B1-Insensitive T2 preparation for improved coronary magnetic resonance angiography at 3 T

Reza Nezafat, Matthias Stuber, Ronald Ouwerkerk, Ahmed M. Gharib, Milind Y. Desai, Roderic I. Pettigrew

Research output: Contribution to journalArticle

99 Scopus citations

Abstract

At 3 T, the effective wavelength of the RF field is comparable to the dimension of the human body, resulting in B1 standing wave effects and extra variations in phase. This effect is accompanied by an increase in B0 field inhomogeneity compared to 1.5 T. This combination results in nonuniform magnetization preparation by the composite MLEV weighted T 2 preparation (T2 Prep) sequence used for coronary magnetic resonance angiography (MRA). A new adiabatic refocusing T2 Prep sequence is presented in which the magnetization is tipped into the transverse plane with a hard RF pulse and refocused using a pair of adiabatic fast-passage RF pulses. The isochromats are subsequently returned to the longitudinal axis using a hard RF pulse. Numerical simulations predict an excellent suppression of artifacts originating from B1 inhomogeneity while achieving good contrast enhancement between coronary arteries and surrounding tissue. This was confirmed by an in vivo study, in which coronary MR angiograms were obtained without a T2 Prep, with an MLEV weighted T2 Prep and the proposed adiabatic T2 Prep. Improved quantitative and qualitative coronary MRA image measurement was achieved using the adiabatic T2 Prep at 3 T.

Original languageEnglish (US)
Pages (from-to)858-864
Number of pages7
JournalMagnetic Resonance in Medicine
Volume55
Issue number4
DOIs
StatePublished - Apr 2006

Keywords

  • Adiabatic pulses, 3 T cardiac MR
  • Contrast enhancement
  • Coronary MR angiography
  • T prep

ASJC Scopus subject areas

  • Radiology Nuclear Medicine and imaging

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