Meeting Banner
Abstract #0245

Self-Calibrated Simultaneous Multi-Slice PROPELLER

Ola Norbeck 1 , Magnus Mrtensson 2,3 , Enrico Avventi 3 , Mathias Engstrm 1,3 , and Stefan Skare 1,3

1 Dept. of Neuroradiology, Karolinska University Hospital, Stockholm, Sweden, 2 EMEA Research and Collaboration, GE Applied Science Laboratory, GE Healthcare, Stockholm, Sweden, 3 Dept. of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden

Simultaneous multi-slice (SMS) MR imaging, sometimes in combination with regular parallel imaging in the phase encoding direction, has led to a dramatic speed up of multi-volume echo-planar imaging (EPI) for fMRI and diffusion MRI. In multi-volume SMS imaging, the first volume can be acquired without acceleration and be used for calibration of the subsequent SMS accelerated volumes.For clinical MRI, most often only involving one volume per scan, one needs to make sure that the SMS calibration does not consume a large fraction of the total scan time. To keep the SMS calibration time short, a low resolution 2D GRE scan may be used. In this work, we have developed SMS RF pulses and applied them to PROPELLER imaging. As PROPELLER uses a large set of blade volumes (~10 per minute), we suggest to perform SMS and regular in-plane GRAPPA calibration on the first propeller blade volume as a part of the scan. With only one blade volume being fully sampled in both the phase encoding direction and the slice direction, and with the remaining blades fully accelerated without any ACS lines, the overall scan time could be kept very short and without needing separate GRE scans. For our accelerated PROPELLER sequence, GRAPPA and split-slice-GRAPPA was used for unfolding, and the GRAPPA kernel was rotated to calculate sets of weights the other blade volumes. The technique was validated with our T1-W SE PROPELLER sequence. Our work shows that PROPELLER scans can be accelerated with SMS in addition to in-plane acceleration, allowing almost 75 % scan time reduction.

This abstract and the presentation materials are available to members only; a login is required.

Join Here