Quantitative magnetization transfer imaging in human brain at 3 T via selective inversion recovery

Area of Science:

• Neuroimaging
• Biophysics
• Medical Physics

Background:

• Quantitative magnetization transfer (qMT) imaging probes proton interactions between water and macromolecules.
• Key indices include the macromolecular to free pool size ratio (PSR) and transfer rate k(mf).
• Previous implementations were limited, hindering clinical application.

Purpose of the Study:

• To implement and validate the selective inversion recovery qMT method on a clinical 3.0-T scanner for in vivo human brain imaging.
• To assess the reproducibility and sensitivity of qMT indices in healthy subjects and multiple sclerosis patients.

Main Methods:

• Selective inversion recovery qMT data acquired at 16 inversion times.
• Fast spin-echo readout and reduced repetition time for a 4-minute single-slice acquisition.
• Study included 9 healthy subjects and 2 relapsing-remitting multiple sclerosis patients.

Main Results:

• Excellent intersubject and intrasubject reproducibility demonstrated in healthy subjects.
• PSR values in white and gray matter consistent with prior literature.
• k(mf) values were approximately 2-fold slower in white and gray matter compared to some previous reports.
• qMT indices detected pathological changes in lesions and normal-appearing white matter in MS patients.

Conclusions:

• The selective inversion recovery qMT method is feasible and reproducible on a clinical 3.0-T scanner for in vivo human brain imaging.
• qMT indices are sensitive to pathological alterations in multiple sclerosis, including in normal-appearing white matter.
• This technique holds promise for characterizing brain tissue microstructure and disease progression.