MRI Protocol for Diagnosing Disc Herniation

Introduction to Diagnostic Imaging

The American College of Radiology recommends MRI lumbar spine without IV contrast as the most appropriate imaging study for diagnosing intervertebral disc herniation due to its superior ability to accurately depict soft-tissue pathology, assess vertebral marrow, and evaluate spinal canal patency 1, 2

MRI provides superior soft-tissue contrast, allowing excellent visualization of disc material, nerve roots, and spinal cord, with a high sensitivity and specificity for detecting lumbar disc herniation 3, 4

For cervical disc herniation, MRI cervical spine without IV contrast should be performed, as it best displays compression of the cord by disc herniation, bone fragments, and hematomas 4, 5
For patients with suspected cauda equina syndrome due to disc herniation, urgent MRI assessment is recommended 1, 2
For post-operative patients with suspected recurrent disc herniation, MRI without and with IV contrast may be helpful to distinguish recurrent/residual disc from post-operative scarring 6

CT myelography can be performed to assess for spinal canal narrowing due to disc herniation, but is inferior to MRI in assessing soft tissue pathology 3, 1
CT without IV contrast can answer whether cauda equina compression is present, with 50% thecal sac effacement on CT predicting significant spinal stenosis 1

MRI findings should be correlated with clinical symptoms, as disc abnormalities are common in asymptomatic patients 6
Failure to correlate MRI findings with clinical findings can lead to overdiagnosis of clinically insignificant soft tissue injuries, highlighting the importance of clinical correlation 3