Search PubMed⌕ Search

Biomedical subjects

H K Beyer

Publications and source records attributed to H K Beyer.

At least 37 records · Page 2Linked to original sources
PubMed1989

[The value of magnetic resonance tomography using gadolinium-DTPA in the diagnosis of the post-lumbar disk surgery syndrome].

Our results have shown that MR tomography - especially if gadolinium-DTPA is used as a contrast medium - is an excellent method to differentiate between the various possible causes of the post-discotomy syndrome. In particular, it is definitely possible to differentiate between a relapsed hernia of an intervertebral disc and a postoperative development of cicatricial tissue which is practically inevitable. This differentiation is of vital importance to the clinician, because a second operation should be performed only in case of a relapse, whereas cicatricial tissue is best left alone, because no matter how carefully the operation is performed with preparation of the neural structures, even more extensive cicatricial plates are bound to develop. Instability of the vertebral column in the operated disc segment, or other causes of complaints, can be identified via MR equally well if not better than by other means. Hence, the method should be the method of choice in postdiscotomy syndrome, since it facilitates the difficult choice between conservative therapy and reoperation.

Contrast Media↗
PubMed1988

[31-P-spectroscopy as a method for studying biochemical changes in skin tumors: exemplified by malignant melanoma and squamous cell carcinoma].

We report on the basic principles concerning in vivo P-31 MR spectroscopy and give a short review of the corresponding studies on skin tumors described in the literature. Malignant melanoma and squamous cell carcinoma are both characterized by high concentrations of phosphomonoester and phosphodiester. By means of the P-31 spectroscopy technique, we are able to detect changes regarding the tumor metabolism as a response to chemotherapy, irradiation, or biological immune modifiers (e.g. interferon).

Carcinoma, Squamous Cell↗
PubMed1988

[Spin-echo sequences and rapid image sequences in a comparison of spinal diseases].

Rapid image sequences of the spine were compared with proton and T2-weighted spin-echo sequences in 30 patients concerning their diagnostic value and image contrast. The rapid series was carried out with an angle of rotation of 30%, TR of 21 and TE of 12 msec., the spin-echo sequences with a TR/TE of 2,000/20/80 msec. The quality and contrast of the rapid series was markedly inferior to the spin-echo sequences; this was particularly marked for demonstrating disc and bone degeneration. At present, the routine use of rapid sequences cannot be recommended as a substitute for spine-echo examinations.

Humans↗
PubMed1988

[Importance of contrast medium administration in determining the age of traumatic renal hemorrhage by NMR tomography--experimental results].

In eleven Han-Wistar rats, experimental renal haematomas were produced and scanned by magnetic resonance tomography at two hours to 21 days. Bleeding during the first three or four days showed prolongation of T1 and T2 relaxation times. On subsequent days there was shortening of the T1 and T2 times. Gadolinium DTPA produced a marked effect in the second to fourth day following the trauma, if the examination was carried out 90 to 120 minutes after the administration of contrast medium. Gadolinium can be used in determining the age and clarifying the differential diagnosis of an bleeding if there is clinical support.

Animals↗
PubMed1988

[Specific detection of various stages of Osler's disease of the brain using high field magnetic resonance tomography (1.5 Tesla)].

MR is a sensitive noninvasive examination method for diagnosing parenchymatous cryptic arteriovenous malformations and sequels of cerebral haemorrhage. In a patient with recurring nosebleed and brain stem syndrome eleven so-called cryptic arteriovenous malformations or their haemorrhage sequels were diagnosed via magnetic resonance tomography. Basing on these specific findings, nosebleeding, and a positive family anamnesis, the findings could be classified as belonging to manifestations of Osler's disease (hereditary haemorrhagic telangiectasia). This rare disease is characterised by a triad of signs: telangiectasias, recurring bleeding, and heredity. In this article the specific MR image is compared with the CT pattern and the results are discussed against the background of literature on Osler's disease which is also known as Rendu-Osler-Weber disease.

Adult↗
PubMed1988

[Follow-up of combined radiotherapy and chemotherapy of advanced bladder cancer using magnetic resonance tomography. Initial results].

A combination of cis-platinum and radiotherapy was applied in five patients with advanced bladder carcinomas. The patients were examined by nuclear magnetic resonance imaging prior to and following therapy. Corresponding to cell-kinetic considerations regarding tissues with slow cell turnover, a maximum therapy effect is shown about nine months after the end of local therapy. Smaller control intervals are recommended in case of bladder carcinomas with lymph node metastases. Due to the possibility of multiple slice imaging, the nuclear magnetic resonance technique is particularly suited for the monitoring of bladder carcinomas. Sagittal and coronary slices show a better image of tumoral extension at the roof and floor of the bladder than axial computed tomography. Lymph node metastases are represented relatively late by both methods.

Aged↗
PubMed1987

[Nuclear magnetic resonance tomographic studies following experimental ligation of the renal artery in rats].

MR was carried out on 22 Han-Wistar rats in relation to ligature of the left renal artery; measurements were obtained before the operation and at two, four, eight and thirty-six hours afterwards. Significant increase in T2 relaxation of the left cortex was observed after thirty-six hours and increased T2 of the medulla on the operated side after two hours. T1 relaxation time in the cortex was also prolonged, but the medulla showed no definite change. Following the operation, there was an increase in the size of the opposite kidney after eight hours; on the operated side, the cortex increased, but the medulla decreased. The results indicate that MR is a very sensitive method for demonstrating renal artery occlusion at an early stage.

Animals↗
PubMed1987

[Nuclear spin tomography and computerized tomography in malignant hypernephroma].

Forty patients with histologically confirmed hypernephromas were examined by MR and CT. As regards T-staging, MR had an accuracy of 97% and CT of 91%; for N-staging, MR had an accuracy of 85% and CT of 91% and, with regard to infiltration of the renal vein, MR was correct in 88% of cases and CT in 81%. MR was most accurate in the pre-operative assessment of tumour spread, demonstrating caval involvement in 100% and lymph node metastases in 97%. On the other hand, infiltration of the renal pelvis could be assessed in only 65% of cases; in 27% the assessment was not possible and in 8% one could not be certain. CT proved to be at its best for staging of lymph nodes, but in 15% it was not possible to identify infiltration of the renal vein. MR was not greatly superior to CT in the preoperative diagnosis and staging of hypernephromas.

Carcinoma, Renal Cell↗
PubMed1987

[NMR tomographic studies in experimental renal vein ligation].

Experimental ligation of the renal veins in rats indicate highly significant and characteristic changes within two hours, consisting of significant prolongation of T2 relaxation time in the cortex and T2 shortening in the medulla. In addition, there is a considerable increase in the size of the kidney, due to swelling of the cortex. T2 prolongation of the cortex is most marked between 30 hours and two to four days after ligation of the vein. In the following weeks there is a return to normal. T2 of the medulla at two to three weeks after ligation shows highly significant reduction compared with the normal side and, at this time, the size of the experimental kidney is significantly less than the opposite kidney. These results indicate that magnetic resonance tomography is a highly sensitive method for the early demonstration of renal vein thrombosis.

Animals↗