title: Quantitative CT analysis of small pulmonary vessels in lymphangioleiomyomatosis.
abstract: BACKGROUND
  Lymphangioleiomyomatosis (LAM) is a destructive lung disease that share clinical, physiologic, and radiologic features with chronic obstructive pulmonary disease (COPD). This study aims to identify those features that are unique to LAM by using quantitative CT analysis.
  
  
  METHODS
  We measured total cross-sectional areas of small pulmonary vessels (CSA) less than 5mm(2) and 5-10mm(2) and calculated percentages of those lung areas (%CSA), respectively, in 50 LAM and 42 COPD patients. The extent of cystic destruction (LAA%) and mean parenchymal CT value were also calculated and correlated with pulmonary function.
  
  
  RESULTS
  The diffusing capacity for carbon monoxide/alveolar volume (DL(CO)/VA %predicted) was similar for both groups (LAM, 44.4 ± 19.8% vs. COPD, 45.7 ± 16.0%, p=0.763), but less tissue damage occurred in LAM than COPD (LAA% 21.7 ± 16.3% vs. 29.3 ± 17.0; p<0.05). Pulmonary function correlated negatively with LAA% (p<0.001) in both groups, yet the correlation with %CSA was significant only in COPD (p<0.001). When the same analysis was conducted in two groups with equal levels of LAA% and DL(CO)/VA %predicted, %CSA and mean parenchymal CT value were still greater for LAM than COPD (p<0.05).
  
  
  CONCLUSIONS
  Quantitative CT analysis revealing a correlation between cystic destruction and CSA in COPD but not LAM indicates that this approach successfully reflects different mechanisms governing the two pathologic courses. Such determinations of small pulmonary vessel density may serve to differentiate LAM from COPD even in patients with severe lung destruction.
authors.affiliation: Department of Internal Medicine, Division of Respiratory Medicine, Juntendo University Graduate School of Medicine, 2-1-1 Hongo, Bunkyo-Ku, Tokyo 113-8421, Japan. kando@juntendo.ac.jp
authors.forename: Katsutoshi
authors.initials: K
authors.lastname: Ando
authors.forename: Kazunori
authors.initials: K
authors.lastname: Tobino
authors.forename: Masatoshi
authors.initials: M
authors.lastname: Kurihara
authors.forename: Hideyuki
authors.initials: H
authors.lastname: Kataoka
authors.forename: Tokuhide
authors.initials: T
authors.lastname: Doi
authors.forename: Yoshito
authors.initials: Y
authors.lastname: Hoshika
authors.forename: Kazuhisa
authors.initials: K
authors.lastname: Takahashi
authors.forename: Kuniaki
authors.initials: K
authors.lastname: Seyama
mesh_terms: D000328:Adult; D000368:Aged; D000465:Algorithms; D000792:Angiography / Q000379:methods; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D008175:Lung Neoplasms / Q000000981:diagnostic imaging*; D018192:Lymphangioleiomyomatosis / Q000000981:diagnostic imaging*; D008297:Male; D011651:Pulmonary Artery / Q000000981:diagnostic imaging*; D029424:Pulmonary Disease, Chronic Obstructive / Q000000981:diagnostic imaging*; D011856:Radiographic Image Enhancement / Q000379:methods; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000379:methods*