Robust T2 Mapping in the Presence of Large B1+ Inhomogeneities

Motivation: Large B1+ variations near metallic implants results in errors in quantitative measurements. Goal(s): We propose a robust T2 relaxometry technique that accounts for large B1+ inhomogeneities near metallic implants. Approach: We developed a multi-echo TSE sequence that uses variable excite and refocusing flip angles to sensitize the sequence to both T2 and B1+ variations. We propose the use of two fitting algorithms to estimate B1+ robust T2 estimates. Results: In the presence of metallic implants, the proposed technique allows improved estimation of the B1+ variations which in turn improves the T2 estimation. Impact: The use of a B1+ sensitized TSE sequence to estimate T2 relaxometry can improve estimation performance in areas of large B1+ inhomogeneities near metallic implants. This would allow quantitative assessment and characterization of bone pathology near the arthroplastic implant interface.