title: Identifying decreased diaphragmatic mobility and diaphragm thickening in interstitial lung disease: the utility of ultrasound imaging.
abstract: OBJECTIVE
  To investigate the applicability of ultrasound imaging of the diaphragm in interstitial lung disease (ILD).
  
  
  METHODS
  Using ultrasound, we compared ILD patients and healthy volunteers (controls) in terms of diaphragmatic mobility during quiet and deep breathing; diaphragm thickness at functional residual capacity (FRC) and at total lung capacity (TLC); and the thickening fraction (TF, proportional diaphragm thickening from FRC to TLC). We also evaluated correlations between diaphragmatic dysfunction and lung function variables.
  
  
  RESULTS
  Between the ILD patients (n = 40) and the controls (n = 16), mean diaphragmatic mobility was comparable during quiet breathing, although it was significantly lower in the patients during deep breathing (4.5 ± 1.7 cm vs. 7.6 ± 1.4 cm; p < 0.01). The patients showed greater diaphragm thickness at FRC (p = 0.05), although, due to lower diaphragm thickness at TLC, they also showed a lower TF (p < 0.01). The FVC as a percentage of the predicted value (FVC%) correlated with diaphragmatic mobility (r = 0.73; p < 0.01), and an FVC% cut-off value of < 60% presented high sensitivity (92%) and specificity (81%) for indentifying decreased diaphragmatic mobility.
  
  
  CONCLUSIONS
  Using ultrasound, we were able to show that diaphragmatic mobility and the TF were lower in ILD patients than in healthy controls, despite the greater diaphragm thickness at FRC in the former. Diaphragmatic mobility correlated with ILD functional severity, and an FVC% cut-off value of < 60% was found to be highly accurate for indentifying diaphragmatic dysfunction on ultrasound.
authors.affiliation: Faculdade de Medicina, Universidade de São Paulo, São Paulo, SP, Brasil.
authors.forename: Pauliane Vieira
authors.initials: PV
authors.lastname: Santana
authors.affiliation: Faculdade de Medicina, Universidade de São Paulo, São Paulo, SP, Brasil.
authors.forename: Elena
authors.initials: E
authors.lastname: Prina
authors.affiliation: Faculdade de Medicina, Universidade de São Paulo, São Paulo, SP, Brasil.
authors.forename: André Luis Pereira
authors.initials: AL
authors.lastname: Albuquerque
authors.affiliation: Faculdade de Medicina, Universidade de São Paulo, São Paulo, SP, Brasil.
authors.forename: Carlos Roberto Ribeiro
authors.initials: CR
authors.lastname: Carvalho
authors.affiliation: Faculdade de Medicina, Universidade de São Paulo, São Paulo, SP, Brasil.
authors.forename: Pedro
authors.initials: P
authors.lastname: Caruso
mesh_terms: D016022:Case-Control Studies; D003964:Diaphragm / Q000000981:diagnostic imaging* / Q000473:pathology / Q000503:physiopathology*; D005260:Female; D006801:Humans; D016015:Logistic Models; D017563:Lung Diseases, Interstitial / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D012016:Reference Values; D012119:Respiration; D012129:Respiratory Function Tests; D012680:Sensitivity and Specificity; D018709:Statistics, Nonparametric; D014463:Ultrasonography