Longitudinal Preprocessing#

Open image

Background#

Longitudinal preprocessing pipeline is designed to process longitudinal data with two or more sessions. Based on Reuter et al. 2012, all secions of subjects are first preprocessed independently and then a within-subject template is created by averaging all sessions of the subject. Subsequently the within-subject template is registered to standard space and all sections are then registered to the longitudinal template in standard space.

Configuring CPAC to Run Longitudinal Preprocessing Pipeline#

../_images/longitudinal.png

  1. Longitudinal - [On, Off]: Run longitudinal preprocessing pipeline or not. Default is Off.

  2. Average Method - [string]: Method to average longitudinal template. Default is median.

  3. DOF - [integer]: Transform degree of freedom in flirt. Default is 12.

  4. Interpolation - [string]: Interpolation in flirt. Default is trilinear.

  5. Cost Function - [string]: Cost function in flirt. Default is corratio.

  6. Thread Pool - [integer]: Number of threads in a thread pool. More threads can speed up the longitudinal template creation process. Default is 2.

  7. Convergence Threshold - [integer]: Convergence threshold of longitudinal template. Default is -1, which uses numpy.finfo(np.float64).eps.

Configuration Without the GUI#

The following nested key/value pairs will be set to these defaults if not defined in your pipeline configuration YAML.

References#

Martin Reuter, Nicholas J.Schmansky, H. Diana Rosas, Bruce Fischl. Within-subject template estimation for unbiased longitudinal image analysis. Neuroimage. 2012 July 16; 61(4): 1402–1418. doi:10.1016/j.neuroimage.2012.02.084.