# Compressed-sensing diffusion spectrum imaging (CS-DSI)

This dataset contains diffusion, anatomical, functional, and field mapping neuroimaging data
from a diffusion protocol comparison study used in
[Radhakrishnan et al. (2024)](https://doi.org/10.1002/hbm.26580).
Specifically, this dataset is the "prospective" dataset used in that paper.

## Diffusion spectrum imaging data

Four runs of segmented k-space and steady state echo planar (EP) diffusion-weighted (dMRI) data were collected (repetition time, TR=4300ms; echo time, TE=90ms; flip angle, FA=90°; field of view, FOV=230x230mm; voxel size=1.69x1.69x1.7mm; matrix size=136x136; MB factor=4). 
Each run was acquired with a different set of diffusion directions, described briefly below:

acq-HASC92: This corresponds to the HA-SC92 CS-DSI scheme from the paper.
There are 92 unique directions.

acq-HASC55 run-01: This corresponds to the HA-SC55–1 CS-DSI scheme from the paper.
There are 55 unique directions.

acq-HASC55 run-02: This corresponds to the HA-SC55–2 CS-DSI scheme from the paper.
There are 55 unique directions.

acq-RAND57: This corresponds to the RAND57 CS-DSI scheme from the paper.
There are 57 unique directions.

The HA-SC92+55–1 and HA-SC92+55–2 CS-DSI schemes can be reconstructed by
preprocessing the HA-SC92 and HA-SC55 files and then concatenating them
before doing any reconstruction.
HA-SC92+55–1 uses HA-SC92 and HA-SC55-1, while HA-SC92+55–2 uses HA-SC92 and HA-SC55-2.

## Anatomical MRI data

One run of T1-weighted segmented k-space, spoiled, and MAG prepared gradient recalled and inversion recovery (GR/IR) single-echo structural MRI data were collected (256 slices; repetition time, TR=2500ms; echo time, TE=2.9ms; flip angle, FA=8°; field of view, FOV=176x256mm; matrix size=176x256; voxel size=1x1x1mm).

## Functional MRI data

One run of rest eyes open segmented k-space echo planar (EP) single-echo fMRI data was acquired according to the ABCD protocol (60 slices in interleaved ascending order; repetition time, TR=800ms; echo time, TE=30ms; flip angle, FA=52°; field of view, FOV=216x216mm; matrix size=90x90; voxel size=2.4x2.4x2.4mm; MB factor=6). Run duration was 5:01 minutes, during which 376 volumes were acquired.

## Field map data

dir-PA_epi: EPI maps with the opposite phase encoding direction to the DWI scans,
meant to be used for distortion correction of the DWI data.

dir-AP_epi: EPI maps with the opposite phase encoding direction to the fMRI scans,
which can be used for distortion correction of the fMRI data.
However, fMRIPrep does not support TOPUP-style distortion correction,
so we recommend using the phase-difference field maps we also acquired for the fMRI data.

phasediff, magnitude1, magnitude2: Phase-difference field maps for the fMRI scans.