[Slice profile measurement using a crossed thin-ramps method in three-dimensional magnetic resonance imaging]

Recent progress in variable-flip-angle fast spin-echo technology has further extended the utility of three-dimensional (3D) magnetic resonance imaging (MRI) for clinical application. The slice profile in 3D MRI is the point spread function that has a sync form in principle, whereas a slice profile in 2D imaging provides information on characteristics of selective radio frequency excitation. We investigated the optimal condition to measure 3D slice profiles using a crossed thin-ramps phantom. We found that the profile data should cover a large area in order to evaluate both the main lobe and side lobes in the slice profile, and that the appropriate slice thickness was 2 mm. We also found that artifacts in the direction perpendicular to the slice create an offset error in the measured slice profile when 3D imaging. In this paper, we describe the optimal condition and some remarks on the slice profile evaluation for 3D MRI.