Serial automated quantitative CT analysis in idiopathic pulmonary fibrosis: functional correlations and comparison with changes in visual CT scores
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To determine whether computer-based CT quantitation of change can improve on visual change quantification of parenchymal features in IPF.
Sixty-six IPF patients with serial CT imaging (6-24 months apart) had CT features scored visually and with a computer software tool: ground glass opacity, reticulation and honeycombing (all three variables summed as interstitial lung disease extent [ILD]) and emphysema. Pulmonary vessel volume (PVV) was estimated by computer only. Relationships between changes in CT features and forced vital capacity (FVC) were examined using univariate and multivariate linear regression analyses.
On univariate analysis, changes in computer variables demonstrated stronger linkages to FVC change than changes in visual scores (CALIPER ILD:R2=0.53, p<0.0001; Visual ILD:R2=0.16, p=0.001). PVV increase correlated most strongly with relative FVC change (R2=0.57). When PVV constituents (vessel size and location) were examined, an increase in middle zone vessels linked most strongly to FVC decline (R2=0.57) and was independent of baseline disease severity (characterised by CT fibrosis extent, FVC, or DLco).
An increase in PVV, specifically an increase in middle zone lung vessels, was the strongest CT determinant of FVC decline in IPF and was independent of baseline disease severity.
• Computer analysis improves on visual CT scoring in evaluating deterioration on CT
• Increasing pulmonary vessel volume is the strongest CT predictor of functional deterioration
• Increasing pulmonary vessel volume predicts functional decline independent of baseline disease severity
KeywordsMultidetector-row computed tomography Pulmonary fibrosis, idiopathic Computer-assisted image Analysis Idiopathic interstitial pneumonias Blood vessels
The authors state that this work has not received any funding.
Compliance with ethical standards
The scientific guarantor of this publication is Prof Athol Wells.
Conflict of interest
The authors of this manuscript declare relationships with the following companies:
Dr. Jacob reports personal fees from Boehringer Ingelheim, outside the submitted work.
BJB, RK, SR report a grant from the Royal Brompton Hospital during the conduct of the study; another from Imbio, LLC, was outside the submitted work; and all have a patent: SYSTEMS AND METHODS FOR ANALYZING IN VIVO TISSUE VOLUMES USING MEDICAL IMAGING DATA licensed to Imbio, LLC.
Dr. Wells reports personal fees from Intermune, personal fees from Boehringer Ingelheim, personal fees from Gilead, personal fees from MSD, personal fees from Roche, personal fees from Bayer, personal fees from Chiesi, outside the submitted work.
Dr. Walsh reports personal fees from Boehringer Ingelheim, personal fees from Roche, outside the submitted work.
The manuscript was supported by the National Institute of Health Research Respiratory Disease Biomedical Research Unit at the Royal Brompton and Harefield NHS Foundation Trust and Imperial College London.
Statistics and biometry
One of the authors has significant statistical expertise.
Written informed consent was waived by the Institutional Review Board.
Institutional Review Board approval was obtained.
Study subjects or cohorts overlap
Some study subjects or cohorts have been previously reported in two studies: a structure function study and a mortality study. However these examined CT and functional variables at baseline and did not look at longitudinal change.
• performed at one institution
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