Biomedical subjects
B Röhrl
Publications and source records attributed to B Röhrl.
[MDCT after balloon kyphoplasty: analysis of vertebral body architecture one year after treatment of osteoporotic fractures].
PURPOSE: To evaluate the value of MDCT in the monitoring of vertebral body architecture after balloon kyphoplasty and observe morphological changes of the vertebral body. MATERIAL AND METHODS: During a period of 26 months, 66 osteoporotic fractures of the vertebral bodies were treated with percutanous balloon kyphoplasty. The height of the vertebral body, width of spinal space, sagittal indices, kyphosis und COBB angle, and cement leakage were evaluated by computed tomography before and after treatment and in a long-term follow up. Statistical analysis was performed by calculating quantitative constant parameters of descriptive key data. In addition, parametric and distribution-free procedures were performed for all questions. RESULTS: After kyphoplasty, the treated vertebral bodies showed a significant gain in the height of the leading edge (0.15 cm; p < 0.0001) and in the central part of the vertebral body (0.17 cm; p < 0.0001). The height of the trailing edge did not change significantly. A corresponding gain in the sagittal index was found. The index remained stable during follow-up. Treated vertebral bodies as well as untreated references showed a comparable loss of height over the period of one year. The shape of the vertebral bodies remained stable. In comparison to these findings, treated vertebral bodies showed a reduced loss of height. A significant change in kyphosis und the COBB angle was noted. In total, pallacos leakage was detected in 71 % of cases. CONCLUSION: MDCT is an accurate method for evaluating vertebral body architecture after treatment with balloon kyphoplasty. Morphological changes in the vertebral bodies, and complications such as pallacos leakage and progression of osteoprosis can be accurately documented. The significant increase in the vertebral body height after treatment is closely correlated with a gain in the sagittal index and reduced kyphosis and COBB angle.
[Whole-body MSCT of patients after polytrauma: abdominal injuries].
PURPOSE: The goal of this retrospective study was to evaluate the spectrum of abdominal injuries and the reliability of computed tomography-based diagnosis in patients after polytrauma. MATERIAL AND METHODS: CT findings and clinical reports for 177 patients after polytrauma were evaluated with regard to abdominal injuries. Clinical patient reports at the time of discharge from the hospital were utilized as the standard of reference. Abdominal injuries resulting from an accident, frequent additional traumas and following therapeutic procedures were recorded. In the case of discrepancies in the reports, the CT scans were viewed retrospectively. RESULTS: In 30 out of 177 patients, 42 abdominal injuries were detected. 69 % of the injuries were caused by traffic accidents while 31 % resulted from falls. Liver and spleen injuries were the most common. 50 % of the cases were treated surgically, and the other half of the cases underwent non-surgical conservative therapy. Massive chest traumas, pelvic injuries, cerebral traumas and injuries to extremities were commonly associated with abdominal injuries. Evaluation of the discrepancies in the clinical reports showed that injury to the pancreas and the small intestine were not successfully detected on CT, thus resulting in a false negative diagnosis. Early stages of organ parenchyma laceration were also initially misdiagnosed on CT. CONCLUSION: Contrast-enhanced whole-body MSCT is a reliable and rapid method for diagnosing abdominal injuries in patients after polytrauma. Only very few patterns of injury are not detected on CT. The appearance of fluid collection in the abdomen is an indicator of possible parenchyma injury and requires further evaluation in cases of clinically suspected organ trauma.
[Cryotherapy of malignant tumors: studies with MRI in an animal experiment and comparison with morphological changes].
PURPOSE: Aim of our study was to investigate the efficacy of 7 F cryoprobes for percutaneous use morpho- and histologically, to examine the role of apoptosis after cryotherapy, and to compare contrast-enhanced MRI with histopathological findings at different time intervals in a tumor-mouse model. METHODS: Percutaneous cryotherapy was performed in 15 immunocompromised nude mice with subcutaneously implanted tumors using the non-small-cell lung cancer cell line Lu 1. In group a) 7 mice were sacrificed after definite time intervals and histological examinations were done for evaluation of necrosis and apoptosis (HE; TUNEL assay); 2 mice are in long-term follow-up. In group b) in 6 mice tumor destruction and perfusion before and after freezing were investigated with native and contrast-enhanced MR imaging (T1- and T2-weighted spin-echo) and compared with histopathological findings. Histological control were done in 2 untreated mice. RESULTS: We observed fast tumor-reduction within two weeks (ca. 50%). On long-term follow-up (> 6 months) no recurrence has been noticed so far. Tumors were well vascularized prior to treatment and did not-show contrast enhancement an any time after cryotherapy. A narrow contrast-enhanced zone was seen on the tumor border subcutaneously as a sign of peripheral hyperemia and central vascular stasis after cryotherapy. On histology there was evidence of both apoptosis and necrosis. CONCLUSION: We have established a tumor-mouse model for further investigations. Two minutes freezing of a 2-cm tumor in the mouse model is sufficient for tumor ablation with scarred healing. Apoptosis may play a role in cryotherapy of experimental tumors. Contrast-enhanced MRI is suitable for the estimation of the cryolasion.