A paired dataset of multi-modal MRI at 3 Tesla and 7 Tesla with manual hippocampal subfield segmentations on 7T T2-weighted images

We disseminate a dataset comprising paired 3T and 7T MRI scans from 20 healthy volunteers, with manual hippocampal subfield annotations on 7T T2-weighted images. This dataset is designed to support the development and evaluation of both 3T-to-7T MR image synthesis models and automated hippocampal segmentation algorithms on 3T images. We assessed the image quality using MRIQC. The dataset is freely accessible on IEEE DataPort, a data repository created by IEEE and can be found at the following URL: https://ieeexplore.ieee.org/document/10218394/algorithms?tabFilter=dataset. The shared dataset comprises four principal directories.The first directory contains raw MRI data in <i>.ima</i> format within <i>rawdata_DICOM</i>. Additionally, the acquired MRI scans were converted from DICOM to the Neuroimaging Informatics Technology Initiative (NIfTI) format and organized in accordance with the Brain Imaging Data Structure (BIDS) format by employing the BIDScoin Python application (version 4.3.0) and stored in <i>rawdata_BIDS</i> directory.The third directory pertains to hippocampal subfield segmentation and includes two subdirectories: '<i>hippo_subfield\7T_T2w_0.7_for_subfield_delineation</i>', featuring 7T T2w MRI data downsampled to a 0.7 mm slice thickness through B-spline interpolation, post Gaussian smoothing denoising and N4 bias field correction using Advanced Normalization Tools (ANTs); and <i>'hippo_subfield\hippo_label</i>', which contains the manual segmentation labels for hippocampal subregions for each subject. The fourth directory,<i> \MRIQC</i>, designated for the results of quality control assessments. For each participant, the<i> \MRIQC </i>directories contain <i>\anat</i> and <i>\func</i> subdirectories, which hold image quality metric reports for T1w, T2w, and resting-state functional scans. These quality metrics, available in both <i>.html</i> and <i>.json</i> formats, aid in evaluating data quality and provide estimates of motion, signal-to-noise ratios, and intensity non-uniformities, supplemented with visual reports.It is noteworthy that, due to detectable head motion during the original scans, the 3T T2w images for two participants were subject to rescanning. Subsequently, only the datasets from these supplementary sessions have been preserved within the <i>rawdata\BIDS</i> directory for further quality evaluation. Additionally, Diffusion Weighted Imaging (DWI) sequences included in the <i>rawdata\DICOM</i> directory for 3T MRI were not matched with 7T MRI sequences and, thus, are excluded from the BIDS-formatted shared dataset.<br>