Optimization of blood oxygenation level-dependent sensitivity in magnetic resonance imaging using intermolecular double-quantum coherence

✍ Scribed by Jianhui Zhong; Zhong Chen; W. Edmund Kwok; Scott Kennedy; Zhiyang You

• Publisher: John Wiley and Sons
• Year: 2002
• Tongue: English
• Weight: 260 KB
• Volume: 16
• Category: Article
• ISSN: 1053-1807
• DOI: 10.1002/jmri.10208

✦ Synopsis

Abstract

Purpose

To optimize timing parameters in an intermolecular double‐quantum coherence (iDQC) imaging pulse sequence for overall image signal‐to‐noise ratio (SNR) and blood oxygenation level‐dependent (BOLD) sensitivity for brain functional imaging.

Material and Methods

Fresh human blood was measured under different oxygenation conditions, and human brain functional magnetic resonance (fMR) images in three normal volunteers were obtained, using iDQC techniques at 1.5 T. The dependence of SNR and BOLD sensitivity was measured as a function of time delays after the iDQC evolution period.

Results

A time delay after the iDQC evolution period τ can be adjusted either to refocus the dephasing accumulated during τ, thus increasing SNR, with full rephasing occurring at delay = ±2τ (for iDQC order n = ±2), or to enhance BOLD effects with consequent reduced image SNR at delay = 0.

Conclusion

Image SNR and BOLD sensitivity often impose different requirements for iDQC image sequence design and timing parameter selections. It is therefore important to select properly relevant parameters for different applications. J. Magn. Reson. Imaging 2002;16:733–740. © 2002 Wiley‐Liss, Inc.