On axial images, dural sac cross-sectional area and anteroposterior (AP) dural sac diameter were measured at the level of the L3/4, L4/5, and L5/S1 discs.

• 在轴位图像上，硬脊膜囊的横截面面积和前后径分别在L3/4,L4/5和L5/S1椎间盘高度进行测量。