There are several kinds of tests that are generally done when you have lumbar spondylosis: X-ray, CT, MRI (magnetic resonance imaging), spinal canal imaging, discography, etc. These tests focus on each other and complement each other, but they cannot replace each other, and you cannot say what is the most expensive to do or what is the best to do. X-rays: mainly look at the sequence of the entire lumbar spine, stability, whether there is narrowing of the intervertebral space, osteophytes, etc. If abnormalities are found to see more specific may need to supplement the CT or MRI. CT: mainly observes the microstructure of the bone, whether there is protrusion of the intervertebral disc, whether there is narrowing of the spinal canal, especially in the observation of the lateral saphenous fossa is more superior, but its disadvantage is that the observation site is more limited, the parts that can not be scanned can not be observed, in the observation of the whole is not as good as X-ray and MRI. MRI: MRI mainly observes nerve compression, disc degeneration and other soft tissues. The advantage of MRI is that the scope of examination is wide, and multiple vertebrae and discs as well as the corresponding spinal cord can be observed in one examination. In addition, it has a unique role in observing spinal tumors and in diagnosing discogenic low back pain, because at this time the disc may not have protruded significantly, but only some changes in the internal structure, CT is not useful when the disc has not yet protruded, and CT cannot see the changes inside the disc. Vertebrogram: It is an invasive test in which a contrast agent is injected into the spinal canal and then an X-ray is performed. This test is being used less and less, but it has a unique role in showing the nerve roots, especially in patients with lumbar scoliosis. Discography: It is the gold standard test to understand the internal changes of the intervertebral discs, where the contrast agent is injected into the discs and an X-ray is performed. Most of them need to be combined with CT to further understand the microstructural changes inside the disc, and a lumbar MRI is needed before doing discography for initial screening of discs that may cause disease. In short, what tests are needed for lumbar spine diseases depends on the specific circumstances of the patient, on the need for diagnosis and treatment, and also on the level of knowledge of the doctor.