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Biomedical subjects

E Wiesen

Publications and source records attributed to E Wiesen.

5 recordsLinked to original sources
PubMed1993

Hyperlucent thorax from rotation. Anatomic basis.

RATIONALE AND OBJECTIVES: The authors studied a large group of patients with a computed tomography (CT)-based model to evaluate the presence, significance, and anatomic basis of unilateral hyperlucency from patient rotation. METHODS: Chest CT sections at three levels in 65 consecutive patients undergoing routine diagnostic studies were read into a microcomputer. Radiographic transmittance data were calculated across each CT section at different degrees of rotation as well as for lateral decentering. Data were analyzed for the pattern of density variation both individually as well as in stratified subgroups. RESULTS: The data showed a trend of increasing radiographic transmission on the side opposite that of the anterior obliquity. The resulting optical density difference was small and was not clinically significant. Lateral decentering produced smaller changes than rotation. The anterior breast/pectoral structures are the etiology for the phenomenon. Optical density differences of 0.1 result from a difference in tissue thickness of 4 mm. CONCLUSIONS: The changes in radiographic transmission with rotation are small and are overshadowed by soft tissue compression. Rotation alone will result in decreased radiographic transmission on the side of anterior obliquity; thus, the left side will be more lucent in an right anterior oblique projection.

Adult↗
PubMed1985

Mammographic needle localization of lesions seen in only one view.

A new xeromammographic needle localization technique for occult breast lesions seen on only one view is described, which permitted successful localization of an occult lesion visible only on mediolateral projection. To test its accuracy, the method was also applied to 15 other cases (16 lesions) where the lesion was seen in two views, but localization was performed as if it were seen in one view only. The technique takes advantage of the geometry of x-ray beam angulation and triangulation.

Adenofibroma↗
PubMed1981

The effect of mAs variation upon computed tomography image quality as evaluated by in vivo and in vitro studies.

The effect of different mAs settings on computed tomobraphy (CT) image quality was evaluated by a clinical study and phantom studies. In the clinical portion of this study, a number of CT images, obtained at various mAs settings, were reviewed by experienced CT interpreters. From these same images, graphs were charted of the root-mean-standard deviation (RMSD) vs. body size; there appeared to be a linear relationship between noise, as measured by RMSD, and body size. A performance phantom was used to evaluate the effect of the different mAs settings on resolution. There was some loss in low contrast resolution at 6 and 20 mAs; however, the resolution was identical at 40 and 100 mAs.

Humans↗