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Biomedical subjects

W Semmler

Publications and source records attributed to W Semmler.

At least 73 records · Page 4Linked to original sources
PubMed1990

[MR-tomographic quantification of infiltrative bone marrow changes and therapeutic follow-up of patients with hairy cell leukemia].

The effect of treatment on bone marrow infiltration in hairy cell leukaemia was followed by means of MRT in five patients. A semi-quantitative method has been developed in order to judge the effect of treatment. The results correlate well with the findings on iliac crest biopsies. The method could partly replace the invasive iliac crest biopsies, which are used for therapy monitoring.

Bone Marrow↗
PubMed1990

Real-time follow-up of 5-fluorouracil metabolism in the liver of tumor patients by means of F-19 MR spectroscopy.

Intraarterial 5-fluorouracil (5-FU) chemotherapy in eight patients, one with primary and seven with secondary liver tumors, was monitored by means of in vivo fluorine-19 magnetic resonance (MR) spectroscopy. F-19 MR spectra were obtained with surface coils and included signal contributions from both liver and tumor tissue. The time course of the relative concentrations of 5-FU and its major catabolite, alpha-fluoro-beta-alanine (FBAL), was followed for up to 100 minutes after the start of drug administration. The time constants for the kinetics of 5-FU ranged from 8 to 75 minutes, whereas the time constants for FBAL were either approximately 15 or 50 minutes. A broad peak comprising nucleoside and nucleotide anabolites of 5-FU was detected in one patient. These investigations demonstrate the feasibility of short-term therapy monitoring with F-19 MR spectroscopy and that catabolites and anabolites of 5-FU can be observed separately. However, since no F-19 MR spectroscopy localization sequence is available at present, the contributions to the total MR signal from normal liver and tumor tissue cannot be discriminated.

Adult↗
PubMed1989

Assessment of muscular metabolism in peripheral arterial occlusive disease using 31P nuclear magnetic resonance spectroscopy. Comparison with metabolite concentrations in femoral blood.

The behaviour of muscular metabolism was investigated in 10 patients with peripheral arterial occlusive disease stage II at rest and after maximum ergometric calf exercise. The intracellular concentrations of phosphocreatine, inorganic phosphate and adenosine triphosphate as well as muscle pH were measured by means of 31P magnetic resonance spectroscopy and compared with those from a control group. In addition, arteriovenous differences in concentrations of lactate, pyruvate, ammonia, hypoxanthine and alanine in the femoral blood were determined. The fall in intracellular phosphocreatine concentration during exercise was significantly greater in the calf muscles of patients with arterial occlusion than in controls and correlated linearly with the increase in femoral arteriovenous differences in lactate, ammonia and alanine. A significant fall in intracellular pH occurred during muscular activity only in the patient group, but not in the identically exercised control group. The fall in pH correlated closely with the rise in arteriovenous lactate difference in the femoral blood. The intramuscular ATP concentration remained constant throughout the exercise procedure. The behaviour of both the directly and indirectly measured metabolites permits the deduction of activation of the creatine kinase reaction, glycolysis, myokinase reaction and the purine nucleotide cycle during exercise-induced hypoxia in the presence of arterial occlusive disease. The anaerobic production of energy is sufficient to maintain the ATP concentration even during claudication pain.(ABSTRACT TRUNCATED AT 250 WORDS)

Acid-Base Equilibrium↗
PubMed1989

[NMR tomographic imaging of bone marrow infiltrates in malignant lymphoma].

10 normals and 37 patients with Hodgkins' and non-Hodgkin's lymphoma were examined by MRT as part of a prospective study (lumbar spine, pelvis, proximal femora). In about half the patients the MR images showed diffuse or focal areas of reduced signal intensity in the bone marrow. The observation of reduced signal areas corresponded with the pathological findings from iliac crest biopsies. To improve diagnostic accuracy, the signal intensity from a chosen region of interest was related quantitatively to a standard level.

Adult↗
PubMed1989

[Bone marrow changes in Hodgkin's disease: MR tomography and chemical shift imaging].

A patient with Hodgkin's disease, who had received various forms of treatment, was examined by MR tomography and scintigraphy; the results are discussed together with the findings of the bone marrow biopsy. A spectroscopic imaging technique (modified Dixon method) and quantitative evaluation of the fat and water components of the RF signal provide new diagnostic information that may improve the differential diagnosis. Serial examinations following supra-lethal therapy and bone marrow transplantation have been able to show changes in the bone marrow and these could be evaluated quantitatively.

Adult↗
PubMed1989

Magnetic resonance imaging of bone marrow in lymphoproliferative disorders: correlation with bone marrow biopsy.

In a prospective clinical study 10 normal volunteers and 30 patients with lymphoma--11 patients with Hodgkin's lymphoma and 19 patients with non-Hodgkin's lymphoma (11 low grade, 8 high grade)--were examined. Proximal femora, pelvis and lumbar spine were imaged with a 1.5 tesla superconducting MR imaging system (Siemens Magnetom). Areas of malignant infiltration in the bone marrow were clearly detected by visual and/or quantitative assessment. In most cases bone marrow involvement was demonstrated by both magnetic resonance imaging and bone marrow biopsies. However, in three of 30 patients magnetic resonance imaging showed evidence of lymphomatous involvement despite normal bone marrow histology. In one patient bone marrow cytology revealed malignant infiltration in the absence of MRI abnormalities. Thus, MRI is a sensitive method for detecting bone marrow infiltration by lymphoma.

Adult↗
PubMed1989

[MR tomography detection of bone marrow infiltration by malignant lymphomas].

In a prospective MRT study, both healthy volunteers (n = 10) and patients with Hodgkin and non Hodgkin lymphomas (n = 32) were examined (lumbar spine, pelvis and proximal femura). A biopsy from the posterior iliac crest was taken in all patients. About one half of the patients showed in MR-images diffuse or patchy areas of decreased signal intensity in the regions of the bone marrow, while the bone marrow of the volunteers showed an almost homogeneous pattern with high signal intensity. Our findings observed by MRT in bone marrow of these patients corresponds with pathological results obtained from crest biopsies. In order to improve the diagnostic accuracy, a quantitative evaluation of the signal intensities in selected ROIs, referring to a standard, was used. This method allows to correct variations of the signal intensity due to technical reasons. As our results show, this leads to a better differentiation of border-line cases. MRT has the advantage to detect localised lesions outside of the iliac crest. In cases of negative crest biopsies, but suspicious areas in MR-images, biopsies could be directed to these lesions.

Biopsy, Needle↗
PubMed1989

[Non-invasive follow-up control of tumor therapy following chemotherapy using 31P-MR spectroscopy in whole body tomography].

The 31P Magnetic Resonance Spectroscopy allows to monitor noninvasively and in vivo the energy and phospholipid metabolism of tissue. At present the high technical demand prevents the application of this new modality in the clinical routine. By means of some cases the advantages and limitations of the 31P-MRS are demonstrated. Recent results show that 31P-MRS monitors effects on the metabolism of tumor cells as early as two days after onset of chemotherapy. Further clinical studies and technical developments are necessary to render 31P-MRS a clinic routine examination.

Computer Graphics↗
PubMed1989

[Magnetic resonance tomography of pituitary tumors].

This paper presents a survey of the current status of the diagnosis of pituitary tumors by means of magnetic resonance imaging. It focuses on the clinical and practical aspects. The recommended procedure and the sequences and slice orientations for magnetic resonance imaging of the pituitary gland are presented, and the features that are essential for the diagnosis of pituitary tumors are discussed.

Humans↗
PubMed1989

[Application of multinuclear in vivo magnetic resonance spectroscopy in oncology].

Cell metabolism and the metabolism of drugs can be monitored noninvasively and in vivo by magnetic resonance spectroscopy (MRS). At present, tumors cannot be differentiated by means of 31P MRS. This method can be used in tumor therapy follow-up for early detection of metabolic tumor response. 31P MRS is not helpful in determining whether patients respond to therapy or not. The first clinical results have been obtained using 1H MRS; however, no clinically relevant results have been obtained as yet. Preliminary experiments demonstrate that 19F MRS can be used to observe the metabolism of drugs.

Antineoplastic Agents↗
PubMed1988

[In vivo 31 phosphorus spectroscopy of tumors: pre-, intra- and post-therapy].

Using 31P-MR spectroscopy spectra with good signal-to-noise ratio were obtained in five different types of tumours (Ewing's sarcoma, osteosarcoma, malignant melanoma, metastases from a squamous cell carcinoma, parotid adenoma). Surface coils were used. Short- and long-term follow-up after chemotherapy was possible in some cases. In the short-term follow-up, changes in the phosphocreatine and inorganic phosphate resonances could be observed within minutes after the start of the infusion. In the longer follow-ups, changes in phosphodiester and phosphomonoester resonances were observed within two days. There were no significant changes in tissue pH during treatment, but increased pH values were observed in all tumours.

Adenoma↗