Purpose RAS has recently been described as a form of CLAD with a decreased TLC and CT scan upper lobe opacities. This pattern seems to have recently appeared. Methods and Materials From 15/07/88 to 31/12/11, 181 adults (>16 years; 108 M/73F; 75 double lung, 75 single lung and 31 heart lung ) patients were transplanted. Initial diagnosis included: cystic fibrosis and bronchiectasis in 30%; emphysema in 24%; primary pulmonary hypertension in 18%. interstitial lung diseases in 16%. Before 15/07/01, 80 were transplanted (pre 01) and 101 after that date. (post 01). Until 2009 we used to routinely repeat CT scan as often as twice yearly in transplanted patients allowing us to describe early features of BOS. We reanalysed the last chest CT scan of each of the 181 patients for the presence in the upper zones of interstitial reticular shadows, interstitial opacities, ground glass opacities and architectural distorsion: traction bronchiectasis, honeycombing. Results Only 10 of them presented with such abnormalities: 3/80 in the pre 2001 period and 7/101 in the post 01. In marked contrast 27 patients of the pre 01 period and 19 of the post 01 period developped BOS≥1. Of note findings of RAS were not observed on CT scan performed before 2004 except on one occurrence in 1993. Among patients with abnormal CT scan, 5 had a double lung and 5 a single lung transplant; only one had no abnormal PFTs. Initial diagnosis included: cystic fibrosis in 1; emphysema in 2; primary pulmonary hypertension in 2 and interstitial lung diseases in 4 suggesting an overrepresentation of interstitial lung disease as a primary diagnosis for transplantation. Conclusions CT scan findings consistent with RAS is rare (10/180 i.e.5.55%) and has seldom been observed before 2004; interstitial lung disease as a cause for transplantation might favor it.