新生児中等症から重症の気管支肺異形成症における3D超短 echo 時間MRIを用いた構造的および機能的肺評価
Samal Munidasa1, Nara S Higano1, Matthew Willmering1,2
1Pulmonary Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA.
Background:
2D multi-slice MRI techniques for evaluating regional ventilation in neonatal lung diseases, including bronchopulmonary dysplasia (BPD), have limited through-plane resolution, potentially missing heterogeneous lung abnormalities. 3D ultra-short echo time (UTE) MRI phase-resolved functional lung (PREFUL) improves spatial resolution but has not been used to evaluate infants with BPD.
Purpose:
To demonstrate the feasibility of 3D UTE MRI for structural and functional assessment in infants with BPD.
Study Type:
Retrospective.
Population:
A total of 28 infants with BPD (female: male = 8:20; 14 required invasive ventilation at MRI, 14 required non-invasive ventilation).
Field Strength/Sequence:
Free-breathing, respiratory bellows-gated (acquired 1.19-1.25 mm3 isotropic) 3D gradient echo UTE MRI on a 1.5 T scanner.
Assessment:
Images were retrospectively reconstructed into 24 respiratory phases with motion-resolved reconstruction using compressed sensing. Regional ventilation (RVent), flow-volume loop cross correlation metric (FVL-CM), and corresponding ventilation defect maps (VDPRVent, VDPFVL-CM, and the combination, VDPcombined) were derived using the 3D PREFUL method. Structural lung abnormalities were assessed by two readers using a modified Ochiai scoring system, and parenchyma was defined as normal intensity, hypointense, or hyperintense.
Statistical Tests:
The Mann-Whitney U Test, Spearman's correlation, and the Kruskal-Wallis test with Dunn's multiple-comparisons tests were used. Statistical significance was defined as p < 0.05.
Results:
In the mechanically ventilated infants VDPFVL-CM (median [IQR] = 45.8 [28.5-55.9]%) and VDPcombined (57.2% [35.2-69.3]%) were significantly higher as compared to non-ventilated patients (VDPFVL-CM = 22.8% [17.2-34.7]% and VDPcombined = 30.7 [25.1-43.9]%). All PREFUL MRI VDP measures significantly correlated with total lung score (all ρ ≥ 0.45). RVent was significantly lower in hyperintense regions (0.06 [0.04-0.08] mL/mL) compared to normal intensity regions (0.09 [0.07-0.13] mL/mL), whereas FVL-CM was significantly decreased in hypointense regions (79 [66-87]%) compared to normal (92 [90-95]%) and hyperintense regions (91 [81-96]%).
Data Conclusion:
UTE MRI is feasible for assessing regional functional lung abnormalities in infants with BPD that directly correlate with reader-based assessments of parenchymal disease severity.
Evidence Level:
4.
Technical Efficacy:
Stage 1.
