MR-guided stereotactic neurosurgery--comparison of fiducial-based and anatomical landmark transformation approaches

Phys Med Biol. 2004 Jun 21;49(12):2705-16. doi: 10.1088/0031-9155/49/12/016.

Abstract

For application in magnetic resonance (MR) guided stereotactic neurosurgery, two methods for transformation of MR-image coordinates in stereotactic, frame-based coordinates exist: the direct stereotactic fiducial-based transformation method and the indirect anatomical landmark method. In contrast to direct stereotactic MR transformation, indirect transformation is based on anatomical landmark coregistration of stereotactic computerized tomography and non-stereotactic MR images. In a patient study, both transformation methods have been investigated with visual inspection and mutual information analysis. Comparison was done for our standard imaging protocol, including t2-weighted spin-echo as well as contrast enhanced t1-weighted gradient-echo imaging. For t2-weighted spin-echo imaging, both methods showed almost similar and satisfying performance with a small, but significant advantage for fiducial-based transformation. In contrast, for t1-weighted gradient-echo imaging with more geometric distortions due to field inhomogenities and gradient nonlinearity than t2-weighted spin-echo imaging, mainly caused by a reduced bandwidth per pixel, anatomical landmark transformation delivered markedly better results. Here, fiducial-based transformation yielded results which are intolerable for stereotactic neurosurgery. Mean Euclidian distances between both transformation methods were 0.96 mm for t2-weighted spin-echo and 1.67 mm for t1-weighted gradient-echo imaging. Maximum deviations were 1.72 mm and 3.06 mm, respectively.

Publication types

  • Clinical Trial
  • Comparative Study
  • Validation Study

MeSH terms

  • Algorithms*
  • Humans
  • Image Interpretation, Computer-Assisted / methods*
  • Imaging, Three-Dimensional / methods*
  • Magnetic Resonance Imaging / methods*
  • Neuronavigation / methods
  • Reproducibility of Results
  • Sensitivity and Specificity
  • Stereotaxic Techniques*
  • Subtraction Technique*
  • Surgery, Computer-Assisted / methods*