Digital chest radiography--optimizing image processing parameters for the visibility of chest lesions and anatomy

The effect of varying the degree of contrast and edge enhancement upon the visibility of chest lesions and anatomy was evaluated in a digital image intensifier system for chest radiography. Visual grading analysis was used as method for the evaluation. Conventional radiographs served as reference images. Ten observers graded the visibility of four regions of interest: (1) fine linear structures, (2) mediastinal anatomy, (3) rounded opacities, (4) vessels, and also graded the overall quality of 17 chest images. The images had been subjected to three grades of image processing: one basic, one intermediate, and one extreme. In all, 2730 observations were made. The basic image processing was the best for the visibility of regions 2, 3, and 4 and for the overall quality. The intermediate image processing was best for the fine linear structures. The extreme image processing rated lowest for all regions and especially for the overall quality.