MRI Assessment of Lung Water Density in Individuals Previously Infected With COVID ‐19: A Cross‐Sectional Study

ABSTRACT Background Lung damage in post‐acute COVID‐19 is a common clinical finding. Lung water density (LWD) imaging using ultrashort echo time (UTE) MRI with proton‐density weighting is sensitive to edema and fibrosis. Purpose To characterize LWD in COVID‐19 survivors, compared with a healthy cohort. Study Type Retrospective cohort. Populations 185 COVID‐19 survivors (63 male; age [median (interquartile range, IQR)]: 51 (25–83) years; 160 (66–363) days from COVID‐19 infection to MRI) and 109 healthy controls (64 male; age: 52 (27–76) years) with no history of COVID‐19 infection. Field Strength/Sequence 2.89T; Yarnball UTE pulse sequence. Assessment Free‐breathing three‐dimensional LWD images were acquired in both cohorts. Clinical demographics (age, sex, body mass index [BMI]), presence of comorbidities (hypertension, dyslipidemia, diabetes, obesity), COVID‐19 hospitalization, pulmonary function, six‐minute walking distance, and plasma biomarkers were recorded. Statistical Tests Student's t ‐tests or Mann–Whitney U tests were used to compare lung water metrics between cohorts. The effect of comorbidities was assessed using Kruskal–Wallis tests followed by pairwise Wilcoxon tests with Bonferroni correction. Categorical variables were compared using chi‐squared tests. p  < 0.05 was considered significant. Results LWD (median (IQR)), was significantly greater in the post‐COVID‐19 cohort than in the healthy cohort, 31.3 (6.6)% versus 27.9 (6.5)% in men and 30.3 (7.4)% versus 27.5 (4.9)% in women. 37% of men and 24% of women in the post‐COVID‐19 cohort had LWD above the healthy cohort 95% confidence limit. Participants with elevated LWD had significantly higher BMI (kg/m 2 ) (32 (5) versus 26 (4) in men, 33 (9) versus 26 (7) in women), incidence of comorbidities (78% vs. 50% in men, 72% vs. 38% in women), rates of COVID‐19 hospitalization (52% vs. 23% in men, 38% vs. 18% in women), and elevated CRP (mg/L) (2.2 (3.4) vs. 1.1 (1.4) in men, 1.8 (4.2) vs. 1.2 (2.1) in women). Data Conclusion MRI‐derived LWD is elevated in COVID‐19 survivors and is related to high BMI, COVID‐19 hospitalization, inflammatory plasma biomarkers, and the presence of comorbidities. Evidence Level 2. Technical Efficacy Stage 3.