A Three-Contrast, Metal Test Pattern (Snellen E-Plate) in Evaluation of Imaging Techniques in Clinical Chest Radiography

Abstract

A metal test pattern based on a minified Snellen-type E-plate was evaluated in testing six imaging techniques for chest radiography. The device consisted of three contrast zones and it was attached to the patient's back over the right lung during chest radiography. The values for visual detectability of the E-figures were compared with the film scores obtained by grading the radiographs with respect to visibility of diagnostically important anatomic details. The test plate proved to be a simple, quick and reproducible tool for testing several imaging techniques at the same time. The E-plate results were similar to those of the visual grading analysis in most respects. A few discrepancies existed, which were probably due to the inability of the test pattern to fully consider the effect of motion unsharpness and varying scattering conditions within the human thorax, as well as to great differences in roentgen ray absorption properties between Au and tissues.

Visual grading regression: analysing data from visual grading experiments with regression models

“…Visual grading experiments have recently increased in popularity for studying image quality in medical imaging systems [1][2][3][4][5][6][7][8][9][10]. With a limited amount of work, requiring access only to images from the routine workflow, the rating by a number of experienced observers may result in information that is highly relevant for evaluating the diagnostic quality of an imaging procedure to be used in clinical practice and for comparisons between alternative techniques.…”

Large-Screen Image Intensifier Photofluorography Compared with Full-Size Screen-Film Technique in Chest Radiography

“…An index of the image quality in each technique was obtained as the average of the readings of all observers and it is referred to here as the visual detectability, D; (expressed in LP/mm). The D, of the E-test plate radiographed on a human thorax is closely interrelated with physical resolution capacity of the imaging chain (8).…”