Can Dependent Atelectasis Affect the Performance of Automated Lung Nodule Matching?

Abstract

AJR 2010; 194:W246 0361–803X/10/1942–W246 © American Roentgen Ray Society Can Dependent Atelectasis Affect the Performance of Automated Lung Nodule Matching? We read with great interest the article by Tao et al. [1], who reported high performance of an automated lung nodule matching program in screening serial chest CT scans. The authors arbitrarily classified nodules as solid parenchymal, solid juxtavascular, solid juxtapleural, or ground-glass opacity. Of those nodules, the matching rate was lowest for juxtapleural nodules. We think that the performance of the lung nodule matching program used in that study was influenced by the presence or absence of dependent atelectasis because a solid parenchymal nodule can assume a juxtapleural location with the development of dependent atelectasis, as we experienced in two patients (Figs. 1 and 2) who underwent CT for lung cancer screening and metastasis workup, respectively. The implication of our observation is that, with persistent dependent atelectasis, peripheral lung nodules will tend to become juxtapleural rather than parenchymal and will become less likely to be matched on serial CT scans. More important, we wonder whether this lung nodule matching program will be able to match nodules in cases in which the nodules look parenchymal on one CT scan and subsequently become juxtapleural on another scan, with development of dependent atelectasis. Jin Kyoung Oh Dae Hee Han Seoul St. Mary’s Hospital The Catholic University of Korea Seoul, Korea