Lumbosacral (LS) spine MRI

Your healthcare practitioner may order this test if you have:

• Pelvic pain or low back pain that does not improve after treatment
• Numbness or weakness in legs that worsens with time
• Birth defects of the lower spine
• Back pain and fever
• Problems emptying or controlling your bladder
• Multiple sclerosis
• Disk herniation, the damage to the tissue between the bones of the lower spine
• Injury or trauma to the lower spine
• History or signs of cancer and pain in the lower back 

MRI LS scan with a contrast dye is especially used in the following conditions:

• To differentiate causes of lower back pain and lumbar radiculopathy
• To distinguish recurrent disc herniation after operation of spine
• To show nerve roots in viral or inflammatory conditions
• To detect tumours

This test is very safe for most people. However, it may not be recommended in the following conditions:

• If you have metal implants or fragments: It does not necessarily mean you cannot undergo the test. The final decision will be taken by the medical staff carrying out the scan. In some cases, it is possible to make metal implants, like pacemakers, MRI-safe.
• If you have tattoos on your body: Most tattoos are safe, but some tattoo ink may contain traces of metal. Inform the radiography staff if you feel heat or discomfort in your tattoo during the scan.

Generally, you are not supposed to eat or drink for four to six hours before the scheduled time of the procedure. If you have a fear of closed spaces (claustrophobia), you may be given a sedative or anaesthesia that will help you feel sleepy or less anxious. 

Also, tell your healthcare provider or radiologist if you have:

• Brain aneurysm clips
• Pacemaker or heart defibrillator
• Artificial heart valves
• Cochlear (inner ear) implant
• Artificial joints that have been placed recently
• Vascular stents
• Kidney disease/dialysis
• Worked with sheet metal in the past

An MRI scan usually involves the following steps:

• The radiography staff will ask you to remove all metal objects, such as a watch, jewellery and keys, before entering the scan room.
• They may give you a hospital gown to change into.
• You will have to lie on the scanner’s narrow table. The table will slide into the large cylindrical tube of the MRI machine. 
• If the procedure requires a contrast dye, it may be administered into your body through IV or injection before the test. The contrast helps to view certain areas more clearly.
• The test may last for 30-60 minutes or longer.

MRI is a painless procedure. You might feel the table of the MRI scanner to be hard/cold. In such instances, you can ask for a pillow or blanket. The scanner may make loud noises during the procedure. The radiography staff will provide you with earplugs to help reduce the noise.

The MRI images will be interpreted by the radiologist, who will send a detailed report to your physician. Then, the physician will discuss the results with you. Abnormal results may be due to any of the following conditions:

• Spinal stenosis (narrowing of the spinal column)
• Lumbar radiculopathy (herniated or slipped disc)
• Spondylitis (abnormal wearing of the spinal bones and cartilage)
• Degenerative changes due to age
• Bone infection
• Osteoporosis resulting in fracture of the lower back
• Spinal cord injury/abscess
• Syringomyelia (a disorder characterised by a fluid-filled pocket formed within the spinal cord)
• Ankylosing spondylitis (inflammation of the joints that primarily affects the spine)
• Cauda equine syndrome (damage to a group of nerves that spread out from the bottom of the spinal cord)
• Diskitis (inflammation of the disk)
  • Spinal tumour
  • Infection of the sacroiliac joint (joint between the sacrum and a hip bone)
  • Sacral meningeal cysts (fluid-filled sacs that affect the nerves of the sacral region)
  • Sacral fractures
  • Sacral fatigue stress fracture (due to abnormal stresses from intense training
  • Sacral tumours
  • Sacral agenesis observed in children (absence of the sacrum and coccyx and portions of lumbar spine)

 The test involves a safe scanning procedure. Some complications that may occur are as follows:

• In rare cases, the contrast injected before the test may cause an allergic reaction.
• The scanner can disrupt the working of pacemakers and other implants.

If sedatives were taken for the test, you might need to rest until its effects wear off and avoid driving or using heavy machinery. 

If you were injected with contrast during the procedure, you would be monitored for side effects like swelling, itching, rash and difficulty in breathing. In case you see any redness or swelling at the site of IV or injection, tell your healthcare practitioner as it may be a sign of infection.

Some of the additional tests that can be performed along with this test include:

• Electromyography
• Nerve conduction velocity

Disclaimer: All results must be clinically correlated with the patient’s complaints to make a complete and accurate diagnosis. The above information is provided from a purely educational point of view and is in no way a substitute for medical advice by a qualified doctor.