Accuracy of MRI vs CT imaging with particular reference to patient specific templates for total knee replacement surgery

Background The present study compares the accuracy of MRI and CT imaging for the manufacture of patient-specific templates for total knee replacement surgery. Methods A total of 10 ovine knees were imaged using MRI and CT scanners. Each set of images was reconstructed in 3D and then used to manufacture physical models of each bone, using rapid prototyping technology. After imaging the soft tissues were removed and specific measurements of the bony anatomy compared with measurements from the MRI and CT models. Results Bone models generated from MRI scans were dimensionally less accurate than those generated from CT scans. Furthermore, the bone models generated from MRI scans were visibly inferior to those generated from the CT scans. Conclusions Current MRI scans do not offer a viable alternative to CT. Although adaptation of the template system to accommodate MRI imaging is possible, the changes required are neither practical nor desirable. Copyright (C) 2008 John Wiley & Sons, Ltd.