An Independent Multichannel Imaging Research System for Ultrashort Echo Time Imaging on Clinical MR Systems

Most clinical magnetic resonance systems do not have access to ultrashort echo time (UTE) imaging. The aim of this project was to develop a fully independent imaging insert for clinical MR systems to provide this new research application without disturbing routine operation. The initial clinical target for the system was improved orthopedic upper limb imaging using ultrashort repeat and echo time acquisitions. Echo times as short as TE 1⁄4 80 ls were attained for standard 2DFT gradient echo sequences and TE 1⁄4 25 ls for asymmetrically sampled radial acquisitions using the 160 mm inside diameter symmetrical cylindrical insert gradient set. The spectrometer was able to acquire 32 channels simultaneously with 14 bit resolution at up to 2.5 MS/s and had broadband operation from 250 kHz up to 200 MHz. Only eight active RF channels were constructed and used for this study. Acoustic noise with the insert coil was up to 30 dbA quieter than a whole body gradient system operating at the same gradient strength. The insert provides a useful method of performing UTE imaging using a standard clinical MRI system with no disturbance to normal operation. 2009 Wiley Periodicals, Inc. Concepts Magn Reson Part B (Magn Reson Engineering) 35B: 80–88, 2009