Lung morphology assessment of cystic fibrosis using MRI with ultra-short echo time at submillimeter spatial resolution

Objectives We hypothesized that non-contrast-enhanced PETRA (pointwise encoding time reduction with radial acquisition) MR (magnetic resonance) sequencing could be an alternative to unenhanced computed tomography (CT) in assessing cystic fibrosis (CF) lung structural alterations, as well as compared agreements and concordances with those of conventional T1-weighted and T2-weighted sequences. Material and methods Thirty consecutive CF patients completed both CT and MRI the same day. No contrast injection was used. Agreement in identifying structural alterations was evaluated at the segmental level using a kappa test. Intraclass correlation coefficients (ICC) and Bland-Altman analysis were used to assess concordances and reproducibility in Helbich-Bhalla disease severity scoring. Results Agreement between PETRA and CT was higher than that of T1-or T2-weighted sequences, notably in assessing the segmental presence of bronchiectasis (Kappa = 0.83; 0.51; 0.49, respectively). The concordance in Helbich-Bhalla scores was very good using PETRA (ICC = 0.97), independently from its magnitude (mean difference (MD) =-0.3 [-2.8; 2.2]), whereas scoring was underestimated using both conventional T1 and T2 sequences (MD =-3.6 [-7.4; 0.1]) and MD =-4.6 [-8.2;-1.0], respectively). Intra-and interobserver reproducibility were very good for all imaging modalities (ICC = 0.86-0.98). Conclusion PETRA showed higher agreement in describing CF lung morphological changes than that of conventional sequences , whereas the Helbich-Bhalla scoring matched closely with that of CT