CEST, ASL, and magnetization transfer contrast: How similar pulse sequences detect different phenomena

Linda Knutsson, Jiadi Xu, André Ahlgren, Peter C Van Zijl

Research output: Contribution to journalReview article

Abstract

Chemical exchange saturation transfer (CEST), arterial spin labeling (ASL), and magnetization transfer contrast (MTC) methods generate different contrasts for MRI. However, they share many similarities in terms of pulse sequences and mechanistic principles. They all use RF pulse preparation schemes to label the longitudinal magnetization of certain proton pools and follow the delivery and transfer of this magnetic label to a water proton pool in a tissue region of interest, where it accumulates and can be detected using any imaging sequence. Due to the versatility of MRI, differences in spectral, spatial or motional selectivity of these schemes can be exploited to achieve pool specificity, such as for arterial water protons in ASL, protons on solute molecules in CEST, and protons on semi-solid cell structures in MTC. Timing of these sequences can be used to optimize for the rate of a particular delivery and/or exchange transfer process, for instance, between different tissue compartments (ASL) or between tissue molecules (CEST/MTC). In this review, magnetic labeling strategies for ASL and the corresponding CEST and MTC pulse sequences are compared, including continuous labeling, single-pulse labeling, and multi-pulse labeling. Insight into the similarities and differences among these techniques is important not only to comprehend the mechanisms and confounds of the contrasts they generate, but also to stimulate the development of new MRI techniques to improve these contrasts or to reduce their interference. This, in turn, should benefit many possible applications in the fields of physiological and molecular imaging and spectroscopy.

Original languageEnglish (US)
Pages (from-to)1320-1340
Number of pages21
JournalMagnetic Resonance in Medicine
Volume80
Issue number4
DOIs
StatePublished - Oct 1 2018

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Protons
Molecular Imaging
Water
Spectrum Analysis

Keywords

  • arterial spin labeling
  • cerebral blood flow
  • CEST
  • chemical exchange
  • compartmental exchange
  • frequency selective
  • immobile proton pool
  • magnetization transfer contrast
  • mobile molecules
  • spatially selective

ASJC Scopus subject areas

  • Radiology Nuclear Medicine and imaging

Cite this

CEST, ASL, and magnetization transfer contrast : How similar pulse sequences detect different phenomena. / Knutsson, Linda; Xu, Jiadi; Ahlgren, André; Van Zijl, Peter C.

In: Magnetic Resonance in Medicine, Vol. 80, No. 4, 01.10.2018, p. 1320-1340.

Research output: Contribution to journalReview article

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