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Biomedical subjects

U Dorenbeck

Publications and source records attributed to U Dorenbeck.

29 records · Page 2Linked to original sources
PubMed2002

[Thoracic computed tomography in intensive care patients - evaluation of clinical usefulness].

PURPOSE: Computed tomography of intensive care patients requires transportation of the patient to the radiology department. This study analyses, whether this consumption of resources is justified by therapeutical and diagnostic consequences derived from helical computertomography of the chest. METHODS: 558 CT studies of the chest were compared with current bedside chest radiographs. The additional information of CT scans and their consequences were evaluated retrospectively. RESULTS: 388 (69.5 %) of these computed tomographies provided additional information compared with projection radiographs. 374 therapeutical procedures resulted from 266 (68.6 %) out of these 388 CT examinations. These therapeutical interventions were significantly more invasive than those 144 procedures derived from 170 (30.5 %) CT studies which did not show any additional findings compared with bedside chest radiographs. CONCLUSION: In more than two thirds (69.5 %) additional diagnoses were found with computertomography. Nearly one half of the CT studies resulted in additional findings and therapeutical consequences. Invasive therapeutical consequences were based on CT studies significantly more frequently than on bedside chest radiographs.

Adolescent↗
PubMed2002

MR imaging of cranial nerve lesions using six different high-resolution T1- and T2(*)-weighted 3D and 2D sequences.

PURPOSE: To find a suitable high-resolution MR protocol for the visualization of lesions of all 12 cranial nerves. MATERIAL AND METHODS: Thirty-eight pathologically changed cranial nerves (17 patients) were studied with MR imaging at 1.5 T using 3D T2*-weighted CISS, T1-weighted 3D MP-RAGE (without and with i.v. contrast medium), T2-weighted 3D TSE, T2-weighted 2D TSE and T1-weighted fat saturation 2D TSE sequences. Visibility of the 38 lesions of the 12 cranial nerves in each sequence was evaluated by consensus of two radiologists using an evaluation scale from 1 (excellently visible) to 4 (not visible). RESULTS: The 3D CISS sequence provided the best resolution of the cranial nerves and their lesions when surrounded by CSF. In nerves which were not surrounded by CSF, the 2D T1-weighted contrast-enhanced fat suppression technique was the best sequence. CONCLUSIONS: A combination of 3D CISS, the 2D T1-weighted fat suppressed sequence and a 3D contrast-enhanced MP-RAGE proved to be the most useful sequence to visualize all lesions of the cranial nerves. For the determination of enhancement, an additional 3D MP-RAGE sequence without contrast medium is required. This sequence is also very sensitive for the detection of hemorrhage.

Contrast Media↗
PubMed2002

Evaluation of arterial bypass grafts of the pelvic and lower extremities with gadolinium-enhanced magnetic resonance angiography: comparison with digital subtraction angiography.

RATIONALE AND OBJECTIVES: The aim of this study was to compare contrast-enhanced magnetic resonance angiography (CE MRA) with digital subtraction angiography (DSA) in the assessment of patency and stenoses in bypass grafts. METHODS: Fifteen patients were examined with both CE MRA and DSA. Fifteen bypass grafts were evaluated by four readers for potential stenosis in five locations. The stenoses were classified in five types: 1 (0% to 24% stenosis), 2 (25% to 49%), 3 (50% to 74%), 4 (75% to 99%), and 5 (occlusion). RESULTS: Using both techniques, 70 of 75 evaluated locations (93.3%) were classified identically. This included six stenoses < 50% and six stenoses > 50%, respectively. Four of five overestimations of stenoses were scaled in DSA as stenoses type 1. One stenosis was categorized as type 3 in DSA. Sensitivity for CE MRA for detecting stenoses >or= 25% was 100% and the specificity 90%. Interobserver agreement for all evaluations was 0.77 (Spearman rank correlation test). CONCLUSION: In the assessment of low-grade stenosis in bypass grafts, CE MRA overestimates stenoses slightly but yields good results in comparison with DSA.

Angiography, Digital Subtraction↗
PubMed2001

Sonographic parenchymal and brain perfusion imaging: preliminary results in four patients following decompressive surgery for malignant middle cerebral artery infarct.

To investigate new methods of diagnostic transcranial sonography for brain parenchymal, vascular and perfusion imaging, we performed 3-D native tissue harmonic transcranial sonography (3D-nthTCS), 3-D transcranial color-coded duplex sonography (3D-TCCS), and "loss-of-correlation" imaging (LOC-TCCS) in four patients following early hemicraniectomy due to space-occupying "malignant" middle cerebral artery infarction (MMCAI). Three-dimensional datasets, utilizing 3D-nthTCS and 3D-TCCS, were created and up to 10 axial 2-D B-mode image planes, similar to CCT, reconstructed in each patient. Three-dimensional reconstructions of the circle of Willis documented one persistent carotid-T occlusion and three recanalizations of the MCA. LOC-TCCS, based on stimulated acoustic emission from an ultrasound (US) contrast agent, demonstrated a perfusion deficit in 2 of 3 patients, with regard to their infarcts. Concluding, 3D-nthTCS, 3D-TCCS and LOC-TCCS are promising tools for bedside monitoring, early prognosis and treatment evaluation for MMCAI in the postoperative period. Further studies should be performed to standardize these new methods and evaluate their applications through the intact calvarina.

Adult↗
PubMed2000

[Pulmonary metastasis of extranodal high malignancy B-cell non-Hodgkin lymphoma of the bulbus duodeni and pylorus of the stomach].

We report a 71-year-old female patient with repeated vomitus, meteorism, epigastric pain and reflux for more than four month. She had a palpable mass in the upper abdomen and lost 7 kg of weight during the last four months. Chest X-ray showed two masses, 2 cm and 3 cm in diameter, in the left and right lower lung. A stenosing polypoid mucosal swelling in the antrum and the duodenal bulb. The pulmonal masses were biopsied under CT-guidance. Biopsy proved a high malignant B-cell non-Hodgkin's lymphoma of the stomach. The masses in the lung were identified as metastases of the gastrointestinal lymphoma. In conclusion on this tumor was an extranodal non-Hodgkin's lymphoma stadium BE IV according to Musshoff. A CHOP-chemotherapy was initiated. Restaging after three cycles of CHOP revealed a complete remission. Primary gastrointestinal non-Hodgkin's lymphomas are relatively rare neoplasms of the abdomen. Unusual and interesting in this case ist the metastatic pattern involving the lung periphery without local lymph node metastases.

Aged↗
PubMed2000

[Volume-artifact reduction technique by spiral CT in the anterior, middle and posterior cranial fossae. Comparison with conventional cranial CT].

PURPOSE: The object of this study was to determine the extent to which a new volume-artifact reduction (VAR) modality using helical CT was able to reduce artifacts in the anterior, middle and posterior fossae in comparison with conventional CT (sequential mode). METHODS: In a prospective, randomized trial, 50 patients underwent helical CT (VAR) and 50 underwent sequential CT. The results were evaluated by three radiologists; influences on image quality where scaled between 1 (no artifact) and 4 (not assessable). Eight regions of the anterior, middle and posterior fossae were evaluated. RESULTS: On average, artifacts were scaled at 2.5 in helical CT (VAR) and 3.1 in conventional CT. Significant differences were seen at the eyeball, anterior to the petrosal bone, at the internal occipital crest, and at the level of the transverse sinus (p < 0.005). CONCLUSIONS: Helical CT with the VAR modality is superior to conventional, sequential CT in the area of the anterior, middle and posterior fossae.

Adolescent↗
PubMed2000

[Contrast media-enhanced MR angiography of the lower extremity arteries using a dedicated peripheral vascular coil system. First clinical results].

PURPOSE: To evaluate contrast enhanced magnetic resonance angiography (ceMRA) of the pelvic and peripheral arteries with a dedicated peripheral vascular coil system and automated table-feed technique in patients with arterial occlusive disease. METHODS: Three-dimensional gadolinium-enhanced MR angiography in a two-step automatic table feed technique was performed in 45 patients using a 1.5 Tesla imager (Magnetom Symphony, Siemens). The pelvic arteries were imaged with a single injection of contrast material. The upper and the lower leg were imaged with a second injection of contrast material in an automated table feed technique using a dedicated vascular coil system. In 20 patients ceMRA was compared with digital subtraction angiography (DSA) as the standard of reference and in 25 patients ceMRA was performed solely. RESULTS: Sensitivity and specificity for grading significant stenoses > or = 50% and occlusions (in parenthesis) were in the pelvic arteries 94.7%, 96.8%, (100%, 100%), in the arteries of the upper leg 92.3%, 93.3% (87.5%, 100%) and in the arteries of the lower leg 96.5%, 95.8%, (95.2%, 96.8%), respectively. Depiction of the runoff vessels of the lower leg was excellent in ceMRA. CeMRA was of diagnostic quality in all the patients. CONCLUSION: Contrast-enhanced MRA using a dedicated peripheral vascular coil system increases the diagnostic quality of the lower leg. The runoff vessels can be evaluated. Thus, ceMRA in the presented technique is a diagnostic alternative to arterial angiography.

Adult↗
PubMed1999

Squamous cell carcinoma arising in an intradiploic epidermoid cyst.

A 71-year-old woman presented with the symptoms of a posterior cranial fossa mass. CT and MRI revealed a lytic lesion in the occipital bone and a tumour infiltrating the dura mater, venous sinuses and cerebellum. Histopathology demonstrated a moderately differentiated squamous cell carcinoma arising from a primarily intradiploic epidermoid cyst. Despite surgery and radiotherapy, the tumour progressed and the patient died 1 year later.

Aged↗
PubMed1997

[Computer tomography-guided gastrostomy, jejunostomy and gastrojejunostomy. A reliable non-surgical method also for contraindications and failure of percutaneous endoscopic gastrostomy].

OBJECTIVE: To analyse retrospectively the results of CT (computed tomography)-guided gastrostomy or gastroenterostomy where an endoscopic procedure was not possible or had failed. PATIENTS AND METHODS: Between August 1993 and March 1997, CT-guided gastrostomy (n = 50) or gastroenterostomy (n = 8) was performed in 58 patients (mean age 56 +/- 6 years; 51 males, 7 females). An endoscopic or fluoroscopic method had been contraindicated in 52 and had failed in 6 patients. RESULTS: Technical success was achieved in all patients. Three patients needed intravenous sedation. There were no procedure related complications requiring treatment. Three patients had a mild infection at the site of the skin puncture. CONCLUSION: CT-guided gastrostomy or gastroenterostomy is a safe and simple procedure which provides a minimally invasive alternative also in patients with contraindications to the established percutaneous method.

Adult↗
PubMedDate not supplied

Diffusion-weighted imaging with calculated apparent diffusion coefficient in intracranial hemorrhagic lesions.

In the literature published so far, measurement of values of the apparent diffusion coefficient (ADC) using an echo-planar imaging (EPI) technique in intracranial hemorrhagic lesions show no uniform results. Furthermore, no data exist for bleedings into intracranial lesions. We investigated the ADCs of 18 intracranial hemorrhagic lesions of different stages using echo-planar diffusion-weighted imaging (DWI). The ADC values measured in the hemorrhagic lesions ranged from 1.42 x 10(-3) to 0.22 x 10(-3) mm(2)/s. There were no significant differences between the ADC values in the hemorrhagic lesions and the contralateral white matter (P=.39). A differentiation between the lesions only with the ADC value was not possible as well. Using EPI DWI in intracranial hemorrhagic lesions of different stages, no reliable ADC values were found and a dependable differentiation between the lesions is not possible.

Adult↗