From the Guidelines
MRI of the lumbar spine is generally the preferred initial imaging modality for most lumbar spine conditions due to its excellent soft tissue detail, non-invasive nature, and comprehensive visualization capabilities. CT myelogram and MRI of the lumbar spine are both imaging techniques used to evaluate spinal conditions, but they have different applications. MRI is particularly good for visualizing disc herniations, nerve compression, spinal cord abnormalities, and inflammatory conditions [ 1 ]. A CT myelogram, which involves injecting contrast dye into the spinal canal followed by CT scanning, is typically reserved for specific situations where MRI is contraindicated (such as in patients with pacemakers or certain metal implants), when MRI results are inconclusive, or when more detailed imaging of bony structures is needed [ 1 ].
Some key differences between CT myelogram and MRI of the lumbar spine include:
- CT myelogram has safety advantages over MRI for patients who have implanted medical devices that are not MRI safe or conditional [ 1 ]
- CT myelogram can be useful in patients with significant artifact from metallic surgical hardware on MRI [ 1 ]
- CT myelogram is more invasive and carries risks including headache, infection, and radiation exposure [ 1 ]
- MRI has excellent soft-tissue contrast and accurately depicts lumbar pathology, including disc degeneration, as well as the thecal sac and neural structures [ 1 ]
The choice between these imaging modalities should be based on the specific clinical question, patient factors, and availability, with MRI generally being the preferred initial option for most lumbar spine evaluations due to its comprehensive visualization capabilities and safety profile [ 1 ].
From the Research
Computed Tomography (CT) Myelogram vs Magnetic Resonance Imaging (MRI) of the Lumbar Spine
The main differences between a CT myelogram and an MRI of the lumbar spine are:
- Imaging technique: A CT myelogram involves the instillation of intrathecal contrast media to evaluate spinal canal pathology, whereas an MRI uses magnetic fields and radio waves to produce detailed images of the lumbar spine 2.
- Soft-tissue contrast: MRI has superior soft-tissue contrast, making it excellent for identifying details of spinal anatomy, including intraspinal contents, neural foramina, joints, ligaments, intervertebral discs, and bone marrow 3.
- Bony structures: CT is better suited for imaging cortical bony structures of the spine 3.
- Indications: CT myelography is an alternative to MR imaging in patients with contraindications to MR imaging or in the evaluation of spinal cerebrospinal fluid leaks 3, 2.
- Sensitivity: CT myelography has a greater sensitivity in revealing stenosis compared to MRI, particularly in patients with multilevel stenosis 4.
Key Findings
- CT myelography can provide additional information beyond MRI in patients with lumbar degenerative disease, particularly in those with multilevel stenosis 4.
- MRI is a useful imaging technique for identifying details of spinal anatomy and can be used in conjunction with CT myelography to provide a more comprehensive evaluation of the lumbar spine 3, 5.
- The choice of imaging modality depends on the specific clinical question and the patient's individual needs 6.
Advantages and Disadvantages
- Advantages of CT myelography:
- Greater sensitivity in revealing stenosis
- Useful in patients with contraindications to MR imaging
- Disadvantages of CT myelography:
- Invasive test
- May not provide additional information in patients with single-level stenosis or no stenosis on MRI
- Advantages of MRI:
- Superior soft-tissue contrast
- Non-invasive
- Disadvantages of MRI: