Magnetization Transfer Magnetic Resonance Fingerprinting Using Spin Lock Preparations

Motivation: Magnetization transfer (MT) techniques allow for quantitative measurement of the macromolecular proton fraction (MPF) of tissues. However, the process of measuring these MT parameters can be lengthy and require many assumptions of T1 and T2. Goal(s): In this study, a magnetic resonance fingerprinting sequence is proposed that acquires T1, T2, and MPF using spin lock preparations. Approach: An MRF sequence was created using spin lock preparations of various off-resonance frequencies to create MT contrast. The sequence was acquired in agarose phantoms and the human brain. Results: Results showed increased MPF with increasing agarose concentration and in white matter. Impact: This study demonstrates the effectiveness of using spin lock pulses for magnetization transfer MRF and allow for quick acquisition of MPF maps that are corrected for the T1 and T2 of the tissue.