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Biomedical subjects

B Wein

Publications and source records attributed to B Wein.

At least 19 recordsLinked to original sources
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↗
PubMed1994

[The phasic imaging of velopharyngeal sphincter movements].

The velopharyngeal function while swallowing water was studied on a healthy volunteer patient with velopharyngeal closure and on a patient with velopharyngeal insufficiency. This patient suffers from open hypernasality as a result of shortened velum. Both subjects underwent nasoendoscopy with a flexible fiber glass optical device while swallowing water and while articulating the plosive consonant /k/. Velopharyngeal function was documented by means of videotaping and then the single video images were placed together along a time scale to form a new temporal image. This image makes possible a quick and comprehensive differentiation between physiological and disturbed motion patterns as demonstrated in this study using velopharyngeal function as the example. The videotaping in lapse time of such disordered movements can provide indicators of the therapeutical steps to be taken.

Adult↗
PubMed1993

Digital radiography versus conventional radiography for the detection of a skull fracture under varying exposure parameters.

RATIONALE AND OBJECTIVES: The effect of varying exposure parameters on the detectability of a fracture with digital and conventional radiography were examined. METHODS: A macerated fractured skull was imaged by film-screen radiography (FSR) and digital storage phosphor radiography (DR) with various exposure values. Five radiologists traced the course of a fracture line. The length of the fracture was reported and the results were analyzed by Student's t test for paired samples. RESULTS: At 35% of the conventional radiation dose, the standard DR screen displayed an average of 48% of the fracture length. The difference from the conventional image (45%) was not significant in this case. An increase of the dose to ten times the conventional dose (250 mAs) yielded no significant improvement in the detectability of the length of the fracture (51%). CONCLUSIONS: This experiment shows that with use of the DR with the standard screen, a dose reduction of approximately 35% appears to be possible without any resulting loss of image quality compared to FSR. Use of the high resolution screens should be avoided, since they require a higher incident image dose than standard screens without offering any diagnostic advantages. The image dose of digital radiographs can be roughly estimated based on the digital device sensitivity value. As a rule, the sensitivity value should range between 100 and 200.

In Vitro Techniques↗
PubMed1993

Comparative evaluation of digital radiography versus conventional radiography of fractured skulls.

OBJECTIVES: The authors assessed the relative efficacy of conventional and digital storage-phosphor radiographs for the detection of skull fractures. METHODS: Fifty conventional film-screen radiographs (FSR) and 50 digital storage-phosphor radiographs (DR) with 66 fractures were compared. Five radiologists evaluated image quality and fracture detectability. The results were analyzed by receiver operating characteristic (ROC) curve analysis. RESULTS: With a standard exposure, the ability to evaluate skull fractures was equally good with either technique (ROC area for DR, 0.8954; for FSR, 0.8870). Digital radiography was superior in evaluating nasal bone. For petrosal bone, the DR image simulates an underexposure. This disadvantage compared with FSR can be compensated by image postprocessing. CONCLUSION: In evaluation of skull fractures, radiologists performance with DR is equivalent to FSR.

Adolescent↗
PubMed1993

The contribution of magnetic resonance imaging of the pelvic floor to the understanding of urinary incontinence.

The anatomy of urinary incontinence and the underlying pathology is still under discussion. We examined 24 stress incontinent patients and 6 healthy volunteers. Magnetic resonance imaging (MRI) clearly shows that the urethra is not connected to the levator ani. The urethra is not fixed to deep perineal muscle layers. In stress incontinence the sharp angulation of the levator ani of healthy volunteers is lost in 65%. MRI shows degeneration of the levator ani muscle in 45% of stress incontinent patients. The extent of damage to the levator can clearly be identified with the aid of MRI.

Adult↗
PubMed1993

Computed tomographic cholangiography using spiral scanning and 3D image processing.

Volumetric computed tomography (CT) scans ("spiral CT") were performed after intravenous (i.v.) cholangiography followed by additional 3D surface reconstructions of gallbladder and biliary ducts. 34 patients were investigated prior to cholecystectomy. No allergic adverse reactions were observed. The scan time was 24 s. Contrast enhancement in the extrahepatic bile duct and gallbladder were measured. All CT image series were reviewed independently by four experienced physicians (two radiologists, two surgeons) and compared for quality with conventional cholangiography on a three-point scale. The average rating for the demonstration of the biliary tract was significantly better for spiral CT than for conventional cholangiography (p < 0.01). In all cases sufficient contrast was found in the common bile duct (mean 315 HU). 3D imaging was considered to be helpful for intraoperative orientation during laparoscopic surgery.

Adult↗
PubMed1993

Surgical or medical treatment of questionable peritonsillar abscess? The use of B-mode ultrasonography.

A prospective study was carried out to evaluate the sensitivity of sonography in the diagnosis of peritonsillar abscesses (quinsy). From 1986 to 1991 all cases of clinically doubtful peritonsillitis were subjected to B-Mode ultrasonography of the tonsils before tonsillectomy. 118 patients were examined. Sensitivity of the method in cases of clinically uncertain peritonsillar abscesses was 87%. The predictive value of the method was calculated to be 0.89; however only five false positive cases ("abscess" in ultrasound but no pus during surgery) were found. We therefore suggest that all patients suffering from questionable peritonsillitis should be examined by ultrasound. If abscess formation is suspected, surgical intervention is indicated. In all other cases I.V. antibiotics should be administered and control sonography should be carried out.

Adolescent↗
PubMed1991

Temporal reconstruction of sonographic imaging of disturbed tongue movements.

Documentation of tongue movement during swallowing has been restricted to the recording of fluorographic or ultrasound images on cine- or videofilm. The new approach of temporal sonographic imaging with reconstruction of one single image for the total act of swallowing presents a direct approach to obtaining substantial information concerning tongue movements and motility. The applicability of this reconstructed image for the documentation, interpretation, and comparison of tongue movements is demonstrated using examples of normal and pathologic swallowing.

Adolescent↗
PubMed1991

[The renaissance of simultaneous tomography with the fluorescent-film storage system].

The handling, technical and exposure details of digital simultaneous tomography are explained, while particular emphasis is placed on image quality. Selected case reports demonstrate the application of this technique by using the digital storage fluorescent system (Fa. Siemens, Erlangen). Simultaneous tomography with storage fluorescent screens is particularly suitable to demonstrate or exclude osseous findings at the skull, the column and large joints.

Adult↗
PubMed1991

[Fracture diagnosis with digital luminescence radiography].

Conventional screen-film radiographs were compared with storage phosphorus images concerning diagnostic performance in traumatologic radiography. We used an image pool of 106 radiographs including 50 conventionally and 56 digitally recorded images. The images were reviewed by four experienced radiologists. Detectability of fractures was coded in a five-point scale of confidence and analysed by ROC statistics. Furthermore the image quality and the optical density was compared. Digital images are superior under difficult exposure conditions and offer advantages by additional image processing and documentation. For some indications (follow-up, functional examination), reduced x-ray exposure is tolerable. The detectability of subtle lesions, which is essential for the primary diagnosis of fractures was significantly better by conventional radiography.

Evaluation Studies as Topic↗
PubMed1991

[Ultrasonography of the tongue in the rehabilitation of speech articulation disorders].

There has been presented a possibility of application of ultrasound examination of the tongue in the diagnosis and phoniatric rehabilitation exemplified by exposing shapes of the lateral surface of the tongue during correct articulation of the Polish vowels and articulatory exercises in the system of visual feedback in a normally hearing child and in a deaf one.

Child↗