A curated list of tools, measures, and references for MRI quality control (QC).
Quality Control (QC) refers to “a real-time prospective process to ensure imaging quality is maintained by comparing it regularly to a defined set of criteria or industry standards” [@Sreedher2021] via [@Das2022].
Inspired by awesome-python and other awesome lists .
QC metric and report generation
MRIQC : extracts no-reference image quality metrics from structural and functional MRI data.
QAP : The QAP package allows you to obtain spatial and anatomical data quality measures for your own data. (Precursor to MRIQC.)
fBIRN QA tools : These tools form the basis of the fBIRN QA procedures [@Glover2012].
MRQy : A quality assurance and checking tool for quantitative assessment of MRI data
MRI analysis packages with built-in QC
AFNI : A suite of programs for looking at and analyzing MRI brain images at all stages of analysis.
3dToutcount
: Calculates number of "outliers" a 3D+time dataset, at each
time point.
3dTqual
: Computes a "quality index" for each sub-brick in a 3D+time dataset.
FSL : A comprehensive library of analysis tools for FMRI, MRI and DTI brain imaging data.
EDDY QC tools : Generates single-subject and group QC reports for diffusion MRI.
FEAT report : HTML report for single-subject and group fMRI analysis.
fsl_motion_outliers
: command-line tool for analyzing single-subject motion.
NiPype : Provides a uniform interface to existing neuroimaging software and facilitates interaction between these packages within a single workflow
C-PAC : A configurable, open-source, Nipype-based, automated processing pipeline for resting state functional MRI data
XCP : A free, open-source software package for processing of multimodal neuroimages with extensive QC metrics for T1w and BOLD MRI images.
DPABI : A toolbox for Data Processing & Analysis for Brain Imaging including GUI-based QC reports.
DSI Studio : A tractography software tool that maps brain connections and correlates findings with neuropsychological disorders. Includes automated QC metrics.
QSIprep : Configures pipelines for processing diffusion-weighted MRI (dMRI) data. Includes QC metrics from DSI Studio .
NiRV : A modern neuroimaging report viewer that aggregates participant level HTML reports for datasets, small and large.
NiReports : The NiPreps' Reporting and Visualization system - report templates and "reportlets"
SQAN : Scalable Quality Assurance for Neuroimaging. A full-stack system for extracting, translating, logging, and visualizing DICOM-formatted medical imaging data.
MIQA : Efficient and accurate QC processing by leveraging modern UI/UX and deep learning techniques
MindControl : An app for quality control of neuroimaging pipeline outputs, especially anatomical segmentations
Braindr : a firebase app for braindr: Tinder for brains
Fibr : An app for quality control of diffusion MRI images from the Healthy Brain Network
dmriprep-viewer : Web app to visualize local QSIprep and dMRIprep outputs
Automated QC with machine learning
Qoala-T : Qoala-T is a supervised-learning tool for quality control of FreeSurfer segmented MRI data
mriqc-learn : Learning on MRIQC-generated image quality metrics (IQMs)
General-purpose image quality estimation
Measure
Summary
Interpretation
References
Coefficient of joint variation (CJV)
Larger values indicate head motion and INU artifacts
lower better
MRIQC , [@Ganzetti2016]
Contrast-to-noise ratio (CNR)
Larger values indicate more GM to WM contrast
higher better
MRIQC , [@Magnotta2006]
Signal-to-noise ratio (SNR)
SNR within brain mask
higher better
MRIQC
Dietrich SNR (SNRd)
SNR relative to air background
higher better
MRIQC , [@Dietrich2007]
Mortamet’s quality index 1 (QI1)
Proportion of "corrupted" voxels vs number of background voxels
lower better
MRIQC , [@Mortamet2009]
Mortamet’s quality index 2 (QI2)
Comparison of background noise with $\Chi^2$ distribution after correcting for QI1
lower better
MRIQC , [@Mortamet2009]
EFC
Shannon entropy as indicator of ghosting due to head motion
lower better
MRIQC , [@Atkinson1997]
FBER
Ratio of "mean energy" within head vs air
higher better
MRIQC , [@Shehzad2015]
INU
Summary stats for INU bias field. Values close to 1 mean less bias.
higher better
MRIQC , [@Tustison2010]
White matter to maximum ratio (WM2max)
Median WM intensity divided by 95 percentile intensity
values in [0.6, 0.8]
are good.
MRIQC
FWHM
Estimation of image smoothness. Higher values mean blurry.
lower better
MRIQC
Measure
Summary
Interpretation
References
ICV
Intracranial volume fraction for each tissue type (WM, GM, CSF)
MRIQC
rPVe
Residual partial voluming error for each tissue type
lower better
MRIQC
Tissue summary stats
Summary stats for signal within tissue masks (mean, stdev, p05, p95)
MRIQC
Tissue prior overlap
Overlap of estimated tissue probability maps with template priors
higher better
MRIQC
Tissue skewness/kurtosis
Skewness and kurtosis of intensity distribution for WM, GM, and background
MRIQC , [@Rosen2018]
WM hypointensities
Voxel count of white matter hypointensities
lower better
Freesurfer , [@Klapwijk2019]
Brain extraction
Measure
Summary
Interpretation
References
Boundary tissue count
Volume of each tissue type lying on brain mask boundary. Large WM values suggest brain extraction failure.
lower WM values better
[@Alfaro-Almagro2018]
Measure
Summary
Interpretation
References
Normalization cost
Cost function between T1 and template under linear and nonlinear alignment
lower better
Normalization magnitude
Amount of nonlinear warping
lower better
[@Alfaro-Almagro2018]
Normalized overlap
Dice or Jaccard overlap coefficient between resampled T1 and template for brain and tissue masks
higher better
XCP , [@Alfaro-Almagro2018]
Measure
Summary
Interpretation
References
Euler number
2 - 2g
where g
is the number of topological holes in the surface. Computed by the Euler–Lhulier formula (V - E + F
)
higher better
[@Rosen2018], [@Dale1999], Freesurfer
Local gyrification index (LGI)
Measures degree of cortical folding in neighborhood of each vertex (spatial map).
Freesurfer
BBR criterion
Measures the magnitude of WM/GM contrast across the WM surface boundary
higher better
[@Greve2009], Freesurfer
Cortical/subcortical segmentation
Measure
Summary
Interpretation
References
Subcortical volume
Volume of each subcortical region in a segmentation (vector).
FIRST , Freesurfer
Cortical volume
Volume of each cortical region in a parcellation (vector).
[@Alfaro-Almagro2018], ANTs Freesurfer , Mindboggle
Cortical thickness
Mean thickness of each region in a parcellation (vector).
[@Rosen2018], ANTs , Freesurfer
Measure
Summary
Interpretation
References
EFC
Shannon entropy as indicator of ghosting due to head motion
lower better
MRIQC , [@Atkinson1997]
FBER
Ratio of "mean energy" within head vs air
higher better
MRIQC , [@Shehzad2015]
FWHM
Estimation of image smoothness. Higher values mean blurry.
MRIQC
SNR
SNR within brain mask.
higher better
MRIQC
BOLD summary stats
BOLD intensity summary stats (mean, stdev, p95, p05)
MRIQC
Global correlation (GCor)
Average correlation between every voxel and every other voxel
AFNI , MRIQC , [@Saad2013]
Temporal standard deviation (tSD)
Map of temporal standard deviation
lower better
MRIQC , [@Marcus2013]
Temporal SNR (tSNR)
Map of temporal mean divided by standard deviation
higher better
MRIQC
Ghost to signal ratio (GSR)
Measures amount of signal in regions prone to ghosting
lower better
MRIQC
AFNI outlier ratio (AOR)
Mean fraction of "outliers" per fMRI volume using AFNI 3dToutcount
lower better
AFNI , MRIQC
AFNI quality index (AQI)
Mean "quality index", which for each volume is 1 - correlation to median volume
lower better
AFNI , MRIQC
Number of dummy scans
Number of non-steady state dummy scans
MRIQC
Carpet plot
BOLD time series for a set of ROIs arranged in a matrix
MRIQC , [@Power2017]
Air signal
mean BOLD time series for a set of background/air slices
MRIQC
Measure
Summary
Interpretation
References
DVARS
Measures amount of signal change between consecutive time points (time series)
spikes indicate significant motion
MRIQC , NiPype , fsl_motion_outliers
, [@Power2012]
Framewise displacement (FD)
Sum of absolute translation and rotation displacements in mm at each time point (time series)
spikes indicate significant motion
MRIQC , NiPype , [@Jenkinson2002], [@Power2012]
Measure
Summary
Interpretation
References
Co-registration cost
Cost function for rigid registration between BOLD and T1
lower better
XCP
Brain mask overlap
Dice or Jaccard brain mask overlap coefficient between resampled BOLD and T1
higher better
XCP
TODO
Diffusion weighted imaging (DWI)
Measure
Summary
Interpretation
References
Mean neighbor correlation
Average Pearson correlation between each diffusion image and its q-space nearest neighbor
expected range [0.6, 0.8]
QSIprep , DSI Studio , [@Yeh2019]
Dropout slice count
Count of slices with significant signal dropout
expected less than 0.1%
QSIprep , DSI Studio , [@Yeh2019]
Fiber coherence index
Measures how well fibers are connected to each other
low values indicate flipped b-vectors
QSIprep , DSI Studio , [@Schilling2019]
Fiber orientation modeling
TODO
TODO
TODO