Rapid velocity-encoded cine imaging with turbo-BRISK

Velocity-encoded cine (VEC) imaging is potentially an important clinical di agnostic technique for cardiovascular diseases. Advances in gradient techno logy combined with segmentation approaches have made possible breathhold VE C imaging, allowing data to be obtained free of respiratory artifacts. Howe ver, when using conventional segmentation approaches, spatial and temporal resolutions are typically compromised to accommodate short breathhold times . Here we apply a spat-se sampling technique, turbo-BRISK (i.e., segmented block regional interpolation scheme for k-space) to VEC imaging, allowing i ncreased spatial and temporal resolution to be obtained in a short breathho ld period. BRISK is a sparse sampling technique with interpolation used to generate unsampled data. BRISK was implemented to reduce the scan time by 7 0% compared with a conventional scan. Further; turbo-BRISK scans, using seg mentation factors up to 5, reduce the scan time by lip to 94%. Phantom and in vivo results are presented that demonstrate the accuracy of turbo-BRISK VEC imaging. In vitro validation is performed using conventional magnetic r esonance VEC. Pulsatile centerline flow velocity measurements obtained with turbo-BRISK acquisitions were correlated with conventional magnetic resona nce imaging measurements and achieved r values of 0.99 +/- 0.004 (mean +/- SD) with stroke volumes agreeing to within 4%. A potential limitation of BR ISK is reduced accuracy for rapidly varying velocity profiles. We present l ow- and high-resolution data sets to illustrate the resolution dependence o f this phenomenon and demonstrate that at conventional resolutions, turbo-B RISK can accurately, represent rapid velocity changes. In vitro results ind icate that centerline velocity waveforms in the descending aorta correlate well with conventional measurements with art average r value of 0.98 +/- 0. 01.