HELICAL COMPUTED-TOMOGRAPHY DIAGNOSIS OF PLEURAL DISSEMINATION IN LUNG-CANCER - COMPARISON OF THICK-SECTION AND THIN-SECTION HELICAL COMPUTED-TOMOGRAPHY

Pleural dissemination in lung cancer was prospectively evaluated by he lical computed tomography (CT), and the usefulness of thick-section CT (IO-mm collimation; pitch 1) and thin-section CT (2-mm collimation; p itch 1) were compared. The study included 54 patients with pulmonary a denocarcinoma in whom plain chest radiographs showed no evidence of pl eural effusion and in whom the primary lesion was seen to be contiguou s with the pleural surface on thick-section CT. Thin-section CT was pe rformed for evaluation of the costal, mediastinal, interlobar, and dia phragmatic pleural surfaces. Pathologic examination revealed pleural d issemination in 20 patients (8 resected, 12 nonresected). Pleural diss emination was diagnosed in 12 patients on thick-section CT, and in 20 patients on thin-section CT. False negatives occurred in ten and two p atients, respectively. The same two patients were false positives by b oth methods. Accuracy was 78% for thick-section CT and 93% for thin-se ction CT, and sensitivity was 50% and 90%, respectively. Thin-section CT provided more useful information than thick-section CT for the eval uation of pleural dissemination in lung cancer.