Abstract
A system for collecting cross-sectional MRI images of the human wrist was developed, using the 0.15 Tesla resistive, whole body MRI system at the University of Surrey. A new patient position was designed. After experimentation and development using phantoms and pigs trotters, 58 normal human wrists were imaged. The carpal tunnel cross-sectional areas of the dominant and non-dominant sides were compared. Significant differences were found (p<0.05). Thus it was necessary to employ a pair matched case control study. In a pair matched case control study, axial wrist images of cases and controls (patients/subjects with and without carpal tunnel syndrome) were collected. 13 cases and controls were matched by gender, age (+/-5 years) and gross hand dominance. The diagnosis of carpal tunnel syndrome was confirmed where possible using electrophysiological tests. Images were analysed on a graphics monitor and measures obtained of the wrist and carpal tunnel; width, depth and cross-sectional areas. The intra and inter observer reliability of the measuring technique was examined. No significant difference was found for intra-observer reliability (p>0.05), when an observer performed the identical analysis, either on the same day or on different days. Differences were found for the inter-observer reliability (p<0.025), indicating the need to provide adequate training for naive observers performing analyses. One observer (the author) analysed all of the images throughout the case control study. No significant differences were found between the cases and controls for any of the carpal tunnel measures.lt was therefore not possible to identify differences between cases and controls using this method and equipment. This result confirms the latest findings where Computed Tomography was used to image the carpal tunnel.