title: Mass and fat infiltration of intercostal muscles measured by CT histogram analysis and their correlations with COPD severity.
abstract: OBJECTIVE
  Chronic obstructive pulmonary disease (COPD) is characterized by progressive respiratory function impairment and respiratory muscle dysfunction. We hypothesized that the mass and fat infiltration of respiratory muscles correlates with COPD severity and emphysema extent.
  
  
  METHODS
  Ninety-eight male patients with COPD underwent chest computed tomography (CT) and spirometry. The mass and fat infiltrations of intercostal and latissimus muscles were quantified as the cross-sectional area (CSA) and attenuation of these muscles using CT histogram analysis. Intercostal index and latissimus index were defined as intercostal CSAs and latissimus CSAs divided by body mass index. The emphysema extent was measured as the ratio of the emphysematous lung volume to the total lung volume using a density-mask technique. Pearson correlation analyses were performed to evaluate the relationships between these parameters. Multiple regression analysis was performed using forced expiratory volume in 1 second (FEV1) as the dependent parameter and the clinical and CT data as the independent parameters.
  
  
  RESULTS
  FEV1 was significantly correlated with intercostal index (r = 0.57), latissimus index (r = 0.34), intercostal attenuation (r = 0.62), and latissimus attenuation (r = 0.38). Emphysema extent was significantly correlated with intercostal index (r = -0.36) and intercostal attenuation (r = -0.50). Multiple regression analysis showed that FEV1 was predicted by intercostal attenuation (B = 0.40), intercostal CSA (B = 0.23), emphysema extent (B = -0.23), and age (B = -0.21, R(2) = 0.64, P < .001).
  
  
  CONCLUSIONS
  A decrease in intercostal mass and an increase in intercostal fat are associated with worsening of COPD severity.
authors.affiliation: Department of Radiology, Gyeongsang National University Hospital, College of Medicine, 90, Chilam-Dong, Jinju City, Gyeongnam-Do, Republic of Korea.
authors.forename: Mi Jung
authors.initials: MJ
authors.lastname: Park
authors.affiliation: Department of Radiology, Gyeongsang National University Hospital, College of Medicine, 90, Chilam-Dong, Jinju City, Gyeongnam-Do, Republic of Korea. Electronic address: pichola@naver.com.
authors.forename: Jae Min
authors.initials: JM
authors.lastname: Cho
authors.affiliation: Department of Radiology, Gyeongsang National University Hospital, College of Medicine, 90, Chilam-Dong, Jinju City, Gyeongnam-Do, Republic of Korea.
authors.forename: Kyung Nyeo
authors.initials: KN
authors.lastname: Jeon
authors.affiliation: Department of Radiology, Gyeongsang National University Hospital, College of Medicine, 90, Chilam-Dong, Jinju City, Gyeongnam-Do, Republic of Korea.
authors.forename: Kyung Soo
authors.initials: KS
authors.lastname: Bae
authors.affiliation: Department of Pulmonology, Gyeongsang National University Hospital, College of Medicine, Jinju City, Gyeongnam-Do, Republic of Korea.
authors.forename: Ho Cheol
authors.initials: HC
authors.lastname: Kim
authors.affiliation: Department of Radiology, Gyeongsang National University Hospital, College of Medicine, 90, Chilam-Dong, Jinju City, Gyeongnam-Do, Republic of Korea.
authors.forename: Dae Seob
authors.initials: DS
authors.lastname: Choi
authors.affiliation: Department of Radiology, Gyeongsang National University Hospital, College of Medicine, 90, Chilam-Dong, Jinju City, Gyeongnam-Do, Republic of Korea.
authors.forename: Jae Boem
authors.initials: JB
authors.lastname: Na
authors.affiliation: Department of Radiology, Gyeongsang National University Hospital, College of Medicine, 90, Chilam-Dong, Jinju City, Gyeongnam-Do, Republic of Korea.
authors.forename: Ho Cheol
authors.initials: HC
authors.lastname: Choi
authors.affiliation: Department of Radiology, Gyeongsang National University Hospital, College of Medicine, 90, Chilam-Dong, Jinju City, Gyeongnam-Do, Republic of Korea.
authors.forename: Hye Young
authors.initials: HY
authors.lastname: Choi
authors.affiliation: Department of Radiology, Gyeongsang National University Hospital, College of Medicine, 90, Chilam-Dong, Jinju City, Gyeongnam-Do, Republic of Korea.
authors.forename: Ji Eun
authors.initials: JE
authors.lastname: Kim
authors.affiliation: Department of Radiology, Gyeongsang National University Hospital, College of Medicine, 90, Chilam-Dong, Jinju City, Gyeongnam-Do, Republic of Korea.
authors.forename: Hwa Seon
authors.initials: HS
authors.lastname: Shin
mesh_terms: D000273:Adipose Tissue / Q000000981:diagnostic imaging* / Q000473:pathology; D000368:Aged; D006801:Humans; D007366:Intercostal Muscles / Q000000981:diagnostic imaging* / Q000473:pathology*; D008297:Male; D009929:Organ Size; D029424:Pulmonary Disease, Chronic Obstructive / Q000000981:diagnostic imaging* / Q000473:pathology*; D012720:Severity of Illness Index; D013147:Spirometry / Q000379:methods / Q000706:statistics & numerical data; D014057:Tomography, X-Ray Computed / Q000379:methods*
keywords: Respiratory muscles; chronic obstructive pulmonary disease; computed tomography; intercostal muscles; pulmonary emphysema