Magnetization Transfer (MT) and Endogenous Chemical Exchange Saturation Transfer (CEST) Effects in Patients with Clinically Isolated Syndrome

Ali Al-Radaideh¹, Olivier Mougin¹, Su-Yin Lim², Christopher Tench², Cris Constantinescu², Penny Gowland¹

Magnetization transfer (MT) is an important MRI measure in MS and the MT effect can be assessed qualitatively using magnetization transfer ratio (MTR) maps.A distinctive peak is observed in the z -spectrum of the human brain, at -1.05k Hz offset from the water frequency at 7T. This is caused by endogenous chemical exchange saturation transfer (CEST) between amide (chemical group attached to the peptide bond) and water protons. Here we obtain MTR images for negative (MTR- sensitive to MT + CEST effects) and positive (MTR+ sensitive to just MT effects) frequency offsets of the saturation and compare the distributions of these parameters in NAWM of healthy controls and patients with Clinically Isolated Syndrome (CIS: a condition that is likely to lead to MS).