Evaluation of Dynamic Contrast-Enhanced MRI Measures of Lung Congestion and Endothelial Permeability in Heart...

Methods for accurate quantification of lung fluid in heart failure (HF) are needed. Dynamic contrast-enhanced (DCE)-MRI may be an appropriate modality.

DCE-MRI evaluation of fraction of fluid volume in the interstitial lung space (v_e ) and vascular permeability (K^trans ).

Prospective, single-center method validation.

Seventeen evaluable healthy volunteers (HVs), 12 participants with HF, and 3 with acute decompensated HF (ADHF).

T₁ mapping (spoiled gradient echo variable flip angle acquisition) followed by dynamic series (three-dimensional spoiled gradient-recalled echo acquisitions [constant echo time, repetition time, and flip angle at 1.5 T]).

Three whole-chest scans were acquired: baseline (Session 1), 1-week later (Session 2), following exercise (Session 3). Extended Tofts model quantified v_e and K^trans (voxel-wise basis); total lung median measures were extracted and fitted via repeat measure analysis of variance (ANOVA) model. Patient tolerability of the scanning protocol was assessed.

This was constructed as an experimental medicine study.

K^trans and v_e at baseline (HV vs. HF), change in K^trans and v_e following exercise, and following lung congestion resolution (ADHF). K^trans and v_e were fitted separately using ANOVA. Secondary endpoint: repeatability, that is, within-participant variability in v_e and K^trans between sessions (coefficient of variation estimated via mixed effects model).

There was no significant difference in mean K^trans between HF and HV (P ≤ 0.17): 0.2216 minutes^-1 and 0.2353 minutes^-1 (Session 1), 0.2044 minutes^-1 and 0.2567 minutes^-1 (Session 2), 0.1841 minutes^-1 and 0.2108 minutes^-1 (Session 3), respectively. v_e was greater in the HF group (all scans, P ≤ 0.02). Results were repeatable between Sessions 1 and 2; mean values for HF and HV were 0.4946 and 0.3346 (Session 1), 0.4353 and 0.3205 (Session 2), respectively. There was minimal difference in K^trans or v_e between scans for participants with ADHF (small population precluded significance testing). Scanning was well tolerated.

While no differences were detected in K^trans , v_e was greater in chronic HF patients vs. HV, augmented beyond plasma and intracellular volume. DCE-MRI is a valuable diagnostic and physiologic tool to evaluate changes in fluid volume in the interstitial lung space associated with symptomatic HF.

2 TECHNICAL EFFICACY STAGE: 2.