29 December 2011

dcemriS4 0.46

The R package dcemriS4 provides routines for the quantitative analysis of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI), along with quantification of diffusion-weighted MRI (ADC = apparent diffusion coefficient) and quantitative T2 maps from Carr-Purcell-Meiboom-Gill (CPMG) sequences.  The latest version (0.46) has been submitted to CRAN and will hopefully be available for download soon.

Voxel-wise posterior median values of Ktrans (volume transfer constant
between the plasma and the extravascular extracellular space) using an MCMC algorithm.

Improvements or modifications from previous versions include:
  • Added dependence on R (>=2.14.0) so that the "parallel" package is used instead of the "multicore" package.
  • Added functions aifParameters() and compartmentalModel() to standardize the output in parameter estimation functions.
  • Allow the user to specify initial guesses for the Levenberg-Marquardt optimization in order to estimate the kinetic parameters.
  • Improved the implementation of CA.fast2 to estimate the T1 relaxation time and corresponding contrast agent concentration when only two flip angles are acquired.
  • Bug fix in dcemri.lm() when user-specified arterial input function (AIF) is provided.
  • Added cerebral blood volume (CBV) estimation functionality.
Please post any questions or suggestions to dcemri-help@lists.sourceforge.net.