Towards high-resolution 4D flow MRI in the human aorta using kt-GRAPPA and B1+?shimming at 7T.

ABSTRACT: To evaluate the feasibility of aortic 4D flow magnetic resonance imaging (MRI) at 7T with improved spatial resolution using kt-GRAPPA acceleration while restricting acquisition time and to address radiofrequency (RF) excitation heterogeneities with B1+?shimming.4D flow MRI data were obtained in the aorta of eight subjects using a 16-channel transmit/receive coil array at 7T. Flow quantification and acquisition time were compared for a kt-GRAPPA accelerated (R?=?5) and a standard GRAPPA (R?=?2) accelerated protocol. The impact of different dynamic B1+?shimming strategies on flow quantification was investigated. Two kt-GRAPPA accelerated protocols with 1.2 × 1.2 × 1.2?mm(3) and 1.8 × 1.8 × 2.4?mm(3) spatial resolution were compared.Using kt-GRAPPA, we achieved a 4.3-fold reduction in net acquisition time resulting in scan times of about 10 minutes. No significant effect on flow quantification was observed compared to standard GRAPPA with R?=?2. Optimizing the B1+?fields for the aorta impacted significantly (P?

SUBMITTER: Schmitter S 

PROVIDER: S-EPMC4947022 | biostudies-literature | 2016 Aug

REPOSITORIES: biostudies-literature