MR Parameter Estimation

ESTIMATE MAGNETIC RESONANCE PARAMETERS ON-LINE

AP Dagher MD, M Fitzpatrick MD, AE Flanders MD, K Chow MD

Pulse Sequences:


T2 Estimates from T2-Weighted Signals

T1 Estimates from Saturation Recovery Signals

T1 Estimates from Inversion Recovery Signals

Both T1 and T2 Estimates from Multiple TE/TR Signals


Download fitting superclass souce code for custom applications




Assumptions for Parameter Estimations

  • TR >> T2* (T2 in the absence of refocusing echoes).
  • A monoexponential relaxation process governs T2 decay and T1 recovery.
  • The rf pulse flip angles are uniform through the slice thickness.
  • The rf pulse duration is negligible.
  • Inhomogeneity of the non-selective 180 rf pulse is assumed to be negligible.
  • Partial volume effects, image data set misregistration, flow, self-diffusion, chemical shift, susceptibility effects at tissue interfaces are negligible.
The parameter estimates influenced by incorrect assumptions may have poor figure-of-merit statistics associated with the estimates, or the estimation may simply fail.

All equations are from Stark & Bradley. Magnetic Resonance Imaging. Moseby Year Book, St. Louis, 1992, unless otherwise indicated.

This site is exhibited at the RSNA 1997 INFORAD, # 9511

For more information or comments contact pdagher@NIH.GOV