SVT 5.2 Program Synopsis

For SGI users we recommend you try to install the graphical user interface (GUI), which tremendously simplifies the software. It also allows linking the SVT, AIR (polynomial warping) and MNI's "Display" and "register" (visualization tools) (display ftp) softwares.

There are two main routines in the SVT 5.2 package. The first one, SVT_MNI9_5_2_SS_flt, is employed for analyzing activation versus rest functional volumes for single subject (SS) studies. It will generate and SVT image containing all: the positively and negatively statistically significant variations between the two functional volumes, and an outline of the probabilistic sub-volume partitioning (see technical notes). The second statistical analysis program included in SVT 5.2 has two versions SVT_MNI9_5_2_MS_flt and SVT_MNI9_4_2_MS_flt, and is geared toward the same type of analysis for determining the statistically significant regions of activation in functional brain data, however, it is applied to multi-subject (MS) and group studies. For example, if a group of patients are scanned under two different paradigms (usually referred to as "A(ctive)" and "R(est)" states), and we are interested in determining and locating the metabolic differences and perfusion between these two stimuli based on the group of data we use "SVT_MNI9_5_2_MS_flt" or "SVT_MNI9_4_2_MS_flt". There are some differences in the level of statistical significance applied in the two versions, see technical notes.

Recently we have added some variations to the SVT_5_2, mainly differing by the methods used to correct for multiple testing. These include: SVT_MNI9_5_3_MS_flt, allows the user to explicitely specify the FWHM in the range [0.1, 19.9] mm, with a stepsize of 0.1 mm; SVT_simple_MS_flt and SVT_simple_SS_flt, where there's no correction for multiple testing; and bootstrap_SVT, a new bootstrap approach for correcting the threshold levels for large number of statistical tests. In addition, several pre- and post-processing procedures are supplied to ease the data registration (flipMy3D_1), intensity distribution (histogram), obtaining ROI statistics (get_MNI_ROI_info) and (mean_var_bin1), intensity normalization (interSubj_normROI1 and intraSubj_normPutamen) and interpretation of the results (see various "batch" files). A number of batch files and shell scripts are also included to help with running SVT (batch_SVT_MS, batch_SVT_SS), registering the data using AIR (batch_warp, batch_makeaheader) and converting and visualizing the data and the results using MNI's MINC data format and their display package.

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