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Biomedical subjects

B B Wein

Publications and source records attributed to B B Wein.

12 recordsLinked to original sources
PubMed2001

Multi-slice CT for visualization of pulmonary embolism using perfusion weighted color maps.

PURPOSE: The purpose of our preliminary study was to evaluate the feasibility of a new technique for the perfusion weighted color display of the density of lung parenchyma derived from multi-slice CT (MSCT) data sets of clinical routine examinations for visualization of pulmonary embolism (PE). MATERIALS AND METHODS: Imaging of patients with suspected PE was performed on a commercially available MSCT (Somatom Volume Zoom; Siemens, Forchheim, Germany) after intravenous application of 120 cc of contrast-medium using a power injector. Scan parameters were 140 kV and 100 mAs, using a thin collimation of 4 x 1 mm and a table speed of 7 mm (pitch: 1.75). Derived from thin collimation axial slices (slice thicknesseff. 1.25 mm, reconstruction increment 0.8 mm), a new image processing technique was deployed. Based on these source images, an automated 3D-segmentation of the lungs was performed followed by threshold based extraction of major airways and vascular structures. The filtered volume data were color encoded and finally overlayed onto the original CT images. This color encoded display of parenchymal density distribution of the lungs was shown in axial, coronal and sagittal plane orientation. In four patients with excluded PE as well as in two patients with proven PE this new technique was performed. RESULTS: In the four patients that were considered negative regarding PE on MSCT, lung densitometry showed a homogeneous distribution of color encoded densities without circumscribed decreased or increased areas, beside the usually present gravity-dependent gradient in ventro-dorsal direction. In the two patients with proven PE, low density values on perfusion weighted color maps were found distally to the occluded pulmonary arteries. CONCLUSIONS: Our initial experience indicates that lung densitometry with an optimized display of the density distribution within the lung parenchyma may provide additional information in patients with suspected or proven PE. However, a comparison with ventilation/perfusion scintigraphy and a larger number of patients are necessary for the full clinical evaluation of this new functional imaging methodology.

Aged↗
PubMed2001

[Automated image analysis of lateral roentgen images of the spine using anatomic models].

PURPOSE: Development of a software for fully automated image analysis of lateral lumbar spine X-rays. MATERIAL AND METHOD: Using the concept of active shape models, we developed a software that produces a form model of the lumbar spine from lateral lumbar spine radiographs and runs an automated image segmentation. This model is able to detect lumbar vertebrae automatically after the filtering of digitized X-ray images. The model was trained with 20 lateral lumbar spine radiographs with no pathological findings before we evaluated the software with 30 further X-ray images which were sorted by image quality ranging from one (best) to three (worst). There were 10 images for each quality. RESULTS: Image recognition strongly depended on image quality. In group one 52 and in group two 51 out of 60 vertebral bodies including the sacrum were recognized, but in group three only 18 vertebral bodies were properly identified. CONCLUSION: Fully automated and reliable recognition of vertebral bodies from lateral spine radiographs using the concept of active shape models is possible. The precision of this technique is limited by the superposition of different structures. Further improvements are necessary. Therefore standardized image quality and enlargement of the training data set are required.

Humans↗
PubMed2000

Potential of a new laser target system for percutaneous CT-guided nerve blocks: technical note.

A prototype of a laser target device was used for CT-guided nerve blocks in a preliminary series of nine interventions. The system provides guidance from any possible approach. High accuracy of needle insertion was achieved; the average deviation of the planned from the actual angle was 1.4 degrees. The target device is valuable for facilitating minimally invasive therapy and can decrease the time required for the procedure.

Adult↗
PubMed2000

[Initial experiences with a new optical target system (SimpliCT) for CT-guided punctures].

PURPOSE: To evaluate the prototype of a new optical target device for CT-guided punctures and interventions. METHODS: An optical target device for CT-guided punctures was applied in 24 interventions. The system consists of a laser target device mounted on a stand. The biopsy needle is adjusted according the course of a laser beam. The target angle has to be adjusted on the laser unit. The laser carrier can be moved along an 90 degrees-angled rail, allowing punctures from any angle in plane. Furthermore, angulation in the z-plane is possible, supporting interventions with gantry tilt. Size and depth of the target lesions, the planned and the actual angle of the inserted needle, the numbers of corrections of the needle position, and the time required for the puncture were evaluated. The user rated the benefit of the system and the ease of the application. RESULTS: All 24 interventions were carried out successfully. The mean difference between the planned and the actual angle of the needle was 1.3 degrees (SD: 0.7 degree). The system was considered as easy to handle and as a valuable aid. CONCLUSIONS: The laser target device is a simple navigation system which allows accurate positioning of a needle. Requiring an acceptable low preparation time, it easily can be integrated into the procedure.

Adult↗
PubMed1999

Mechanical thrombectomy in hemodialysis access shunts using a 5F pigtail rotation catheter. In vitro and in vivo investigations.

RATIONALE AND OBJECTIVES: To evaluate the feasibility of mechanical thrombectomy in occluded hemodialysis access shunts by using a newly developed 5F pigtail rotation catheter. METHODS: Thrombosed hemodialysis access shunts were simulated by clotted bovine blood in silicone tubing (diameter 6 mm). After retrograde and antegrade sheath placement (6F), mechanical fragmentation was performed using a 5F rotatable pigtail device. Average tube length was 27 to 47 cm; average thrombus weight was 5 to 11.9 g (8.2 +/- 1.59). Clinical application involved six patients with fresh shunt occlusions (three Brescia-Cimino shunts, three Gore-Tex shunts). RESULTS: Using the in vitro setup, the device was able to restore a continuous lumen within 10 minutes with no remaining wall-adherent thrombi. The average amount of particles in the effluent was 3.0 g (2.0 to 3.9) for particles < or = 1.0 mm and 0.67 g (0.44 to 0.96) for particles > or = 0.2 mm wet weight; (compared with initial thrombus weight, 30.7% and 1.1%, respectively). Clinically, all six hemodialysis access shunts were successfully recanalized. Technical problems did not occur. There were no clinical symptoms indicating pulmonary embolism in any of the treated patients. CONCLUSIONS: In our experimental setup as well as under clinical conditions, effective treatment of occluded hemodialysis access sites was achieved. The pigtail rotation device is an easy-to-handle, inexpensive alternative to mechanical thrombus fragmentation in occluded hemodialysis access shunts. The rate of emboli in the effluent vein of approximately one third of the initial thrombus weight must be taken into consideration in frequent intraindividual use of this technique.

Adult↗
PubMed1998

[Embolization with gelatin-impregnated microspheres].

PURPOSE: This paper presents a new, easy to handle material for embolisation which comes up with sharply defined particle size and spherical shape, very suitable for peripheral embolisation in the small end arteries. METHODS: In 13 superselective embolisations with coaxial catheters the gelatine coated microspheres-sized 300-500, 500-700, 700-900 microns--were injected in the region of bronchial arteries (n = 7), vertebral bodies (n = 4) and pudendal arteries (n = 2). RESULTS: In all cases complete occlusion of the desired vessels was achieved. With the exception of one transient dysesthesia in the relevant dermatome during embolisation of the third lumbal vertebra, no adverse effects were noted. The microspheres were suspended in contrast medium and could be easily located by indirect methods, and hence the embolisation procedure was well controlled. DISCUSSION: Compared with other embolisation materials the ready-for-use gelatine coated microspheres due to their physical properties are an excellent alternative to superselective embolisation materials of end arteries.

Adult↗
PubMed1997

[Sector-related grey scale analysis of video ultrasound recorded tongue movements in swallowing].

Diseases of the oral cavity, floor of the mouth, and nervous system can be accompanied by disturbances in tongue movement during swallowing. These disturbances can be diagnosed by videosonography whereby the examiner has to evaluate extensive video documentation of lingual motion. It was the aim of this study to facilitate this evaluation by the application of a reproducible computer-assisted quantitative analysis procedure. Video sequences of 56 healthy adults and 19 patients with dysphagias of different etiologies were analysed. A numerical estimation of swallowing movements was carried out in abstraction from the structures imaged (bolus, air, muscles of the tongue, floor of the mouth, hyoid, etc.). Intensity changes of the pixels within previously defined radial image sectors were quantified in relationship to time and depicted as sector curves. The healthy adults demonstrated a characteristic pattern of two motion maxima that appeared within almost all sector curves. These maxima represented bolus transport movements and the reset movement of the tongue. Patients with diseases of the tongue or neuromuscular changes caused by disturbances of the central nervous system showed pathological deviations on videosonography. These appeared as local or general reductions in movement, slow speed motions, repetitive swallowing or unsorted additional movements of the tongue during swallowing.

Adolescent↗
PubMed1997

[Protective pneumothorax in CT-guided mediastinal puncture].

PURPOSE: To achieve an extrapulmonary pathway for biopsy of mediastinal masses. METHODS: In 6 patients a protective, temporary pneumothorax was established before performing large-bore needle biopsies of mediastinal masses using a Verres-needle. RESULTS: Transpleural, extrapulmonary access was easy to achieve. One patient developed a tension pneumothorax after biopsy which was drained by percutaneous small chest tube. Another patient showed mediastinal tumor bleeding through the biopsy needle. As a prophylactic measure the bleeding was stopped by injection of tissue glue through the biopsy needle. CONCLUSION: The use of protective pneumothorax allows cutting needle biopsies of mediastinal masses where aspiration cytology yields no secure specific diagnosis.

Adult↗
PubMed1997

Esophageal perforation: comparison of use of aqueous and barium-containing contrast media.

PURPOSE: To assess the need for follow-up esophagography with barium-containing contrast medium after examination with a water-soluble contrast medium in the detection of esophageal perforation. MATERIALS AND METHODS: Sixty-seven patients suspected of having esophageal perforation were examined prospectively with use of an aqueous contrast medium during a 1-year period. The examinations were performed with a digital fluoroscopy unit. Eighteen patients without proved extravasation at esophagography performed with aqueous contrast medium and without other contraindications underwent esophagography with barium-containing contrast medium. RESULTS: In four of 18 patients (22%) with unremarkable findings at esophagography performed with a water-soluble contrast medium, a perforation was detected subsequently with use of a barium-containing contrast medium. No complications related to barium extravasation occurred. CONCLUSION: Patients suspected of having esophageal perforation and who have unremarkable findings at esophagography with water-soluble contrast media need to undergo follow-up esophagography with a barium-containing contrast medium. The use of a digital fluoroscopy unit does not obviate the follow-up examination.

Adult↗
PubMed1993

Aseptic spondylodiscitis: a complication of chemonucleolysis? A case report.

Discitis after intradiscal injection of chymodiactin is nearly always associated with an infection introduced by the needle tip. The authors report a patient with a postchemonucleolysis spondylodiscitis who recovered complete without surgery or antibiotics. The clinical findings and results of CRP and MRI suggested an aseptic spondylodiscitis due to chymodiactin.

Adult↗
PubMedDate not supplied

Evaluation of functional positions of tongue and soft palate with MR imaging: initial clinical results.

Magnetic resonance imaging was used to analyze functional positions of the tongue and soft palate in 10 patients and 10 healthy volunteers. The patients had velopharyngeal insufficiency and/or dysfunction of the tongue. With snapshot FLASH (fast low-angle shot) sequences (data acquisition time, less than 1 second), malpositions of the articulatory apparatus were imaged and recorded for follow-up documentation.

Adult↗