurements with dynamic PET: fast determination of input function delay and dispersion by multilinear minimization.

Accurate determination of local blood flow in tissue using the Kety-Schmidt one-compartment model for freely diffusible tracers requires knowledge of the true arterial input function in tissue. Because measured input functions are usually delayed and dispersed with respect to true influx, a correction of the experimental input function is necessary. We describe a technique that uses a fast multilinear least-squares minimization procedure to determine simultaneously the dispersion, the blood flow and the partition coefficient as a function of delay. In this approach, a few multilinear fits are sufficient to determine the complete set of parameters necessary to describe the data. Because of the high speed of the procedure, dispersion effects may be taken into account on a pixel-by-pixel basis in calculating parametric images of blood flow and partition coefficient. The described procedure has been used at our institute for about 1 yr in more than 160 investigations and has proven well suited for routine use in a clinical environment.

Blood Flow Velocity↗

PubMed1992

Noninvasive procedures for diagnosis of renovascular hypertension in renal transplant recipients--a prospective analysis.

The purpose of this study was to clarify the selectivity and specificity of noninvasive procedures for diagnosis of clinically suspected posttransplant renovascular hypertension. We prospectively investigated 25 renal transplant recipients with arterial hypertension and clinically suspected stenosis of the graft artery (8 female and 17 male patients; ages 45 +/- 15 years). We performed a captopril test with 25 mg captopril (n = 25), renography with technetium-99m diethylene triamine penta-acetic acid (99mTc-DTPA) before and after angiotensin-converting enzyme (ACE) inhibition with determination of glomerular filtration rate (GFR) and effective renal plasma flow (ERPF) (n = 23) and color-coded duplex ultrasonography of the transplant kidney vessels (n = 24). Renal transplant artery stenosis (RTAS) was excluded by renal arteriography in 20 patients and by operative evaluation or clinical follow-up in 5 patients. We identified 4 patients with RTAS and renovascular hypertension. The noninvasive methods showed the following results (sensitivity/specificity): (1) captopril test: 75%/67%; (2) renography combined with ACE-inhibition: 75%/84%; and (3) color-coded duplex ultrasonography: 100%/75%. We conclude that in patients with clinical evidence of RTAS most noninvasive diagnostic procedures are not sufficiently accurate to exclude the diagnosis. Only color-coded duplex ultrasonography did not fail to detect all patients with RTAS and may act as a screening test. Intraarterial renal angiography remains the most reliable and as-yet indispensable diagnostic test for transplant recipients to rule out RTAS.

Adult↗

PubMed1992

Radiation-induced heart disease: morphology, changes in catecholamine synthesis and content, beta-adrenoceptor density, and hemodynamic function in an experimental model.

To study further the pathophysiology of radiation-induced cardiomyopathy, we investigated resting hemodynamics, myocardial catecholamine synthesis and storage, and beta-adrenoceptor density after local heart irradiation. In Wistar rats, a radiation dose of 20 Gy eventually leads to compromised myocardial function which is characterized by a reduction in cardiac output to 43 +/- 11% and in the left ventricular ejection fraction to 66 +/- 7.5%, and an increase in the left ventricular end-diastolic volume to 187 +/- 17% of control values. This reduction in function is correlated with focal degeneration of 23 +/- 4% of the myocardium. Measurement of tyrosine hydroxylase activity and catecholamine content revealed that catecholamine biosynthesis is unchanged in the adrenals but is significantly reduced in the hearts of irradiated animals, while cardiac beta-adrenoceptor density is increased to about 140% of that in age-matched controls. This is in contrast to findings in dilated or ischemic cardiomyopathy. Time-course studies showed that the development of myocardial degeneration starts simultaneously with the decrease in cardiac output and ejection fraction and the increase in beta-adrenoceptors at 50-80 days postirradiation. Myocardial degeneration is maximal in extent and severity at 100 days and does not progress thereafter. Cardiac output decreases at 80-100 days postirradiation to 60 +/- 7% of control values. A significant further decrease is seen only when congestive heart failure becomes manifest at 249 +/- 21 days after 20 Gy. Thus there is a delay between structural myocardial injury and hemodynamic deterioration which could be due to a compensatory increase in beta-adrenoceptor density during the initial stages of the cardiomyopathy.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1991

[Comparative diagnosis of focal liver changes using computed tomographic and scintigraphic methods].

The value of scintigraphic methods for the diagnosis of focal lesions of the liver (IDA, colloids, blood pool) in comparison to dynamic sequential computer tomography (CT) has been examined in this study. We found CT to be diagnostic in typical cases. For example, focal nodular hyperplasia is characterized by a rapid, strong increase and subsequent decrease after application of contrast medium (71%), whereas hemangiomas show a delayed density increase mostly at the rim (20%). In the event of deviations from the typical pattern, scintigraphic methods have to be applied which then often yield a specific diagnosis, especially in hemangiomas, focal nodular hyperplasia, and adenomas (71%). Ultrasound findings indicating the possible presence of hemangiomas or focal nodular hyperplasia should lead to scintigraphic studies prior to CT, not only for reasons of economy.

Adult↗

PubMed1991

Detection of infection in postoperative orthopedic patients with technetium-99m-labeled monoclonal antibodies against granulocytes.

A prospective study of 106 orthopedic patients was performed for the detection of infection in the early postoperative stage using 99mTc-labeled murine Mabs directed against epitopes on granulocytes. Accuracy was 81% in the hips (n = 26), 81% in the thigh (n = 21), 84% in the knee (n = 19), and 100% in the tibia (n = 27). The technique did not work well in the spine where false-negative results were observed in the three patients studied. One patient suffered transient swelling of the eyelids following injection. Optimal imaging results were obtained 2-6 hr postinjection.

Adolescent↗

PubMed1991

[Comparison of lisinopril and captopril in treatment of severe heart failure (NYHA III-IV) in high risk patients. Preliminary results of the trial].

We present preliminary data of a study comparing captopril, a short acting, with lisinopril, a long acting ACE-inhibitor in 8 of 12 projected patients with severe chronic heart failure (NYHA III-IV) and one additional risk factor (e.g. diabetes mellitus, renal failure). The 8 patients were treated in a cross over design for 12 weeks with either drug. While lisinopril improved NYHA-class in all patients, captopril reached this goal in only 3. Renal function was stable in all patients. Captopril influenced hormones (renin, aldosterone, norepinephrine, epinephrine) and microalbuminuria less than lisinopril. The number of adverse reactions was smaller in lisinopril treated patients. These preliminary data demonstrate at least an equal efficacy of lisinopril compared to captopril in high risk patients with severe chronic heart failure.

Angiotensin-Converting Enzyme Inhibitors↗

PubMed1990

[Low-dose enalapril as additional medication in severe chronic heart failure].

A prospective, randomized efficacy study of low-dose enalapril was undertaken in 38 outpatients (24 men, 14 women; mean age 58 [41-69] years) with chronic heart failure (NYHA functional class III-IV). All patients were pretreated with digitalis and diuretics, some also with conventional vasodilators. 19 patients (group E) received in addition to their previous medication, 5 mg enalapril daily, while the other 19 (group K) continued with their previous therapy. Three months later, 15 patients in group E improved by at least one NYHA functional class and none died (P less than 0.02). Four patients in group K died and only one patient improved by one class. After three months, left ventricular ejection fraction was significantly higher (P less than 0.0001) in group E (39 +/- 19%) compared to group K (30 +/- 14%). In group E, plasma aldosterone concentration decreased significantly (P less than 0.0001) by 33.4 +/- 6.5 ng/dl, while in group K no significant change occurred (delta 1.1 +/- 1.2 ng/dl). Thus, low-dose enalapril in addition to conventional therapy may improve the clinical status of patients in severe chronic heart failure. This improvement is associated with an increase in left ventricular ejection fraction and reduction in secondary hyperaldosteronism.

Chi-Square Distribution↗

PubMed1990

[Determination of the arterio-portal blood flow relations of the liver--results using 99mTc-hepatobida and a review of methods].

The arterial-to-portalvenous blood flow ratio (APV) has been determined routinely within liver bile studies carried out with 99mTc-hepatobida. Out of 1300 patients studied since 1978, 80 were analysed in detail concerning the fixed time parameters to separate the arterial and the portalvenous phase. The arterial phase was assumed to end 4 s after the first aortal peak, immediately followed by a portalvenous phase of 12 s duration. The "triangular area approach" of Biersack (1977) and George (1974) developed for pertechnetate and colloid, was directly applied to hepatobida. The fixed phase limits of hepatic circulation described above were compared to circulation parameters obtained from the beginning of the right ventricular recirculation and from the first decline of the spleen curve (for the end of the arterial phase), and from the second left ventricular peak (for the end of the portal phase). Our 4 s of aortal to end-arterial time agreed excellently with a corresponding control value of 4.1 s, as did the duration of the portal phase with 12 s compared to a control value of 12.1 s. An upper normal value of 45% APV was established, based upon sensitivity, specificity and a classification of hepatic curves. The "triangular area approach" appears at first to be inconsistent from a methodological point of view. We present a critical typology of assessing the APV. Basically we distinguish between strictly intravasal and all other types of tracer. The former are studied adequately by deconvolution and subsequent "real" area approaches, reflecting the full tracer passage through the liver. All not strictly intravasal tracers (pertechnetate, colloid, hepatobida) are subjected to a model assumption of a pure uptake without relevant tracer elimination during the first pass. We conclude that the Biersack-George method may be regarded as a heuristic correction of an amplitude approach within our typology, and that our fixed phase limits are justified by circulation analysis.

Hepatic Artery↗