When should one go for MRI scan & CT scan for spine for low back pain? – Dr. Kodlady Surendra Shetty

It is not advisable to go for a CT scan unless advised by a surgeon because CT scan has the disadvantage of radio waves like X rays are nor good for health. So exposure of more X rays to the body are not good. So it should be done only with the advice of a surgeon. There are certain advantages of Ct scan like we can make out bony structures better than MRI. Otherwise MRI is always beneficial. Suppose there is a pain for 3 to 5 days, pain is mild and not producing a neurological deficiency then we don’t have to go for MRI. A simple X ray or sometimes a clinical examination will be enough. With some pain killers or muscle relaxant the pain disappears. It will not last for a week or so. Suppose the pain persists for more than 3 months then we call it as a chronic low back pain. In chronic low back pain to assess the condition of the spine, MRI is very essential. In this the standing MRI is much better than the sleeping regular MRI because most of the back and neck pain are posture related. So when the patient stands or walks or sits the pain increases. When he lies down pain decreases. That is why the standing MRI has a better place than the regular MRI. MRI will give clear picture about the disc, whether it is degenerated or whether it is normal, whether it si bulging or whether there is a protrusion of the disc or there is a herniation of the disc. At the same time it will also give nerve structure, whether there is pressure on the nerve, degeneration of the nerve. All these things we can make out with an MRI. So one should go for MRI if the pain is more than 3 months and even in some cases when it is less than 3 months and the pain is too severe. A cruciating pain with radiating pain along the legs, then for assessment we need an MRI. Sometimes with a nerve weakness, there is foot drop, suddenly the patient is not able to lift the foot, in those cases we have to go for an MRI. In case of Cauda equina syndrome, when there is a severe pressure on the lower part of the spinal cord, below or at L1 level vertebra there will be certain loss of control of bowel and bladder. So suppose that happens even if the pain is for one day we go for an MRI because that needs immediate surgical attention.