CT Manifestations of Tumor Spread Through Airspaces in Pulmonary Adenocarcinomas Presenting as Subsolid Nodules

The aim of this study was to identify potential computed tomography manifestations of pulmonary adenocarcinomas presenting as subsolid nodules and associated with the histologic evidence of spread of tumor through air spaces (STAS).From a radiologic-pathologic repository of resected pulmonary adenocarcinomas including 203 subsolid nodules, 40 STAS-positive nodules were randomly selected and matched to 40 STAS-negative nodules. Total average diameter, as well as average and long-axis diameters of the solid component, was measured. The proportion of solid component diameter to total average diameter was calculated. Measurements and proportions between STAS-positive and STAS-negative nodules were compared with paired samples t test, χ test, or the Fisher exact test.The total average diameter in STAS-positive nodules was significantly larger than in STAS-negative nodules (P=0.024). The average and long-axis diameters of the solid component of STAS-positive nodules were significantly larger than that of STAS-negative nodules (P=0.001 and 0.003). The proportion of solid component to total average diameter was significantly larger in STAS-positive than in STAS-negative nodules (P=0.041). At a threshold of ≥10 mm for the average and the solid component long-axis diameters, significantly more nodules were STAS-positive than STAS-negative (P=0.015 and 0.001).Total average diameter, average and long-axis diameters of the solid component, and a high proportion of solid component diameter compared with total average diameter are computed tomography manifestations of subsolid pulmonary adenocarcinomas with STAS. These findings could serve as an in-vivo tool for the likelihood estimation of STAS, and consequently influence management of subsolid adenocarcinomas.