Problem 10.5 Assume that the slice select gradient amplitudes are changed from those shown in Fig. 10.11 to be Gp. = Gny, = 2Gp.. What are the angles @ and of the resulting slice? Draw the excited plane (use Fig. 10.10 as a guide). The angles are shown in Fig. 10.10. It must also be remembered that the read and phase encoding directions are required to be orthogonal to the slice select direction. The Cartesian components for the associated gradients must therefore satisfy the orthogonality conditions & T (},,,, =G pp Gy = 0. Fig. 10.10: Slice selection at an arbitrary direction by a gradient vector perpendicular to the slice selection axis. Here the arbitrary gradient vector requires all three gradients ., G, and G- to be e used. The spherical angles of the gradient vector are the polar angle and the azimuthal angle