New diffusion phantoms dedicated to the study and validation of high-angular-resolution diffusion imaging (HARDI) models

We present new diffusion phantoms dedicated to the study and validation of high‐angular‐resolution diffusion imaging (HARDI) models. The phantom design permits the application of imaging parameters that are typically employed in studies of the human brain. The phantoms were made of small‐diameter acrylic fibers, chosen for their high hydrophobicity and flexibility that ensured good control of the phantom geometry. The polyurethane medium was filled under vacuum with an aqueous solution that was previously degassed, doped with gadolinium‐tetraazacyclododecanetetraacetic acid (Gd‐DOTA), and treated by ultrasonic waves. Two versions of such phantoms were manufactured and tested. The phantom's applicability was demonstrated on an analytical Q‐ball model. Numerical simulations were performed to assess the accuracy of the phantom. The phantom data will be made accessible to the community with the objective of analyzing various HARDI models. Magn Reson Med 60:1276–1283, 2008. © 2008 Wiley‐Liss, Inc.