MRI is ideal because it is a multi-series, multi-directional scan that can be performed in transverse, sagittal and coronal positions, which is more conducive to observing whether the spinal canal is narrowed and whether the surrounding nerve roots are compressed. However, there are disadvantages to MRI. It takes about 10 minutes to perform an MRI, and if the patient is in pain and cannot lie down, the image will be blurred and the patient’s condition cannot be accurately determined. If the patient is in severe pain and cannot hold on, CT is used first because it is fast and less expensive. If the patient’s condition is stable, MRI is recommended for detailed and accurate observation.