Gray-Scale Reversal for the Detection of Pulmonary Nodules on a PACS Workstation

OBJECTIVE. The purpose of this article is to evaluate the impact of gray-scale reversal on the detection of small pulmonary nodules in two-view chest radiography. MATERIALS AND METHODS. One hundred twenty-eight patients (mean age, 62 years) who underwent CT and chest radiography within 6 weeks were retrospectively selected for this study. Seventy-three percent of patients showed variable degrees of radiographic findings of a “dirty lung.” A total of 129 solid pulmonary nodules were present in 74 patients (nodule diameter range, 5–30 mm; mean diameter, 13 mm). The remaining 54 patients served as negative control subjects. Six readers with varying experience levels evaluated the images without and with the availability of gray-scale reversal in two separate reading sessions. Figure of merit (FOM), sensitivity per lesion, mean number of false-positive marks per image, and accuracy were calculated. RESULTS. Five of the six readers showed a slight increase in sensitivity with the use of gray-scale reversal, bu...