Internal Growth of Nonsolid Lung Nodules: Radiologic-Pathologic Correlation

Purpose:To determine whether computed tomographic (CT) attenuation values correlate with the histologic measurements of a lung cancer manifesting as a nonsolid nodule and to quantify the extent to which the tumor replaces the airspace within the nodule. Materials and Methods:Informed consent was obtained to analyze images from CT and pathologic examination under an institutional review board-approved protocol.Fifteen patients who had undergone resection of nonsolid lung cancer were evaluated.On the basis of the CT attenuation values of nonsolid nodules, nonneoplastic lung, soft tissue, and air, the overall proportion of soft tissue in the nodule and nonneoplastic lung and the difference between these two measures were calculated.The analogous measures were obtained from a representative digitized histologic slide.The area of each nodule and the proportion of air within it were measured, and the proportion of soft tissue in the nodule and nonneoplastic lung and the difference between the two were calculated.The difference between the two proportions at CT and histologic examination are the proportions attributable to the cancer on the basis of CT and histologic examinations, respectively.Linear regression was performed to assess the relationship between these measures.