The knowledge of the relationship that links radiation dose and image quality is a prerequisite to any optimization of medical diagnostic radiology. Image quality depends, on the one hand, on the physical parameters such as contrast, resolution, and noise, and on the other hand, on characteristics of the observer that assesses the image. While the role of contrast and resolution is precisely defined and recognized, the influence of image noise is not yet fully understood. Its measurement is often based on imaging uniform test objects, even though real images contain anatomical backgrounds whose statistical nature is much different from test objects used to assess system noise. The goal of this study was to demonstrate the importance of variations in background anatomy by quantifying its effect on a series of detection tasks. Several types of mammographic backgrounds and signals were examined by psychophysical experiments in a two-alternative forced-choice detection task. According to hypotheses concerning the strategy used by the human observers, their signal to noise ratio was determined. This variable was also computed for a mathematical model based on the statistical decision theory. By comparing theoretical model and experimental results, the way that anatomical structure is perceived has been analyzed. Experiments showed that the observer's behavior was highly dependent upon both system noise and the anatomical background. The anatomy partly acts as a signal recognizable as such and partly as a pure noise that disturbs the detection process. This dual nature of the anatomy is quantified. It is shown that its effect varies according to its amplitude and the profile of the object being detected. The importance of the noisy part of the anatomy is, in some situations, much greater than the system noise. Hence, reducing the system noise by increasing the dose will not improve task performance. This observation indicates that the tradeoff between dose and image quality might be optimized by accepting a higher system noise. This could lead to a better resolution, more contrast, or less dose.

Improvement in pain seemed to be most important aspect in ACDF patients regarding the subjective SQ. Therefore, we strongly recommend focusing on pain-reducing therapies when choosing treatment for these patients during the postoperative period.

Although the survival time of patients with vertebral metastases from lc has increased over the last 10 years, the overall outcome is still poor. For the prediction of an individual prognosis in the group of lc patients the score of Tokuhashi seems to be a suboptimal tool. We conclude that therapeutic decisions for such patients should be made based on interdisciplinary platforms, especially in the light of improved systemic treatment options.

Hoof kick injuries account for a significant proportion of equine injuries and occur when riders are dismounted, most frequently when grooming without wearing protective equipment. Head and facial injuries occur most frequently and suggest that mandatory helmet and facial grill use should be considered during all horse-related activities.

Of 10,000 mammographies done over a 9-year period, 16 cases of hamartoma of the breast were diagnosed. The entity is a well delimited mass composed of dysplastic-appearing mammary tissue admixed to fat. It can be readily recognized and should not be confused with fibroadenoma or mammary dysplasia. The accuracy with which it can be diagnosed by mammography makes possible the avoidance of surgical excision in selected patients.