Improved signal spoiling in fast radial gradient-echo imaging: Applied to accurate T(1) mapping and flip angle correction.

In conventional spoiled gradient echo imaging utilizing quadratic radio frequency (RF) spoiling, nonideal signal intensities are often generated, particularly when repetition time is short and/or excitation flip angle (FA) becomes larger. This translates to significant errors in various quantitative applications based on T(1)-weighted image intensities. In this work, a novel spoiling scheme is proposed, based on random gradient moments and RF phases. This scheme results in a non-steady-state condition, but achieves ideal mean signal intensity. In order to suppress artifacts created by the inter-TR signal variations and at the same time attain the ideal signal intensity, radial data acquisition is utilized. The proposed method achieves ideal spoiling for a wide range of T(1), T(2), TR, and FAs. Phantom and in vivo experiments demonstrate improved performance for T(1) mapping and FA correction when compared with conventional RF spoiling methods.