Image technique optimization in MR imaging of a titanium alloy joint prosthesis.

The purpose of this study was to explore systematically the effect of the imaging parameters changeable by the user in spin-echo (SE) imaging sequences to minimize image distortion when imaging joint prostheses. A titanium alloy hip joint prosthesis was studied at I.O.T. The SE imaging parameters were bandwidth/pixel(BW/ p), TE, strength of encoding gradients (matrix size), echo train length (ETL), and direction of phase and frequency encoding. The effect of ETL in rapid acquisition relaxation enhanced (RARE) sequences was also evaluated with a turbo-SE sequence using a different ETL with the same TR and an effective TE. It is concluded that an optimized image quality can be achieved in SE imaging by using a high bandwidth/pixel value (at least 130 Hz/pixel), a high resolution matrix (256-512), sequences with multiple refocusing, and a frequency-encoding axis parallel to the long axis of the prosthesis. The degree of distortion is reduced with this optimized technique.