Real-time magnetic resonance cine imaging with sparse sampling and iterative reconstruction for ventricular measures: comparison with gold-standard segmented steady-state free precession

Background Segmented cine imaging with a steady-state free precession sequence (CINE-SSFP) is currently the gold standard technique for measuring ventricular volumes and mass. It requires multiple breath-holds to cover the entire ventricles, thus being prone to misalignment of consecutive slices, time consuming and dependent on breath-hold (BH) capability. Real-time cine avoids those limitations, however poor spatial and temporal resolution of conventional sequences have prevented its routine application. We sought to examine if a newly developed real-time sequence featuring sparse sampling and iterative reconstruction (CINE-RT), which is an investigational prototype, would yield similar results when compared with conventional CINE-SSFP in a group of healthy volunteers. Methods Stacks of short-axis cines were acquired covering both ventricles in a 1.5T system (MAGNETOM Aera, Siemens AG, Germany), using gold standard CINE-SSFP and CINE-RT. Acquisition parameters for CINE-SSFP were: voxel size 1.6x1.6x7.0mm, GRAPPA acceleration factor of 2, temporal resolution of 39 ms, retrospective gating, with an average of 8 heart beats per slice and 2 slices/BH. For CINE-RT: voxel size 1.6x1.6x7.0mm, sparse sampling net acceleration factor of 11.5, temporal resolution of 41 ms, prospective gating, real-time acquisition of 2 heart-beats/slice and all slices in one BH. Left and right ventricle contours were blindly drawn by an experienced observer at end diastole and systole to derive volumes and LV mass.