Abstract #1651

Optimized contrast-to-noise ratio efficiency of Magnetization Transfer brain imaging at 0.55T

David Leitão¹, Daniel West¹, Sarah McElroy², Raphael Tomi-Tricot², Jo Hajnal^1,3, Tobias Wood⁴, and Shaihan Malik^1,3

¹Imaging Physics & Engineering Research Department, School of Biomedical Engineering & Imaging Sciences, King's College London, London, United Kingdom, ²MR Research Collaborations, Siemens Healthcare Limited, Frimley, United Kingdom, ³Early Life Imaging Research Department, School of Biomedical Engineering & Imaging Sciences, King's College London, London, United Kingdom, ⁴Department of Neuroimaging, King's College London, London, United Kingdom

Synopsis

Keywords: Low-Field MRI, Low-Field MRI, Acquisition Methods, Magnetization Transfer, Pulse Sequence Design

Motivation: Magnetization Transfer (MT) is an important contrast in neuroimaging that is typically limited by specific absorption rate (SAR) safety limits.

Goal(s): Improve contrast-to-noise ratio (CNR) efficiency of MT ratio (MTR) mapping in the brain at 0.55T where SAR constraints are less restrictive and longer, more efficient readouts are feasible.

Approach: Sequence parameters were fully constrained by hardware limits and optimized for maximum CNR efficiency of MTR between white and gray matter. A range of repetition times (TR) were explored.

Results: In-vivo 3D MTR maps showed improved CNR efficiency with longer TR, with optimized sequence parameters operating at the limits of the system.

Impact: Efficient acquisitions at lower field resolves the two greatest difficulties of deploying Magnetization Transfer Ratio images in the clinic, namely scan time and SAR concerns.

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