Multi-Site Fat-Water Phantom MRI Data

<p><strong>Dataset description:</strong> Accompanying data for manuscript &ldquo;Multi-Site,</p> <p>Multi-Vendor Validation of the Accuracy and Reproducibility of</p> <p>Proton-Density Fat-Fraction Quantification at 1.5T and 3T using a</p> <p>Fat-Water Phantom&rdquo;, submitted for publication in Magnetic Resonance in</p> <p>Medicine in January 2016.</p> <p>&nbsp;</p> <p><strong>Details:</strong> The &#39;datasets&#39; folder contains multiple MATLAB MAT-files</p> <p>files with chemical shift-encoded (CSE) MRI data for validation of fat</p> <p>quantification techniques in a fat-water phantom. Data was acquired at</p> <p>six sites with different MRI vendors, two field strengths (1.5T and</p> <p>3T) per site, and two protocols per field strength. The goal of these</p> <p>techniques is to measure proton-density fat-fraction (PDFF) accurately</p> <p>and reproducibly. Data from site 1 was acquired both at the beginning</p> <p>(October 2014) and at the end (December 2015) of this study, in order</p> <p>to evaluate the integrity of the phantom.&nbsp;</p> <p>&nbsp;</p> <p>Details on the vendors, platforms and protocols are described in the</p> <p>file &#39;vendors_platforms_protocols.pdf&#39; in this same folder.</p> <p>&nbsp;</p> <p>The phantom consists of 11 vials with different fat concentrations</p> <p>(PDFF = 0%, 2.6%, 5.3%, 7.9%, 10.5%, 15.7%, 20.9%, 31.2%, 20.9%,</p> <p>31.2%, 41.3%, 51.4% and 100%, respectively). At each magnet, the vials</p> <p>were arranged horizontally along the B0 field and scanned with axial</p> <p>slices using a 3D multi-echo spoiled gradient echo pulse sequence.</p> <p>&nbsp;</p> <p>Each of the MAT-files contains the acquired complex-valued images over</p> <p>the three central slices within the phantom vials. The structure</p> <p>&#39;imDataAll&#39; contains the acquired data, with the following fields:</p> <p>&#39;TE&#39; (echo times), &#39;FieldStrength&#39; (in Tesla), &#39;PrecessionIsClockwise&#39;</p> <p>(describing whether water has higher resonance frequency than fat</p> <p>according to the reconstruction convention), &#39;echo_polarity&#39; (relative</p> <p>polarity of the acquired echoes, ie: monopolar vs bipolar readouts),</p> <p>&#39;images&#39; (five-dimensional array containing the complex valued images,</p> <p>coil-combined in datasets received with multiple channels, with</p> <p>dimensions X x Y x Slices x Coils x Echoes).</p> <p>&nbsp;</p> <p>Additionally, the MAT-files contain reconstruction results as</p> <p>described in the manuscript, in the arrays &#39;fwmc_*&#39; of size X x Y x</p> <p>Slices. Note that the nomenclature &#39;fwmc&#39; stands for &#39;Fat-Water</p> <p>separated with Magnitude fitting (performed after complex fitting in</p> <p>order to obtain full 0-100% range of PDFF while avoiding errors</p> <p>related to phase shifts in the data), and a Common initial phase for</p> <p>the water and fat signals. The specific arrays are &#39;fwmc_ff&#39; (PDFF</p> <p>map), &#39;fwmc_r2star&#39; (R2*=1/T2* decay rate), &#39;fwmc_w&#39; (water image),</p> <p>&#39;fwmc_f&#39; (fat image).</p>