Connectometry Analysis

Use --action=cnt to run group connectometry from a .dz connectometry database.

Examples

Multiple regression

Use a regression model with three variables (0:SEX, 1:BMI, 2:AGE) and test BMI as the variable of interest:

dsi_studio --action=cnt \
  --source=CMU60.dz \
  --index_name=qa \
  --effect_size=0.3 \
  --demo=CMU60.txt \
  --variable_list=0,1,2 \
  --voi=1

Cohort selection and anatomical constraints

dsi_studio --action=cnt \
  --source=study.dz \
  --demo=demo.csv \
  --effect_size=0.2 \
  --roa=excluded_mni_region.nii.gz \
  --select="scanner=1,group/3" \
  --variable_list=2,4,5 \
  --voi=5

Core Parameters

Parameter	Description
--source	Connectometry database (.dz; legacy .db.fz and .db.fib.gz remain supported).
--index_name	Diffusion index to analyze, such as qa or dti_fa. If omitted, the first available index in the database is used.
--demo	Demographic CSV or text file. This is required when demographics are not already stored in the database.
--variable_list	Comma-separated zero-based column indices included in the regression model, for example 0,1,2.
--voi	Zero-based index of the variable of interest within the demographic variables. For longitudinal analysis, use --voi=longitudinal.

DSI Studio prints the available index names and demographic-variable indices when the analysis starts. Check all available demographic columns before launching a batch analysis rather than assuming a fixed column layout.

For a derived or longitudinal database, do not assume demographics from the source database were embedded or carried forward. Verify the available variables again and supply --demo=<file> when the required study variable or covariates are missing.

Analysis Parameters

Parameter	Default	Description
--effect_size	0.3	Correlation/effect-size threshold when --t_threshold is not specified.
--t_threshold	optional	Use a local T threshold instead of --effect_size.
--length_threshold	data dependent	Minimum tracking length in voxel distance; derived from the database dimensions when omitted.
--fdr_threshold	0	Set a nonzero value such as 0.05 to enable FDR thresholding.
--permutation	2000	Number of permutations.
--exclude_cb	0	Set to 1 to exclude the cerebellum.
--no_tractogram	1	Do not generate 3D tractogram images in command-line mode.
--normalize_iso	1	Normalize QA/RDI by ISO for non-longitudinal databases.
--tip_iteration	16	Topology-informed pruning iterations.
--region_pruning	1	Remove fragmented findings using tract-coverage information.

Cohort and Region Options

Parameter	Description
--select	Select a subset of subjects using demographic conditions, for example --select="Gender=1,Age>20".
--seed, --roi, --roa, --end, --ter, --nend, --lim	Anatomical constraints using the same region syntax as --action=trk.
--output	Prefix for output files. If omitted, DSI Studio derives an output name from the demographics/study variable.

If no seed is provided, DSI Studio uses whole-brain seeding. Region constraints change the tested anatomical hypothesis and should be chosen before interpreting the result.

For the GUI workflow, database creation, demographic loading, longitudinal-database handling, and interpretation of FDR, see Correlational Tractography / Connectometry.