Evaluation of Pleural Invasion of Lung Cancer by Thin-sliced CT

Pleural invasion is one of the most important factors in the clinical diagnosis of lung cancer. Many studies have been conducted to evaluate extrapulmonary invasion by lung cancer. Gross extrapulmonary invasion into the chest wall and the mediastinum can be confidently diagnosed with computed tomography (CT) and magnetic resonance (MR) imaging. However, contiguity of the tumor to adjacent extrapulmonary structures is not equivalent to definite invasion. To assess the usefulness of thin-sliced CT in detection of chest wall and mediastinal invasion of lung cancer, we performed a prospective study of 12 patients whose tumors were contiguous to the extrapulmonary structures on conventional CT scans. Comparison of diagnoses based on findings of thin-sliced CT and pathologic examination showed that thin-sliced CT was 83% accurate for pleural invasion. Conventional CT, however, was 58% accurate for pleural invasion. This leads to the conclusion that thin-sliced CT is helpful in accurate evaluation of the pleural invasion in lung cancer, especially for patients in whom findings on conventional CT suggest tumor invasion of the chest wall and mediastinum.