Chronic cystic lung disease: diagnostic accuracy of high-resolution CT in 92 patients

The objective of this study was to determine whether the various chronic cystic lung diseases can be differentiated on the basis of the pattern and distribution of abnormalities on high-resolution CT.High-resolution CT scans in 92 patients with chronic cystic lung diseases (18 with pulmonary Langerhans cell histiocytosis, 18 with pulmonary lymphangioleiomyomatosis, 17 with usual interstitial pneumonia, 16 with lymphocytic interstitial pneumonia, 15 with emphysema, and eight with desquamative interstitial pneumonia or respiratory bronchiolitis interstitial lung disease) were retrospectively assessed by two independent observers without knowledge of the clinical or pathologic data. The observers recorded the abnormalities, the most likely diagnosis, and the degree of confidence in that diagnosis.The two observers made a correct first-choice diagnosis in 148 (80%) of 184 interpretations. The correct diagnosis was made in 100% of interpretations of usual interstitial pneumonia, 81% of desquamative interstitial pneumonia or respiratory bronchiolitis interstitial lung disease, 81% of lymphocytic interstitial pneumonia, 77% of emphysema, 72% of lymphangioleiomyomatosis, and 72% of Langerhans cell histiocytosis. The two observers made a diagnosis with a high degree of confidence in 105 (57%) of 184 interpretations. The confident diagnosis was correct in 98 (93%) of 105 interpretations.Although various chronic cystic lung diseases often have a characteristic appearance that allows their distinction on high-resolution CT, considerable overlap exists among the CT findings. Therefore, lung biopsy is often required for a definitive diagnosis.