Reproducibility of functional lung parameters derived from free-breathing non-contrast-enhanced 2D ultrashort echo-time.

Background

Imaging the lung parenchyma with magnetic resonance imaging (MRI) is challenging due to cardiac and respiratory motion, the low proton density and short T

Methods

In this study, a 2D UTE technique was combined with tiny golden angle (tyGA) ordering. Data were acquired either during breath-holds (BH) or continuously during free-breathing (FB) at a field strength of 3T. Retrospective self-gating (image- and k-space-based) was used to reconstruct respiratory and cardiac multistage images from the FB acquisitions. The reproducibility of functional lung parameters derived from BH and FB acquisitions was assessed for three independent examinations (M1-3). M1 and M2 were acquired within 2 h, whereas M3 was acquired at least 14 d after M1/2. Different respiratory and cardiac phases were reconstructed for three coronal slices. Quantitative analysis including proton fraction (

Results

All scans could be performed successfully in all volunteers. Intraclass correlation coefficients (ICC) of inter-measurement and inter-observer variability, and Bland-Altman analysis showed good to very good reproducibility. Larger breathing amplitudes were observed in the BH acquisitions, which also showed lower reproducibility when compared with the FB acquisitions. For the FB approach, the ICC ranged between 0.70 and 0.98 for all measurements, and ranged between 0.86 and 0.97 for the two observers. No bias or significant differences were observed between the three measurements or the two observers in healthy volunteers.

Conclusions

The study proves the feasibility of FB 2D tyGA UTE for lung imaging. Functional parameters derived from FB acquisitions are reproducible in healthy volunteers, allowing for further investigation of this technique in patients with various underlying diseases.

Informations de copyright

2022 Quantitative Imaging in Medicine and Surgery. All rights reserved.

Déclaration de conflit d'intérêts

Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://qims.amegroups.com/article/view/10.21037/qims-22-92/coif). BY reports that she was supported by the China Scholarship Council (CSC). VR and MB report that this work was partly funded by a research grant of German Research Foundation (No. 465599659, to VR), and Boehringer Ingelheim (to VR and MB). The funding parties were not involved in the study design, manuscript writing, editing, approval, or decision to publish. The other authors have no conflicts of interest to declare.