Non-contrast-enhanced pulmonary vein MRI with a spatially selective slab inversion preparation sequence

We propose a non-contrast-enhanced, three-dimensional, free-breathing, electrocardiogram-gated, gradient recalled echo sequence with a slab-selective inversion for pulmonary vein (PV) MRI. A sagittal inversion slab was applied prior to data acquisition to suppress structures adjacent to the left atrium (LA) and PVs, thereby improving the conspicuity of the PV and LA. Compared with other MR angiography methods using an inversion pulse, the proposed method does not require signal subtraction and the inversion slab is not parallel to the imaging slab. The feasibility of the proposed method was demonstrated in healthy subjects. The inversion slab thickness and inversion time were optimized to be 60 mm and 500 ms, respectively. Compared to conventional gradient recalled echo imaging without inversion, the proposed technique significantly increased the contrast-to-noise ratios between the LA and the right atrium by 20-fold (P < 0.01), increased the contrast-to-noise ratios between the PVs and right atrium by 10-fold (P < 0.03), and increased the contrast-to-noise ratios between the PVs, LA and pulmonary artery by 4-fold (P < 0.01 for both). The signal-to-noise ratios of the PVs and the LA were similar with and without the inversion slab (P > 0.3). The proposed technique greatly enhances the conspicuity of the PVs and LA without significant loss of signal-to-noise ratio.