Diagnostic value of cone beam computed tomography (CBCT) in occult scaphoid and wrist fractures

Abstract

Objective: Evaluate the diagnostic value of cone beam computed tomography (CBCT) for scaphoid and wrist fractures that are missed on standard radiographs.

Materials and methods: Between September 2014 and October 2015, we prospectively enrolled 49 patients with a clinically suspected scaphoid fracture following an acute injury but had normal radiographs. Each patients underwent radiographs, CBCT and (magnetic resonance imaging) MRI within 7days of the initial injury event. Both exam were evaluated independently by two radiologists.

Results: For scaphoid cortical fractures CBCT sensitivity is 100% (95% CI: 75%-100%), specificity 97% (95% CI: 83%-100%). CBCT diagnosed all 24 corticals wrist fractures, corresponding to a sensitivity of 100% (95% CI: 83%-100%), specificity of 95% (95% CI: 75%-100%). Kappa agreement rate between the two radiologists was K=0.95 (95% CI: 0.85-1) for scaphoid fractures and K=0.87 (95% CI: 0.73-1) for wrist fractures.

Conclusions: CBCT is superior to radiographs for diagnosing occult cortical fractures. Because of its low radiation dose, we believe that CBCT can be used in current practice as a replacement or supplement to radiographs to detect these fractures and optimize the cost-effectiveness ratio by limiting the number of needless immobilizations.

Keywords: Cone beam computed tomography; Magnetic resonance imaging; Occult fracture; Scaphoid fracture; Wrist fracture.