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

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. J. Magn. Reson. Imaging 2011;. © 2011 Wiley‐Liss, Inc.