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Biomedical subjects

E Bücheler

Publications and source records attributed to E Bücheler.

At least 37 records · Page 2Linked to original sources
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↗
PubMed1994

[The value of spiral computed tomography in the imaging of aortocoronary bypass vessels].

Spiral computer tomography (Sp-CT) was performed on 25 patients with 81 aorto-coronary bypasses, with persistent symptoms, following selective coronary angiography. The purpose was to determine to what extent Sp-CT is able to demonstrate patency or occlusion of individual bypasses. From the raw data, transverse sections and standardised 3D reconstructions were obtained. Statistical evaluation showed a sensitivity of 93% and a specificity of 100% with regard to patency. Sp-CT provides optimal contrast and complete demonstration of the bypass without movement artifacts from respiration. 3D reconstructions aid in the evaluation of complex anatomical situations but occasionally lead to incorrect diagnosis of stenoses or occlusions. Compared with other non-invasive procedures (conventional CT and NMR) Sp-CT has proved significantly better for the evaluation of bypass occlusions. Sp-CT cannot completely replace angiography but in some cases may be an acceptable alternative.

Aged↗
PubMed1993

[Liver regeneration in man. A prospective CT-volumetric study].

To get reliable data on human liver regeneration we performed CT volumetry in 25 patients who underwent partial hepatectomy for benign and malignant liver tumours preoperatively and at least one year postoperatively in regular intervals in a prospective study. All patients received standardised CT-scans preoperatively and two weeks, 3, 6 and 12 months post-operatively. The resected specimen size was determined by water displacement. We were able to demonstrate human liver regeneration. Contrary to the well-known animal model the amount of regeneration in humans is less and regeneration takes a longer time. We did not find any statistical correlation to extent of resection, age of patients and other parameters. On the contrary, the human liver seems to regenerate until a certain relationship of liver volume and body-surface area is reached: 0.8 l/m2.

Adult↗
PubMed1993

[The diagnosis of inflammatory muscular and vascular diseases using MRT with STIR sequences].

The role of MRT in the prebiopsy diagnosis of muscular and vascular inflammatory conditions was evaluated prospectively and an optimal method of examination was investigated. 92 patients with a suspected diagnosis of myositis (60 cases) or vasculitis (32 cases) were examined, in each case two extremities were studied using transverse T1 and T2 weighted SE sequences and double echo STIR sequences on a 0.5 Tesla (56 patients) or 1.5 Tesla magnet (36 patients; T5/S15 Gyroscan, Philips). The site of the biopsy depended on the MRT findings. In 41 patients the suspected diagnosis was confirmed histologically, in two patients an infective myositis was diagnosed on clinical grounds despite negative histology. MRT demonstrated muscle oedema in 86% of patients. There were negative findings after immuno-suppressive therapy (two patients), in focal myositis (3 out of 4 patients) and in one of 7 patients with untreated vasculitis. Amongst 49 patients in whom the suspected diagnosis could not be confirmed there was muscle oedema in 11 cases (9 neuropathies out of 22, two myopathies out of 10). Oedema indicated inflammatory muscular or vascular disease with a sensitivity of 97% (except in treated patients and for focal myositis). The number of false negative biopsies can be greatly reduced by the use of MRT.

Adult↗
PubMed1992

Magnetic resonance imaging and pulsed Doppler sonography of poststenotic jets: correlation between signal void and flow velocity distribution.

To correlate the appearance of poststenotic jets on gradient echo images with features of localized Doppler spectra of the jets, we studied an in vitro model of steady flow-through stenoses of 86, 96, and 99% area reduction. As fluids, water and a 40% glycerol solution in water were used. MRI was performed with a 1.5 T whole body imager and gradient echo images were obtained in planes parallel to the direction of flow. Doppler spectra were acquired separately from the MR measurements at 1 cm intervals for a distance of 10 cm downstream from the stenosis. Poststenotic signal void was observed for water and for the 40% glycerol solution only if the mean velocity within the stenosis exceeded a limit of 50-60 cm/sec. On the MR images, the jets could be divided into two segments: A proximal jet segment of uniform width equal to the diameter of the stenosis, followed by a distal jet segment which was characterized by broadening and then dissipating signal void. Except for the 99% stenosis, a high signal intensity core was present within the proximal jet segment. In the proximal jet segment, the Doppler measurements showed a low temporal fluctuation of the maximal flow velocity and only little flow opposite to the main flow direction. In the distal jet segment, the velocity fluctuation and the intensity of reverse flow increased sharply. The high signal intensity core of the jet was associated with a poststenotic zone of constant maximal flow velocity. The results demonstrate a close relationship between characteristic features of poststenotic jets in MRI and pulsed Doppler sonography.

Blood Circulation↗
PubMed1992

Noninvasive liver-iron quantification by computed tomography in iron-overloaded rats.

RATIONALE AND OBJECTIVES: The benefit of computed tomography (CT) for the noninvasive determination of liver-iron concentration in human iron-overload diseases is a controversy in the literature. To study the sensitivity of CT for liver-iron quantification under experimental conditions, the authors measured single- and dual-energy CT numbers in vivo in the livers of iron-overloaded rats. METHODS: Thirty-five rats were subjected to an iron-rich diet for various periods, from 1 to 20 weeks, then scanned by single- and dual-energy CT. CT absorption was correlated to liver-iron content, which was determined by wet ashing and spectrophotometry. RESULTS: Whereas a good correlation (r = 0.99 at 96 kV; r = 0.95 at 125 kV) between CT numbers and liver-iron concentration was found, CT was insensitive to low concentrations of iron. Dual-energy CT scanning results showed greater scattering in liver-iron quantification compared with single-energy CT. CONCLUSIONS: In rats, the sensitivity of single- and dual-energy CT is too low to quantify liver iron in the diagnostically most relevant region of mild liver siderosis (1-3 mg iron/g wet weight [w.wt]).

Animals↗
PubMed1992

[Superselective interventional angiography].

The authors report on the clinical application of superselective interventional angiography within the framework of revascularisation and occlusion. A coaxial catheter system is used for probing, consisting of an F 5 angiography catheter as guiding catheter and an F 3 catheter as internal catheter. The internal catheter is equipped with a shaft with segments of different flexibility and can take up a guide wire of 0.018" that is sufficiently stable to be rotated and guided. The interplay between the guide wire, which can be manipulated, and the flexible internal catheter enables superselective probing even of peripheral vascular areas. As may be required by the basic disease, the necessary interventional measures can be taken via the superselectively placed microcatheter. Superselective interventional angiography is indicated as an occlusive measure in preoperative vascular occlusion followed by palliative tumour resection, embolisation in haemangioma, chemoembolization in tumours of the liver. Superselective angiography is used for revascularisation in the local lysis of peripheral vessels. Due to the on-target superselective approach, side effects are markedly less than those observed with the interventions performed to date.

Angiography↗
PubMed1991

Appearance of poststenotic jets in MRI: dependence on flow velocity and on imaging parameters.

A flow model was used to study the appearance of poststenotic jets in MRI. Jets in CuSO4-doped water and bovine blood were imaged by spin-echo (SE) and fast-field-echo (FFE) pulse sequences at different degrees of stenosis and various flow rates. On flow-compensated FFE images, the jets were characterized by signal void if the mean flow velocity within the stenosis exceeded a limit, which was independent of the degree of the stenosis and the type of the fluid. On SE images and on FFE images without flow compensation, signal void occurred at significantly lower flow velocity. The extension of the poststenotic signal void on flow-compensated FFE images was increased by either reduction of the pixel diameter or by prolongation of the echo time. However, it was independent of the orientation of the imaging plane relative to the direction of flow. The results have an impact on attempts to use signal void for the assessment of turbulent jets with MRI.

Animals↗
PubMed1991

[Chemoembolization in primary hepatocellular carcinoma].

The only generally recognised form of treatment for primary liver cell carcinomas is partial liver resection; occasionally this may be curative. This form of treatment is only applicable in 5% to 30% of patients. All drug-based forms of treatment have proved of little value. The new interventional radiological method of chemo-embolisation has shown results in improving survival rates which are comparable with resection. By using a new coaxial catheter system, embolisation can be performed as a selective intrahepatic procedure; it has few side effects and the quality of life subsequently does not deteriorate.

Carcinoma, Hepatocellular↗
PubMed1991

[Initial experiences with the use of gadolinium DTPA in infants and children under 2 years of age].

The use of Gadolinium-DTPA as a paramagnetic contrast agent in MRI with adults and juveniles concerning brain and spinal cord pathology is well proven since years. Tolerance and safety were excellent. In the FRG it is only introduced for children over two years of age. Therefore this report deals with the experience in four infants and small children under the age of two, who received gadolinium-DTPA for diagnostic purposes in pre- or post-operative circumstances. They all were suffering from neurological tumors and got additional diagnostic information in three cases. Clinical side-effects like urticaria, vomiting or convulsions had not been observed nor had pathologic changes of the biochemical parameters been noticed.

Central Nervous System Neoplasms↗
PubMed1990

[Computed tomographic differential diagnosis of primary pelvic osteo-, chondro- and Ewing's sarcomas].

The value of CT for the differential diagnosis of primary malignant tumours in the pelvis was investigated in the case of three types of tumour: osteosarcomas, chondrosarcomas and Ewing's sarcomas. A total of 78 CT examinations in 29 patients was used. The results show that CT, using suitable techniques (high resolution etc.) constitutes a valuable diagnostic method for differentiating these bone tumours. This applies not only for the localisation of the tumour and for defining its extent, but also for showing the morphology of intra- and extra-osseous soft tissue components and their patterns of calcification. It is possible to recognise patterns of growth and of tissue destruction that are typical of individual tumours.

Bone Neoplasms↗
PubMed1990

[The diagnostic value of MR tomography following gadolinium-DTPA compared to computed tomography in bladder tumors].

In a prospective study, 58 patients with carcinomas of the bladder were examined by CT and MRI; in 48, gadolinium-DTPA was administered intravenously. MRI provided exact staging in 89%, compared with 80% with CT. There was 13% over-staging with CT and 11% with MRI. MRI, unlike CT did not result in any under-staging. In 36 patients a quotient could be calculated from the signal intensity of the tumour and surrounding soft tissues both before and after the intravenous contrast medium and the increased quotient after contrast administration could be estimated. There was a significant increase in the tumour/muscle quotient with a mean of 72 +/- 22% (minimum 43%, maximum 153%), corresponding to a marked increase of the signal from the tumour when compared with the pre-contrast images. This had the following advantages compared with CT: accurate differentiation between superficial and intramural spread. MRI was better than CT at demonstrating tumours in the roof of the bladder and at the trigone.

Adult↗
PubMed1990

[MRT of acute soft tissue hematomas at 1.5 T: animal experimental results].

In 16 Göttingen minipigs 31 soft-tissue haematomas of different location were produced by reinjection of freshly drawn arterial and venous blood. Immediately after the injection, MRI of the haematomas was performed and continued for 2-3 h. The MRI appearance of the haematomas depended on the site of the injection. Intramuscular haematomas demonstrated on T2-weighted gradient-echo images a decrease in signal intensity within a few minutes after injection. With the same scan parameters, subcutaneous haematomas had a high signal intensity still at 3 h after injection. When section of the cadaver was performed, the subcutaneous haematomas consisted of compact clot, whereas with intramuscular injection diffuse infiltration of the muscle was present.

Acute Disease↗
PubMed1990

[Magnetic resonance tomographic diagnosis of retrobulbar neuritis using inversion recovery sequences].

Inversion recovery sequences with short inversion periods (STIR sequences) are particularly suitable for the examination of the intra-orbital and intracanalicular portion of the optic nerve, since they selectively suppress interference from neighbouring fat. This technique makes possible direct demonstration of retrobulbar neuritis that had to be diagnosed exclusively by clinical criteria up to now. As evidence of inflammatory changes in 15 out of 18 patients with acute retrobulbar neuritis, there were areas of increased signal intensity in the affected nerve; in six cases the nerve was also swollen. In eight normals and five patients with healed retrobulbar neuritis, the signal and calibre of the optic nerves were normal.

Adult↗