TSNR (Temporal Signal to Noise Ratio)ΒΆ

Influenced by the magnetic field inhomogeneity at air-tissue interfaces, rs-fMRI signals at orbitofrontal and temporal medial and polar areas suffer from a certain degree of distortions and signal loss. To exclude spurious voxels, we use the thresholded voxel-wise TSNR, which is calculated as the average intensity of time series divided ty the standard deviation, to generate subject-level or group-leval whole-brain mask.

  • mask: could be whole brain mask or gray matter mask.
  • id index: identifier to find unique string for each subject
  • filetype: files in the filetype will be searched in input directories.
  • 4D nifti files: if the input data is 4D, check this item. Otherwise uncheck.
  • input dirs: directories can be input either using a *.txt file or spm select window.
  • threshold: intensity threshold for mean TSNR (to generate a binary mask).
  • out dir: output directory for saving results.
  • Buttons:
    • S: Save parameters of the current panel to a *.mat file. The *.mat can be further loaded for the panel or be used in a script processing.
    • L: Load parameters from *.mat for the current panel.
    • ?: Help information.
  • References:
  1. Tomasi D, Volkow ND. Functional connectivity density mapping. Proceedings of the National Academy of Sciences of the United States of America 2010; 107(21): 9885-90.
  2. Yeo BT, Krienen FM, Sepulcre J, Sabuncu MR, Lashkari D, Hollinshead M, et al. The organization of the human cerebral cortex estimated by intrinsic functional connectivity. J Neurophysiol 2011; 106(3): 1125-65.
  3. Welvaert M, Rosseel Y. On the definition of signal-to-noise ratio and contrast-to-noise ratio for FMRI data. PLoS One 2013; 8(11): e77089.