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Biomedical subjects

B Wein

Publications and source records attributed to B Wein.

At least 19 recordsLinked to original sources
PubMed2006

Defecation mechanisms after anterior resection with J-pouch-anal and side-to-end anastomosis in dogs.

BACKGROUND: Colonic J-pouch-anal anastomosis or colonic side-to-end anastomosis is the reconstruction of choice after low anterior resection. However, the mechanisms of defecation after both reconstruction forms are still speculative. METHODS: Low anterior rectal resections were performed in 12 dogs with six colonic J-pouch-anal (pouch) and six coloanal side-to-end (SE) reconstructions. Four months postoperative stool frequency, intestinal transit time, and neorectal compliance were determined by radiography and barostat. Defecation mechanisms were evaluated radiographically during expulsion of artificial stool. RESULTS: One dog with pouch reconstruction could not be evaluated due to an anastomotic leak, while the others had uncomplicated course. Spontaneous stool frequency was significantly increased with both reconstruction methods (control 2.0+/-0.9, pouch 2.7+/-1.2, SE 3.3+/-0.9 day; p<0.05). Intestinal transit time was significantly higher with pouch reconstruction due to storage of stool in the pouch and the descending colon compared to SE (control 760+/-82, pouch 592+/-97, SE 550+/-87 min; p<0.05). Compliance and functional capacity were higher in pouch than in side-to-end reconstructions (pouch 5.0+/-0.7 ml/mmHg, 124+/-23 ml; SE 2.7+/-0.3 ml/mmHg, 92+/-24 ml; p<0.05). During defecation, there were no contractions of the pouch detectable. CONCLUSIONS: The colonic J-pouch reconstruction results in better functional outcome than side-to-end coloanal anastomosis. Our results show that pouch evacuation is passive and independent from pouch motility. The functional principle of the colonic J-pouch is not its reservoir function but a delay of colonic motility.

Anal Canal↗
PubMed2005

[Current developments in DICOM and IHE].

The broadening use of imaging management systems in radiology and other disciplines is due in large part to the success of the DICOM standard (Digital Imaging and Communications in Medicine), which has been accepted worldwide for more than 10 years and meanwhile represents one of the most successful standards in medicine. The central intent of establishing the initiative "Integrating the Healthcare Enterprise" (IHE) was to ensure interoperability of different IT systems in medical processes. IHE is essentially based on widespread standards such as DICOM or HL7. This overview article briefly addresses the principles and organization of DICOM and IHE and describes the current developments in both domains.

Database Management Systems↗
PubMed2004

[Local lysis with alteplase for the treatment of acute embolic leg ischemia following the use of the duett closure device: preliminary results].

PURPOSE: To analyze retrospectively the result of the alteplase lysis therapy of embolic complications following the use of the Duett closure device. METHODS AND MATERIALS: For 3.5 years, the Duett closure device was used in 1,398 angiographies to close the femoral puncture site. The Duett device consists of a balloon and a liquid procoagulant containing collagen and thrombin, which is injected into the puncture tract under endovascular balloon protection of the arterial puncture site. In 9 patients (0.64 %), the procoagulant was incidentally injected into the femoral artery causing acute leg ischemia. Eight patients received local lysis therapy with alteplase via a contralateral femoral access. One patient underwent surgery. On average, 21 mg alteplase (4 - 35 mg) were administered within 14 h (4 - 21 h). The course of the lysis was followed angiographically and clinically. All patients were interviewed by telephone 23 months (4 - 35 months) later. RESULTS: In 3 patients, lysis was complete. In 5 patients, only little thrombotic material remained. In all patients, symptoms of ischemia resolved completely within the first hours after initiation of lysis. In 5 cases, bleeding occurred at the puncture site closed with the Duett device during lysis, including development of a false aneurysm in 2 cases. Complications led to premature termination (n = 2) or interruption of the lysis (n = 3). All complications were treated conservatively. Clinically, long-term sequelae were paresthesia and hypoesthesia in the lower leg and foot in 2 patients treated with lysis, and in the patient who underwent surgery. CONCLUSION: Very rarely occurring embolic complications after use of the Duett closure device can be effectively treated with alteplase lysis. A high rate of complications is to be expected at the puncture site closed with the Duett device.

Acute Disease↗
PubMed2003

Defecation mechanisms after proctocolectomy and ileal pouch--anal anastomosis in dogs.

BACKGROUND AND AIMS: The role of intrinsic pouch motility after ileal pouch-anal anastomosis (IPAA) during defecation is still speculative. MATERIALS AND METHODS: IPAA was performed in 12 dogs. Defecation mechanisms were evaluated by motility recordings during spontaneous defecation and during expulsion of an endoluminal balloon and by radiography with sequential sector-related gray scale analysis. RESULTS: Spontaneous defecations appeared without significant changes in electrical or mechanical activity of the pouch. Sequential filling of the pouch led to defecation in only seven dogs while the others did not succeed in emptying their pouch even with maximal balloon inflation. Neither strain gauge measurements nor electromyography demonstrated peristaltic contractions of the pouch during defecation while sector-related gray scale analysis revealed strong contractions of the abdominal wall during pouch emptying. CONCLUSION: Pouch emptying is independent of intrinsic pouch motility. The ileoanal pouch acts as a functionally passive reservoir, and its evacuation is initiated by a rise of the intra-abdominal pressure.

Anal Canal↗
PubMed2003

[Virtual organization in the digital age of radiology - principle and solution for radiologic research?].

The research project "VICORA - Virtual Institute for Computer-Assisted Radiology", funded by the German Federal Ministry of Education and Research, was initiated in the year 2000. Its virtual organization brings together physical science, engineering, information technology, clinical radiology and the medical technology industry. In the German radiology research domain VICORA serves as a model for interdisciplinary collaboration for the changing radiology paradigm illustrated by a "radiologycube". The project does not only aim at scientific goals but also considers the infrastructure, components and human resource management within a virtual organization. The common rapid prototyping platform ILAB 4 ensures user-friendly and time-efficient software that assists with the routine radiology work-flow including full DICOM functionality. By offering a new work environment and collaborative culture based on telematics and knowledge exchange in radiology research, VICORA overcomes limitations of traditional research organization.

Diagnosis, Computer-Assisted↗
PubMed2000

Teleradiology requirements and aims in Germany and Europe: status at the beginning of 2000.

Specific radiological requirements have to be considered for realization of telemedicine. In this article the goals and requirements for an extensive implementation of teleradiology are defined from the radiological user's point of view. Necessary medical, legal and professional prerequisites for teleradiology are presented. Superior requirements, such as data security and privacy or standardization of communication, must be realized. Application specific requirements, e. g. quality and extent of teleradiological functions as well as technological alternatives, are discussed. Each project must be carefully planned in relation to one's own needs, extent of functions and system selection. Topics like legal acceptance of electronic documentation, reimbursement of teleradiology and liability must be clarified in the future.

Europe↗
PubMed2000

Recanalization of thrombosed dialysis access with use of a rotating mini-pigtail catheter: follow-up study.

PURPOSE: To evaluate the feasibility, efficacy, and safety of mechanical thrombectomy of occluded dialysis access with use of a rotating mini-pigtail catheter. MATERIALS AND METHODS: Thrombus was fragmented by mechanical action of the rotating pigtail tip (5-mm diameter), while the guide wire exited a sidehole at the pigtail curvature and served as a fixed rotation axis. Twenty-six procedures were performed in 22 patients (12 men, 10 women; mean age, 55.5 years). Native fistulas were treated in 15 instances, polytetrafluoroethylene (PTFE) grafts were treated in 11 instances. Average occlusion time was 20 hours +/- 13 (range, 5-46 hours), average occlusion length was 25.6 cm +/- 10.1 (range, 6-45 cm). Thrombus fragmentation was followed by balloon angioplasty of underlying stenoses. RESULTS: In all 26 procedures, the dialysis access was successfully declotted with subsequent dialysis using the access (clinical success rate, 100%). Handling of the mini-pigtail catheter was simple and rapid, regardless of whether a graft or a native fistula was treated. Average duration of the intervention was 118 minutes +/- 30. Mean primary patency was 165 days +/- 167. Primary patency rate was 82% at 30 days, 65% at 3 months, and 47% at 6 months. There was no evidence of complications due to the thrombus fragmentation procedure. CONCLUSION: The results suggest that declotting of occluded dialysis grafts and fistulas with the mini-pigtail catheter is as effective and safe as other more established percutaneous therapies. It may serve as an easy-to-handle, low-budget alternative to current thrombectomy devices.

Adult↗
PubMed1997

[Preoperative spiral CT cholangiography with 3-dimensional surface reconstruction: the anatomical imaging potentials, limits and application strategies].

PURPOSE: Evaluation of CT cholangiography compared to i.v. cholangiography concerning its diagnostic value before laparoscopic cholecystectomy and optimisation of CT cholangiography. METHOD: I.v. and CT cholangiographies of 54 patients were retrospectively evaluated by two radiologists. The time interval between contrast infusion and CT was correlated with the assessment of CT cholangiographies to detect the optimal timing for CT scanning. RESULTS: CT cholangiography was judged to be generally better than i.v. cholangiography. The optimal time interval for CT scanning is between 30 min and 60 min post contrast infusion. CONCLUSION: CT cholangiography should replace the conventional tomograms if i.v. cholangiography does not yield sufficient depiction of the biliary tree. It should be performed within 60 min post contrast infusion. Complete abolishment of i.v. cholangiography is not warranted. This is due to the fact that conventional cholangiography can sufficiently delineate the biliary tree and thereby reduce x-ray exposure and cost compared to initial performance of CT cholangiography.

Adult↗
PubMed1997

[Goals, requirements and prerequisites of teleradiology. An assessment of current status].

Specific radiological requirements have to be considered for the realization of telemedicine. In this article the goals and requirements for an extensive introduction of teleradiology will be defined from the radiological user's point of view. Necessary medical, legal and professional prerequisites for teleradiology are presented. Essential requirements, such as data security, maintenance of personal rights and standardization, must be realized. Application-specific requirements, e.g. quality and extent of teleradiological functions, as well as technological alternatives, are discussed. Each project must be carefully planned in relation to one's own needs, extent of functions and system selection. Topics, such as acknowledgement of electronic documentation, reimbursement of teleradiology and liability, must be clarified. Legal advice and the observance of quality guidelines are recommended.

Forecasting↗
PubMed1996

Guidelines for cost-effective implementation of Picture Archiving and Communication Systems. An approach building on practical experiences in three European hospitals.

This paper describes a comprehensive approach for the assessment of the impact of (partial) Picture Archiving and Communication Systems (PACS). The approach is developed, based on actual clinical experience in three European hospitals and tested in these environments. The approach departs from a thorough analysis of the working procedures and information flows before implementation, both descriptive and quantitative. On the basis of this analysis, quantitative (and hence testable) objectives of the implementation are defined. The implementation strategy is defined after comparison of various scenarios, taking costs and effects for both the final and the transition phases into account. The approach is supported by a comprehensive evaluation protocol and a software package (PACER). The approach is demonstrated in this paper by applying it on a hypothetical PACS implementation for CT, ultrasound and for the part of the radiology department serving ICU. The objectives of this PACS are: (1)--to shorten the turn around time between the radiology department and ICU from 4 h to 30 min, (2)--to save 2000 m2 of film per year and (3)--to save personnel time. In this case the PACS is introduced in three phases and completed after three years. The cost analysis shows that, if started in 1995, a financial break even point is reached after 6 years, when comparing costs for the film-based system with those of the PACS. Experiences in the three sites show that the approach helps to harvest potential benefits, allowing a cost-effective implementation of PACS.

Cost-Benefit Analysis↗
PubMed1996

[MRI examination of laryngeal height during vowel singing].

Larynx height positions were determined in 12 singing students and singers with magnetic resonance imaging. The examinations were carried out during the singing of 9 different pitch and loudness combinations of the vowels /a/, /u/ and /i/. It could be demonstrated that vertical larynx position differences were smaller in professional singers than in students. In 10 of 12 examined volunteers a correlation between raised larynx position and high pitch singing or between lowered larynx position and low pitch singing could be observed in at least one of the examined vowels. Loudness-dependent and vowel-dependent differences of larynx height position could not be identified.

Adult↗
PubMed1995

[Functionally determined area changes in the oro-pharyngo-laryngeal vocal tract of singers as shown by magnetic resonance tomography].

The oro-pharyngeal-laryngeal resonating spaces were studied in 12 singers at varying stages of their training by means of medio-sagittal MRI images, and the results were compared. The singers were requested to sing /a/ /u/ and /i/ at various pitches and with increasing loudness. The total oro-pharyngo-laryngeal areas were integrated by means of the MRI sections. The relationship between the oro-pharyngeal and pharyngo-laryngeal areas was determined, as well as their ratio to total area. With increasing volume there was increase in the area of the oro-pharyngeal component with no change in the pharyngo-laryngeal component. The relationship of the partial areas depends on the extent of training of the singer.

Adult↗
PubMed1995

[The computed tomographic morphology of Crohn's disease and ulcerative colitis].

PURPOSE: To assess the value of computed tomography for the diagnosis of Crohn's disease and ulcerative colitis. METHOD: We analysed the CT examinations of 109 patients with 197 involved bowel locations. 81 patients suffered from Crohn's disease, 28 from ulcerative colitis. Diagnosis was based on the combination of clinical, endoscopic and histopathologic findings. Three radiologists evaluated the CT series concerning the presence of morphologic changes analogous to conventional radiographic findings. RESULTS: In Crohn's disease, we found irregular outer contours in 26% of cases. The bowel wall was thickened in 82%. In acute phases, the bowel wall was thickened in 100%. Abscess and fistula as complications of inflammatory disease were present in 26 and 14% respectively. In ulcerative colitis, a target sign of the bowel wall was present in 40%, whereas in Crohn's disease a homogeneous wall density was present in all but two cases. Reduced attenuation due to submucosal fat deposits was found in 16% and mucosal tunneling in 27% of cases with ulcerative colitis. Even if severe mucosal destructions were found, the outer contour of the gut was smooth and regular in 95% of the ulcerative colitis cases. CONCLUSION: CT can provide additional information on acuity, extent and complications in inflammatory bowel disease. In combination with conventional radiographic findings a three-step classification for Crohn's disease and ulcerative colitis (early changes, acute and chronic phase) can be proposed.

Adolescent↗
PubMed1995

[The potentials of digital image-intensifier radiography exemplified by digital spot imaging (DSI)].

PURPOSE: We performed a comparative study of digitally and conventionally acquired images in gastrointestinal examinations. MATERIAL AND METHODS: Radiation dose and spatial resolution were determined in a water phantom. In 676 examinations with either conventional or digital imaging (system: Diagnost 76, DSI) the number of images and the duration of the fluoroscopy time were compared. 101 examinations with digital as well as conventional documentation were evaluated by using 5 criteria describing the diagnostic performance. RESULTS: The entrance dose of the DSI is 12% to 36% of the film/screen system and the spatial resolution of the DSI may be better than that of a film/screen system with a speed of 200. The fluoroscopy time shows no significant difference between DSI and the film/screen technique. In 2 of 4 examination modes significantly more images were produced by the DSI. With exception of the criterion of edge sharpness, DSI yields a significantly inferior assessment compared with the film/screen technique. CONCLUSION: The DSI system was well integrated in the daily routine of gastrointestinal examinations. Low dose imaging, direct availability of images and dynamic studies with a frame rate up to 8 images per second are the advantages of the DSI. The lower spatial resolution in some cases is a diagnostic disadvantage that can reduce the diagnostic information.

Contrast Media↗
PubMed1995

[RADIOLIS. A radiologic instruction and training system for systematic evaluation of roentgen images exemplified by focal bone lesions].

RADIOLIS is an instructional software system for radiological training that guides the user through a systematic analysis of an image. The backbone of the analysis is a detailed and structured questionnaire which, as applied to our example, includes all relevant differential-diagnostic criteria for focal bone lesions. The variation range of the radiomorphologic characteristics in the questionnaire is introduced to the user with digitized X-ray images, making the simulation of an image analysis possible. In preparation, diverse teaching/learning methods reinforced by instructional psychology were incorporated during the system's development. At the core of the training system are an expandable image database and a database containing descriptions of image material formulated by radiology experts. The field of focal bone lesions, for instance, has already been integrated into RADIOLIS. A graphic user interface and an interactive dialogue enable both comfortable and simple use of the system and the user-specific structuring of the learning process.

Bone Neoplasms↗