CT-Derived Functional Imaging Biomarkers to Predict 10-Year All-Cause Mortality in COPDGene Cohort

Document Type

Conference Proceeding

Publication Date

5-2024

Publication Title

American Journal of Respiratory and Critical Care Medicine

Abstract

Rationale: COPD is one of the leading causes of mortality. CT-derived functional imaging (CTFI) biomarkers offers a unique method of computing ventilation and magnitude pulmonary blood mass changes apparent from maximum inhalation and exhalation non-contrast CT scans. Purpose: To determine the predictive ability of combined lung function (obtained by forced expiratory volume in 1s (FEV1)) and CTFI derived lung function metrics at baseline for all-cause 10-year-mortality in COPD patients. Methods: The CTFI method applies image processing and physical modeling to an Inhale/Exhale CT image pair to generate a CT-ventilation (CTV) and pulmonary blood mass (PBM) image. We performed a longitudinal analysis of 8583 patients from the COPDGene study stratified according to severity of obstruction. For each patient, we estimated mean CT-V and PBM at the voxel level and averaged to lobar and global lung volume. Results: 3550 patients with definite obstruction (FEV1/FVC < 70) were included in the study. The average age of the included population was 63-years with an all-cause mortality of 34.7%. Mortality was higher in GOLD stage IV (70.3%) compared to stage I(14.5%). The global median CTV and median PBM are significantly different across the different GOLD stages, [ CTV: GOLD I: 2.73 L (1.99, 3.46), GOLD-II 2.13 L (1.65, 2.71), GOLD-III 1.76 L (1.32, 2.31), GOLD-IV 1.52 L (1.11, 1.86)] and [ PBM: GOLD I: 95.60 gm/mm3 (61.11, 130.73), GOLD-II 73.80 gm/mm3 (45.90, 110.54), GOLD-III 57.55 gm/ mm3 (32.78, 90.10), GOLD-IV 46.89 gm/mm3 (28.70, 69.54)] respectively. There were significant differences in regional ventilation and blood mass changes across the GOLD stages. A Random Survival Forest using 5-fold cross-validation, adjusted for age, BMI and scanner type showed significant improvement in Area Under the Curve (AUC) for combined FEV1+CTFI compared to FEV1 alone starting from year 2 (AUC 0.72 vs. 0.71) to year 10 (AUC 0.76 vs. 0.73) (Figure 1) A Net Reclassification Index (NRI) adjusted for same covariates further confirm the prediction increment of CTFI (NRI: 0.082, 95% CI: 0.047, 0.141, p<0.00001). Conclusion: CTFI combined with FEV1 obtained at baseline offers substantial additional mortality insight for COPD patients.

Volume

209

Issue

Suppl

First Page

A5119

Comments

International Conference of the American Thoracic Society, May 17-22, 2024, San Diego, CA

DOI

10.1164/ajrccm-conference.2024.209.1_MeetingAbstracts.A5119

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