Figure 3.

61-year-old man undergoing lung cancer screening CT. Axial image from baseline CT examination demonstrates a solid nodule (arrow) in the right upper lobe adjacent to the right minor fissure, with mean diameter of 8.5 mm (for both readers). Reader 1 did not consider the nodule to have triangular, polygonal, or ovoid shape and classified the nodule as Lung-RADS category 3. Reader 2 considered the nodule to have triangular, polygonal, or ovoid shape and classified the nodule as Lung-RADS category 2 given the size, perifissural location, and shape. The nodule slowly increased in size on follow-up imaging (not shown) and was eventually diagnosed as lung cancer. Category 2 assignment by reader 2 represented a false-negative interpretation.