Use of CT to Evaluate Pleural Invasion in Non–Small Cell Lung Cancer: Measurement of the Ratio of the Interface between Tumor and Neighboring Structures to Maximum Tumor Diameter

When diagnosing T3 or T4 lung cancer based on arch distance-to-maximum tumor diameter ratios, a higher performance level was achieved than that with use of conventional criteria. Measurement of the ratios is a simple noninvasive technique for evaluating pleural invasion at CT.