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Biomedical subjects

P Uhrmeister

Publications and source records attributed to P Uhrmeister.

At least 19 recordsLinked to original sources
PubMed2003

[Electronic distribution of patient records and images through PACS: implementation of data protection at the University Hospital in Freiburg].

In large installations of a Picture Archiving and Communication System (PACS), data protection becomes an issue. Above all, not every employee should have access to all data stored in the system. At the Freiburg University Hospital, we developed a concept of dynamic assignment of authorization, assuring that every physician is authorized to the data of all patients under his care. We describe the technical implementation of data protection developed for the integration of PACS and electronic patient records in Freiburg. The system was installed in January 2001 and the experience of its two years in operation is reported.

Computer Security↗
PubMed2002

Epithelioid angiosarcoma of the aorta.

Primary malignant tumors of the aorta are extremely rare. Review of the literature indicates that there are nearly 100 recorded cases of primary malignant tumors of the aorta. The purpose of this article is to present an additional case of the primary malignant tumors of the aorta which initially has been misinterpretated as atherosclerosic disease. This aortic tumor was of endothelial origin and immunohistochemical studies classified the tumor as an epithelioid angiosarcoma. The treatment resulted in an abdominal aortic repair. MRI of the spine revealed multifocal metastatic disease of the axial skeleton and a subsequent chemotherapy was performed. The patient died 17 months after the initial diagnosis.

Aorta, Thoracic↗
PubMed2001

[Quality assessment using AGIR: results and experience].

PURPOSE: To evaluate whether a new software from the working group for interventional radiology (AGIR) is an appropriate tool for quality assurance in interventional radiology, and presentation of results acquired within the quality improvement process in 1999. PATIENTS AND METHODS: AGIR-defined parameters such as patient data, risk profile, given interventions as well as complications were registered by a recently developed software. Based on monthly data analyses, possible complications were identified and discussed in morbidity and mortality conferences. RESULTS: 1014 interventions were performed in our institution in 1999. According to criteria established by AGIR, the complication rate was 2.7%. In addition and according to SCVIR criteria, complications were distinguished quantitatively in five classes and semiquantitatively in minor and major groups. The result was a minor complication rate of 1.8%, and a major rate of 0.9%. There were no cases of death associated with the intervention. Further strategies were developed in order to reduce the complication rate. CONCLUSION: Extensive quality assurance methods can be integrated in daily routine work. These methods lead to an intensive transparency of treatment results, and allow the implementation of continuous quality improvements. The development of the software is a first step in establishing a nation-wide quality assurance system. Nevertheless, modification and additional definition of the AGIR predefined parameters are required, for example, to avoid unnecessary procedures.

Adolescent↗
PubMed2001

[Explantation of aortic stent-grafts].

BACKGROUND: Endoluminal stent graft placement for the treatment of infrarenal aortic aneurysms (AAA) has gained widespread acceptance because it is associated with lower perinterventional morbidity than conventional transabdominal surgery. In this study the long-term morbidity of the procedure was evaluated. METHODS AND RESULTS: Between 9/94 and 12/98, 150 patients (age = 69.6 +/- 8.5 y; m = 142, f = 8) with AAA were treated by placing an intravascular nitinol stent graft (Stentor, n = 55; Vanguard-System, n = 95; 8 tubular grafts, 142 bifurcated grafts). Initial placement of the stent graft was successful in 144 patients. In 12 % of stent graft placements we encountered one of the following complications (n, days after stent placement): migration or dislocation of the prosthesis (4, 914 +/- 220 d), rupture of the aorta (2, 452 d/802 d), recurrent thrombosis of the stent graft (3, 478 +/- 359 d), endoleak (3, 955 +/- 472 d), infection of the prosthesis (5, 798 +/- 495 d). There was no correlation between the complications and the type of stent used. All of these patients were treated by surgical replacement of the prosthesis with a dacron graft. CONCLUSIONS: 1. The results suggest that most complications are due to a continuation of the disease process leading to loosening of the prosthesis. 2. Explantation of the prosthesis and surgical repair is feasible but bears additional risks. 3. Since the onset of reperfusion of the excluded aneurysm can not be predicted, all patients with infrarenal aortic stent grafts require frequent computer tomographic follow up. 4. Lastly, the results call for further improvements in the design of the stent graft.

Aged↗
PubMed2001

Serious complications that require surgical interventions after endoluminal stent-graft placement for the treatment of infrarenal aortic aneurysms.

BACKGROUND: Endoluminal stent-graft placement for the treatment of infrarenal abdominal aortic aneurysms has gained widespread acceptance because it is associated with lower peri-interventional morbidity than conventional transabdominal surgery. In this study the long-term morbidity of the procedure was evaluated. METHODS AND RESULTS: Between September 1994 and December 1998, 150 patients (age, 69.6 +/- 8.49 years; 142 men, 8 women) with abdominal aortic aneurysms were treated with the placement of an intravascular nitinol stent-graft (Stentor [55] and Vanguard-System [95]); there were eight tubular grafts and 142 bifurcated grafts. Initial placement of the stent-graft was successful in 144 patients. Mean follow-up was 49 +/- 25 months. In 13.3% of stent-graft placements we encountered the following complications: 4 cases of migration or dislocation of the prosthesis (30.5 +/- 7.4 months after placement); 2 ruptures of the aorta (26.7 and 15.0 months after placement); 3 recurrent thromboses of the stent-graft (25.5 +/- 5.3 months after placement); 3 endoleaks (27.5 +/- 15.7 months after placement); and 5 infections of the prosthesis (26.6 +/- 16.5 months after placement). There was no correlation between the complications and the type of stent used. All of these patients were treated by surgical replacement of the prosthesis with a Dacron graft. CONCLUSIONS: (1) The results suggest that most complications are due to a continuation of the disease process leading to loosening of the prosthesis. (2) Explantation of the prosthesis and surgical repair is feasible but bears additional risks. (3) Because the onset of reperfusion of the excluded aneurysm cannot be predicted, all patients with infrarenal aortic stent-grafts require frequent computer tomographic follow-up. (4) Finally, the results call for further improvements in the design of the stent-graft.

Aged↗
PubMed2000

[Preoperative examination of potential kidney transplantation donors: value of gadolinium-enhanced 3D MR angiography in comparison with DSA and urography].

PURPOSE: To assess a contrast-enhanced standardized MRA protocol for the presurgical evaluation of potential renal transplant donors. METHODS: Twenty-three potential donors for renal transplantations were examined with gadolinium-enhanced, two-phase MR angiograms (1.5 T) and DSA/urography for the number of renal arteries, the presence of aberrant arterial and venous branches, renal artery stenoses and anatomy of the renal collecting system and ureters. The diagnostic value was assessed by evaluating different image processing modalities and interobserver variability. RESULTS: Using maximum intensity projections (MIP) together with multiplanar reformatting (MPR), accessory arteries were detected with a sensitivity/specificity of 100%/98%. Depending on diagnostic experience, exclusive evaluation of MIP yielded a sensitivity/specificity of 67-100%/95-100%. Using MIP/MPR, venous depiction was good in 80%, with MIP solely in 30-40%. At least the proximal third of the ureter was visible in 67%. CONCLUSION: MPR/MIP evaluation of two-phase, contrast-enhanced MRA provides an excellent depiction of renal vessel anatomy for presurgical evaluation of renal transplant donors. Exclusive MIP assessment is less reliable and depends strongly on the examiner's experience. For sufficient visualization of the ureters, either additional measurements or low-dose diuretic injection have to performed.

Adult↗
PubMed1999

Chest wall infiltration by lung cancer: value of thin-sectional CT with different reconstruction algorithms.

The aim of this investigation was to evaluate whether thin-sectional CT with different reconstruction algorithms can improve the diagnostic accuracy with regard to chest wall invasion in patients with peripheral bronchogenic carcinoma. Forty-one patients with intrapulmonary lesions and tumor contact to the thoracic wall as seen on CT staging underwent additional 1-mm CT slices with reconstruction in a high-resolution (HR) and an edge blurring, soft detail (SD) algorithm. Five criteria were applied and validated by histological findings. Using the criteria of the intact fat layer, HRCT had a sensitivity of 81 % and a specificity of 79 %, SD CT had a sensitivity of 96 % and a specificity of 78 %, and standard CT technique had a sensitivity of 50 % and a specificity of 71 %, respectively. Regarding changes of intercostal soft tissue, HRCT achieved a sensitivity of 71 % and a specificity of 96 %, SD CT had a sensitivity of 94 % and a specificity of 96 % (standard CT technique: sensitivity 50 % and specificity 96 %). For the other criteria, such as pleural contact area, angle, and osseous destruction, no significant differences were found. Diagnostic accuracy of chest wall infiltration can be improved by using thin sectional CT. Especially the application of an edge-blurring (SD) algorithm increases sensitivity and specificity without additional costs.

Adult↗
PubMed1999

Pelvic imaging with a selenium-based detector (Thoravision). Comparison with screen-film radiography in 75 patients.

OBJECTIVE: To evaluate whether the selenium detector (Thoravision) provides sufficient diagnostic confidence in digital pelvic imaging compared with a conventional screen-film combination. METHODS: In 75 patients, pelvic imaging with conventional screen-film and isodose selenium radiography using a dedicated postprocessing mode was compared independently by three radiologists. The depiction of cortical and cancellous bone was evaluated in the iliac wings, sacral and pubic bones, acetabulum, femoral head, and trochanter. Demarcation of soft tissue was assessed in the iliac and trochanteric region. RESULTS: Visualization of cortical bone and soft tissue in the iliac area as well as soft tissue and cortical and cancellous bone in the trochanteric region was significantly superior with the selenium detector. However, conventional imaging was better in the trabecular bone of the sacral region, where results with the selenium system were particularly poor. CONCLUSIONS: The selenium detector (Thoravision) is advantageous in imaging soft tissue adjacent to the iliac wings and the trochanter, but results for the cancellous sacral bone are poor. Further modifications of postprocessing modes may lead to improved depiction of this critical pelvic area.

Adult↗
PubMed1999

Stents for the treatment of aortic aneurysms. Review of devices, technique and results.

The endovascular treatment of abdominal aortic aneurysms has generated a great deal of interest since the early 1990s, and many different devices are currently available. The procedure of endovascular repair has been evaluated in many institutions and the different devices are compared. The first results were encouraging, but complications like endoleak, dislocation or thrombosis of the graft occurred. By the available devices the stent application is only promising, if the known exclusion criteria are strictly respected. Therefore a careful preinterventional assessment of the patient by different imaging modalities is necessary. As the available results up to now are preliminary and the durability of the devices has to be controlled, multicenter studies are required to improve the devices and observe their long-term success in the exclusion of abdominal aortic aneurysms.

Aortic Aneurysm↗
PubMed1998

Functional MR imaging of the cervical spine in patients with rheumatoid arthritis.

PURPOSE: To evaluate functional MR imaging in patients with rheumatoid arthritis (RA) involving the cervical spine. MATERIAL AND METHODS: We used a device that allows MR examination to be made of the cervical spine in infinitely variable degrees of flexion and extension. Dynamic functional MR imaging was performed on 25 patients with RA. RESULTS: Functional MR imaging was able to show the degree of vertebral instability of the occipito-atlantal or atlanto-axial level as well as the subaxial level. By performing functional MR imaging, we were able to demonstrate the extent of synovial tissue around the dens, and the impingement and displacement of the spinal cord during flexion and extension. The basilar impression, the cord impingement into the foramen magnum, the cord compression, the slipping of vertebrae, and the angulation of the cord were all much more evident in functional than in static MR imaging. CONCLUSION: Functional MR imaging provided additional information in patients with RA, and is valuable in patients who have a normal MR study in the neutral position and yet have signs of a neurological deficit. Functional MR imaging is important in the planning of stabilizing operations of the cervical spine.

Adult↗
PubMed1997

Prospective evaluation of bone marrow signal changes on magnetic resonance tomography during high-dose chemotherapy and peripheral blood stem cell transplantation in patients with breast cancer.

RATIONALE AND OBJECTIVES: The authors evaluate bone marrow signal changes on magnetic resonance (MR) imaging during high-dose chemotherapy and peripheral blood stem cell transplantation (PBSCT). METHODS: Fourteen patients with breast cancer without bone metastases underwent four sagittal MR imaging studies with T1-weighted, T2-weighted turbo spin-echo and inversion recovery sequences with short inversion time (STIR) of the lumbar spine: (1) during initial staging, (2) prior to high-dose chemotherapy after two cycles of induction chemotherapy, (3) early after PBSCT with a leukocyte exceeding 2000/microL, and (4) 6 to 8 weeks after PBSCT. Signal intensity ratios of averaged lumbar bone marrow to nucleus pulposus were measured and homogeneity was evaluated visually using a semiquantitative score. RESULTS: Compared with the initial finding (1): Signal intensity ratios were altered significantly at (2): T1-weighted: -22% +/- 14, P < 0.001; T2-weighted: -11% +/- 11, P < 0.01; STIR: +33% +/- 31, P < 0.01; Signal intensity ratios were altered significantly at (3): T2-weighted: -23% +/- 12, P < 0.001, STIR: -22% +/- 23, P < 0.01; and Signal intensity ratios were altered significantly at (4): only STIR: -16% +/- 19, P < 0.01. Homogeneity scores decreased at (3) for T1-weighted and STIR sequences (-1.6 +/- 0.5 to -2.0 +/- 0.7, P < 0.01 and -1.0 +/- 0.5 to -1.4 +/- 0.5, P < 0.01, respectively) and at (4) for the latter sequence (-1.0 +/- 0.5 versus -1.4 +/- 0.5, P < 0.01). At (4), T1-weighted images were less homogenous than initially in 3 of 14 (21%) patients. CONCLUSIONS: Magnetic resonance imaging demonstrates significant alterations of bone marrow composition during PBSCT but allows differentiation of benign therapy-related changes from those known in metastatic disease after completion of PBSCT.

Antineoplastic Agents↗
PubMed1997

Comparative diagnostic accuracy of magnetic resonance imaging and immunoscintigraphy for detection of bone marrow involvement in patients with malignant lymphoma.

PURPOSE: To compare the diagnostic accuracy of magnetic resonance imaging (MRI) and immunoscintigraphy (IS) for detection of bone marrow infiltration in malignant lymphoma. PATIENTS AND METHODS: In 32 patients with Hodgkin's disease (HD) or non-Hodgkin's lymphoma (NHL), MRI of the axial skeleton and whole-body IS using technetium-99m (99mTc)-labeled monoclonal antibodies were reviewed and compared with iliac crest biopsies. Criterion for marrow infiltration was a positive biopsy or concordant positive results of MRI and IS. RESULTS: In 16 patients (50%), MRI, IS, and iliac crest biopsies were negative for marrow infiltration. Iliac crest biopsy showed infiltration in only four patients (13%). Infiltration was missed in two of 32 patients with IS and in one patient with MRI. In one additional patient, MRI was false-positive because of pelvic hematopoietic hyperplasia. A subset of nine patients (28%) with negative biopsies had bone marrow involvement according to MRI and IS with identical location and pattern of infiltration. In eight of these nine patients, diagnostic imaging indicated marrow involvement only in noncrest marrow. Subsequent biopsy confirmed infiltration in five patients. The clinical course suggested true-positive imaging results in the remaining four patients. Two patients (6%) remained equivocal. Overall concordance of MRI and IS for marrow infiltration was 88% (28 of 32 patients). CONCLUSION: Diagnostic imaging is essential for optimal staging in malignant lymphoma, as blind biopsies appear to have low sensitivity for bone marrow infiltration because of frequent involvement in noncrest marrow. both imaging modalities show a high rate of detection of bone marrow infiltration.

Adolescent↗
PubMed1993

Clinical and radiologic features, lung function and therapeutic results in pulmonary histiocytosis X.

Clinical appearance, radiologic findings, lung function and results of corticosteroid therapy were analyzed in 42 adult cases of biopsy-proven pulmonary histiocytosis X. Symptoms were present in only 64%. Using the ILO classification 1980, the evaluation of chest radiographs revealed all categories of profusion, size and shape of nodules. The characteristic 'ring figures', i.e. thin-walled cysts, in the parenchyma were detected in 78% of conventional tomographies (n = 27) and in all patients examined by CT (n = 5). In patients with early disease, lung function tests (n = 26) including body plethysmography, pulmonary diffusing capacity and ergospirometry revealed that parameters of gas exchange are most sensitive (TL,CO 84%, KCO 72%). Bronchial reactivity to carbachol was significantly higher than in controls (n = 12). Lung perfusion scintigram showed an abnormal, but uncharacteristic pattern in 81% (n = 26). During corticosteroid therapy, no progression was observed (n = 36). 85% of patients with radiographic evidence of progressive disease improved after administration of corticosteroids (n = 14).

Adolescent↗
PubMed1993

[Cerebral manifestations of progressive facial hemiatrophy (Romberg's disease). Nuclear spin tomographic findings and literature review].

Progressive facial hemiatrophy (PFH) is a sporadic disease of unknown etiology. It is characterized by shrinking and deformation of one side of the face. Potential CNS involvement has repeatedly been suspected in some patients, but is still a matter of controversy. In this article we describe the clinical and MR imaging findings of the CNS in three female patients with PFH and present a comprehensive review of the literature. One of three PFH patients had partial epilepsy. MRI showed ventricular enlargement, white matter lesions, flattening of the cortical surface and meningeal adhesions homolateral to the facial hemiatrophy. Two other patients had completely normal intracranial findings. These findings confirm that cerebral hemiatrophy occurs in a subgroup of PFH patients. The MRI pattern, however, does not seem to be consistent with a simple atrophic or malnutritional process. We consider chronic localized meningoencephalitis with vascular involvement as a possible underlying mechanism for the occasional CNS involvement in PFH.

Adult↗