Quantitative description of the asymmetry in magnetization transfer effects around the water resonance in the human brain

✍ Scribed by Jun Hua; Craig K. Jones; Jaishri Blakeley; Seth A. Smith; Peter C.M. van Zijl; Jinyuan Zhou

• Publisher: John Wiley and Sons
• Year: 2007
• Tongue: English
• Weight: 374 KB
• Volume: 58
• Category: Article
• ISSN: 0740-3194
• DOI: 10.1002/mrm.21387

✦ Synopsis

Abstract

Magnetization transfer (MT) imaging provides a unique method of tissue characterization by capitalizing on the interaction between solid‐like tissue components and bulk water. We used a continuous‐wave (CW) MT pulse sequence with low irradiation power to study healthy human brains in vivo at 3 T and quantified the asymmetry of the MT effects with respect to the water proton frequency. This asymmetry was found to be a difference of approximately a few percent from the water signal intensity, depending on both the RF irradiation power and the frequency offset. The experimental results could be quantitatively described by a modified two‐pool MT model extended with a shift contribution for the semisolid pool with respect to water. For white matter, this shift was fitted to be 2.34 ± 0.17 ppm (N = 5) upfield from the water signal. Magn Reson Med 58:786–793, 2007. © 2007 Wiley‐Liss, Inc.