title: Reversed Halo Sign: Presents in Different Pulmonary Diseases.
abstract: OBJECTIVE
  To observe the incidence of reversed halo sign in different pulmonary diseases and the pathological correspondence of reversed halo sign.
  
  
  METHODS
  Retrospectively studied the high resolution computer tomography scans of all the patients who were admitted in our department with abnormal pulmonary imaging, from 1st of January 2011 to 31st of December 2013, and all the cases with reversed halo sign on the high resolution computer tomography were collected. Clinical data such as pathological findings and confirmed diagnosis of the patients with reversed halo sign on the high resolution computer tomography scan were collected and summarized.
  
  
  RESULTS
  Of 1546 abnormal High resolution computer tomography scans 108 had a reverse halo sign present, including 108 cases were observed with reversed halo sign in the high resolution computer tomography, including 40 cases of pulmonary tuberculosis, 43 cases of cryptogenic organizing pneumonia, 16 cases of lung cancer, 7 cases of sarcoidosis, and 1 case of pulmonary cryptococcosis, 1 case of granulomatosis with polyangiitis. Reversed halo sign had a higher incidence in granulomatous diseases (16.28%) compared with non-granulomatous diseases (9.97%).
  
  
  CONCLUSIONS
  Reversed halo sign is relatively non specific; it can be observed in different lung diseases, and different phases of diseases; reversed halo sign is more commonly found in granulomatous diseases compared with non-granulomatous diseases, and is most commonly observed in pulmonary tuberculosis among the granulomatous diseases, and in cryptogenic organizing pneumonia among the non-granulomatous diseases.
authors.affiliation: Department of Respiratory and Critical Care Medicine, Beijing Chao-Yang Hospital, Capital Medical University, Beijing, 100020, China; Beijing Key Laboratory of Respiratory and Pulmonary Circulation, Beijing Institute of Respiratory Medicine, Beijing, 100020, China.
authors.forename: Xi
authors.initials: X
authors.lastname: Zhan
authors.affiliation: Department of Radiology, Beijing Chao-Yang Hospital, Capital Medical University, Beijing, 100020, China.
authors.forename: Lei
authors.initials: L
authors.lastname: Zhang
authors.affiliation: Department of Respiratory and Critical Care Medicine, Beijing Chao-Yang Hospital, Capital Medical University, Beijing, 100020, China; Beijing Key Laboratory of Respiratory and Pulmonary Circulation, Beijing Institute of Respiratory Medicine, Beijing, 100020, China.
authors.forename: Zheng
authors.initials: Z
authors.lastname: Wang
authors.affiliation: Department of Pathology, Beijing Chao-Yang Hospital, Capital Medical University, Beijing, 100020, China.
authors.forename: Mulan
authors.initials: M
authors.lastname: Jin
authors.affiliation: Department of Radiology, Beijing Chao-Yang Hospital, Capital Medical University, Beijing, 100020, China.
authors.forename: Min
authors.initials: M
authors.lastname: Liu
authors.affiliation: Department of Respiratory and Critical Care Medicine, Beijing Chao-Yang Hospital, Capital Medical University, Beijing, 100020, China; Beijing Key Laboratory of Respiratory and Pulmonary Circulation, Beijing Institute of Respiratory Medicine, Beijing, 100020, China.
authors.forename: Zhaohui
authors.initials: Z
authors.lastname: Tong
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D006105:Granulomatous Disease, Chronic / Q000000981:diagnostic imaging / Q000453:epidemiology; D006801:Humans; D015994:Incidence; D008168:Lung / Q000000981:diagnostic imaging; D008171:Lung Diseases / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed