7.1 Vertebral Fracture Assessment (VFA) Technique & Indications
Key Takeaways
VFA is lateral densitometric imaging for vertebral fracture detection. Record which vertebral levels are actually visible.
The ISCD adult indication requires a T-score below −1.0 and an age, historical height-loss, undocumented vertebral fracture, or glucocorticoid trigger.
Genant grading is a visual semiquantitative method. Vertebral height measurements can support, but cannot alone establish, the fracture diagnosis.
A confirmed vertebral fragility fracture affects clinical risk and treatment consideration even when DXA BMD is above the osteoporosis threshold.
Use lateral DXA imaging to look for vertebral fractures
Vertebral fracture assessment (VFA) is lateral spine imaging with a dual-energy X-ray absorptiometry (DXA) system for detecting vertebral fractures. The exam outline also uses the older term lateral vertebral assessment (LVA). A VFA image addresses vertebral shape. A separate PA lumbar acquisition measures bone mineral density (BMD). Many vertebral fractures are unrecognized clinically, so VFA can reveal a fracture that changes the risk assessment even when BMD is above the densitometric osteoporosis threshold.
Depending on the scanner, acquire the lateral image with the patient on their side or with the patient supine and the C-arm in a lateral position. Aim to visualize and label the thoracolumbar vertebrae, commonly T4 through L4, and check the actual range before reporting. Overlapping anatomy, soft tissue and motion can obscure levels, particularly in the upper thoracic spine. VFA generally has a lower radiation dose than conventional spine radiography and can be performed during a DXA visit. Image detail and dose depend on the device and protocol.
Apply the two-part ISCD adult indication
The International Society for Clinical Densitometry (ISCD) indicates lateral spine imaging by VFA or standard radiography when the patient has a T-score below −1.0 and at least one of the following:
| Trigger | Adult ISCD criterion |
|---|---|
| Age | Woman aged 70 or older, or man aged 80 or older |
| Historical height loss | More than 4 cm from prior peak height |
| Fracture history | A self-reported prior vertebral fracture without documentation |
| Glucocorticoids | At least 5 mg of prednisone or equivalent daily for at least three months |
A T-score of exactly −1.0 or historical height loss of exactly 4 cm does not meet the respective strict threshold. For example, a 69-year-old woman with a T-score of −1.4 and a 4.0 cm historical loss has neither the age nor the historical height-loss trigger. An 80-year-old man with a T-score of −1.2 meets the age trigger and the T-score criterion.
Keep the guideline and the clinical purpose explicit. U.S. Bone Health and Osteoporosis Foundation (BHOF) guidance separately considers prospective height loss of at least 0.8 inches in the relevant adult population. New focal back pain or suspected pathological fracture may call for diagnostic imaging outside the ISCD adult case-finding rule. The ISCD pediatric positions use a separate clinical framework. They allow VFA for vertebral fracture identification in children and call for additional imaging when an unevaluable level, a single grade 1 finding, or atypical pathology could affect care.
Identify fracture visually, then grade severity
Use the Genant visual semiquantitative method. Review vertebral configuration and distinguish fracture from projection, developmental or degenerative deformity. Measurements of anterior, middle or posterior height and projected area may support the visual judgment. Morphometry alone is insufficient to diagnose a fracture.
| Genant visual grade | Usual height reduction in a vertebra identified as fractured |
|---|---|
| 0 | Normal appearance for the method |
| 1, mild | Approximately 20–25% |
| 2, moderate | Approximately 25–40% |
| 3, severe | More than approximately 40% |
Anterior loss produces a wedge pattern, predominant middle loss produces a biconcave pattern, and more generalized height loss produces a crush pattern. The shape and the severity are separate. For example, visual review identifies an anterior wedge fracture at T11. Its anterior height is 18 mm compared with an expected 25 mm based on neighboring levels. The approximate anterior loss is . This supports a grade 2 wedge fracture. In a patient with longstanding kyphosis, smoothly patterned wedging or irregular endplates across adjacent levels can be developmental. A height percentage alone cannot settle the distinction.
Report the assessed levels and next decision
Identify the patient, referrer, indication, technical quality and interpretation. Give the levels that cannot be assessed, describe deformities and whether they represent fractures, and record severity when a fracture is present. Mention unexplained vertebral or extra-vertebral findings. For follow-up, state whether the studies are comparable and explain clinically meaningful interval changes. Recommendations for additional studies and fracture-risk estimates are optional VFA report elements.
A confirmed vertebral fragility fracture supports clinical evaluation and consideration of treatment under the U.S. BHOF guidance even if the T-score is above −2.5. A grade 3 vertebral fracture is a statement about deformity severity. It does not automatically assign the historical severe densitometric category or select a drug. For equivocal or atypical findings, use the spine radiography and follow-up imaging approach.
ISCD Adult Official Positions · ISCD Pediatric Official Positions · Genant visual grading · BHOF Clinician’s Guide
Which patient meets the 2023 ISCD adult indication for lateral spine imaging?
A 72-year-old woman with a femoral neck T-score of −1.4.
A 62-year-old woman with a lowest T-score of −0.8 and historical height loss of 4.5 cm.
A 78-year-old man with a lowest T-score of −1.2 and historical height loss of exactly 4 cm, with no other trigger.
A 65-year-old woman with a lowest T-score of −1.2 whose only additional finding is prospective height loss of 2.2 cm.
Visual review of a lateral VFA confirms a T11 fracture with predominant anterior wedging. The anterior height is 18 mm versus an expected 25 mm based on adjacent levels. Middle and posterior height are relatively preserved. Which Genant description is most consistent?
Grade 1 biconcave fracture.
Grade 2 wedge fracture.
Grade 2 crush fracture.
Grade 3 wedge fracture.
A VFA study does not adequately show T8. What is the most appropriate report language?
There is no fracture from T4 through L4.
The inability to see T8 proves a grade 3 fracture.
T8 is unevaluable. Consider additional imaging if clarification is clinically indicated.
Assign the T8 fracture grade from the lumbar spine BMD.
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