Tip
Try MRIQC online on OpenNeuro - without installation!
MRIQC is a BIDS-App [BIDSApps], and therefore it inherently understands the :abbr:`BIDS (brain imaging data structure)` standard [BIDS] and follows the BIDS-Apps standard command line interface:
mriqc bids-root/ output-folder/ participant
That simple command runs MRIQC on all the T1w and BOLD images found
under the BIDS-compliant folder bids-root/
.
The last participant
keyword indicates that the first level analysis
is run. (i.e. extracting the :abbr:`IQMs (image quality metrics)` from the
images retrieved within bids-root/
).
The second level (group
) is automatically run if no particular subject
is provided for analysis.
Note
If the argument --participant-label
is not provided, then all
subjects will be processed and the group level analysis will
automatically be executed without need of running the command in item 3.
To specify one particular subject, the --participant-label
argument
can be used:
mriqc bids-root/ output-folder/ participant --participant-label S01 S02 S03
That command will run MRIQC only on the subjects indicated: only
bids-root/sub-S01
, bids-root/sub-S02
, and bids-root/sub-S03
will be processed.
In this case, the group
level will not be triggered automatically.
We generate the group
level results (the group level report and the
features CSV table) with:
mriqc bids-root/ output-folder/ group
Examples of the generated visual reports are found in :ref:`The MRIQC Reports <reports>`.
Warning
MRIQC by default attempts to upload anonymized quality metrics to a publicly accessible
web server (mriqc.nimh.nih.gov). The uploaded data consists
only of calculated quality metrics and scanning parameters. It removes all personal
health information and participant identifiers. We try to collect this data to build normal
distributions for improved outlier detection, but if you do not wish to participate you can
disable the submission with the --no-sub
flag.
BIDS data organization
The software automatically finds the data the input folder if it follows the :abbr:`BIDS (brain imaging data structure)` standard [BIDS]. A fast and easy way to check that your dataset fulfills the :abbr:`BIDS (brain imaging data structure)` standard is the BIDS validator.
BIDS-App levels
In the participant
level, all individual images to be processed are run
through the pipeline, and the :ref:`MRIQC measures <measures>` are extracted and
the individual reports (see :ref:`The MRIQC Reports <reports>`) generated.
In the group
level, the :abbr:`IQMs (image quality metrics)` extracted in
first place are combined in a table and the group reports are generated.
.. argparse:: :ref: mriqc.cli.parser._build_parser :prog: mriqc :nodefault: :nodefaultconst:
We have profiled cores and memory usages with the resource profiler tool of nipype.
An MRIQC run of one subject (from the ABIDE) dataset, containing only one run, one BOLD task (resting-state) yielded the following report:
Using the
MultiProc
plugin of nipype withnprocs=10
, the workflow nodes run across the available processors for 41.68 minutes. A memory peak of 8GB is reached by the end of the runtime, when the plotting nodes are fired up.
We also profiled MRIQC on a dataset with 8 tasks (one run per task), on ds030 of OpenfMRI:
Again, we used
n_procs=10
. The software run for roughly about the same time (47.11 min). Most of the run time, memory usage keeps around a maximum of 10GB. Since we saw a memory consumption of 1-2GB during the the 1-task example, a rule of thumb may be that each task takes around 1GB of memory.