Predictive CT findings of malignancy in ground-glass nodules on thin-section chest CT: the effects on radiologist performance

Our purpose was to identify thin-section chest computed tomography (CT) findings of malignancy other than the presence of a solid portion within ground-glass nodules (GGNs) and to evaluate whether the radiologists’ performance in determining malignancy can be enhanced with this information. The predictive CT findings of malignancy extracted from the CT findings of 80 GGNs (47 malignant, 33 benign) were a size of >8 mm [odds ratio (OR), 10.930; P = 0.045] and a lobulated border (OR, 13.769; P = 0.016) for pure GGNs and a lobulated border (OR, 10.200; P = 0.024) for mixed GGNs. Four chest radiologists and five radiology residents participated in the observer performance study with CT of 130 GGNs (67 malignant, 63 benign). Receiver-operating characteristic (ROC) analysis was used to compare radiologists’ performances before and after providing these predictive findings. For pure GGNs, mean areas under the curve (A_z) of all readers without and with CT predictive information were significantly different (0.621 ± 0.052 and 0.766 ± 0.055, P < 0.05). For mixed GGNs, the A_z values achieved without and with predictive information were not significantly different (0.727 ± 0.064 and 0.764 ± 0.056, P > 0.05). Information about lesion size and morphological characteristics can enhance radiologists’ performance in determining malignancy of pure GGNs.