Acute vs Chronic Compression Fracture¶
Overview¶
Distinguishing an acute vertebral compression fracture from a chronic (healed) fracture is a common and important clinical question, particularly in elderly patients with multiple compression deformities. The distinction affects management — acute fractures require pain management, monitoring, and potentially vertebral augmentation, while chronic fractures are incidental findings that do not require acute treatment. MRI is the most reliable imaging modality for making this distinction.
MRI Features¶
Acute Compression Fracture¶
- STIR/T2 fat-saturated — High signal (bright) within the fractured vertebral body, representing bone marrow edema. This is the most reliable indicator of acuity.
- T1-weighted — Low signal (dark) within the vertebral body due to replacement of normal fatty marrow by edema
- Enhancement — Diffuse or band-like enhancement on post-contrast T1 images
- Morphology — The fracture line may be visible, and the posterior vertebral body wall may show acute retropulsion
- Band pattern — Edema often follows a horizontal band pattern adjacent to the fractured endplate
Chronic Compression Fracture¶
- STIR/T2 fat-saturated — Normal (low) signal — no edema. The marrow has returned to its normal fatty composition.
- T1-weighted — Normal (high) signal — fatty marrow has been restored. A chronic fracture may show slightly altered morphology but maintains normal fatty marrow signal.
- Enhancement — No significant enhancement
- Morphology — Stable height loss, sclerosis at the fracture site, possible Schmorl node formation
Subacute Compression Fracture¶
In the subacute phase (weeks to months), there may be partial resolution of edema with a mixed signal pattern — some residual STIR hyperintensity along with areas of normalizing fatty marrow signal. This intermediate stage makes precise dating of the fracture difficult.
CT Features¶
CT is less reliable than MRI for determining fracture acuity but may provide clues:
- Acute — Sharp fracture lines, cortical disruption without sclerosis, possible vacuum cleft (intravertebral gas)
- Chronic — Sclerotic fracture margins, remodeled bone, stable deformity on comparison with prior imaging
- Vacuum cleft sign — Intravertebral gas (seen on CT as a linear lucency within the vertebral body) can be present in both acute (traumatic disruption) and chronic non-united fractures (Kümmel disease)
Distinguishing Benign from Malignant Compression Fractures¶
This distinction is equally important and frequently arises in the same clinical context:
| Feature | Benign (Osteoporotic) | Malignant (Pathological) |
|---|---|---|
| Posterior body contour | Retropulsion (angular fragment) | Convex (bulging) |
| Pedicle signal | Normal | Abnormal (involved) |
| Epidural mass | Absent | May be present |
| Marrow edema pattern | Band-like (along endplate) | Diffuse (entire body) |
| Other vertebral bodies | Normal or with similar fractures | May show focal lesions |
| Enhancement pattern | Band-like | Heterogeneous, entire body |
| DWI | Variable | Restricted diffusion |
| Paravertebral mass | Absent | May be present |
Clinical Pearl
The single most reliable MRI feature for distinguishing acute from chronic compression fractures is STIR signal: bright = acute (edema present), dark = chronic (no edema). For distinguishing benign from malignant fractures, pedicle involvement and a convex posterior vertebral body contour are the most specific findings for malignancy.
Key Points¶
- STIR signal is the most reliable indicator of fracture acuity — high signal (edema) indicates an acute fracture
- Chronic fractures show normal fatty marrow signal on T1 and no STIR hyperintensity
- CT is less reliable for dating fractures but may show sclerotic margins in chronic fractures
- Distinguishing benign from malignant compression fractures requires attention to pedicle involvement, posterior body contour, and marrow signal pattern
- Comparison with prior imaging, when available, is invaluable for determining fracture age
References¶
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- Baker LL, Goodman SB, Perkash I, Lane B, Enzmann DR. Benign versus pathologic compression fractures of vertebral bodies: assessment with conventional spin-echo, chemical-shift, and STIR MR imaging. Radiology. 1990;174(2):495-502. PMID: 2296658.
- Maldague BE, Noel HM, Malghem JJ. The intravertebral vacuum cleft: a sign of ischemic vertebral collapse. Radiology. 1978;129(1):23-29. PMID: 693884.
- Romeo V, Ugga L, Stanzione A, Cocozza S, Cuocolo R, Brunetti A. Differential diagnosis of benign and malignant vertebral compression fractures using conventional and advanced MRI techniques. BJR Open. 2019;1(1):20180033. PMID: 33178924.
- Radiopaedia. Kümmell disease. Available at: https://radiopaedia.org/articles/kummell-disease-1