Observer variation in MRI for suspected scaphoid fractures

The aim of this study was to evaluate prospectively the observer variation in the detection of pathology on MRI for suspected acute scaphoid fracture. 79 consecutive MR scans were included to calculate the inter-observer variation. All patients were suspected of having a scaphoid fracture but had no fracture on radiographs. 38 randomly chosen MR scans were used to calculate the intra-observer variation. Four observers, with varying levels of expertise, blinded scored three items: (i) scaphoid fracture, (ii) localization of a scaphoid fracture, and (iii) another fracture. The observer variation was analysed using the kappa statistic. The inter-observer variation for a scaphoid fracture showed substantial agreement. For the localization of a scaphoid fracture and another fracture, there was a moderate and substantial agreement, respectively. The intra-observer variation for a scaphoid fracture had an almost perfect agreement. For the localization of a scaphoid fracture and another fracture, there was an almost perfect and substantial agreement, respectively. In conclusion, the observer variation in MRI of suspected scaphoid fractures was low. The influence of expertise with MRI in daily practice should be taken into consideration. Observers with little experience of MRI will identify all scaphoid fractures but are likely to over-diagnose injuries. Based on these results, it is recommended that all scans are reviewed by an experienced radiologist.