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Biomedical subjects

D Uhlenbrock

Publications and source records attributed to D Uhlenbrock.

At least 37 records · Page 2Linked to original sources
PubMed1988

[Magnetic resonance studies of sex, age and disease relations of iron deposits in the brain].

Using a 1.5 Tesla super-conducting magnet T2 weighted images of the brain not seldom exhibit a reduced signal intensity in the region of the basal ganglia as an expression of increased iron deposits in these regions. We examined 180 patients (a control group, and groups of patients with vascular, inflammatory or tumorous disease of the brain) in order to answer the question whether the T2-relaxation times of the basal ganglia show a correlation to age, sex and the disease of the patient. We measured a significant decrease of the T2-relaxation times in women compared to men in the region of the basal ganglia. We observed increased T2-relaxation times in the region of basal ganglia with aging in the control group. We were able to show disease-specific alterations in the iron distributions in the region of the basal ganglia in patients with vascular and inflammatory disorders of the brain.

Adult↗
PubMed1987

The myelon in cervical spinal canal stenosis: imaging by X-ray and MRI.

Methods which produce findings relevant to diagnosis and therapy of cervical vertebral canal stenosis are described. Especially MRI provides insights into the structure of the myelon; abnormal image signals may possibly correlate with cervical myelopathy based on disorders of microcirculation.

Adult↗
PubMed1987

Relationship of nuclear magnetic resonance examinations to clinical data, cerebrospinal fluid findings and visual evoked potentials in multiple sclerosis.

We examined 150 patients with a 0.5 Tesla MR system. Fourteen patients were excluded from the study, because, in addition to the clinical signs of multiple sclerosis, they showed other abnormalities (spinal canal narrowing, embolic disease, Vitamin B12 deficiency, etc.). The results of the 136 examinations were related to the duration of disease, index of impairment on Kurtkze's disability scale, the clinical course, and the CSF and VEP results. The MR studies were evaluated in a semiquantitative manner. Patients with a long duration of disease demonstrated more changes than did cases with a short course. We found more periventricular confluences and more white matter plaques in the centrum semiovale. In addition, more lesions were seen in patients with a severe course of disease. All patients with negative CSF results (n = 13) showed positive MR examinations, and vice versa, patients with positive CSF findings showed negative MR results (n = 5). First results of a follow-up study demonstrate that most abnormalities in MR are not related to the clinical course or therapeutical procedure.

Brain↗
PubMed1987

Magnetic resonance imaging (MRI), cranial computerized tomography (CCT), evoked potentials and cerebrospinal fluid (CSF) analysis in five patients with funicular myelosis.

Five Patients with vitamin B12 deficiency were examined by means of MRI, CCT, VEP, BAEP, EEG, and CSF. In 3 patients medianus-SEP and EMG/ENG were recorded as well. Partly, findings of MRI, CCT, VEP, BAEP, SEP, and CSF were similar to those in multiple sclerosis. This is not very surprising considering that the central nervous system lesions in vitamin B12 deficiency consist of disseminated demyelination. Because of this all these investigative techniques must be considered non-specific. Appraisal of findings is only possible in connection with the case history, clinical findings, and supplementary diagnostic measurements.

Antibodies, Anti-Idiotypic↗
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↗
PubMed1987

Magnetic resonance imaging in evaluating focal liver lesions.

We report the results of magnetic resonance imaging (MRI) of the liver in 46 patients with various previously confirmed focal lesions. A characteristic signal pattern was found in hemangiomas (n = 11), with marked signal hyperintensity on T2 and proton weighted images as compared to normal liver tissue. Cysts (n = 7) also showed marked hyperintensity on T2 images, but could easily be differentiated by a lesser intensity on proton weighted images and signal hypointensity on T1 weighted images. Primary liver tumors (n = 4), metastatic liver disease (n = 18), focal nodular hyperplasia (n = 5), and liver adenoma (n = 1) revealed a weak signal hyperintensity on T2 images, with varying signals in T1 and proton weighted modalities. These data combined with other recent communications in the literature indicate that MRI is a promising diagnostic technique in the detection of focal liver lesions and that it may offer a high degree of specificity in the diagnosis of hepatic hemangiomas and benign cysts.

Cysts↗
PubMed1987

[Relaxation times and proton density of the healthy kidney and its lesions and graphic view of T2 decay].

Kidney diseases, healthy kidney tissue and adjacent organs like liver, musculature and fatty tissue were evaluated in respect to their T1-, T2-relaxation times and proton density values. In addition the results of an evaluation of T2-short, T2-long, Rho-short, Rho-long, which were calculated from the T2-relaxation times, are reported. The T2-times are very sensitive in demonstrating differences between the tissues, as significantly different values for healthy kidney tissue and hypernephromas could be found. Different values could be seen dependent on the calculation mode, whereby the calculations had been made from double echo and multiple echo sequences. The T1-relaxation times were less sensitive, differences could be also found between the calculations from the IR and SE mode. The values of T2-long and T2-short and the proton density values differed very much for the same organ in the examined groups of patients, therefore these additionally calculated values unlikely will help in the differential diagnosis of unknown kidney diseases.

Abscess↗
PubMed1986

[Results of nuclear spin tomography of facial bone tumors].

We examined 21 patients with tumours of the mouth, one with tumour involvement of the facial skeleton and three with lymph node involvement in the upper neck, by nuclear tomography. Twenty patients with carcinomas of the mouth were also examined by CT. Nuclear tomography was superior to CT in showing the extent of the tumour; in ten patients the extent of the tumour could not be accurately determined, since there was no clear demarcation from normal tissue. Amongst our patients, nuclear tomography was also superior for showing lymph node metastases. Computed tomography is better at showing bone infiltration. Our results indicate that nuclear tomography is better than CT for showing the tumour and lymph nodes. If there is a suspicion of bone involvement, CT should be used in addition.

Fibroma↗
PubMed1986

[Analysis of the NMR signal for biological information in spinal diagnosis].

Discs of 23 patients and volunteers were examined for the purpose of obtaining T1 and T2-relaxation times. First of all, the signal characteristics of the surface coil were evaluated. The relaxation times of 100 discs were then measured by using standard spin echo sequences. There was a correlation between age and T2-values for healthy discs (R = -0.744). This was not found in case of degenerated discs. The mean value of T1 for healthy discs was found to be 825 ms. The results show a possibility of using relaxation measurements in routine diagnosis for the early identification of disc degeneration.

Adult↗
PubMed1986

[Value of NMR tomography in the diagnosis and staging of prostatic neoplasms].

MR imaging (MRI) possesses good sensitivity in diagnosis of carcinoma of the prostate. It is often not possible to distinguish clearly between carcinoma of the prostate and prostate hypertrophy. MRI can assess the local extension of a prostate carcinoma with a high degree of accuracy (85%); this applies in particular to periprostatic infiltration. MRI possesses only moderate sensitivity in diagnosis of regional lymph node metastases in the minor pelvis.

Evaluation Studies as Topic↗