Comparison of Chest Tomosynthesis and Chest Radiography for Detection of Pulmonary Nodules: Human Observer Study of Clinical Cases

Abstract

To compare chest tomosynthesis with chest radiography in the detection of pulmonary nodules by using multidetector computed tomography (CT) as the reference method. The Regional Ethical Review Board approved this study, and all participants gave informed consent. Four thoracic radiologists acted as observers in a jackknife free-response receiver operating characteristic (JAFROC) study conducted in 42 patients with and 47 patients without pulmonary nodules examined with chest tomosynthesis and chest radiography. Multidetector CT served as reference method. The observers marked suspected nodules on the images by using a four-point rating scale for the confidence of presence. The JAFROC figure of merit was used as the measure of detectability. The number of lesion localizations relative to the total number of lesions (lesion localization fraction [LLF]) and the number of nonlesion localizations relative to the total number of cases (nonlesion localization fraction [NLF]) were determined. Performance of chest tomosynthesis was significantly better than that of chest radiography with regard to detectability (F statistic = 32.7, df = 1, 34.8, P < .0001). For tomosynthesis, the LLF for the smallest nodules (< or = 4 mm) was 0.39 and increased with an increase in size to an LLF for the largest nodules (> 8 mm) of 0.83. The LLF for radiography was small, except for the largest nodules, for which it was 0.52. In total, the LLF was three times higher for tomosynthesis. The NLF was approximately 50% higher for tomosynthesis. For the detection of pulmonary nodules, the performance of chest tomosynthesis is better, with increased sensitivity especially for nodules smaller than 9 mm, than that of chest radiography.