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Biomedical subjects

U Linsenmaier

Publications and source records attributed to U Linsenmaier.

32 records · Page 2Linked to original sources
PubMed2002

[Interdisciplinary interventional therapy for tracheobronchial stenosis with modern metal net stents].

STUDY OBJECTIVES: Assessment of the therapeutic potential of tracheobronchial stenting for obstructive tracheobronchial disease, in-vivo comparison of different stent types and development of helpful criteria for choosing the suitable stent type. MATERIAL AND METHODS: Prospective case analysis. Between 1993 and 1999 53 stents were implanted into the tracheobronchial system of 39 consecutive patients with benign or malignant airway obstruction. Every single stent (26 Strecker Stents, 18 Wallstents, 6 Accuflex Nitinolstents, 1 Dumon-, 1 Rüsch- and 1 Palmazstent) was recorded in an unified database. Analysis comprised clinical effectiveness, lung function if possible, relevant complications and radiologic follow-up parameters. The probability of their remaining within the tracheobronchial system, of their remaining undislocated and uncompressed was calculated using Kaplan-Meier analysis for three stent types. RESULTS: Stent placement proved itself to be an effective treatment in 86 % of the patients. Resistance could be normalized in 9/9 patients. Kaplan-Meier analysis clearly revealed a higher probability for the Wall- and Nitinolstent to remain within the tracheobronchial system and to remain uncompressed. Dislocation also occurred more rarely. Explantation of the Wallstent, however, if desired, was much more difficult compared to the Strecker stent. The Wallstent also occasionally led to the formation of granulation tissue especially at the proximal stent end and, as such, required reintervention. CONCLUSION: Any of the 3 stent types proved to be an effective therapeutic option in the management of obstructive tracheobronchial disease. Choise of the stent type should be determined through definition of the therapeutic intention. It is useful to distinguish between (a) benign stenosis, (b) malignant stenosis but curative therapeutic situation and (c) malignant stenosis in a palliative therapeutic situation with limited life expectancy. In spite of its superior mechanical properties the Wallstent is rather suited for a palliative situation because explantation may be difficult. The Strecker Stent requires more reinterventions but removal is easy to perform. The Nitinolstent possibly represents a reasonable compromise.

Adolescent↗
PubMed2002

[Focal secondary malignant liver lesions: MnDPDP-enhanced MRT at 0.2 tesla vs. helical CT-arterioportography].

PURPOSE: Prospective evaluation of the efficacy of MnDPDP- enhanced MRI using an open low-field scanner for the detection of focal malignant liver lesions in comparison with helical CT- arterioportography (CT AP). MATERIAL AND METHODS: As part of a phase III study, 27 consecutive patients we enrolled for comparison, with seven patients later eliminated for failing the inclusion criteria. Native and MnDPDP-enhanced MRI of the liver at a field-strength of 0.2 Tesla (Siemens Magnetom Open) and DSA with helical CT AP (Siemens Somatom Plus 4) were performed within one week. The lesions were compared collectively and after categorization by size: (a) < 1 cm, (b) 1 - 2 cm, and (c) > 2 cm. For statistical evaluation, the sign test with a significance level of p < 0.05 was used. RESULTS: CT AP depicted 114 lesions, whereas native MRI detected 62 and MnDPDP-enhanced MRI revealed 69 lesions. Significant differences were shown for collective comparison and for selective comparison of category (b), and of categories (a) and (b) combined. No significant differences were found between native and contrast-enhanced MRI. CONCLUSION: MnDPDP should be reserved for high-field strengths since low field strengths cannot be expected to confirm or exclude malignant liver lesions reliably.

Adult↗
PubMed2002

[Choristoma of the diaphragm. Case report of a rare tumor and approach through lateral thoracotomy].

Tumors of the diaphragm are rare and caused by there special localisation difficult to diagnose. We describe the case of a 31 year old man with a choristoma of the left diaphragmal crux where the localisation and genesis could only be cleared through lateral thoracotomy. Nor the CT guided puncture or the laparoscopy-although sufficient samples for the pathology could be gained-allowed the right diagnose. The importance of good diagnostic approach to select the right operative procedure-in this case the anterolateral thoracotomy-is described.

Adult↗
PubMed2001

[Introduction of a new mobile C-arm/CT combination equipment (ISO-C-3D). Initial results of 3-D sectional imaging].

Preclinical evaluation of a new mobile C-arm image amplifier with an option for three-dimensional computed tomography (CT) imaging (prototype Iso-C3D) with respect to high-contrast resolution and possible clinical applications. Cadaveric specimens (n = 30) of different joints of the lower and upper extremities and specimens of the spinal column were examined with the Iso-C3D and evaluated for image quality. In addition, using a high-contrast phantom (Catphan, Phantom Laboratory, Salem, N.Y., USA) and a fracture model of the femoral bone, measurements of high-contrast resolution were performed in comparison to spiral CT. With the exception of the shoulder, all joint regions including the entire spinal column could be examined. Adequate image quality could be achieved in smaller joints such as the wrist, elbow, ankle, and knee, whereas a remarkably decreased image quality was found when imaging the hip as well as the lumbar and thoracic spine. Images of the phantom study and high-contrast fracture model showed a high-contrast resolution comparable to helical CT (9 Lp/cm in xy-axis). In smaller joints, the image quality of the mobile C-arm CT imaging system (Iso-C3D) is comparable to that of helical CT. Image quality in examinations of the hip and lumbar and thoracic spine seems to be sufficient for intraoperative control studies of osteosynthesis. Problems still occur in shoulder examinations.

Arthrography↗
PubMed2001

[3-D imaging with a mobile surgical image enhancement equipment (ISO-C-3D). Initial examples of fracture diagnosis of peripheral joints in comparison with spiral CT and conventional radiography].

To analyze a prototype mobile C-arm image amplifier (Iso-C3D) in the evaluation of different joint fractures of the upper and lower limbs using multiplanar reconstruction (MPR). Different cadaver joint specimens (n = 14) were examined with a prototype (Iso-C3D, Siemens AG, Erlangen, Germany), plain radiographs (CR), and spiral computed tomography (CT). The motorized C-arm provides fluoroscopic images during a 190 degrees orbital rotation computing a 119-mm data cube. These three-dimensional data sets yielded MPR images, which were evaluated by two readers for the detection and extent of fracture lines. Initial data show that fractures were easily depicted and correctly classified on MPR images with the Iso-C3D and that there was no difference between the Iso-C and CT in the detection of fractures. The preliminary results suggest a remarkably good detection of joint fractures with the Iso-C3D. Studies in an adequate number of patients are required to elucidate whether these promising results can also be obtained in a clinical setting.

Ankle Injuries↗
PubMed2001

[Comparative study of the quality of C-arm based 3D imaging of the talus].

Malposition of extraosseous or intra-articular screws, e.g., in osteosyntheses of joint fractures or in the vicinity of joints, frequently remains undiscovered in intraoperative fluoroscopy and is only recognized on postoperative computed tomography (CT) scans. The aim of the study, therefore, was to assess the value of a new mobile C-arm three-dimensional imaging device in comparison with fluoroscopy, conventional radiographs, and CT scans using an extremity model. Screws were inserted ventrally in four anatomic lower leg specimens without talus fractures parallel to the longitudinal axis to simulate surgical management of fractures of the talus. The specimens supplied were examined with fluorscopy, conventional radiography, spiral CT, and the new three-dimensional imaging with the SIREMOBIL Iso-C3D. These four modalities were evaluated by ten radiologists and ten trauma surgeons and were compared regarding subjective image quality and position of the screws. The quality of information acquired with the SIREMOBIL Iso-C3D was equal to that of the CT examinations, although image quality was considered inferior to fluoroscopy, conventional radiography, and CT (p < 0.001). In contrast to the previous procedure with intraoperative fluoroscopy and subsequent postoperative X-ray control, the results obtained with the SIREMOBIL IsoC3D were superior. The SIREMOBIL Iso-C3D is useful for the intraoperative diagnosis of small joints with few artifacts producing osteosynthesis material, i.e., for recognizing the position of screws in the region of glenoid surfaces.

Bone Screws↗
PubMed2001

[Radiological diagnosis in polytrauma: interdisciplinary management].

The presence of a radiologist within the admitting area of an emergency department and his capability as a member of the trauma team have a major impact on the role of diagnostic radiology in trauma care. The knowledge of clinical decision criteria, algorithms, and standards of patient care are essential for the acceptance within a trauma team. We present an interdisciplinary management concept of diagnostic radiology for trauma patients, which comprises basic diagnosis, organ diagnosis, radiological ABC, and algorithms of early clinical care. It is the result of a prospective study comprising over 2000 documented multiple injured patients. The radiologist on a trauma team should support trauma surgery and anesthesia in diagnostic and clinical work-up. The radiological ABC provides a structured approach for diagnostic imaging in all steps of the early clinical care of the multiple injured patient. Radiological ABC requires a reevaluation in cases of equivocal findings or difficulties in the clinical course. Direct communication of radiological findings with the trauma team enables quick clinical decisions. In addition, the radiologist can priority-oriented influence the therapy by using interventional procedures. The clinical radiologist is an active member of the interdisciplinary trauma team, not only providing diagnostic imaging but also participating in clinical decisions.

Diagnostic Imaging↗
PubMed2001

[Evaluation of spine boards for X-Ray diagnostics].

PURPOSE: Spine boards are frequently used in preclinical emergency care. Different models were examined with regard to their feasibility for plain film radiography and computed tomography (CT). METHODS: Five current spine board models were measured for their dimensions and weight. Transmission of radiation [microGyls] and dose area product [cGy x cm(2)] were determined with a patient equivalent aluminium phantom. Image artifacts, image quality and resolution of anatomic details were evaluated with an anthropomorphic Alderson phantom. RESULTS: With only 6.3 kg new models show a 28 % reduction in weight, three spine boards generate lateral artifacts due to a narrow width of 41 - 42 cm. Radiation transmission of all boards was similar, however dose area products differed by up to 59 %. Image quality was impaired in 4 out of 5 boards because of image artifacts, CT scanning was not impaired with all boards. CONCLUSION: Only one board (Ferno Millenia(R)) showed sufficient properties for plain film radiography and CT. There is no suitable spine board for preclinical and clinical applications as well as for trauma radiology, further improvements of current designs are essential.

Artifacts↗
PubMed2001

Elevated serum levels of S-100B reflect the extent of brain injury in alcohol intoxicated patients after mild head trauma.

Elevated systemic levels of S-100B are proposed as a potential indicator of brain damage in identifying high-risk patients after mild head trauma (MHT). Although incidence of alcohol intoxication is high in these patients, the influence of alcohol intoxication on S-100B levels is unclear. Therefore, the aim of our study was to investigate serum concentrations of S-100B in intoxicated (group 1) and sober (group 2) patients after MHT in comparison with those of mild (group 3) or severely intoxicated (group 4) individuals without trauma. S-100B was significantly increased in MHT patients exhibiting posttraumatic lesions in initial cranial computed tomography scan. Alcohol intoxication did not elevate S-100B levels in group 3 or 4 subjects. Our data indicate for the first time that alcohol intoxication does not influence the diagnostic value of S-100B measurements in patients after MHT.

Alcohol Drinking↗
PubMed1999

[Temporary balloon occlusion as therapy of uncontrollable arterial hemorrhage in multiple trauma patients].

PURPOSE: Presentation of temporary balloon occlusion as an interventional radiological method for managing hemorrhage in multiply injured patients with uncontrollable loss of blood. METHOD: Temporary, non-selective arterial occlusion by introduction of a balloon catheter contralaterally to the source of bleeding has been performed since 1992 on 7 patients with multiple injuries, hemorrhagic shock requiring reanimation, and angiographic demonstration of an arterial hemorrhage in the supply region of the internal iliac artery with complex pelvic fracture. In each case a PTA balloon catheter was introduced transfemorally, non-selectively positioned proximal to the bleeding source, and left in place for 24-48 h under manometric control. Control angiographies were performed prior to catheter removal. RESULTS: The bleeding was stopped immediately in all 7 patients. The hemodynamic stability made transport and thus further surgical management and/or a short-term treatment in the intensive-care station possible. Control angiographies confirmed that the bleeding had stopped in all patients. CONCLUSIONS: We recommend temporary balloon occlusion as a rapid and effective method for the management of bleeding in otherwise uncontrollable traumatic hemorrhages in the supply region of the internal iliac artery.

Adult↗
PubMed1993

Isolation and partial molecular characterization of basic fibroblast growth factor from isolated porcine thyroid follicles and entire porcine thyroid glands.

Immunoreactive basic fibroblast growth factor (bFGF) could be isolated from the cytosol preparation of isolated porcine thyroid follicles as well as in the conditioned medium from thyroid follicles in suspension culture. A double band with 16,500 and 15,500 D was detected on sodium dodecyl sulfate polyacrylamide gel electrophoresis. In dot blot and western blot the isolated peptide was immunoreactive with a specific anti-bovine bFGF antibody. For further biochemical characterization, bFGF was isolated from entire porcine thyroid glands by ammonium sulfate precipitation, cation exchange chromatography and heparin affinity chromatography. The material obtained from all three origins was identical concerning affinity to heparin and immunoreactivity with the specific anti-bovine bFGF antibody and induced neovascularization in the chorioallantois membranes of chick embryos. Amino acid sequence analysis of the 16-amino-terminal amino acids of the isolated bFGF was in accordance with the established complete 146-amino-acid bFGF molecule except that glycine in position 10 is replaced by phenylalanine. An additionally identified minor peptide presumably is an amino-terminal-truncated form of bFGF, missing the first 15 amino acids. We conclude that the physiological significance of bFGF released by thyroid cells may be the regulation of angiogenesis during thyroid development and goiter growth.

Allantois↗
PubMedDate not supplied

Indications, management, and complications of temporary inferior vena cava filters.

PURPOSE: We describe the results of a preliminary prospective study using different recently developed temporary and retrievable inferior vena cava (IVC) filters. METHODS: Fifty temporary IVC filters (Günther, Günther Tulip, Anthéor) were inserted in 47 patients when the required period of protection against pulmonary embolism (PE) was estimated to be less than 2 weeks. The indications were documented deep vein thrombosis (DVT) and temporary contraindications for anticoagulation, a high risk for PE, and PE despite DVT prophylaxis. RESULTS: Filters were removed 1-12 days after placement and nine (18%) had captured thrombi. Complications were one PE during and after removal of a filter, two minor filter migrations, and one IVC thrombosis. CONCLUSION: Temporary filters are effective in trapping clots and protecting against PE, and the complication rate does not exceed that of permanent filters. They are an alternative when protection from PE is required temporarily, and should be considered in patients with a normal life expectancy.

Adult↗