PubMed Health⌕ Search

Biomedical subjects

M Meves

Publications and source records attributed to M Meves.

At least 19 recordsLinked to original sources
PubMed1991

[Whole-body MRT studies--the results of the "Multicenter study on the evaluation of magnetic resonance tomography"].

In a nation-wide multicentre study, the use of MRI was examined in its clinical context and in relation to other imaging methods and as a routine examination. It was found that examinations of the brain and spine were predominant. MRI is accurate for certain problems affecting the extremities, the pelvis and the liver. The findings also show that there are still technical limitations. A high degree of accuracy can only be obtained if there is adequate information concerning individual problems. Technical limitations include the frequent appearance of artifacts. In its present state, MRI can only supply additional information, concerning the trunk only, in certain situations. The study also outlines the development of MRI and the role of other conventional diagnostic procedures.

Evaluation Studies as Topic↗
PubMed1990

[NMR studies of the whole body--results of a multicenter study for evaluating nuclear magnetic resonance tomography].

Within the framework of a national multi-centre study the spectrum of application and the ranking of magnetic resonance tomography were investigated. Although scans of the brain and vertebral column still dominate the scene, it has become evident that whole body scanning via MR can be very accurate for certain indications. This is particularly true for examinations of gynaecological diseases (95%) and for lesions of the liver (97%). However, the number of problems in which MR can provide answers to diseases in the whole body range is still limited, and hence it would be most desirable to achieve further instrumental and methodical improvements.

Brain Diseases↗
PubMed1990

[Obstacles to the routine use of magnetic resonance imaging--results of a multicenter study for evaluating nuclear magnetic resonance tomography].

Within the framework of this study, the factors that impair the value of MR scans were also investigated and analysed. It was found that artifacts occurred in a large number of examinations that exercised a negative effect on the results. Artifacts are particularly seen in the thorax (54%) and upper abdomen (57%), but they have also been reported in 23% of the CNS examinations. The sources of such artifacts were mainly movements in the investigated layer, whereas other causes were negligible. In the 21,633 examined patients no undesirable effects caused by the examination were noted that would have impaired the patient or the course of the study. On an average, 88% of the examinations were performed with normal tolerance of the examination. In the remaining cases there was motor unrest or claustrophobia requiring special measures, thus hampering the course of the examination.

Diagnosis, Differential↗
PubMed1990

[Evaluating magnetic resonance tomography studies of the extremities--results of a multicenter study for evaluating nuclear magnetic resonance tomography].

MR examinations of the extremities occupy the first place in whole body examinations via MR. Highest accuracy quotas in this area with an average of 93.8% were obtained for tumours, trauma and necroses of the bones. These high accuracy quotas, however, were achieved only if sufficient preliminary information was available. Other statistically significant factors were found to be the field strength, the combined use of spin echo and fast imaging sequences and the use of the multislice technique.

Bone Neoplasms↗
PubMed1986

[Possibilities in using a specific pulse sequence (interlocking sequence) to improve the specificity in NMR tomography].

Methods and possibilities of application of a doubled and interlaced pulse sequence ("interlaced sequence") are discussed. This makes it possible to perform contrast variations and pulse sequence variations subsequently, as well as to determine the parameters proton density, T1 and T2. The selectivity of the combination of all three parameters for tissue classification is demonstrated by means of an individual case and seems to promise a higher specificity of MR tomography.

Brain Neoplasms↗
PubMed1985

[Use of long spin-echo sequences for imaging demyelinating diseases].

A multiple spin-echo-sequence has been evaluated in diagnosis of demyelinating diseases. TE in these MR-experiments was between 14 and 336 msec, TR between 860 and 1660 msec. Three groups of patients were examined, and it could be shown that the probability to detect MS-plaques grows with long TE's up to 300 msec. T2-relaxation-time-values range between 126 and 250 msec. Different MS-plaques in the same patient might show different T2-values.

Brain↗
PubMed1985

[T2-analysis of normal and pathological structures of the head].

Analyses of T2 values (spin-spin relaxation time constant) in magnetic resonance tomography were carried out in 29 patients with brain tumours. 21 of these had tumours of the glioma group (17 astrocytomas WHO I-III and oligoastrocytomas, 4 glioblastomas). Measurements were effected both pixel by pixel and according to relevant ROI (regions of interest). Although the measurements yielded a T2 value which was typical of the disease, it was individually difficult to effect proper grading on account of the scatter occurring from case to case. Markedly more relevant information was obtained by the introduction of profile measurements in T2 images. The relation between T2 profile and histology of the gliomas permits rough grading between more or less differentiated gliomas.

Adolescent↗
PubMed1985

[Present status and developmental trends in NMR tomography of the CNS].

The image quality of MR tomography, which is of particular value in diagnosis, is due to the possibility offered by MR of presenting a maximum of intrinsic biological information via suitable configuration of equipment and adjustment of parameters. Contrast resolution and spatial resolution are closely linked in this presentation. In the near future we may expect to be able to quantify the MR parameters rho, T1 and T2. Unconventional and newly developed impulse sequences will reduce the time required for an examination, which is at present still rather high at more than an hour. Hence, standardisation of data acquisition will be developed further, together with subsequent weighting of the MR parameters specifically according to findings. This will be achieved via computer-assisted evaluation and assessment.

Brain Diseases↗
PubMed1979

[Gastric emptying in patients with ulcus ventriculi (author's transl)].

The half life time (T 1/2) of gastric emptying was measured in 53 patients suffering from atrophic gastritis or gastric ulceration, by use of a radiolabelled standardized test-meal. In healthy controls the T 1/2 was 58.8 +/- 9.1 min (median 59 min). In 35 gastric ulcer patients the T 1/2 of median 85 min was significantly slowed if compared to the normal value (2 p less than 0.01). After healing of the ulcer in 12 patients this value returned to normal. In 8 patients with diffusely atrophic gastritis the T 1/2 value was slowed significantly (median 123 min), if the gastritis was confined to the antrum, gastric emptying was accelerated (median 48 min).

Adult↗
PubMed1979

[Gastric motility after vagotomy (author's transl)].

1. Ulcer disease cause a change of gastric emptying; in patients with gastric ulcer gastric emptying of a semisolid meal is delayed as well as in patients with stenosis in the pyloricregion; patients with an uncomplicated duodenal ulceration shows an accelerated gastric emptying. 2. Vagotomy results in relation to the type of vagotomy and to the degree of desection of anteral muscles a delay of gastric emptying of a semi solid and liquid food until over the 6th postoperative month. 3. After selective proximal vagotomy (SPV) the gastric emptying is also but shortly delayed. 4. There is a correlation between the disturbed gastric emptying after vagotomy and the altered absorption of glucose.

Duodenal Ulcer↗
PubMed1979

[Gastric emptying in duodenal ucler (author's transl)].

In 196 patients suffering from duodenal ulcer disease, gastric emptying was measured by use of a radiolabelled testmeal. The measurements were performed during the digestive phase of gastric activity. On the basis of the predominantly exponential form of gastric emptying the T 1/2 was chosen as a measure of this function. The results were: 1. In 50 subjects without gastrointestinal disease the median T 1/2 was 59 min, mean and standard deviation were 58.8 +/- 9.13 min; 2. the T 1/2 value in 71 patients with deformed duodenal bulb (median 53 min) was significantly accelerated if compared to the normal value (2 p less than 0.01); 3. T 1/2 in 88 patients with deformed bulb combined with acute ulcer (median 49 min) was shorter than T 1/2 of the normal subjects (2 p less than 0.001); 4. T 1/2 in 25 patients with pyloric stenosis (median 102 min) was longer than normal value (2 p less than 0.001).

Adult↗
PubMed1977

[Isolated stenoses and occlusion of the coeliac artery--a comparative angiographic and clinical study (author's transl)].

14 patients with occlusion (7 patients) or extreme stenosis (7 patients) of the arteria coeliaca underwent operation because of heavy abdominal complaints. The constriction of the arteria coeliaca was caused by arteriosclerosis (2 patients), ligamentum arcuatum medianum (8 patients), ligamentum arcuatum medianum and ganglion tissue (2 patients). For the restitution of a normal blood circulation in the epigastric organs the following was necessary: in 10 patients a decompression, in 3 patients an aortocoeliacal bypass and in 1 patients an enlargement plastic with vein patch. The angiographic findings indicate a connection between the arteria coeliaca occlusion or extreme stenosis and the extent of the collateral blood supply. High pressure gradients between aorta and arteria coeliaca, significantly decreased medium pressures in the arteria hepatica communis and noticably frequent morphologic changes in the epigastric organs could be seen intraoperatively.

Adult↗