stereotactic, without contrast 0.6 mm reference exam; MRI provides high anatomical CT – – resolution, while CT eliminates MRI distortion. T2: axial (VCU) cube GE (VA) – dark fluid SPACE - Siemens T1: T1-weighted 3D Magnetization Prepared-Rapid Acquisition Gradient Echo (MPRAGE) - sagittal (VCU) or axial (VA); postcontrast to see vessels. – Fast Gray Matter Acquisition T1 Inversion Recovery (FGATIR) on 3T MRI scanner DTI (2NEX scan duration 8 minutes; or 3NEX 12 minutes) – MRI must be 3D (volumetric), i.e. without gaps between slices. CT O-arm Ceretom small bore – Bodytom, Airo large bore, good soft tissue resolution – if patient cannot have MRI (e.g. pacemaker), intraop ventriculogram can be used: standard EVD catheter is passed free-hand through the right frontal burr hole into the lateral ventricle Omnipaque → 3 cm3 (180 mg/mL) is injected into the ventricle immediate O-arm; → anterior commissure is not well visualized in the ventriculogram as a result of gravitational layering of the contrast but still be estimated from the preop CT scan (fused to O-arm). A. - target visually chosen directly from CT / MRI); prior to introduction of CT / MRI, target localization involved injecting or air into lateral ventricle to outline third ventricular structures positive contrast (ventriculography) adjacent to diencephalic targets with current MRI, GPi and STN are but VIM is derived from Schaltenbrand and visualized directly, Wahren utilizing intercommissural plane and midcommissural point for reference. atlas, ongoing debates (without MER); should stereotaxis be just image-guided Larson et al. place DBS on first trajectory in 98% patients. Montgomery et al. (2012) found that imaging-based targeting was consistent with the physiologically defined target only 70% of the time; in 30% of subjects, additional MER trajectories were required (25% required 2 additional MER penetrations and remaining 5% required 3 additional penetrations). B. MRI - based upon position of AC-PC:
CT – stereotactic, without contrast 0.6 mm – reference exam; MRI provides high anatomical resolution, while CT eliminates MRI distortion. T2: axial (VCU) cube – GE (VA) dark fluid SPACE - Siemens T1: T1-weighted 3D Magnetization Prepared-Rapid Acquisition Gradient Echo (MPRAGE) - sagittal (VCU) or axial (VA); postcontrast – to see vessels. Fast Gray Matter Acquisition T1 Inversion Recovery (FGATIR) on 3T MRI scanner DTI (2NEX scan duration 8 minutes; or 3NEX – 12 minutes) MRI must be 3D (volumetric), i.e. without gaps between slices. CT O-arm Ceretom – small bore Bodytom, Airo – large bore, good soft tissue resolution if patient cannot have MRI (e.g. pacemaker), intraop ventriculogram can be used: standard EVD catheter is passed free-hand through the right frontal burr hole into the lateral ventricle → Omnipaque 3 cm3 (180 mg/mL) is injected into the ventricle → immediate O-arm; anterior commissure is not well visualized in the ventriculogram as a result of gravitational layering of the contrast but still be estimated from the preop CT scan (fused to O-arm). A. - target visually chosen directly from CT / MRI); prior to introduction of CT / MRI, target localization involved injecting air or positive contrast into lateral ventricle to outline third ventricular structures (ventriculography) adjacent to diencephalic targets with current MRI, GPi and STN are visualized directly, but VIM is derived from Schaltenbrand and Wahren atlas, utilizing intercommissural plane and midcommissural point for reference. ongoing debates should stereotaxis be just image-guided (without MER); Larson et al. place DBS on first trajectory in 98% patients. Montgomery et al. (2012) found that imaging-based targeting was consistent with the physiologically defined target only 70% of the time; in 30% of subjects, additional MER trajectories were required (25% required 2 additional MER penetrations and remaining 5% required 3 additional penetrations). B. MRI - based upon position of AC-PC:
Op360.%20DBS.docx