Evaluation of the Spatial Accuracy of Magnetic Resonance Imaging-based Stereotactic Target Localization for Gamma Knife Radiosurgery of Functional Disorders
- 1 November 1999
- journal article
- research article
- Published by Ovid Technologies (Wolters Kluwer Health) in Neurosurgery
- Vol. 45 (5), 1156-1163
- https://doi.org/10.1097/00006123-199911000-00028
Abstract
This study was undertaken to determine the impact of geometric distortions on the spatial accuracy of magnetic resonance imaging (MRI)-guided stereotactic localization for gamma knife functional radiosurgery The spatial accuracy of MRI was evaluated by comparing stereotactic coordinates of intracranial targets, external fiducials, and anatomic structures defined by computed tomographic and MRI studies of the Radionics skull phantom (Radionics, Inc., Burlington, MA), the Rando head phantom, and 11 patients who underwent gamma knife functional radiosurgery. The distortion in MRI was assessed from computed tomographic and MRI fusion studies for these patients, as well as from MRI studies acquired by swapping the direction of the magnetic field gradients for five patients who underwent gamma knife radiosurgery and three patients who underwent MRI-guided frameless surgery. A follow-up program to compare the location of the created lesion with the intended target complemented the analysis. The average difference between computed tomographic and MRI stereotactic coordinates of external fiducials, intracranial targets, and anatomic landmarks was of the order of 1 pixel size (0.9 × 0.9 × 1 mm3) along the x, y, and zaxes. The average linear scaling along these axes as determined by fusion studies was approximately 0.8% and consistent with a single pixel. The follow-up studies, available for seven patients, revealed good agreement between the location of the created lesion and the intended target. The spatial accuracy of an MRI-based localization system can be comparable to computed tomography-based localization with the added benefit of MRI resolution. Both machine- and object-related MRI distortions can be reduced to an acceptable level with contemporary scanners, optimized scanning sequences, and distortion-resistant stereotactic instruments.Keywords
This publication has 17 references indexed in Scilit:
- MRI Distortion and Stereotactic Neurosurgery Using the Cosman-Roberts-Wells and Leksell FramesStereotactic and Functional Neurosurgery, 1996
- A Universal Method for Geometric Correction of Magnetic Resonance Images for Stereotactic NeurosurgeryStereotactic and Functional Neurosurgery, 1996
- Technical Note. Effect of Geometrical Distortion Correction in MR on Image Registration AccuracyJournal of Computer Assisted Tomography, 1996
- Stereotactic radiosurgery for trigeminal neuralgia: a multiinstitutional study using the gamma unitJournal of Neurosurgery, 1996
- Effects of coregistration of MR to CT images on MR stereotactic accuracyJournal of Neurosurgery, 1995
- On the problem of geometric distortion in magnetic resonance images for stereotactic neurosurgeryMagnetic Resonance Imaging, 1994
- Image fusion for stereotactic radiotherapy and radiosurgery treatment planningInternational Journal of Radiation Oncology*Biology*Physics, 1994
- Analysis of machine-dependent and object-induced geometric distortion in 2DFT MR imagingMagnetic Resonance Imaging, 1992
- A Comparison between Magnetic Resonance Imaging and Computed Tomography for Stereotactic Coordinate DeterminationNeurosurgery, 1992
- Susceptibility artefacts in NMR imagingMagnetic Resonance Imaging, 1985