From 17bbb89515e15169349950f43771886b32e63be0 Mon Sep 17 00:00:00 2001
From: Mathieu Boudreau
\n", - "Efforts have been made to develop quantitative MRI phantoms to assist in standardizing T1 mapping methods (Keenan et al. 2018). A quantitative MRI standard system phantom was created in a joint project between the International Society for Magnetic Resonance in Medicine (ISMRM) and the National Institute of Standards and Technology (NIST) (Stupic et al. 2021), and has since been commercialized (Premium System Phantom, CaliberMRI, Boulder, Colorado). The spherical phantom has a 57-element fiducial array containing spheres with doped liquids that model a wide range of T1, T2, and PD values. The reference values of each sphere were measured using NMR at 1.5T and 3T (Stupic et al. 2021). The standardized concentration for relaxometry values established as references by NIST are also used by another company for their relaxometry MRI phantoms (Gold Standard Phantoms Ltd., Rochester, England). The cardiac TIMES phantom (Captur et al. 2016) is another commercially available system phantom focusing on T1 and T2 values in blood and heart muscles, pre- and post-contrast. The ISMRM/NIST phantom has been used in several large multicenter studies already, for example in (Bane et al. 2018) where they compared measurements at eight sites on a single ISMRM/NIST phantom using the inversion recovery and VFA T1 mapping protocols recommended by NIST, as well as some site-specific imaging protocols used for dynamic contrast enhanced (DCE) imaging. Bane et al. (Bane et al. 2018) concluded that the acquisition protocol, field strength, and T1 value of the sample impacted the level of accuracy, repeatability, and interplatform reproducibility that was observed. In another study led by NIST researchers (Keenan et al. 2021), T1 measurements were done at two clinical field strengths (1.5T and 3.0 T) and 27 MRI systems (three vendors) using the recommended NIST protocols. That study, which only investigated phantoms, found no significant relationship between T1 discrepancies of the measurements and the MRI vendors used.\n", + "Efforts have been made to develop quantitative MRI phantoms to assist in standardizing T1 mapping methods (Keenan et al. 2018). A quantitative MRI standard system phantom was created in a joint project between the International Society for Magnetic Resonance in Medicine (ISMRM) and the National Institute of Standards and Technology (NIST) (Stupic et al. 2021), and has since been commercialized (Premium System Phantom, CaliberMRI, Boulder, Colorado). The spherical phantom has a 57-element fiducial array containing spheres with doped liquids that model a wide range of T1, T2, and PD values. The reference values of each sphere were measured using NMR at 3T (Stupic et al. 2021). The standardized concentration for relaxometry values established as references by NIST are also used by another company for their relaxometry MRI phantoms (Gold Standard Phantoms Ltd., Rochester, England). The cardiac TIMES phantom (Captur et al. 2016) is another commercially available system phantom focusing on T1 and T2 values in blood and heart muscles, pre- and post-contrast. The ISMRM/NIST phantom has been used in several large multicenter studies already, for example in (Bane et al. 2018) where they compared measurements at eight sites on a single ISMRM/NIST phantom using the inversion recovery and VFA T1 mapping protocols recommended by NIST, as well as some site-specific imaging protocols used for dynamic contrast enhanced (DCE) imaging. Bane et al. (Bane et al. 2018) concluded that the acquisition protocol, field strength, and T1 value of the sample impacted the level of accuracy, repeatability, and interplatform reproducibility that was observed. In another study led by NIST researchers (Keenan et al. 2021), T1 measurements were done at two clinical field strengths (1.5T and 3.0 T) and 27 MRI systems (three vendors) using the recommended NIST protocols. That study, which only investigated phantoms, found no significant relationship between T1 discrepancies of the measurements and the MRI vendors used.\n", "
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