spant (version 3.7.0)

lb_renoise: Apply line-broadening to dynamic MRS data and add normally distributed noise (renoise) to reverse any associated improvement in SNR.

Description

This function mimics a strategy used by : "Bednařík P, Tkáč I, Giove F, DiNuzzo M, Deelchand DK, Emir UE, Eberly LE, Mangia S. Neurochemical and BOLD responses during neuronal activation measured in the human visual cortex at 7 Tesla. J Cereb Blood Flow Metab. 2015 Mar 31;35(4):601-10. doi: 10.1038/jcbfm.2014.233. PMID: 25564236; PMCID: PMC4420878." Note that set.seed(XX) should be used for reproducible analyses.

Usage

lb_renoise(
  mrs_data,
  lb,
  lg = NULL,
  sig_region = c(4, 0.5),
  noise_region = c(-0.5, -2.5),
  p_order = 2
)

Value

line-broadened and renoised data.

Arguments

mrs_data

data to be broadened.

lb

amount of line-broadening in Hz, length should be equal to the number of dynamics in mrs_data.

lg

Lorentz-Gauss lineshape parameter (between 0 and 1). Defaults to a fully Lorentzian value of 0. If one value is given, will be recycled to match the number of dynamics in mrs_data.

sig_region

a ppm region to define where the maximum signal value should be estimated.

noise_region

a ppm region to defined where the noise level should be estimated.

p_order

polynomial order to fit to the noise region before estimating the standard deviation.