scale_amp_molal: Apply water reference scaling to a fitting results object to...

In spant: MR Spectroscopy Analysis Tools

Apply water reference scaling to a fitting results object to yield metabolite quantities in millimolar (mM) units (mol / kg of tissue water).

Description

Note, this function assumes the volume contains a homogeneous voxel, eg pure WM, GM or CSF. Also note that in the case of a homogeneous voxel the relative densities of MR-visible water (eg GM=0.78, WM=0.65, and CSF=0.97) cancel out and don't need to be considered. Use scale_amp_molal_pvc for volumes containing multiple compartments. Details of this method can be found in "Use of tissue water as a concentration reference for proton spectroscopic imaging" by Gasparovic et al MRM 2006 55(6):1219-26.

Usage

scale_amp_molal(
  fit_result,
  ref_data,
  te,
  tr,
  water_t1,
  water_t2,
  metab_t1,
  metab_t2,
  ...
)

Arguments

fit_result	result object generated from fitting.
ref_data	water reference MRS data object.
te	the MRS TE in seconds.
tr	the MRS TR in seconds.
water_t1	assumed water T1 value.
water_t2	assumed water T2 value.
metab_t1	assumed metabolite T1 value.
metab_t2	assumed metabolite T2 value.
...	additional arguments to get_td_amp function.

Value

A fit_result object with a rescaled results table.

spant documentation built on Sept. 11, 2024, 9:13 p.m.