Anatomic and Functional Guidance of Neurosurgery. Robert L. Galloway Jr. Associate Professor of Biomedical Engineering and Neurosurgery Director, Center for Technology-Guided Therapy TGT

Technology-Guided Therapy The use of technology to improve the spatial and temporal specificity of the delivery of therapy TGT

Technology -Guided Therapy Pre-therapeutic data (images, population data, therapy plan…) Registration methodology (matching pre- therapeutic data to specific patient in specific position) Intraoperative guidance and data collection. Display of position, plan, anatomy, function and disease.

TGT History of Image-Guided Therapy 1896 J.H. Clayton. X-Ray use in surgery 1904 Horsley and Clarke. Stereotactic frame 1946 Spiegel and Wycis. Stereotactic frame using xrays. 1940’s~1950s: Leksell, Riechert- Mundinger, Talairach, Cooper...

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Problems with X-Ray film Stereotaxy Target must be clearly visible in both images Lack of apparent relationship between arc settings and position. Best for electrophysiology-based ablation

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Problems with Frame-Based Stereotaxy Still point-based Frame obstructs surgical field Arc-based approach obscures relationship between target points and arc settings.

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Registration When the mathematical relationship between a point in one space and the homologous point in another space is known, the spaces are considered registered. If that relationship can be reduced to a single common translation and rotation, the registration is considered rigid,

TGT Translate Rotate Rigid Registration

TGT Point Based Registration Fiducial point (landmarks) Intrinsic Fiducials (anatomic landmarks) Extrinsic Fiducials (markers)

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Marker -Based Registration

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New Methods of Registration Surface-Based Registration

Image to Physical Space Registration Use the outer surface of the skull Segmentation in CT forms a surface Measure points on the outer surface of the skull with ultrasound Surface-based registration of physical space with CT images using A-mode ultrasound localization of the skull

Advantages –No separate surgical procedure –No additional imaging scans Disadvantages –Residual Error is less predictive of actual error –More time consuming in the OR Comparison with Fiducial Markers

Tomographic Images Can show anatomy Can show function (PET and functional MR) Can show extent of disease. All of the above are qualified statements

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Surface Normal Uncertainty Surface

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Tomographic Angiography

Surgically Appropriate MIPs 1) Threshold image, make binary image 2) Calculate center of mass from binary image 3) Fit center of mass points from each slice to a line 4) Extend plane from the line perpendicular to MIP trajectory

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Depth-Buffer Based Targeting

TGT Originals Global transformation Local transformation

TGT Implantation of Thalamic Stimulators

Population Data Goal - to provide information from multiple subjects during surgery Create a functional Atlas (MR or CT)

T global T local T local + T global

Optical Flow Differences between images considered as motion from one time frame to the next This motion is observed as a change in intensity, represented as a field of velocity vectors called the optical flow

Atlas Atlas  Patient Patient

3D Visualization Display

Intraoperative Tracking and Data Collection

Interactive, Image Guided Endoscopic Surgery Tomographic VolumeEndoscopic View

Image to Physical Space Registration Endoscopic image space (u,v) was registered with physical space (x,y,z). If distortions are minimized, registration from physical space points to image space points can be described by the direct linear transformation (DLT):

TGT Integration of Intraoperative Imaging

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Tracked Ultrasound

Preliminary Experiments Vertebral surface point extraction using tracked U/S on phantom spine Spinal CT surface extraction Point-to-surface registration Qualitative assessment of registration accuracy

Visual Results: Phantom Ultrasound Points

New Software Design Video Tomogram Rotational 2-D Images Display Optotrak Polaris Art. Arms Magnetic Localizer Render Biopsy Preop Plan Transparency Graphic A-Mode US Electrophys. Biomechanical Optical Biopsy IO Quaternion SVD HTM ICP Registration Deformation Functional Correction ORION

TGT What’s Next? Functional Mapping Deformable Models In-Vivo Tissue Identification Image-Guided Delivery of FEL Beam Direct Injection Chemotherapy Guided Gene Therapy Delivery Brachytherapy seed placement

The Center For Technology- Guided Therapy Robert L. GallowayBME&Neurosurgery Cynthia B. PaschalBME &Radiology Anita Mahadevan-JansenBME E. Duco JansenBME J. Michael FitzpatrickEECS&Radiology &Neurosurgery Benoit M. Dawant EECS TGT

The Center For Technology- Guided Therapy William C. Chapman, MDSurgery Anthony Cmelak, MDRadiation Oncology Charles Coffey, PhDRadiation Oncology Dennis Duggan, PhDRadiation Oncology Dennis Hallahan, MDRadiation Oncology & BME Robert M. Kessler, MDRadiology Peter E. Konrad, MD, PhDNeurosurgery & BME Steven Toms, MD, MPHNeurosurgery TGT

The Center For Technology- Guided Therapy Andy Bass Jim Stefansic Diane Muratore Steve Hartmann David Cash Tuhin Sinha Steve Gebhart BME Jeannette Herring Jay West Duane Yoder Rui Li Yi Quiao EECS Alan Herline, MD Surgery Blake Arrington Gwen Banks Ryan Beasley Caryl Brzymialkiewicz Calley Hardin Elaine Isom Tammy McCreary Kristjan Onu Danielle Pinson Stacey Scheib Chee Xiong REU