Ultrashort echo time MRI of cortical bone at 7 tesla field strength: a feasibility study.

ABSTRACT

PURPOSE: To implement and examine the feasibility of a three-dimensional (3D) ultrashort TE (UTE) sequence on a 7 Tesla (T) clinical MR scanner in comparison with 3T MRI at high isotropic resolution. MATERIALS AND METHODS: Using an in-house built saddle coil at both field strengths we have imaged mid-diaphysial sections of five fresh cadaveric specimens of the distal tibia. An additional in vivo scan was performed at 7 Tesla using a quadrature knee coil. RESULTS: Using the same type of saddle coil at both field strengths, a significant increase in SNR at 7T compared with 3T (factor 1.7) was found. Significantly shorter T2* values were found at the higher field strength (T2* = 552.2 ± 126 µs at 7T versus T2* = 1163 ± 391 µs at 3T). CONCLUSION: UHF MRI at 7T has great potential for imaging tissues with short T2.