Contrast MRI of the whole spine: find the infected disc and endplates, then the collections and the canal — and read the pattern that separates tuberculosis (disc relatively spared, large paraspinal abscess, skip lesions) from pyogenic infection.
Orient first
- Pyogenic spondylodiscitis centres on the disc: the disc and the endplates on both sides of it are involved together, early.
- Tuberculous spondylitis (Pott disease) favours the thoracolumbar junction, spreads under the anterior longitudinal ligament to several levels, relatively spares the disc early, and forms large, thin-walled paraspinal or psoas abscesses, sometimes with skip lesions.
- The management questions are an epidural collection compressing the cord or cauda equina, instability or kyphosis, and a target for biopsy.
Acquire the study
- Whole-spine sagittal T1, T2 and STIR screening; axial T2 and post-contrast fat-saturated T1 through affected levels.
The manoeuvre
- Sagittal STIR of the whole spine: every level with marrow oedema — tuberculosis often involves several or non-contiguous levels.
- Disc: T2 high signal and enhancement (pyogenic) versus relative preservation with subligamentous spread (tuberculosis).
- Endplates on T1: loss of the dark cortical line and erosion.
- Post-contrast T1 fat-saturated: paraspinal and psoas abscess (rim-enhancing), epidural abscess or phlegmon; measure the collection in mm.
- Canal: degree of cord or thecal sac compression and cord signal change on axial T2.
- Alignment: vertebral collapse, gibbus and posterior element involvement.
What confirms it
- Disc and adjacent endplate involvement with enhancement, with or without collections, supporting infection — tissue or culture decides the organism.
What licenses you to exclude it
- A normal contrast MRI of the whole spine makes spondylodiscitis very unlikely.
The classic misread
- Calling Modic type 1 degenerative change infection — it lacks disc T2 hyperintensity, enhancement of the disc and collections.