Diagnostic imaging is used to confirm an anatomical lesion or injury as a cause of back pain or neck pain. It can be useful in determining the source and extent of the underlying problem to establish the diagnosis and development of an appropriate treatment plan for the patient’s pain problems.
Radiological imaging shows only anatomy, it cannot show pain. Only the doctor can determine if something that looks abnormal on a scan is the source of the pain or just an incidental finding on a radiological test. If the abnormality seen on a radiological image is a source of the pain, then anesthetizing the area nerves should make the pain better. If the pain improves temporarily, then the abnormality was contributing to the pain. If the pain does not improve, then the source of the pain is somewhere else.
Diagnostic Radiological Imaging and Tests
|test||structures seen||what it detects||example|
|X-ray||bone||extent of wear, bone disease, misalignment||osteoarthritic changes, fracture, bone spurs, slippage|
|CT||bone, soft tissue||relationship of bones, soft tissues, nerve roots||stenosis, bone spurs, spinal canal narrowing, disc herniation|
|MRI||soft tissue||detail of soft tissues, discs, nerve roots, spinal cord||disc herniation, tumor|
(x-ray fluoroscope), CT/myleogram
|spinal canal seen by dye injection||view of spinal cord and nerve roots in relation to bone||pinched nerve, bony overgrowth, spinal abcess, tumor|
|Nerve Conduction Study
|nerve, muscle||test of muscle and nerve function||nerve damage|
Diagnostic Pain Management Procedures
Injections, often referred to as “nerve blocks,” are sometimes called diagnostic injections when they help pinpoint the source of the pain.
There are selective nerve root injection, medial branch block (MBB), sacro-iliac joint block, and others. The choice of diagnostic injection is usually based on the patient’s history, examination, and findings on radiological imaging.
Nerve Root Injection is a procedure in which one of the major nerves that comes from the spine is numbed. It is much more useful for diagnosis than an epidural. If we think of an epidural as a shotgun, then a selective nerve root injection is like using a rifle with a laser scope.
Sacro-iliac joint injection is used to verify whether the sacro-iliac joint causes the pain. If we anesthetize the sacro-iliac joint, and pain goes away – it was coming from the sacro-iliac joint. Then we can inject it with anti-inflammatory medication, and that might help take away the edema and relieve the pain.
Medial Branch Block is the procedure that is used to determine whether any of facet joints contribute to neck or back pain. There is no much correlation between the X-ray or CT image of the facet joint and the pain. Joints that look bad may not be a source of pain, and joints that appear normal may cause pain. The medial branches are the nerves that surround the facet joints. If we numb these nerves related to a specific joint, and the pain goes away – then it was caused by this particular joint. In such a case we can destroy the nerve and it may help control the pain for up to eighteen months.
Discography or Discogram is a very useful test. It is usually used when a surgery is under consideredation. Discography can tell whether a disc that looks problematic on an MRI scan actually causes the pain. When we inject a healthy disc, it does not hurt, but when the procedure is performed on an abnormal disc it usually hurts. and the pain is similar to the pain the patient complains for.