Turbo Spin Echo Imaging at 7T with Bilateral Orthogonality Generative Acquisitions Method for Homogeneous T_1, T_2 and Proton Density Contrasts

TL;DR

This paper introduces a novel BOGA method adaptation for TSE imaging at 7T, enabling homogeneous T_1, T_2, and proton density contrasts by compensating for RF inhomogeneities without prior data.

Contribution

The study adapts the BOGA method for TSE imaging at 7T, achieving homogeneous contrasts by using multiple acquisitions and RF modes, independent of TSE factors.

Findings

Homogeneous T_1, T_2, and proton density images obtained.

RF inhomogeneity effects removed without prior data.

Simultaneous resolution of mixed contrast effects.

Abstract

Purpose: Bilateral Orthogonality Generative Acquisitions (BOGA) method, which was initially implemented for T_2^* contrast via gradient echo acquisitions, is adapted for TSE imaging at 7T using parallel transmission (pTx) system for obtaining homogeneous T_1, T_2 and proton density weighted images. Theory and Methods: Multiple TSE images with complimentary RF modes and scan parameters are acquired as input images for the BOGA method where RF modes have complimentary transmit and receive field inhomogeneity patterns and scan parameters have varying echo and repetition times. With the application of the BOGA method using different subsets of the data acquisitions for each contrast, homogeneous T_1, T_2 and proton density contrast in the final images obtained. Furthermore, to demonstrate the effect of the TSE factor, two TSE factors are used individually. Normalized intensity profiles and signal to noise ratio maps are utilized for the comparison of the CP mode images and the TSE factors respectively. Results: Homogeneous T_1, T_2 and proton density weighted images are obtained with the TSE implementation of the BOGA method without the transmit and receive field inhomogeneity effects. Furthermore, mixed contrast effects of the TSE acquisition are simultaneously resolved independently of the TSE factor. Conclusion: TSE application of BOGA method results in homogeneous T_1, T_2 and proton density contrasts at 7T, as the inhomogeneity effects are removed from the final contrast without any prior data acquisitions.