title: Bronchiolitis obliterans after allogenic bone marrow transplantation: HRCT findings.
abstract: OBJECTIVE
  To evaluate the high resolution computed tomography (HRCT) findings of bronchiolitis obliterans (BO) after bone marrow transplantation (BMT).
  
  
  METHODS
  During the past three years, 11 patients were diagnosed as having BO after BMT when they developed irreversible air flow obstruction, with an FEV(1) value of less than 80% of the baseline value, without any clinical evidence of infection. All 11 patients underwent HRCT, of whom eight also underwent follow-up HRCT. The HRCT images were assessed retrospectively for the presence of decreased lung attenuation, segmental or subsegmental bronchial dilatation, diminution of peripheral vascularity, centrilobular nodules, and branching linear structure on the inspiratory images. The lobar distribution of the decreased lung attenuation and bronchial dilatation was also examined. The presence of air trapping was investigated on the expiratory images. The interval changes of the HRCT findings were evaluated in those patients who had followup images.
  
  
  RESULTS
  Abnormal HRCT findings were present in all cases; the most common abnormalities were decreased lung attenuation (n=11), subsegmental bronchial dilatation (n=6), diminution of peripheral vascularity (n=6), centrilobular nodules or branching linear structure (n=3), and segmental bronchial dilatation (n=3). Expiratory air trapping was noted in all patients. The decreased lung attenuation and bronchial dilatations were more frequent or extensive in the lower lobes. Interval changes were found in all patients with follow-up HRCT: increased extent of decreased lung attenuation (n=7); newly developed or progressed bronchial dilatation (n=4); and increased lung volume (n=3).
  
  
  CONCLUSIONS
  HRCT scans are abnormal in patients with BO, with the most commonly observed finding being areas of decreased lung attenuation. While the HRCT findings are not specific, it is believed that their common features can assist in the diagnosis of BO in BMT recipients.
authors.affiliation: Department of Radiology, St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea. jijung@catholic.ac.kr
authors.forename: Jung Im
authors.initials: JI
authors.lastname: Jung
authors.forename: Won Sang
authors.initials: WS
authors.lastname: Jung
authors.forename: Seong Tai
authors.initials: ST
authors.lastname: Hahn
authors.forename: Chang Ki
authors.initials: CK
authors.lastname: Min
authors.forename: Chun Choo
authors.initials: CC
authors.lastname: Kim
authors.forename: Seog Hee
authors.initials: SH
authors.lastname: Park
mesh_terms: D000328:Adult; D016026:Bone Marrow Transplantation / Q000009:adverse effects*; D001989:Bronchiolitis Obliterans / Q000175:diagnosis / Q000000981:diagnostic imaging* / Q000209:etiology*; D001995:Bronchography; D005260:Female; D006801:Humans; D008168:Lung / Q000000981:diagnostic imaging; D008297:Male; D014057:Tomography, X-Ray Computed; D014184:Transplantation, Homologous