Dispersion in magnetization transfer contrast at a given specific absorption rate due to variations of RF pulse parameters in the magnetization transfer preparation Academic Article Article uri icon

Overview

MeSH Major

  • Breast Diseases
  • Calcinosis
  • Radiographic Image Enhancement
  • Radiographic Image Interpretation, Computer-Assisted

abstract

  • The effects of RF pulse parameters on magnetization transfer contrast (MTC) were investigated using a magnetization prepared segmented fast gradient echo sequence. MTC was found not to be uniquely determined by the specific absorption rate (SAR). RF pulse parameters (RF amplitude, number of RF pulses and RF duration) also affect MTC. There can be 40% variation in MTC due to differences in RF parameters at SAR = 1 W/kg for a 70-kg subject. Increasing the number of RF pulses is a more efficient way to increase MTC than increasing RF amplitude. This phenomenon is likely caused by the fact that the time scale for magnetization transfer between the free and restricted proton pools is on the same order or longer than the duration of the MT pulse. Accordingly, increase in the MT pulse duration by increasing the number of RF pulses in the MT pulse allows more effective magnetization transfer. Such information can be used as a guide to select RF pulse parameters for a magnetization transfer (MT) pulse. An off-resonance MT pulse designed under this guide for coronary MR angiography improved the depiction of distal vessels.

publication date

  • June 1997

Research

keywords

  • Academic Article

Identity

Digital Object Identifier (DOI)

  • 10.1002/mrm.1910370622

PubMed ID

  • 9178249

Additional Document Info

start page

  • 957

end page

  • 62

volume

  • 37

number

  • 6