Degenerative spine disease is among the most common causes of back pain. MRI is the modality of choice, as it provides excellent soft tissue detail of discs, ligaments, marrow, and neural elements.
🔎 Key MRI Findings in Degenerative Spine Disorders
1. Intervertebral Disc Degeneration
- Decreased T2 signal (loss of hydration)
- Reduced disc height
- Disc desiccation → early degenerative change
2. Disc Herniation Types
- Bulge → circumferential, symmetric extension beyond disc margin
- Protrusion → focal, base wider than dome
- Extrusion → dome wider than base, may extend cranially/caudally
- Sequestration → free fragment, separated from disc
➡️ Best seen on T2 sagittal + axial images
3. Modic Endplate Changes (on T1/T2)
- Type I → T1 hypointense, T2 hyperintense (edema, active degeneration)
- Type II → T1 hyperintense, T2 iso/hyper (fatty marrow replacement)
- Type III → T1 & T2 hypointense (sclerosis)
4. Spinal Canal Stenosis
- Central stenosis:
- Narrowed anteroposterior canal diameter
- Hypertrophy of ligamentum flavum, disc bulge, osteophytes
- “Trefoil-shaped canal” on axial MRI
- Lateral recess stenosis: nerve root compression within canal
- Foraminal stenosis: narrowing of exit foramina by osteophytes/disc
5. Facet Joint Arthropathy
- Hypertrophied, irregular facet joints
- Joint effusion (hyperintense on T2)
- Can cause foraminal or central stenosis
6. Ligamentous Hypertrophy
- Ligamentum flavum thickening → major contributor to lumbar stenosis
- Appears as hypointense band compressing thecal sac
7. Spondylolisthesis
- Forward/backward slip of vertebral body
- MRI shows associated disc degeneration, stenosis, and nerve compression
🧠 Teaching Points
- MRI is gold standard for degenerative spine disease → shows both anatomical changes and neural compression.
- Always assess:
- Disc signal and contour
- Endplate marrow (Modic changes)
- Canal and foraminal patency
- Facet and ligamentum flavum hypertrophy
- Correlate with clinical symptoms (radiculopathy, claudication) for management decisions.
