Format

Send to

Choose Destination
See comment in PubMed Commons below
Magn Reson Med. 2012 Oct;68(4):1048-55. doi: 10.1002/mrm.24420. Epub 2012 Jul 26.

Detection of rapidly exchanging compounds using on-resonance frequency-labeled exchange (FLEX) transfer.

Author information

1
Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA.

Abstract

Frequency-labeled exchange transfer is a promising MRI technique for labeling and detecting exchanging protons of low-concentration solutes through the water signal. Early frequency-labeled exchange studies have used off-resonance excitation-based labeling schemes that are well suited to study rapidly exchanging protons or molecules far from the water resonance (e.g., water in paramagnetic contrast agents) or slowly exchanging protons close to the water resonance (e.g., some amide protons). However, off-resonance labeling is not efficient for rapidly exchanging protons close to water. Here, we show that a new frequency-labeled exchange labeling scheme with excitation pulses applied on the water resonance gives much higher exchange contrast for rapidly exchanging protons resonating close to the water resonance frequency. This labeling scheme is particularly suited for studying rapidly exchanging hydroxyl, amine, and imino protons in diamagnetic chemical exchange saturation transfer agents.

PMID:
22837066
PMCID:
PMC3458160
DOI:
10.1002/mrm.24420
[Indexed for MEDLINE]
Free PMC Article
PubMed Commons home

PubMed Commons

0 comments
How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for Wiley Icon for PubMed Central
    Loading ...
    Support Center