Nonspecific Interstitial Pneumonia Associated with Collagen Vascular Disease: Analysis of CT Features to Distinguish the Various Types

Objective The purpose of this study was to analyze the CT findings of interstitial lung diseases that are associated with collagen vascular disease (CVD), with particular attention to nonspecific interstitial pneumonia (NSIP), and to examine whether it is possible to predict the clinical diagnosis of CVDs based on the CT findings alone. Methods CT scans of 49 patients with NSIP associated with CVD ( 15 males, 34 females; mean age, 55 +/- 10 years; age range, 25-76 years) were included in this retrospective study. All patients underwent a surgical biopsy. The clinical diagnosis comprised rheumatoid arthritis (RA) (n=15), systemic sclerosis (SSc) (n=8), polymyositis and dermatomyositis (PM/DM) (n=18), Sjogren's syndrome (SjS) (n=4), and mixed connective tissue disease (MCTD) (n=4). Each CT was reviewed by two independent observers who made a clinical diagnosis based on the CT findings alone. Results The observers made a correct diagnosis for 22 (45%) of the 49 patients. A correct diagnosis was made for: RA in 7 (47%) of 15 patients; SSc in 3 (38%) of 8 patients; PM/DM in 11 (61%) of 18 patients; SjS in 1 (25%) of 4 patients. None of the 4 MCTD cases was diagnosed. Conclusion It is difficult to make a correct clinical diagnosis of the various types of CVDs based solely on CT findings. However, it is probable to make a reasonably accurate clinical diagnosis in cases that show the typical CT findings, especially for PM/DM patients.