Collette Louise English BMBS, FRCR, Presenter: Nothing to Disclose

Andrew Churg, Abstract Co-Author: Nothing to Disclose

Mark Teh MBBS, Abstract Co-Author: Nothing to Disclose

John R. Mayo MD, Abstract Co-Author: Speaker, Siemens AG

Stephen Lam, Abstract Co-Author: Nothing to Disclose

Ana-Maria Bilawich MD, Abstract Co-Author: Nothing to Disclose

A CT pattern of patchy areas of reticular changes around areas of emphysema seen in smokers without evidence of intersititial lung disease has been described. Pathologically it has been labelled smoking-related interstitial fibrosis (SRIF), respiratory bronchiolitis-intersititial lung disease with fibrosis or airspace enlargement with fibrosis. Recently, in order to avoid confusion with other interstial lung disease, it is suggested that this pattern be called respiratory bronchiolitis with fibrosis (RBF). The frequency of this lesion and whether it is stable or progresses to more severe disease is not known. The aim of our study was to estimate the prevalance of RBF in a cohort of smokers and where possible, to demonstrate the stability of this pattern over an interval period of time.

This was a retrospective study of a sample of 200 consecutive participants who were current or former smokers between 50-75 years of age without a history of lung cancer. CTs were reviewed by two radiologists with specific training in chest radiology. Presence of RBF and characteristics including lobar predominance were noted. Subsequent CTs were reviewed where available and interval change or stability was documented.

13 out of the 200 patients (7%) were noted to have evidence of reticular change around areas of emphysema. 100% of the patients had changes in the upper lobes and 2 patients (15%) had additional changes in the lower lobes. 46% of patients showed no progression of changes. The remaining 54% had only very mild progression with time intervals ranging from 2 to 6 years between CT scans. The progressive changes typically appeared to be increasing severity of emphysema rather than increasing evidence of fibrosis.

In this study we demonstrate a prevalance of 7% of RBF in a cohort of smokers and its lack of significant interval progression. RBF probably accounts for a significant number of the cases identified as interstitial lung disease in cigarette smokers on large HRCT surveys. It is important to recognise this CT pattern as a benign entity and not as coexisiting diffuse intersitial fibrosis.

It is important to recognise this CT pattern as a benign entity and not as coexisiting diffuse intersitial fibrosis.

English, C, Churg, A, Teh, M, Mayo, J, Lam, S, Bilawich, A, Respiratory Bronchiolitis with Fibrosis: Study of the Prevalence, Radiological features and Progression.  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14045502.html