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.