A 3D stack-of-spirals approach for rapid hyperpolarized Xe-129 ventilation mapping in pediatric cystic fibrosis lung disease

PurposeTo demonstrate the feasibility of a rapid 3D stack-of-spirals (3D-SoS) imaging acquisition for hyperpolarized Xe-129 ventilation mapping in healthy pediatric participants and pediatric cystic fibrosis (CF) participants, in comparison to conventional Cartesian multislice (2D) gradient-recalled echo (GRE) imaging. MethodsThe 2D-GRE and 3D-SoS acquisitions were performed in 13 pediatric participants (5 healthy, 8 CF) during separate breath-holds. Images from both sequences were compared on the basis of ventilation defect percent (VDP) and other measures of image similarity. The nadir of transient oxygen saturation (SpO(2)) decline due to xenon breath-holding was measured with pulse oximetry, and expressed as a percent change relative to baseline. Results(129)Xe ventilation images were acquired in a breath-hold of 1.2-1.8 s with the 3D-SoS sequence, compared to 6.2-8.8 s for 2D-GRE. Mean +/- SD VDP measures for 2D-GRE and 3D-SoS sequences were 5.02 +/- 1.06% and 5.28 +/- 1.08% in healthy participants, and 18.05 +/- 8.26% and 18.75 +/- 6.74% in CF participants, respectively. Across all participants, the intraclass correlation coefficient of VDP measures for both sequences was 0.98 (95% confidence interval: 0.94-0.99). The percent change in SpO(2) was reduced to -2.1 +/- 2.7% from -5.2 +/- 3.5% with the shorter 3D-SoS breath-hold. ConclusionHyperpolarized Xe-129 ventilation imaging with 3D-SoS yielded images approximately five times faster than conventional 2D-GRE, reducing SpO(2) desaturation and improving tolerability of the xenon administration. Analysis of VDP and other measures of image similarity demonstrate excellent agreement between images obtained with both sequences. 3D-SoS holds significant potential for reducing the acquisition time of hyperpolarized Xe-129 MRI, and/or increasing spatial resolution while adhering to clinical breath-hold constraints.