Parallel transmission 2D RARE imaging at 7T with transmit field inhomogeneity mitigation and local SAR control.

ABSTRACT:

Purpose

We develop and test a parallel transmit (pTx) pulse design framework to mitigate transmit field inhomogeneity with control of local specific absorption rate (SAR) in 2D rapid acquisition with relaxation enhancement (RARE) imaging at 7T.

Methods

We design large flip angle RF pulses with explicit local SAR constraints by numerical simulation of the Bloch equations. Parallel computation and analytical expressions for the Jacobian and the Hessian matrices are employed to reduce pulse design time. The refocusing-excitation "spokes" pulse pairs are designed to satisfy the Carr-Purcell-Meiboom-Gill (CPMG) condition using a combined magnitude least squares-least squares approach.

Results

In a simulated dataset, the proposed approach reduced peak local SAR by up to 56%

SUBMITTER: Yetisir F 

PROVIDER: S-EPMC9789791 | biostudies-literature | 2022 Nov

REPOSITORIES: biostudies-literature