Can X-ray Show Spinal Stenosis?
X-rays can show indirect signs of spinal stenosis such as osteophytic narrowing of the spinal canal, but they are inadequate for diagnosis and should not be used as the initial imaging modality—MRI is the gold standard. 1
Why X-rays Are Insufficient
X-rays may demonstrate bone destruction and osteophytic narrowing of the spinal canal in spondylotic myelopathy, but CT provides superior visualization of the osseous spine compared to radiographs. 1
There is no relevant literature supporting the use of radiographs as the initial imaging evaluation of chronic or progressive myelopathy or spinal stenosis. 1
MRI provides far better visualization of the spinal cord, marrow, and spinal canal contents—the critical structures involved in spinal stenosis—compared to plain radiographs. 1
The Appropriate Imaging Algorithm
First-Line Imaging: MRI Without Contrast
MRI lumbar or cervical spine without IV contrast is the preferred initial imaging modality for evaluating suspected spinal stenosis, as it accurately depicts soft-tissue pathology, assesses vertebral marrow, and evaluates spinal canal patency. 1, 2, 3
MRI has superior soft-tissue resolution and multiplanar capability, making it ideal for evaluation of the spinal canal and its contents as well as surrounding structures. 1
When CT May Be Useful
CT can depict bony encroachment on the spinal canal from disc-osteophyte complexes with better resolution than radiographs, but MRI still provides better visualization of the marrow and spinal cord. 1, 3
CT lumbar spine without IV contrast can answer whether cauda equina compression is present—50% thecal sac effacement on CT predicts significant spinal stenosis, and <50% reliably excludes cauda equina impingement. 1
Limited Role for X-rays
- Lateral radiographs can be obtained only as an adjunct to cross-sectional imaging (MRI or CT) to help assess alignment parameters and dynamic instability—not for diagnosing stenosis itself. 1
Critical Clinical Pitfalls
Radiographic changes associated with stenosis are very common with aging, and not all patients with anatomic narrowing develop symptoms—clinical correlation is essential. 4, 5
The term "lumbar spinal stenosis" refers to a clinical syndrome of lower extremity pain caused by mechanical compression, not merely the pathoanatomic finding of canal narrowing on imaging. 4
Imaging findings alone may not correlate with clinical presentation—failing to correlate symptoms with imaging can result in unnecessary interventions. 2, 3
Spinal stenosis can result from various pathologies including degenerative changes, ligamentum flavum hypertrophy, facet joint arthropathy, and congenital narrowing—not just disc pathology. 3
When Advanced Imaging Is Needed
CT myelography may be useful before surgical intervention or when MRI shows borderline stenosis but clinical history strongly suggests symptomatic stenosis, as it demonstrates the dynamic component that cannot be appreciated on plain CT or MRI. 1, 6
In patients with good history of symptomatic stenosis and borderline findings on MRI, CT myelography with erect lateral flexion/extension views is recommended as the definitive pre-operative investigation. 6