Utilization of an Ultrasonography–Computed Tomography Fusion System in the Lumbar Spine

BACKGROUND: Fluoroscopy and computed tomography (CT) are standard imaging modalities for spinal interventions but expose patients and health care professionals to ionizing radiation. Ultrasonography-CT (US-CT) fusion systems enable co-registration of real-time ultrasonography with pre-existing CT images, offering enhanced anatomical visualization without radiation. This study evaluates the feasibility and accuracy of a US-CT fusion system for vertebral level identification. MATERIALS AND METHODS: Seventeen patients scheduled for lumbar CT were enrolled. Using a GE Logiq E9 US-CT fusion system, lumbar vertebrae (L1-L5) underwent imaging in the prone position, with facet joints and sacroiliac joints as coregistration landmarks. A randomly selected vertebra was marked with a pin, and its level was verified by a subsequent CT image. RESULTS: In 17 patients, 15 vertebral levels (88%) were correctly identified using the US-CT fusion system. Facet joints and sacroiliac joints were reliable landmarks for coregistration, enabling synchronized ultrasonography and CT visualization. Two errors occurred, likely due to pin displacement or misidentification. CONCLUSIONS: The US-CT fusion system is a promising tool for lumbar vertebral identification, with the potential to reduce radiation exposure during spinal procedures. This observational study has several limitations, including a small sample size and an operator learning curve. Further studies are needed to optimize its application; however, its potential clinical relevance remains high.