Quantitative CT imaging with vascular analysis in combined pulmonary fibrosis and emphysema

<bold>Introduction:</bold> Combined pulmonary fibrosis and emphysema (CPFE) is a chronic progressive disease with poor survival. Studies looking at mortality have had mixed results when compared to emphysema or fibrosis alone, but the extent of combined emphysema and fibrosis, along with DLCO reduction have shown to be associated with mortality. <bold>Aims and objectives:</bold> We aim to quantitatively assess findings on CT chest imaging with a focus on vascular findings to determine an association with mortality. <bold>Methods:</bold> A retrospective cohort study was performed from 1/1/2013 to 12/31/2018, to give 5 years of followup, with two independent chest radiologists identifying patients that had combined emphysema and an usual interstitial pneumonia fibrotic pattern. A quantitative CT image software was used, giving the percent emphysema, reticulation, honeycombing, ground-glass, and vessel volume (Zavaletta et al. Acad Radiol 2007; 14(7):772-87). A multivariate cox regression model was used for analysis. <bold>Results:</bold> 42 patients were identified with a mean age of 74.4 years and the majority being male (78.6%) and white (97.6%). The mean pack years for smoking was 54.4. A total of 19 (45.2%) patients and pulmonary hypertension on echocardiogram and 22 (52.4%) patients died. There was no difference between the percentage of emphysema, honeycombing, ground-glass, and reticulation between patients who died and those who did not. There was decreased vessel volume in patients who died (median: 2.58% [IQR:1.87-3.30] vs 4.48% [IQR:3.45-5.51]; p<0.01). The survival model showed that only the vessel volume was significant (p<0.01). <bold>Conclusions:</bold> Decreased vessel volume in the lungs of CPFE patients was associated with increased mortality.