Erste klinische Erfahrungen mit einem grossformatigen Flächendetektorsystem bei Aufnahmen des peripheren Skelettsystems. Teil 2: Nachverarbeitung mit einem neu entwickelten adaptiven Autofensteralgorithmus

In part 1 of the presented paper the results when using half of the normally applied dose on a full field flat panel detector were presented. Purpose of the second part of the investigation was the evaluation of a newly developed adaptive autowindow algorithm in comparison to the system processing radiographs of the wrist and ankle to further optimize the image quality with softcopy reading. Material and Methods: All 120 radiographs of the wrist and all 100 radiographs of the ankle used in the 1 st part of this paper were processed with the adaptive autowindow algorithm. The evaluation was again performed by 5 radiologists with softcopy reading. For the data analysis a variation of the Visual Grading Analysis (VGA) was used. Results: Up to 19% of the wrist radiographs and 2% of the ankle radiographs processed with the system software had to be processed manually afterwards to get acceptable results. By the application of the adaptive autowindow algorithm a manual post-processing was no longer necessary. Highly significant (p ≤ 0.001) differences for all criteria to be evaluated were found for the wrist radiographs and in the case of the ankle radiographs for the bone contrast, the contrast in soft-tissue regions, the fine details in the bone and the artifacts, the adaptive autowindow algorithm performed always better than the system software. Conclusion: Using half of the exposition dose on a flat-panel detector, an optimized post-processing leads to comparable or better results compared to the conventional film-screen-system concerning the image quality.