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Biomedical subjects

K Bohndorf

Publications and source records attributed to K Bohndorf.

At least 19 recordsLinked to original sources
PubMed1992

[Metal endoprostheses for endoscopic therapy in malignant bronchial tumors].

Self-expanding metal stents were implanted in the trachea or main bronchus in 12 patients (eleven men, one woman; mean age 60 +/- 8 years) with nonresectable bronchial carcinoma (n = 11) or tracheal metastasis of a hypernephroma (n = 1). They all had pulmonary complications caused by tumour stenoses (group I: severe dyspnoea [n = 6], group II: retention pneumonia [n = 4] or lung abscess [n = 2] after unsuccessful antibiotic treatment). The procedure was undertaken after local anaesthesia with a flexible bronchoscope (in the first three cases still with a rigid bronchoscope under general anaesthesia) under fluoroscopic control. Immediate reduction in dyspnoea occurred in five of the six patients in group I. In five of the six patients in group II antibiotics cured the infection after stent placement. The therapeutic effect was immediate in severe dyspnoea and retention of secretions. The clinical improvement lasted longer in patients with abscess and retention pneumonia than those with dyspnoea (41 +/- 16 vs. 26 +/- 10 days). If strict indications are observed in cases with malignant bronchial stenosis, implantation of self-expanding stents provides rapidly effective, well-tolerated palliation.

Aged↗
PubMed1992

Subsequently occurring leiomyosarcoma and desmoid tumor of the right thigh.

We present the case of a 44-year-old patient with a primary leiomyosarcoma of the right upper thigh, who developed a second mesenchymal lesion at the same thigh, diagnosed as an extra-abdominal desmoid tumor, some months after surgical treatment of his leiomyosarcoma. Clinically, histomorphologically, DNA cytometrically, immunohistochemically and radiologically the different histogenetic origin of the two lesions could be proven. The patient died 17 months after his first tumor diagnosis of lung metastases of his leiomyosarcoma.

Adult↗
PubMed1992

[The signal behavior of parathyroid adenomas in MRT--the contrast ratio of the thyroid and fatty tissue].

A quantitative analysis of signal relationships using T1, proton and T2 weighted spin echo sequences was carried out using 20 parathyroid adenomas demonstrated by MRI. T1 weighted sequences from 15 adenomas were also examined following intravenous injection of Gd-DTPA. No typical signal relationship could be defined. In 4 cases the administration of contrast medium markedly increased the contrast between the adenoma and the thyroid gland. In 12 cases the tumour could be examined histologically following removal. In 2 cases there was oedema of the tumour and corresponding increased intensity of the T2 weighted sequences; in none of the other cases was there any clear correlation between the signals and the histology.

Adenoma↗
PubMed1992

[MR tomography of colorectal diseases with a negative rectal contrast medium].

The potential of the generic kaopectate (Upjohn) as a negative rectal contrast agent in MR imaging was investigated in the assessment of colorectal disease. 45 MR examinations in patients with colorectal disease (colorectal carcinoma 25 patients, inflammatory disease 12 patients, miscellaneous disorders of the colon 8 patients) were evaluated. All examinations were performed with T1 and T2 weighted SE sequences after rectal application of kaopectate. Gd-DTPA enhanced T1 SE sequences were obtained as well. Kaopectate revealed a signal void of the lumen of the large intestine in T1 and T2 weighted SE sequences. Intravenous administration of Gd-DTPA enabled good differentiation of contrast-enhanced malignant or inflammatory tissue and the low signal lumen of the bowels. No side effects were noted.

Adult↗
PubMed1992

[The radiological findings in adamantinoma of the long tubular bones].

The radiological findings of adamantinomas of long bones are described in 22 patients. The diagnosis was confirmed by a team of experts (pathologist, radiologist, orthopaedic surgeon) of the "Bone tumour study group" at the German Cancer Research Center. There were 12 male and 10 female patients aged 5 to 67 years (most commonly in the second and third decade). In 21 patients the tibia was involved and in one patient the fibula. The tumour was nearly always in the diaphysis (20 cases). The most striking radiological feature was a diaphyseal lesion confined to the bone showing multicentric translucencies. The latter showed surrounding or central ring shaped or focal areas of increased density. The lesions tended to be longitudinal, averaging 11 cm (between 3 and 25 cm). All lesions showed a sclerotic margin separating it from normal bone, at least over part of the lesion. Expanding lesions were mostly separated from the soft tissues by a bony rim (18 cases).

Adolescent↗
PubMed1992

[Late pulmonary changes following bleomycin administration in computed tomography. Nodular fibrosis mimicking a seminoma metastasis].

This is a case report of a patient with multiple metastases to the lung due to a seminoma, treated with a chemotherapeutic regimen containing bleomycin. The typical subpleural fibrosis of the lung related to bleomycin damage disappeared 6 months after the start of chemotherapy. 4 weeks later, a solitary nodule at a prior unchanged site of the lung appeared, mimicking recurrent metastasis. Explorative thoracotomy revealed a nodular fibrosis of the lung, representing a late reaction of the lung to chemotherapy damage.

Adult↗
PubMed1992

[New developments in the computer-assisted diagnosis of focal bone lesions].

Since the 1960s there have been numerous reports in the literature about computer-aided medical diagnosis and therapy. However, so far computer-aided diagnosis has not become important in the clinical routine or in the field of radiology. This paper describes the hitherto existing proposals for expert systems to evaluate focal bone lesions and presents a new concept. The basic ideas of this program are: (1) a PC-based interactive dialogue along on the basis of a defined questionnaire; (2) the use of certainty factors to handle uncertainty and vagueness in evaluating the different radiological findings and their correlation with diagnoses; (3) the link between visual information and the questionnaire. The aims of such expert systems are (a) a complete and systematic analysis of the films, (b) independency of association with previously diagnosed cases in reporting the films, (c) the procurement and use of radiological descriptive terms, and (d) aid in the radiological evaluation of focal bone lesions.

Bone Neoplasms↗
PubMed1992

Osteosarcoma of the nude rat. A model for experimental magnetic resonance imaging studies of bone tumors.

A 144cerium-induced osteosarcoma was transplanted to athymic nude rats (Han:rnu/rnu). Nineteen of the tumor-bearing animals were used to demonstrate the characteristics of the osteosarcoma on magnetic resonance imaging (MRI) in comparison with a group of nine animals that had not received any tumor transplant. The tumor-free animals showed homogeneous results in the measurements of their lower legs (T1, 800-898 mseconds; T2, 33-45 mseconds). The osteosarcomas of the tumor-bearing rats were clearly demonstrated and delineated from adjacent structures by MRI at tumor volumes between 0.3 and 7.5 cm3. A significant increase in T1 and T2 relaxation times was found, which corresponded to the increase in tumor volume. T1 relaxation times decreased slightly when tumor volumes reached greater than 5 cm3, whereas T2 relaxation times remained constant at tumor volumes greater than 2.5 cm3. Histologic changes in the structure of the tumors, occurring naturally during their growth, were proven by immersion-fixed sections embedded in paraffin and stained with hematoxylin-eosin. The water content of small and large tumors was determined by lyophilization and heat drying. Both histologic changes and differences in water content were reflected in the variations of relaxation times.

Animals↗
PubMed1991

Muscle cross-section measurement by magnetic resonance imaging.

Muscle cross-section areas were measured by magnetic resonance imaging (MRI) in the thigh of a human cadaver, the results being compared with those obtained by photography of corresponding anatomic macroslices. A close correlation was found between MRI and photographic evaluation, differences between the methods ranging from nil to 9.5%, depending on the scan position and the muscle groups. In vivo MRI measurements were performed on 12 female and 16 male students, the objectivity, the test-retest reliability and the variability of the MRI measurements being studied by fixing the scan position either manually or by coronary scan. The latter method appeared to be more objective and reliable. The coefficients of variation for muscle cross-section areas measured by MRI were in the range of those for the planimetry of given cross-section areas. Allowing for differentiation between several small muscle bundles in a given area, MRI proved to be a suitable method to quantify muscle cross-sections for intra- and interindividual analysis of muscle size.

Adult↗
PubMed1991

Stability of osteochondral fragments of the femoral condyle: magnetic resonance imaging with histopathologic correlation in an animal model.

The stability of surgically induced osteochondral fragments of the femoral condyle was examined by magnetic resonance imaging (MRI) using T1- and T2-weighted spin echo sequences in 7 dogs; contrast-enhanced T1-weighted spin-echo sequences were also obtained. Animals were sacrificed between the 34th and 196th day after surgery. MR images were compared with the histopathologic findings. Two loose and five stable fragments were found after injection of contrast medium. With the loose fragments, a well-defined line of high signal intensity between the fragment and the epiphysis showed marked enhancement. Histological examination revealed vascularized granulation tissue at the interface. Stable fragments also showed a similar, but irregularly defined line on plain sequences, but no enhancement after injection of contrast medium; histological examination showed no granulation tissue at the interface but intact bone trabeculae within the completely repaired fracture. Fibrocartilaginous repair at the articular cartilage surface also showed enhancement. Contrast-enhanced MR imaging allowed an exact delineation of the line of separation of unstable osteochondral fragments in this animal model with differentiation from a similar line occurring in stable fragments. However, this interface line in relation to stable fragments could not be explained histologically and probably reflects differences of binding or distribution of protons in healing osteochondral fragments.

Animals↗
PubMed1991

[Contrast-enhanced MRT of malignant melanoma of the uvea].

Twenty-one patients with malignant melanoma of the uvea or iris, some with intra-ocular bleeding, were examined by MRT before and after the administration of Gd/DTPA. In 13 patients, several examinations were performed over a period of 1.5 to 20 months after irradiation of the melanoma. After Gd-DTPA there was an average increase of 13% in the signal intensity from all non-irradiated melanomas (17 cases). Three months following radiation therapy, there was an average increase in signal intensity after Gd-DTPA of 65.7%, and after seven months of 100%. Amelanotic melanomas (two cases) showed a primary increase in intensity of 100%. Two melanomas of the iris were demonstrated by sonography; of these, only one could be shown with certainty by MRT. Small tumours and tumour residues after irradiation were better defined after contrast. In the presence of suspected intra-ocular bleeding, the examination should always be performed after the administration of Gd-DTPA.

Adult↗
PubMed1991

[Angiography of the a. pudenda and its branches in erectile dysfunction. A modified angiographic technic and optimized use of vasodilator substances].

A new simplified technique for evaluating the internal pudendal artery and the penile vessels is described using a new catheter configuration with a very short 90 degrees-angled tip. In 30 consecutive patients, a superselective catheterisation of the internal pudendal artery was achieved in 93%. To improve visualisation of the penile arteries, the selective intraarterial application of 0.2 mg nitroglycerin in addition to the mandatory intracavernous injection of papaverin or prostaglandin E1 has proved to be of value. Examination of the blood blow velocity in the dorsal penile artery with Doppler ultrasound 2 minutes after intra-arterial application of 0.2 mg nitroclyerin showed a mean elevation of the Doppler amplitude by the factor 2.4 (range 0.4-9). With regard to the maximal increase of the blood velocity (range 1-6 minutes), a high interindividual difference was observed.

Arteries↗
PubMed1991

[The implantation of self-expanding metal prostheses (stents) into the bronchial system in central neoplasms].

This paper reports the use of an endobronchial metallic prosthesis (wall stent) for palliative management of 6 patients with central neoplasms and life-threatening airway obstruction. In five of six patients implantation of the stent resulted in improvement of their dyspnoea. However, functional data showed only a slight amelioration. In case of endobronchial growth, tumour may protrude easily through the meshwork of the stent. Therefore, use of the stent in these patients only seems appropriate if combination with other forms of therapy (radiation, laser) is possible. The easy feasibility of stent implantation and the lack of severe side effects and migration indicate that the stent may be an effective means in patients suffering from peribronchial tumour compression.

Airway Obstruction↗
PubMed1991

Rheumatoid arthritis of the knee: value of gadopentetate dimeglumine-enhanced MR imaging.

In an attempt to differentiate among joint effusion, synovitis, pannus, and subchondral sclerosis in patients with clinically proved chronic rheumatoid arthritis, we used gadopentetate dimeglumine-enhanced MR imaging to examine 23 patients with acute knee symptoms. All patients had had rheumatoid arthritis for more than 6 months and satisfied four or more of the criteria of the American Rheumatism Association for rheumatoid arthritis. MR imaging was performed on a 1.5-T machine by using unenhanced T1-weighted spin-echo imaging, unenhanced T2*-weighted gradient-echo imaging, and unenhanced and enhanced T1-weighted gradient-echo imaging. Signal intensities of the synovium and bone marrow were measured with the region-of-interest technique on unenhanced and enhanced T1-weighted gradient-echo scans. Conventional radiographs were available for each patient. Joint effusion, synovitis, intraarticular pannus, subchondral sclerosis, and subchondral pannus had the same signal intensities on unenhanced T1-weighted spin-echo, unenhanced T1-weighted gradient-echo, and unenhanced T2*-weighted gradient-echo MR images, and could not be differentiated from one another. On enhanced T1-weighted gradient-echo sequences, pannus and synovitis showed marked enhancement in 15 patients, whereas joint effusion and sclerosis did not. Synovitis was diagnosed if the synovial membrane showed high enhancement; pannus was diagnosed if enhancing masses were seen within the joint space or in the subchondral area. In eight of the 23 joints, there was no enhancement of the synovium or intraarticular or subchondral tissue. We conclude that gadopentetate dimeglumine-enhanced MR imaging allows differentiation between synovitis and joint effusion and between subchondral pannus and subchondral sclerosis. Enhancement of the synovium and pannus indicates acute inflammation of the joint.

Adolescent↗
PubMed1991

[Bronchial endoprostheses (stents) in inoperable bronchial carcinoma].

Three patients suffering from bronchial carcinoma with severe bronchial obstruction have been successfully treated by implantation of metallic stents. Two of them suffered from peribronchial tumor growth while the third one complained about dyspnoea caused by the instability of the central airways. Stents were implanted into the left main bronchus or the intermediate bronchus either through a flexible bronchoscope under local anaesthesia and sedation or through a rigid bronchoscope under general anaesthesia. The successful dilatation of the stenosis could be demonstrated by bronchography. The patients tolerated the stents well. We found no dislocation, deformation or ulceration of the bronchial mucosa. The implantation of metallic stents thus seems to offer new possibilities for the palliative treatment of bronchial carcinoma.

Aged↗