Direct application of MR images to computer-assisted XXXX surgery.

@entity1 @entity511 @entity7197 @entity3478 @entity5 @entity421
BACKGROUND: We describe a method for the direct application of MR images to navigation-assisted @entity3478 surgery as an alternative to CT-MRI fusion. METHOD: Six @entity1 with an orthopedic malignancy were employed for this method during navigation-assisted @entity5 resection. Tumor types included @entity421 (4), high-grade @entity511 (1), and @entity7197 (1). Mean @entity1 age was 25.3  years (range 18-52  years). Mean duration of follow-up was 25.8  months (range 18-32  months). Resorbable pin placement and rapid 3-dimensional spoiled gradient echo sequences made the direct application of MR images to computer-assisted @entity3478 surgery without CT-MR image fusion possible. A paired-point registration technique was employed for @entity1 -image registration in all @entity1 . RESULTS: It took 20  min on average to set up the navigation (range 15-25  min). The mean registration error was 0.98  mm (range 0.4-1.7  mm). On histologic examination, distances from @entity5 to resection margins were in accord with preoperative plans. No @entity1 had a local recurrence or distant metastasis at the last follow-up. CONCLUSION: Direct @entity1 -to-MRI registration is a very useful method for @entity3478 surgery, permitting the application of MR images to intraoperative visualization without any additional costs or exposure of the @entity1 to radiation from the preoperative CT scan.
