Free-breathing 3D phase-resolved functional lung MRI vs breath-hold hyperpolarized ¹²⁹Xe ventilation MRI in patients with chronic obstructive pulmonary disease and healthy volunteers

Objectives

3D phase-resolved functional lung (PREFUL) MRI offers evaluation of pulmonary ventilation without inhalation of contrast agent. This study seeks to compare ventilation maps obtained from 3D PREFUL MRI with a direct ventilation measurement derived from ¹²⁹Xe MRI in both patients with chronic obstructive pulmonary disease (COPD) and healthy volunteers.

Methods

Thirty-one patients with COPD and 12 healthy controls underwent free-breathing 3D PREFUL MRI and breath-hold ¹²⁹Xe MRI at 1.5 T. For both MRI techniques, ventilation defect (VD) maps were determined and respective ventilation defect percentage (VDP) values were computed. All parameters of both techniques were compared by Spearman correlation coefficient (r) and the differences between VDP values were quantified by Bland–Altman analysis and tested for significance using Wilcoxon signed-rank test. In a regional comparison of VD maps, spatial overlap and Sørensen–Dice coefficients of healthy and defect areas were computed.

Results

On a global level, all 3D PREFUL VDP values correlated significantly to VDP measure derived by ¹²⁹Xe ventilation imaging (all r > 0.65; all p < 0.0001). ¹²⁹Xe VDP was significantly greater than 3D PREFUL derived VDP_RVent (mean bias = 10.5%, p < 0.001) and VDP_FVL-CM (mean bias = 11.3%, p < 0.0001) but not for VDP_Combined (mean bias = 1.7%, p = 0.70). The total regional agreement of ¹²⁹Xe and 3D PREFUL VD maps ranged between 60% and 63%.

Conclusions

Free-breathing 3D PREFUL MRI showed a strong correlation with breath-hold hyperpolarized ¹²⁹Xe MRI regarding the VDP values and modest differences in the detection of VDs on a regional level.

Clinical relevance statement

3D PREFUL MRI correlated with ¹²⁹Xe MRI, unveiling regional differences in COPD defect identification. This proposes 3D PREFUL MRI as a ventilation mapping surrogate, eliminating the need for extra hardware or inhaled gases.

Key Points

Current non-invasive evaluation techniques for lung diseases have drawbacks; ¹²⁹Xe MRI is limited by cost and availability.

3D PREFUL MRI correlated with ¹²⁹Xe MRI, with regional differences in identifying COPD defects.

3D PREFUL MRI can provide ventilation mapping without the need for additional hardware or inhaled gases.