Inter-observer agreement between 2-dimensional CT versus 3-dimensional I-space model in the diagnosis of occult scaphoid fractures

Background: The I-Space is a radiological imaging system in which Computed Tomography (CT)-scans can be evaluated as a three dimensional hologram. The aim of this study is to analyze the value of virtual reality (I-Space) in diagnosing acute occult scaphoid fractures. Methods: A convenient cohort of 24 patients with a CT-scan from prior studies, without a scaphoid fracture on radiograph, yet high clinical suspicion of a fracture, were included in this study. CT-scans were evaluated in the I-Space by 7 observers of which 3 observers assessed the scans in the I-Space twice. The observers in this study assessed in the I-Space whether the patient had a scaphoid fracture. The kappa value was calculated for inter- and intra-observer agreement. Results: The Kappa value varied from 0.11 to 0.33 for the first assessment. For the three observers who assessed the CT-scans twice; observer 1 improved from a kappa of 0.33 to 0.50 (95% CI 0.26-0.74, P=0.01), observer 2 from 0.17 to 0.78 (95% CI 0.36-1.0, P < 0.001), and observer 3 from 0.11 to 0.24 (95% CI 0.0-0.77, P=0.24). Conclusion: Following our findings the I-Space has a fast learning curve and has a potential place in the diagnostic modalities for suspected scaphoid fractures.