OSI²ONE Low-field MRI Reference System Data

This dataset was acquired with the OSI²ONE reference system, submitted to the special issue "How to Build Your Own Low-Field MR Scanners, the Open-Source Way" of NMR in Biomed and includes all data used for the publication. The reconstructions can be reproduced using Jupyter notebooks, which can be run in the browser via Google Colab. Just click the “Open in Collab” button at the top of the respective notebook under /src The system is fully open source and composed of the following components which described in further detail in the paper (the links point to the corresponding repository). Permanent magnet in ROMA configuration with an inner diameter of 322 mm and a weight of approx. 100 kg. $B_0$ of 48.47 mT measured at a room temperature of 24.7 °C and the measured inhomogeneity is 1602 ppm in 200 mm DSV (without active shimming) 3 channel A4IM gradient coil with a rotated basis pointing along (X+Y), (X-Y) and Z with calculated mean efficiencies of 0.39, 0.4 and 0.39 mT/m/A. Gradient power amplifier (GPA) with +/- 15 A peak current and 30 % duty cycle per channel RF power amplifier (RFPA) designed and manufactured by barthel HF-Technik GmbH, Aachen, Germany (RFPA-Shoebox), will be released as open source Nexus console with M2p.6546-x4 and M2p.5933-x4 measurement cards from Spectrum Instrumentation GmbH operated by Nexus console software System control unit (SCU) equipped with a passive Tx/Rx-switch and preamplifier with a noise figure of approx. 3 dB and 46 dB gain Head RF coil with elliptical cross-section (inner diameter of 233 x 213 mm) Phantom RF coil with circular cross section (inner diameter of 150 mm) Data was acquired for three different phantoms: Open source OSI²ONE Hello World phantom was used for the quality assessment scan (QA) The CaliberMRI phantom for low-field MRI with quantitative reference values was used for $T_1$-mapping, $T_2$-mapping, $B_0$-mapping, $PD$-weighted and $T_2$-weighted imaging The open source digital CaliberMRI phantom was used for $T_1$-mapping and $T_2$-mapping simulations A sphere phantom with a diameter of 165 mm filled with deionized water and 1.25 g/L NiSO4 x 6H20 Each acquisition folder contains the following files: The raw data in ISMRMRD format: ismrmrd_data.h5 The pulseq sequence used for the acquisition: sequence.seq Meta information containing the console configuration: meta.json Dicom image containing the image magnitude information: image_magnitude.dcm Dicom image containing the image phase information: image_phase.dcm If applicable a quantitative dicom result: e.g. t2_map.dcm / t1_map.dcm / b0_map.dcm Note that the simulation results, i.e. the quantitative result and the image magnitude and phase, are stored as nifti images