Katharina Marten MD, Presenter: Nothing to Disclose

David Milne MD, Abstract Co-Author: Nothing to Disclose

Andrew G. Nicholson MD, Abstract Co-Author: Nothing to Disclose

Rachel Tenant, Abstract Co-Author: Nothing to Disclose

Athol U Wells, Abstract Co-Author: Nothing to Disclose

David Matthew Hansell MD, Abstract Co-Author: Nothing to Disclose

To investigate whether there is clustering between CT features of smoking-related NSIP (srNSIP) and emphysema, and secondly, whether there are discriminatory CT features between srNSIP and idiopathic NSIP (iNSIP).

30 patients were classified by histopathologic criteria as fibrotic srNSIP or iNSIP, and according to smoking history as current, ex-, or never-smokers. Presence and extent of pulmonary emphysema in srNSIP patients were compared with a matched population of 133 asymptomatic smoking controls. Two blinded independent observers scored 5 CT sections of all NSIP patients to the nearest 5% for the extent of emphysema, ground-glass opacification with or without traction bronchiectasis (GGO+/-tr), honeycombing, crazy-paving, reticulation, nodules, lobular air-trapping, Langerhans’ cell histiocytosis pattern, and consolidation. Patterns occurring in < 5 patients were excluded from statistical analysis. The observers assigned a diagnosis (srNSIP or iNSIP) based on the overall CT appearances .

7 patients had srNSIP, and 23 patients had iNSIP on histopathologic examination. 10 patients were current, 10 were ex-, and 10 were never-smokers. Prevalence of emphysema was significantly higher in srNSIP patients (7/7) than in smoking controls (38/133), p<0.0005, and the extent of emphysema was significantly higher in srNSIP patients (median 18%, range 3.2-48%) than in smoking controls (median 0%, range 0-71.9%), p=0.0001. Extent of emphysema was significantly greater in srNSIP patients vs. iNSIP patients (p=0.02), and differed significantly in current, ex-, and never-smokers (p=0.01). Total extent of disease, GGO+/-tr, and reticulation did not differ significantly between the histopathologic and the smoking subgroups, respectively. Crazy-paving was present in 10/23 iNSIP patients and absent in all srNSIP cases (p=0.03), and was observed in 0/10 current, 3/10 ex-, and 7/10 never-smokers (p=0.004). All srNSIP patients, and all current and never-smokers were correctly identified using CT (p=0.003-0.012).

There is definite clustering between emphysema and NSIP in smokers. Crazy-paving appears to be a discriminatory CT feature between srNSIP and iNSIP patients.

Marten, K, Milne, D, Nicholson, A, Tenant, R, Wells, A, Hansell, D, Smoking-related Non-specific Interstitial Pneumonia: Clustering with Pulmonary Emphysema and CT-based Differentiation from Idiopathic Disease.  Radiological Society of North America 2005 Scientific Assembly and Annual Meeting, November 27 - December 2, 2005 ,Chicago IL. http://archive.rsna.org/2005/4412481.html