title: Automated computer-based CT stratification as a predictor of outcome in hypersensitivity pneumonitis.
abstract: BACKGROUND
  Hypersensitivity pneumonitis (HP) has a variable clinical course. Modelling of quantitative CALIPER-derived CT data can identify distinct disease phenotypes. Mortality prediction using CALIPER analysis was compared to the interstitial lung disease gender, age, physiology (ILD-GAP) outcome model.
  
  
  METHODS
  CALIPER CT analysis of parenchymal patterns in 98 consecutive HP patients was compared to visual CT scoring by two radiologists. Functional indices including forced vital capacity (FVC) and diffusion capacity for carbon monoxide (DLco) in univariate and multivariate Cox mortality models. Automated stratification of CALIPER scores was evaluated against outcome models.
  
  
  RESULTS
  Univariate predictors of mortality included visual and CALIPER CT fibrotic patterns, and all functional indices. Multivariate analyses identified only two independent predictors of mortality: CALIPER reticular pattern (p = 0.001) and DLco (p < 0.0001). Automated stratification distinguished three distinct HP groups (log-rank test p < 0.0001). Substitution of automated stratified groups for FVC and DLco in the ILD-GAP model demonstrated no loss of model strength (C-Index = 0.73 for both models). Model strength improved when automated stratified groups were combined with the ILD-GAP model (C-Index = 0.77).
  
  
  CONCLUSIONS
  CALIPER-derived variables are the strongest CT predictors of mortality in HP. Automated CT stratification is equivalent to functional indices in the ILD-GAP model for predicting outcome in HP.
  
  
  CONCLUSIONS
  • Computer CT analysis better predicts mortality than visual CT analysis in HP. • Quantitative CT analysis is equivalent to functional indices for prognostication in HP. • Prognostication using the ILD-GAP model improves when combined with quantitative CT analysis.
authors.affiliation: Department of Radiology, Royal Brompton Hospital, Royal Brompton and Harefield NHS Foundation Trust, London, UK. akelajacob@gmail.com.
authors.forename: Joseph
authors.identifier: http://orcid.org/0000-0002-8054-2293
authors.initials: J
authors.lastname: Jacob
authors.affiliation: Division of Radiology, Mayo Clinic Rochester, Rochester, MN, USA.
authors.forename: B J
authors.initials: BJ
authors.lastname: Bartholmai
authors.affiliation: Biomedical Imaging Resource, Mayo Clinic Rochester, Rochester, MN, USA.
authors.forename: S
authors.initials: S
authors.lastname: Rajagopalan
authors.affiliation: Biomedical Imaging Resource, Mayo Clinic Rochester, Rochester, MN, USA.
authors.forename: R
authors.initials: R
authors.lastname: Karwoski
authors.affiliation: Department of Radiology, Royal Brompton Hospital, Royal Brompton and Harefield NHS Foundation Trust, London, UK.
authors.forename: S M
authors.initials: SM
authors.lastname: Mak
authors.affiliation: Department of Radiology, Royal Brompton Hospital, Royal Brompton and Harefield NHS Foundation Trust, London, UK.
authors.forename: W
authors.initials: W
authors.lastname: Mok
authors.affiliation: Universita degli Studi di Modena e Reggio Emilia, Modena and Reggio Emilia, Modena, Emilia-Romagna, Italy.
authors.forename: G
authors.initials: G
authors.lastname: Della Casa
authors.affiliation: Toho University Omori Medical Centre, Tokyo, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Sugino
authors.affiliation: Kings College Hospital, London, UK.
authors.forename: S L F
authors.initials: SLF
authors.lastname: Walsh
authors.affiliation: Interstitial Lung Disease Unit, Royal Brompton Hospital, Royal Brompton and Harefield NHS Foundation Trust, London, UK.
authors.forename: A U
authors.initials: AU
authors.lastname: Wells
authors.affiliation: Department of Radiology, Royal Brompton Hospital, Royal Brompton and Harefield NHS Foundation Trust, London, UK.
authors.forename: D M
authors.initials: DM
authors.lastname: Hansell
mesh_terms: D000368:Aged; D000542:Alveolitis, Extrinsic Allergic / Q000000981:diagnostic imaging* / Q000401:mortality / Q000503:physiopathology; D005260:Female; D006801:Humans; D053208:Kaplan-Meier Estimate; D008131:London / Q000453:epidemiology; D017563:Lung Diseases, Interstitial / Q000000981:diagnostic imaging / Q000401:mortality / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D011379:Prognosis; D011653:Pulmonary Diffusing Capacity / Q000502:physiology; D012129:Respiratory Function Tests; D014057:Tomography, X-Ray Computed / Q000379:methods; D014797:Vital Capacity / Q000502:physiology
keywords: Computed tomography; Computer-assisted image analysis; Hypersensitivity pneumonitis; Interstitial lung disease; Staging