title: Centrilobular nodules correlate with air trapping in diffuse panbronchiolitis during erythromycin therapy.
abstract: BACKGROUND
  Low-dose erythromycin therapy improves airflow limitation and airway inflammation in patients with diffuse panbronchiolitis (DPB). However, to our knowledge there has been no study to determine whether physiologic improvement during erythromycin therapy correlates with radiologic findings.
  
  
  OBJECTIVE
  To clarify whether improvement in pulmonary function correlates with specific changes on chest CT.
  
  
  METHODS
  The relationship between five CT findings and five pulmonary function parameters was evaluated before and 3 months after low-dose erythromycin therapy in 24 patients with DPB retrospectively.
  
  
  RESULTS
  After erythromycin therapy, the predicted percentage of vital capacity (%VC; 87.0 +/- 3.07% vs 98.9 +/- 3.39%; p = 0.00006) and 50% of the maximum midexpiratory flow rate of FVC (1.41 +/- 0.26 L/s vs 1.61 +/- 0.27 L/s; p = 0.03) significantly increased, and the residual volume/total lung capacity ratio (RV/TLC%; 44.5 +/- 1.93% vs 40.7 +/- 1.83%; p = 0.0019) significantly decreased, but the FEV(1) to FVC ratio and 25% of the maximum expiratory flow rate of FVC did not. In five CT findings, centrilobular nodules (3.7 +/- 0.4 vs 1.5 +/- 0.3; p = 0.0001), peripheral bronchiolar wall thickness (3.8 +/- 0.3 vs 2.6 +/- 0.4; p = 0.0007), and peripheral bronchiolectasis (2.8 +/- 0.3 vs 2.2 +/- 0.4; p = 0.0058) had significantly improved, whereas low attenuation area and central bronchiectasis had not. There were positive correlations of improved scores of centrilobular nodules with improved %VC (r = 0.58, p = 0.0062) and RV/TLC% (r = 0.64, p = 0.0022).
  
  
  CONCLUSIONS
  Decreased air trapping in DPB correlates with an improvement of centrilobular nodules, which reflects the obstructive lesions of bronchioles during the erythromycin therapy.
authors.affiliation: Third Department of Internal Medicine, Sapporo Medical University, School of Medicine, Sapporo, Japan. gyamada@sapmed.ac.jp
authors.forename: G
authors.initials: G
authors.lastname: Yamada
authors.forename: T
authors.initials: T
authors.lastname: Igarashi
authors.forename: E
authors.initials: E
authors.lastname: Itoh
authors.forename: H
authors.initials: H
authors.lastname: Tanaka
authors.forename: K
authors.initials: K
authors.lastname: Sekine
authors.forename: S
authors.initials: S
authors.lastname: Abe
mesh_terms: D001988:Bronchiolitis / Q000000981:diagnostic imaging* / Q000188:drug therapy / Q000473:pathology / Q000503:physiopathology; D004917:Erythromycin / Q000008:administration & dosage*; D006801:Humans; D008168:Lung / Q000000981:diagnostic imaging* / Q000473:pathology; D008450:Maximal Midexpiratory Flow Rate; D012115:Residual Volume; D015656:Respiratory Mechanics; D014057:Tomography, X-Ray Computed; D014109:Total Lung Capacity; D014797:Vital Capacity
chemical_list: D004917:Erythromycin