On-resonance low B1 pulses for imaging of the effects of PARACEST agents

Elena Vinogradov, Shanrong Zhang, Angelo Lubag, James A. Balschi, A. Dean Sherry, Robert E. Lenkinski

Research output: Contribution to journalArticle

41 Citations (Scopus)

Abstract

Application of the exchange-sensitive, low-power RF pulses positioned on the bulk water resonance for imaging of the effects of PARACEST agents is proposed as an alternative to the standard CW off-resonance irradiation. Specifically, we applied a low-power WALTZ-16 RF train, with the 90°pulse unit replaced by a pulse of the fixed length (WALTZ-16*). Using this sequence, the bulk water signal was found to be sensitive to exchange lifetimes with PARACEST complex bound protons, the transverse relaxation time of bulk water, and longitudinal relaxation time of bound protons. In this report, the concept of using WALTZ-16* to "activate" a PARACEST effect is introduced and some of the salient features of this technique with respect to experimental conditions and performance levels are discussed. Computational predictions are verified and explored by comparison with experimental spectroscopic and imaging data. It is shown that WALTZ-16* can be used to detect PARACEST agents with an RF intensity as low as 200 Hz for concentrations as low as a few tens of μM for lanthanide chelates having appropriate water-exchange rates (Tm,Dy).

Original languageEnglish (US)
Pages (from-to)54-63
Number of pages10
JournalJournal of Magnetic Resonance
Volume176
Issue number1
DOIs
StatePublished - Sep 2005

Fingerprint

Imaging techniques
Water
pulses
Relaxation time
water
Protons
relaxation time
Lanthanoid Series Elements
protons
chelates
Irradiation
life (durability)
irradiation
predictions

Keywords

  • Contrast
  • Exchange
  • Low B WALTZ-16
  • PARACEST
  • Relaxation

ASJC Scopus subject areas

  • Molecular Biology
  • Physical and Theoretical Chemistry
  • Spectroscopy
  • Radiology Nuclear Medicine and imaging
  • Condensed Matter Physics

Cite this

On-resonance low B1 pulses for imaging of the effects of PARACEST agents. / Vinogradov, Elena; Zhang, Shanrong; Lubag, Angelo; Balschi, James A.; Sherry, A. Dean; Lenkinski, Robert E.

In: Journal of Magnetic Resonance, Vol. 176, No. 1, 09.2005, p. 54-63.

Research output: Contribution to journalArticle

Vinogradov, Elena ; Zhang, Shanrong ; Lubag, Angelo ; Balschi, James A. ; Sherry, A. Dean ; Lenkinski, Robert E. / On-resonance low B1 pulses for imaging of the effects of PARACEST agents. In: Journal of Magnetic Resonance. 2005 ; Vol. 176, No. 1. pp. 54-63.
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