Tests and Diagnosis
Imaging Tests
X-Ray
Purpose
An X-ray examines the condition of your bones.
What It Can and Cannot Show
| What It Can Show | What It Cannot Show |
|---|---|
| Bone deformity (bone spurs) | The condition of your nerves |
| Disc height (indirectly) | Soft tissues (discs, ligaments) |
| Spondylolisthesis (slipping) | The degree of stenosis |
| Scoliosis, kyphosis | Herniated discs |
Key Features
- Quick and simple -- can be done right away
- Involves a small amount of radiation -- but the dose is low
- Taken while standing -- shows how your spine looks under your body weight
- Can reveal instability -- by comparing images taken while bending forward and leaning backward, your doctor can see whether a vertebra shifts with movement
MRI (Magnetic Resonance Imaging)
Purpose
MRI provides detailed images of your nerves and soft tissues. It is the single most important test for diagnosing spinal stenosis.
What It Shows
| What It Can Show |
|---|
| The degree of spinal canal narrowing |
| Whether nerves are being compressed |
| The condition of your discs |
| Thickening of the ligaments |
| Herniated discs |
Features
| Advantages | Disadvantages |
|---|---|
| Excellent detail of nerves | The scan takes time (20-40 minutes) |
| No radiation | You lie inside a narrow tube |
| Shows soft tissues clearly | The machine is loud |
| Discuss with your doctor if you have metal implants | |
| Pacemakers and SCS devices require special precautions |
Tips for Your MRI
- Stay still -- movement blurs the images
- Claustrophobia -- if small spaces make you anxious, let your doctor know beforehand
- Remove metal items -- take off jewelry and accessories
- Tattoos -- there is a small risk of skin burns; inform your doctor in advance
CT Scan (Computed Tomography)
Purpose
A CT scan provides detailed images of your bones.
What It Shows
| What It Can Show |
|---|
| Detailed bone anatomy |
| Location and size of bone spurs |
| The neural foramen (the opening where nerves exit) |
| Surgical planning information |
Features
| Advantages | Disadvantages |
|---|---|
| Excellent bone detail | Involves radiation |
| Quick scan time | Does not show nerves as well |
| More comfortable than MRI | Contrast dye may be used |
Myelography
Before MRI became widely available, a contrast dye was injected into the spinal sac and X-rays and CT scans were taken -- a procedure called myelography. Because it is invasive, MRI has largely replaced it for diagnosis. However, myelography may still be performed when the doctor suspects that spinal movement (bending forward and backward) plays a major role in your symptoms, since standard MRI is taken while lying still.
How Tests Are Combined
Tests are typically performed in the following order:
[!note] Typical sequence of tests
- X-ray — Get an overall picture of the bones
- MRI — Examine the nerves in detail
- CT (if needed) — Confirm bone details (especially if fusion surgery is being considered)