A phantom for diffusion-weighted MRI (DW-MRI)

Purpose To develop tissue‐equivalent diffusivity materials and build a spherical diffusion phantom which mimics the conditions typically found in biological tissues. Also, to assess the reproducibility of ADC measurements from a whole‐body diffusion protocol. Materials and Methods Nickel‐doped agarose/sucrose gels were manufactured and used to build a spherical diffusion phantom with tissue‐equivalent relaxation and diffusion compartments. The temporal stability of the gels was monitored for a period of 8 weeks and, using the same measurements, the reproducibility of ADC was assessed in a 1.5 Tesla (T) clinical system. Results The temporal stability of the nickel‐doped agarose/sucrose gels diffusion properties was excellent (average coefficient of variation [CV] for ADC in all phantom compartments = 1.27%). The average CV for ADC measurements, excluding the phantom compartments affected by artifacts, was 0.76% showing that the reproducibility of ADC measurements using an EPI DW‐MRI protocol is very good. Conclusion Nickel‐doped agarose/sucrose gels can be used as reference materials for MRI diffusion measurements and show excellent short‐term stability with respect to ADC. A phantom made of these materials can be invaluable in optimizing DW‐MRI protocols, developing novel pulse sequences for DW‐MRI, or comparing ADC values among field strengths, vendors, and imaging centers. J. Magn. Reson. Imaging 2013;38:173–179. © 2013 Wiley Periodicals, Inc.