Early post-transplant ventilation and perfusion assessment using phase-resolved functional lung MRI

Post-transplant functional lung surveillance relies on global ventilatory assessment using spirometry, lacking regional ventilation and perfusion measures. We aimed to assess early post-transplant lung function in clinically stable recipients using phase-resolved functional lung (PREFUL) MRI.

In this prospective, single-center study (March 2022-December 2024), clinically stable bilateral lung transplant recipients and 1:1 age- (± 5 years) sex-matched participants (n = 100) underwent PREFUL MRI and spirometry. Ventilation and perfusion MRI was voxel-based quantified: Regional ventilation (RVent, [mL/mL]), flow-volume loop ventilation (FVL, [au]) and perfusion (Q, [mL/min/100 mL]). Whole lung defect maps (VDP, QDP [%]), V/Q ratios (%) based on RVent, FVL and Q were generated. Median MRI parameters were compared with controls, spirometry and perioperative data (Bonferroni correction P<.0045 considered significant).

84 participants (42 transplant recipients and 42 healthy participants) were evaluated at median 16 days post-transplantation. In lung transplant recipients RVent, FVL and Q did not differ from controls (all P > 0.01). Transplant recipients demonstrated increased RVent VDP (10% vs 3.7%, P < 0.001), VDP_combined (14% vs 7.1%, P < 0.001) and QDP (7.9% vs 2.4%, P < 0.001). In transplant recipients FVL, FVL VDP, QDP and V/Q matched defects correlated with spirometry. QDP was associated with prolonged cold ischemic times of first lung allografts (ρ = 0.43, P = 0.004), V/Q mismatch with cold ischemic times of first and second implanted lungs (ρ = 0.48, P = 0.001; ρ = 0.46, P = 0.002).

Free-breathing phase-resolved functional lung MRI-derived parameters revealed increased regional ventilation and perfusion heterogeneity in stable lung transplant recipients two weeks post-transplantation and correlated with spirometry and prolonged cold ischemic times of allografts.