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Biomedical subjects

R Vosshenrich

Publications and source records attributed to R Vosshenrich.

At least 73 records · Page 4Linked to original sources
PubMed1993

[The acetabular prosthesis: detection of a migration using ruler and pencil? Measurements on a pelvic phantom in comparison with a 3D computer simulation].

Conventional X-ray films were made with varying degrees of tilt of a pelvic phantom containing an acetabular prosthesis. The position of the prosthesis was then reconstructed graphically. The measurement errors were calculated and an estimate was made for the tilt. There is a linear correlation between the measurement error and the tilt of the prosthesis. Therefore a tilt dependent maximum error can be calculated. This error is very small for small degrees of tilt, so that acetabular migration can in this instance be evaluated with greater confidence than with other graphical methods. The error also correlates with the determination of the selected region of the acetabulum, but not with the position of the central focus spot or image magnification.

Acetabulum↗
PubMed1993

[Initial experiences with the MR "magnitude contrast angiography of the lower extremities].

45 patients with occlusive peripheral vascular disease were examined by MR angiography in a retrospective study. A FISP 3D sequence was used by acquiring a rephased and a dephased data set. The individual slices were post-processed by using a maximum-intensity-projection algorithm. The MRA results of the popliteal and tibioperoneal arteries were compared to conventional or digital angiography. In comparing these techniques MR angiography cannot be accepted for pre- and postoperative staging of patients with occlusive peripheral vascular disease. In future new MRA techniques may be useful in postoperative staging of patients with peripheral vascular stenosis.

Arterial Occlusive Diseases↗
PubMed1992

Digital radiography in urologic imaging: radiation dose reduction on urethrocystography.

Digital luminescent radiography (DLR) is a new form of digital radiographic technology which can be used as an alternative to conventional radiologic systems; it replaces conventional screen-film systems by photostimulable phosphorus. Due to the linear dynamic range of photostimulable phosphorus, x-ray examinations can be performed with significantly lower radiation exposure. In this study radiation dose was reduced by about 90% using DLR for urethrocystography.

Humans↗
PubMed1992

[Experiences with digital luminescence radiography (DLR) in pediatric radiology].

X-ray examinations represent a variety of indications with different demands on exposure latitude, spatial and contrast resolution of screen-film-system combinations in paediatric radiography. The value of digital luminescent radiography (DLR) was compared to conventional x-ray examinations carried out with screen-film-systems, speed class 200, by analysing matched digital and conventional exposures in 200 abdominal, 600 skeletal and 300 chest examinations. The exposure of DLR was reduced to 50% of conventional exposure. Analysing the results in abdominal and skeletal radiography, DLR proved to be diagnostically equivalent to conventional radiography despite the reduction in exposure dose. DLR of the newborn chest compared to conventional x-ray studies was not always sufficient due to lower digital spatial resolution.

Adolescent↗
PubMed1992

[The tilted screen-cassette ("grid cut-off" effect). A problem of bedside thoracic diagnosis].

Tilting of a grid during portable radiography leads to uneven exposures, and errors greater than 3 degrees can lead to errors in interpretation. Differentiation from abnormal findings can be made by recognising exposure difference of extrathoracic comparable areas. The difficulties caused by tilting of the grid can be reduced by increasing the film focus distance and by using suitable grids. A new cassette holder with an integrated balance makes it possible to correct tilting of the grid rapidly and effectively. This results in improved image quality which can be applied not only to conventional exposure systems but is also of advantage when using digital methods.

Diagnostic Errors↗
PubMed1992

[The value of digital luminescence radiography within the scope of traumatologic follow-up examinations].

At the present time we cannot unhesitatingly recommend the general use of digital luminescence radiography in traumatological follow-up examinations. Marked drawbacks of this method are, for example, sudden changes in contrast in the marginal areas of osteosynthesis material, occasional limitations in the detailed assessment of spongious structures and problems in respect of imaging geometry. By modifying the image processing parameters, increasing the image matrix and enlarging the format spectrum, however, these problems should be capable of being resolved in the future. Positive features, on the other hand, are even now the possibility of reducing the dosage to a marked degree in many traumatological follow-up examinations, especially in children and adolescents, and in case of conservatively treated fractures. In the long run we can foresee the routine use of digitalised examination methods on traumatology coupled with the possibility of storage in an image filing and communication system, although this is at present not yet feasible due to lack of requisite experience and the cost of the necessary equipment.

Computer Systems↗
PubMed1992

[The place of computed tomography and magnetic resonance tomography in the diagnosis of bone sequestra].

Conventional radiographs of 45 patients with chronic osteomyelitis, mostly of posttraumatic origin, were compared with computed tomography (CT) and operative findings. In addition, magnetic resonance imaging (MRI) was performed in 6 of these patients. In 28 patients (65%) bony sequestra were identified and in most cases histologically confirmed by surgical exploration. CT proved to be the method of choice for the preoperative diagnosis of sequestra in patients with chronic osteomyelitis. MRI provided no significant additional diagnostic information, its advantage appears to be a more detailed and accurate imaging of the extent of the intra- or extraosseous inflammation, thereby facilitating surgical planning.

Adult↗
PubMed1991

[Splenogonadal fusion].

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Angiography, Digital Subtraction↗
PubMed1991

[Cystic space-occupying lesions in the femoral trigone].

The differential diagnosis of cystic tumours in the region of the so-called Trigonum femorale is presented and discussed. In this context the topography of this area is demonstrated. In addition to the clinical findings sonography and computed tomography are the method of choice in finding the right diagnosis. Invasive methods such as angiography and lymphography are indicated in only few cases. US-guided fine-needle-aspiration should be preferred instead, if it is of any therapeutic relevance.

Aneurysm↗
PubMed1990

[Radiologic diagnosis and treatment of Ormond's disease].

Retroperitoneal fibrosis is a rare entity of various causes. The clinical findings are not specific. In some cases the diagnosis is suggested by the characteristic appearance on urography. The purpose of this investigation is to evaluate the typical ultrasound and CT findings of patients with retroperitoneal fibrosis. A discussion of the current diagnostic procedure and treatment is presented.

Female↗
PubMed1989

[A new concept for conventional x-ray diagnosis in intensive medicine].

A modified examination concept to improve conventional x-ray diagnostics in a intensive-care unit is presented. This planning is based on the development of new technical components in the field of mobile diagnostics and the availability of improved basic materials that can certainly promote such a project. This is presently being installed in the Clinical Centre of the University of Göttingen and will be subjected to a critical cost/efficiency analysis during a run of one year.

Academic Medical Centers↗