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E Bücheler

Publications and source records attributed to E Bücheler.

At least 19 recordsLinked to original sources
PubMed1999

[Ultra-small superparamagnetic iron oxide particles: the signal behavior and relaxation times of the bone marrow after repeated i.v. application in the pig model at 1.5 tesla].

PURPOSE: Evaluation of the influence of an iron-containing MR contrast agent on the signal behaviour and the relaxation time of the bone marrow at 1.5 tesla after repeated doses. ANIMALS AND METHODS: 14 pigs received i.v. on days 1, 9, and 15 ultra-small (core diameter 6-8 nm) superparamagnetic iron oxide particles at doses of 20 (low dose = LD) or 200 mumol/kg body weight (high dose = HD). RESULTS: Following the first administration a dose-independent reduction in the bone-marrow signal intensity in the T2-weighted gradient-echo sequence (FFE) was observed together with a reduction in the T1 and T2 relaxation times. Following the second application there were no further signal-reductions in the HD-group; in contrast, there was a signal reduction in the LD-group, made possible by a signal recovery in the meantime. On the other hand, the relaxation times T1 and T2 were shortened after each administration of contrast medium. CONCLUSION: Nano-SIPS result at both doses in a signal reduction in the bone marrow. Only in the LD-group may repeated examinations with new contrast agent offer diagnostically sufficient images. Relaxometry shows a shortening of T1 as well as T2. This effect could be summed up after repeated doses. Almost no iron remained in the medullary space three weeks after i.v. administration of the contrast agent, which suggests mobilization and metabolization.

Animals↗
PubMed1999

[Importance of digital thoracic radiography in the diagnosis of pulmonary infiltrates in patients with bone marrow transplantation during aplasia].

PURPOSE: Evaluation of digitized chest x-ray for the detection of pulmonary infiltrations in bone marrow transplant patients during aplasia. METHODS: Digitized chest x-rays of 40 patients (21 female, 19 male) with "Fever of unknown origin" (FUO) were evaluated concerning radiological signs of pulmonary infiltrations and correlated to clinical findings, blood chemistry, microbiology and bronchoscopy. Additionally, an individual risk profile was established. RESULTS: In 11/40 patients pulmonary infiltrations were detected in digitized chest x-rays (group 1). 10/11 developed an infectious pulmonary infiltration. 29/40 patients developed no pulmonary infiltration (group 2). When fever increased for the first time (initial chest x-ray) a sensitivity, specificity, positive and negative predictive value of 46%, 86%, 56%, 81% and for the chest x-rays in progress of 61%, 79% 68% and 73% was found. C-reactive protein and temperature increase occurred statistically significantly earlier (p < 0.05) in group 1 compared to group 2. The average latency of digital chest x-rays in comparison to c-reactive protein and temperature increase was 6 days. The incidence of risk factors was significantly higher in group 1 in comparison to group 2 (p < 0.05). CONCLUSION: Digitized chest x-rays are not a reliable method for primary detection of pulmonary infiltrations after bone marrow transplantation. Individual risk factors have to be taken into consideration to indicate further diagnostic methods such as computed tomography at an earlier time.

Adult↗
PubMed1998

[Transmyocardial laser revascularization--the initial experiences of imaging in MRT].

PURPOSE: Imaging of myocardial signal alteration and perfusion differences after transmyocardial laser revascularization (TMLR). METHODS AND MATERIAL: 5 patients suffering from coronary vessel disease underwent MRI (0.5 T) pre- and 4-7 d post-TMLR. T1-weighted spin echo sequences were acquired ECG-triggered native and after injection of gadolinium. Qualitative analysis was performed on both native and contrast-enhanced images. Myocardial signal alterations and wall changes were evaluated. Qualitative and quantitative analyses of contrast-enhanced images were performed with regard of post-therapeutic perfusion differences. Analysis was based on contrast-to-noise (C/N) data obtained from operator defined "regions of interest". RESULTS: Visualization of laser-induced channels was not possible. Native scans obtained before and after TMLR revealed no significant change with regard to the qualitative analysis. Both qualitative and quantitative analyses demonstrated a posttherapeutic increase of C/N in both the left ventricular myocardium (64.4 pre-TMLR; 89.1 post-TMLR; p = 0.06) and the septum in the majority of cases. No significant difference between laser-treated left myocardium and untreated septum was observed (p > 0.05). DISCUSSION: Single myocardial laser channels could not be visualized with a 0.5-T MRI. However, visualization of increased myocardial contrast enhancement in laser-treated left ventricular myocardium was evident in the majority of cases on the basis of qualitative and quantitative analyses. CONCLUSIONS: The MRI technique used enabled a first, limited depiction of TMLR-induced myocardial changes. The clinical value and impact still have to be defined.

Aged↗
PubMed1998

[Computerized tomography and F-18-FDG positron emission tomography in staging of malignant lymphomas: a comparison].

PURPOSE: To determine the value of F-18-FDG-positron emission tomography (FDG-PET) compared with computed tomography (CT) in the staging of malignant lymphomas. MATERIAL AND METHOD: 50 patients with biopsy-proven lymphoma were studied with FDG-PET and CT. The results in initial, posttherapeutic and staging of recurrence were compared. RESULTS: 37 of 65 FDG-PET were identical with CT. 28 studies showed differences. 14 post-therapeutically and one of the initial studies led to downstaging by FDG-PET were as upstaging resulted in one case of initial staging. In two cases false positive pulmonary FDG accumulations caused an upstaging. CONCLUSION: FDG-PET was at least comparable to CT in recording the extension of a newly diagnosed lymphoma, or its recurrence. Upstaging according to FDG-PET occurred only once in initial staging. FDG-PET plays its most important role in the evaluation of residual mass in CT after therapy by accumulating FDG in viable tumour rather than in fibrotic tissue. 14 cases of downstaging according to FDG-PET resulted.

Adolescent↗
PubMed1998

[Liver tumors in children: spiral CT findings and differential diagnostic classification].

Liver tumors in childhood are rare. They can be subdivided in benign or primary and secondary malignant liver tumors. The prognosis of malignant liver disease has improved due to extended therapy in the past few years. Thus, diagnosis of liver tumors in childhood gains in significance. After a suspect ultrasound diagnosis, usually computed tomography (CT) is used as a radiologic sectioning method. Guided by a retrospective analysis of 15 cases, the importance of the Helical-CT is presented. Helical-CT is a good diagnostic method for pediatric cases due to reduced scan times. By the basis of clinical data, distribution, and density, various differential diagnoses can be made. Benign liver tumors, especially cysts and frequently haemangioma, can easily be diagnosed and controlled because of their typical echogenicity and contrast visualisation. In cases of hamartoma, focal nodal hyperplasia, and adenoma computed tomography diagnosis is often necessary. Primary malignant liver tumors can prove to be unilocular hepatoblastomas or hepatocellular carcinomas, while disseminated liver invasions usually are considered as metastatic liver tumors of kidney or adrenal cancer.

Child↗
PubMed1998

[Pleural drainage in acute thoracic trauma. Comparison of the radiologic image and computer tomography].

PURPOSE: Estimation of chest tube placement in patients with thoracic trauma with regard to chest tube malposition in chest radiography in the supine position compared to additional computed tomography of the thorax. MATERIAL AND METHODS: Apart from compulsory chest radiography after one or multiple chest tube insertions, 31 severely injured patients with thoracic trauma underwent a CT scan of the thorax. These 31 patients with 40 chest tubes constituted the basis for the present analysis. RESULTS: In chest radiography in the supine position there were no chest tube malpositions (n = 40); In the CT scans 25 correct positions, 7 pseudo-malpositions, 6 intrafissural and 2 intrapulmonary malpositions were identified. Moreover 16 sufficient, 18 insufficient and 6 indifferent functions of the chest tubes were seen. CONCLUSION: In case of lasting clinical problems and questionable function of the chest tube, chest radiography should be supplemented by a CT scan of the thorax in order to estimate the position of the chest tube.

Acute Disease↗
PubMed1998

[MRI diagnosis of a female urethral diverticulum].

Magnetic resonance tomography reliably provides all anatomic information necessary for the differential diagnosis of a urethral diverticulum even when other imaging procedures cannot provide conclusive evidence. In general, the methodological limitations concern only the less important detail findings such as representation of the neck of the diverticulum or the distinction between septated and multiple diverticula. In addition, possible complications and the pelvic anatomy are shown in one examination. Thus magnetic resonance tomography has a key position among the imaging processes and should be used as the imaging procedure of choice for diagnostically doubtful cases.

Aged↗
PubMed1997

[CT and supplementary HR-CT of Kaposi's sarcoma of the pulmonary parenchyma--the morphology of the findings and the diagnostic value].

AIM OF THE STUDY: was an analysis of the CT appearances of Kaposi's sarcoma (KS) in the lung and to determine the diagnostic value of CT and supplementary high resolution CT. MATERIALS AND METHOD: 38 AIDS patients with cutaneous and/or mucocutaneous KS were examined by conventional radiography and CT of the chest during a prospective study. RESULTS: Evaluation of the CT appearances in 16 patients with proven pulmonary KS showed a typical pattern consisting of patchy and flame-shaped infiltrates in relation to the bronchovascular bundle these may be combined with non-necrotic confluent shadows surrounded by areas of ground glass opacity, thickened interlobular septa and round foci. In 12 patients the CT appearances were regarded as characteristic and in four as suggestive but not diagnostic. CONCLUSION: Combination of these features in patients with cutaneous or mucocutaneous manifestations but otherwise negative findings of pulmonary infection allows one to make a diagnosis of pulmonary KS with a high degree of certainty and helps to avoid invasive diagnostic procedures.

Adult↗
PubMed1997

[The significance of the arterial vascular supply of segment IV in living liver donation].

PURPOSE: Postoperative CT's in living liver donors were analysed retrospectively to examine whether atrophies of segment IV occur after procurement depending on arterial vascular supply. PATIENTS AND METHODS: Postoperative CT's from 19 living donors were retrospectively analysed. DSA of the upper abdomen had been performed on all donors prior to donation. RESULTS: The pre-operative DSA images demonstrated an arterial vascular supply of segment IV from the right hepatic artery in 10/19 cases, from the left hepatic artery in 7/19 cases and from both, left and right hepatic artery, in 2/19 cases. Atrophies were seen in 3/7 patients in which segment IV was perfused via left hepatic artery, in further two patients with perfusion from the right hepatic artery or from both sides respectively. Clinically only one patient presented with an abscess. CONCLUSIONS: The patterns of vascular supply to segment IV seen in our patients differ from those published by Couinaud. Since only 3/7 patients with an arterial supply from the left hepatic artery developed a segmental atrophy, we conclude that there must be additional, radiologically not identifiable portal venous branches or collaterals from the right portal vein that maintain perfusion of segment IV.

Adult↗
PubMed1996

Acute pulmonary embolism: value of transthoracic and transesophageal echocardiography in comparison with helical CT.

OBJECTIVE: The goal of this study was to prospectively compare the accuracy of transthoracic and transesophageal B-mode and Doppler echocardiography with helical CT for detecting acute pulmonary embolism. SUBJECTS AND METHODS: Thirty-five consecutive patients underwent transthoracic and transesophageal echocardiography and contrast-enhanced helical CT. Echocardiographic examinations were analyzed for indirect criteria, including increased main pulmonary artery diameter, tricuspid regurgitation, and dilatation of the right ventricular cavity, as well as for direct thrombus visualization. Sensitivity, specificity, and negative and positive predictive values were calculated. RESULTS: Pulmonary embolism was revealed by helical CT in 22 of 35 patients; in 11 of these 22 cases, central pulmonary embolism was seen. Transthoracic and transesophageal B-mode echocardiography failed to reveal pulmonary embolism in nine patients, two of whom had central pulmonary embolism. The sensitivity and specificity of the combination of both echocardiographic investigations were 59% and 77% respectively (82% and 92% for central pulmonary embolism). In three patients, pulmonary embolism was diagnosed by direct clot detection with transesophageal echocardiography. In two patients, only the indirect parameters indicated pulmonary embolism. Overall indirect echocardiographic parameters were characterized by a low sensitivity that ranged from 50% for tricuspid regurgitation to 21% for main pulmonary artery diameter. CONCLUSION: In comparison with helical CT, transthoracic and transesophageal echocardiography had limited accuracy for detecting pulmonary embolism.

Acute Disease↗
PubMed1996

[MRI of musculature in myalgia--indications and image findings].

This paper deals with the question of the clinical circumstances in which MRI seems to be promising in patients with myalgia. 241 patients suffering from myalgic symptoms were examined by axial scans of the muscular system with T1w and STIR-sequences. All patients underwent a complete neuromuscular examination, which included an MRI guided muscle-biopsy of 203 patients. The images were retrospectively analysed as to the typical characteristics of differential diagnosis. In cases of idiopathic or bacterial/viral induced myositis, primary vasculitis, and rhabdomyolysis, edematous changes of the muscles could always be found. Abscesses were only found in bacterial myositis. In cases of poly- and dermatomyositis as well as inclusion-body-myositis, MRI showed a uniform distribution pattern with emphasis on the quadriceps muscles. In contrast to other neuromuscular diseases in bacterial induced myositis, focal myositis, and rhabdomyolysis a strong contrast agent enhancement was seen. All patients with myalgic syndromes without any other additional neuropathological findings and 86% of the patients suffering from polymyalgia rheumatica had normal MR-findings. MRI allows a correct exclusion of an inflammatory, tumorous, or rhabdomyolitic cause of a myalgia and leads to pathognomonic findings for these diseases. Diseases belonging to the group of endocrine, toxic, or metabolic myopathies might be normal in MRI. We believe that an indication for MRI is given when muscular pain is associated with additional neuromuscular symptoms, especially if an inflammatory origin of the myalgia is suspected or if a muscle biopsy is planned.

Adolescent↗
PubMed1996

[Comparative roentgenometry of the hand in aging].

Increasing age is a risk factor for the development of osteoarthrosis of the joints of the hand in adults between 21 and 60 years of age. Only in the very old (> or = 80 years) is osteoarthrosis of the hand part of the age related degeneration. The literature contains different parameters and indices correlating the amounts of minerals and ashes of metacarpal bones. Our results speak in favour of the presumptions published by Exton-Smith et al. (1969 b) that bone mass belongs among the biological characteristics of old age. Our investigations of hand roentgenograms reveal that remodeling of the joint socket as described by pathologists is not a general but an elective phenomenon. With age the wrist shows only an increasing angle of the radial joint surface (males, right hand) and there is a variation of form in the medial sesamoid bone at the first metacarpus (males, left hand).

Absorptiometry, Photon↗
PubMed1994

[Localized fibrous pleural mesothelioma. Value of image-producing methods for the differentiation from supradiaphragmatic tumors of the liver].

A 38-year-old woman in good health suddenly developed pain in the right chest and mild dyspnoea. She reported two bronchial infections in the preceding year. Physical examination revealed cyanosis of the lips and finger clubbing, slightly dulled percussion sounds and decreased breath sounds at the basis of the right chest, but no other abnormalities. Activity of the tumour marker CA 125 was raised (60 kU/l). The chest radiography showed a shadow in the right lower segment, resembling a high diaphragm. Computed tomography failed to separate the abnormal structure from the liver substance. Needle puncture discovered a small haemorrhagic effusion with mesothelial cells. Magnetic resonance imaging and a scintigraphy of the liver provided evidence that the mass was separate from the liver. At thoracotomy a tumour, 20 x 15 x 10 cm in size and connected by a pedicle to the pleura, was identified and excised. Immunocytochemical tests showed it to be a fibrous pleural mesothelioma without signs of malignancy. The patient was discharged 10 days postoperatively in good general condition.

Adult↗
PubMed1994

Liver iron quantification: studies in aqueous iron solutions, iron overloaded rats, and patients with hereditary hemochromatosis.

For the noninvasive liver iron quantification by MRI in human iron overload diseases, fundamental proton relaxation mechanisms were studied in aqueous solutions with ferritin and other iron compounds, in experimentally iron overloaded rats, and in patients with iron overload diseases. MR-relaxation rates as a function of iron concentrations in the range of 0-7.5 mg Fe/g aqueous iron solutions, 0-5.4 mg Fe/g rat liver in vivo, and 0.16-4.9 mg Fe/g human liver in vivo were determined from multi- and sets of single-spin echo sequences (1.5 T imager). As predicted by theory, transverse relaxation rates (1/T2) in aqueous iron solutions, in liver tissue of rats, and in human liver tissue increased linearly with the iron concentration. A preliminary calibration for the liver iron quantification by MRI was performed from in vivo measurements of liver 1/T2-relaxation rates and liver iron quantification by atomic absorption spectroscopy in biopsies from 13 patients. With the single spin-echo method, precise in vivo liver iron quantification in humans also above 2.0 mg Fe/g liver tissue (T2 < 15 ms) should be accomplished on any imager with shortest spin-echo time available, at least TE < 20 ms.

Adult↗