Quantitative high-resolution computed tomography fibrosis score: performance characteristics in idiopathic pulmonary fibrosis

Abstract

We evaluated performance characteristics and estimated the minimal clinically important difference (MCID) of data-driven texture analysis (DTA), a high-resolution computed tomography (HRCT)-derived measurement of lung fibrosis, in subjects with idiopathic pulmonary fibrosis (IPF).The study population included 141 subjects with IPF from two interventional clinical trials who had both baseline and nominal 54- or 60-week follow-up HRCT. DTA scores were computed and compared with forced vital capacity (FVC), diffusing capacity of the lung for carbon monoxide, distance covered during a 6-min walk test and St George's Respiratory Questionnaire scores to assess the method's reliability, validity and responsiveness. Anchor- and distribution-based methods were used to estimate its MCID.DTA had acceptable reliability in subjects appearing stable according to anchor variables at follow-up. Correlations between the DTA score and other clinical measurements at baseline were moderate to weak and in the hypothesised directions. Acceptable responsiveness was demonstrated by moderate to weak correlations (in the directions hypothesised) between changes in the DTA score and changes in other parameters. Using FVC as an anchor, MCID was estimated to be 3.4%.Quantification of lung fibrosis extent on HRCT using DTA is reliable, valid and responsive, and an increase of ∼3.4% represents a clinically important change.

Conflict of interest statement

Conflict of interest: S.M. Humphries reports service contract for quantitative analysis of RAINIER HRCT scans from Gilead Sciences, during the conduct of the study; personal fees from Boehringer Ingelheim, grants from NHLBI, and service contract from PAREXEL Informatics, outside the submitted work; in addition, S.M. Humphries has a patent “Systems and methods for automatic detection and quantification of pathology using dynamic feature classification” pending to National Jewish Health. Conflict of interest: J.J. Swigris has nothing to disclose. Conflict of interest: K.K. Brown reports multiple lung fibrosis grants from NHLBI, personal fees from AstraZeneca, Bayer, Biogen, Fibrogen, Galecto, MedImmune, Novartis, Aeolus, ProMetic, Patara, Third Pole, aTyr and Boehringer Ingelheim, conversations under CDAs with Genoa, Galapagos and Global Blood Therapeutics, grants and personal fees from Gilead Sciences, and submitted grant from Roche/Genentech, outside the submitted work. Conflict of interest: M. Strand has nothing to disclose. Conflict of interest: Q. Gong has nothing to disclose. Conflict of interest: J.S. Sundy reports being a full-time employee and stockholder in Gilead Sciences, Inc. Conflict of interest: G. Raghu has been a consultant on IPF and fibrotic lung diseases for Boehringer Ingelheim, BMS, Bellerophan, Roche/Genentech and Veracyte, and a consultant on IPF studies for Biogen, Fibrogen, Gilead Sciences, Nitto, Promedior, Patara and Sanofi, outside the submitted work. Conflict of interest: M.I. Schwarz has nothing to disclose. Conflict of interest: K.R. Flaherty reports grants and personal fees from Boehringer Ingelheim and Roche/Genentech, personal fees from Veracyte, Aeolus, Pharmakea, Fibrogen and Sanofi-Genzyme, and grants from Afferent, outside the submitted work. Conflict of interest: R. Sood reports that Gilead Sciences paid for cost of services for running the IPF clinical trial, during the conduct of the study. Conflict of interest: T.G. O'Riordan is a full-time employee and stockholder of Gilead Sciences. Conflict of interest: D.A. Lynch reports grants from NHLBI, personal fees and research support from PAREXEL and Veracyte, personal fees from Boehringer Ingelheim, Genentech/Roche and Acceleron, outside the submitted work; in addition, D.A. Lynch has a patent “Systems and methods for automatic detection and quantification of pathology using dynamic feature classification” pending to National Jewish Health.

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