Rapid pulmonary 129Xe ventilation MRI of discharged COVID‐19 patients with zigzag sampling

Abstract

AbstractPurposeTo demonstrate the feasibility of zigzag sampling for 3D rapid hyperpolarized 129Xe ventilation MRI in human.MethodsZigzag sampling in one direction was combined with gradient‐recalled echo sequence (GRE‐zigzag‐Y) to acquire hyperpolarized 129Xe ventilation images. Image quality was compared with a balanced SSFP (bSSFP) sequence with the same spatial resolution for 12 healthy volunteers (HVs). For another 8 HVs and 9 discharged coronavirus disease 2019 subjects, isotropic resolution 129Xe ventilation images were acquired using zigzag sampling in two directions through GRE‐zigzag‐YZ. 129Xe ventilation defect percent (VDP) was quantified for GRE‐zigzag‐YZ and bSSFP acquisitions. Relationships and agreement between these VDP measurements were evaluated using Pearson correlation coefficient (r) and Bland–Altman analysis.ResultsFor 12 HVs, GRE‐zigzag‐Y and bSSFP required 2.2 s and 10.5 s, respectively, to acquire 129Xe images with a spatial resolution of 3.96 × 3.96 × 10.5 mm3. Structural similarity index, mean absolute error, and Dice similarity coefficient between the two sets of images and ventilated lung regions were 0.85 ± 0.03, 0.0015 ± 0.0001, and 0.91 ± 0.02, respectively. For another 8 HVs and 9 coronavirus disease 2019 subjects, 129Xe images with a nominal spatial resolution of 2.5 × 2.5 × 2.5 mm3 were acquired within 5.5 s per subject using GRE‐zigzag‐YZ. VDP provided by GRE‐zigzag‐YZ was strongly correlated (R2 = 0.93, p < 0.0001) with that generated by bSSFP with minimal biases (bias = −0.005%, 95% limit‐of‐agreement = [−0.414%, 0.424%]).ConclusionZigzag sampling combined with GRE sequence provides a way for rapid 129Xe ventilation imaging.