Sharpness and noise in digital chest radiographs, assessed by visual rating

Abstract

Missed lung lesions are one of the most frequent causes of malpractice issues, caused by several reasons; among them suboptimal radiography. When radiographers interpret acquired images of a patient, an acceptance or rejection must be decided. When a retake is required, radiographers need to know how to improve the image quality. Improvements in image quality properties as contrast, sharpness and noise often lead to improved perception, which in turn should enable more information to the observer and also allow computer-assisted detection (CAD) to be more successful. Our aim was to create a scoring system of the principal limiting factors sharpness and noise, in a clinical setting, and to determine whether it is possible to agree on image quality on digital chest radiographs. To enable a variation in rating due to body habits, a three-graded scale for each of sharpness and noise were created. Five different anatomical landmarks in each of patients having body sizes lean, normal and large were evaluated by 27 radiographers; totally 810 scores were given. The results showed a high inter-observer agreement with respect to rating grades of both sharpness and noise, independent of projection, anatomical landmark and body habits. The present study is a first step in the development of a scale for assessing sharpness and noise in digital chest radiography. The method of quality assessment might become more valid with increased use. We propose that this study can be followed up by a systematic mentor-guided training program that links perception of image quality to feedback about the image retake decisions if required.