Joint Imaging-Therapy Symposium
Imaging, Guidance, and New Technologies
in IG Interventions
DQE
FDK
TRE
These and Other TLAs in the Development
of New Technologies for Image-Guided Surgery
Jeff Siewerdsen, PhD
Department of Biomedical Engineering
Johns Hopkins University
David Hawkes, PhD
Jeff Siewerdsen, PhD
Department of Biomedical Engineering
Johns Hopkins University
University College
London UK
Paul Keall, PhD
Department of Radiation Oncology
Stanford University
Overview
• “Closing the loop” in image-guided surgery
- Operating rooms of the future
• Imaging modalities for IGS
- MR… US… CT… and cone-beam CT
• From DQE to TRE
- Translation of a new imaging technology
from the laboratory to the OR
• Coming advances in IGI
- Evolution and revolution in image-guided
procedures
- Meeting new standards in technology
assessment
Johns Hopkins University
Schools of Medicine and Engineering
Depts. of Biomedical Engineering,
Computer Science and Surgery
New Opportunities in IGI
High-precision imaging / guidance / monitoring / adaptation:
- Maximize the performance of existing techniques
Increased target ablation
Avoidance of critical structures
More efficient therapeutic delivery, workflow
- Expand the application of current techniques
Management of otherwise “untreatable” disease
Increasingly patient-specific therapies
- Develop entirely new therapeutic approaches
Advanced delivery systems (e.g., robotics, PDT, …)
Investigate the synergy of adaptive, multi-modality therapies
(physical / molecular / cellular / pharmaceutical)
- Expose fundamental factors determining outcome
Image-Guided Intervention (IGI)
Image-Guided Intervention (IGI)
Current technologies for IGI do not provide a “closed loop.”
Intra-operative imaging helps to close the loop.
Treatment Delivery
Treatment Delivery
The Patient
The Surgeon
The Patient
The Surgeon
Planning and Navigation
Planning and Navigation
Intra-Operative Imaging
Cycle of IGI
ORs of the Future
For example: AMIGO: Advanced Multi-Modality Image-Guided OR
F Jolesz, C Timpani, et al., CIMIT, BWH
Imaging
Response
Planning and
Navigation
Ultrasound
Fluoroscopy
Endoscopy
Microscopy
Intervention
Patient transport
3T MRI
PET-CT
ORs of the Future
• Emerging themes:
- Computerized integration of systems / technologies
(e.g., planning and real-time navigation)
- A wealth of data presented intra-operatively
- Advanced therapy delivery systems (e.g., robotics)
- Multi-modality imaging
- Implementation, integration, and evaluation
- Comparative effectiveness
• The longer-term challenges:
- Cost
- Entirely new technology advances, specific to the OR
- Streamlined integration with therapy workflow
Imaging Modalities for IGI
CT
• Imaging technologies
- Continuous advances in Dx imaging technology apply
to Tx imaging as well
- However, challenges for Tx imaging go beyond direct
implementation in the arena of therapy
• Imaging for Tx guidance involves distinct:
• The immediate challenges:
X-ray Fluoro / CBCT
Imaging for Therapy Guidance
Ultrasound
- Imaging tasks
- Requirements (image quality, speed, accuracy, etc.)
- Constraints (dose, patient access, etc.)
• Overall challenge:
- Develop imaging strategies motivated directly by the
objectives and constraints of therapy guidance
Imaging Modalities for IGI
X-ray Fluoro / CBCT
Key Characteristics
• Real-time
(or near-real-time)
• Radiation dose
~1/10 – 1/2 of Dx CT
• Sub-mm resolution
• Soft-tissue visibility
MR
Optical
Nuclear Medicine
Mobile C-Arm
for Intraoperative Cone-Beam CT
Cone-Beam CT
Multiple projection images
acquired over ~180o
2D Image acquisition
- Nominal:
60 s
- High-speed motor: 10 s
3D Image reconstruction
- Nominal:
60 s
- High-speed recon: 10 s
Radiation dose
- ~1/10th that of Dx CT
Projection data
Multiple projections
over ~180o
Volume reconstruction
Sub-mm spatial resolution
+ soft tissue visibility
Mobile Isocentric C-Arm
Mobile Isocentric C-Arm
Cone-Beam CT-Capable C-Arm
Siemens PowerMobil
Motorized
Orbit
Replace XRII with
Flat-Panel Detector
Control System
Control System
Geometric
Calibration
Tube + Collimator
Modification (FOV)
Image Acquisition
3D Reconstruction
Image Acquisition
3D Reconstruction
Pre-clinical platform for multi-mode Fluoro / CBCT guidance
Applications in IG Surgery
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Orthopedic Surgery
Spine Surgery
Brachytherapy
Ear Surgery
Interventional Radiology
Urology
Platform for optimizing /
integrating imaging and
navigation
• Lung Surgery
• Breast Surgery
• Head and Neck Surgery
Applications in IG Surgery
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Orthopedic Surgery
Spine Surgery
Brachytherapy
Ear Surgery
Interventional Radiology
Urology
Lung Surgery
Breast Surgery
Head and Neck Surgery
In vivo studies
of image quality and
geometric precision
• Lung Surgery
• Breast Surgery
• Head and Neck Surgery
Applications in IG Surgery
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Orthopedic Surgery
Spine Surgery
Brachytherapy
Ear Surgery
Interventional Radiology
Urology
Soft-tissue visualization
and real-time planning
Applications in IG Surgery
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Orthopedic Surgery
Spine Surgery
Brachytherapy
Ear Surgery
Interventional Radiology
Urology
Lung Surgery
Breast Surgery
Head and Neck Surgery
Resection of
sub-palpable lesions
Applications in IG Surgery
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Orthopedic Surgery
Spine Surgery
Brachytherapy
Ear Surgery
Interventional Radiology
Urology
Maximal target ablation
and critical structure
avoidance
An Integrated
Image Guidance System
for Head and Neck Surgery
• Lung Surgery
• Breast Surgery
• Head and Neck Surgery
Real-Time Tracking
3D / 4D Multi-ModalityVisualization
Image-to-World
Deformable Reg
Intra-Op CBCT
(POST-Resection)
Endo-to-CBCT
Reg
1
Pre-Op CT, MR, etc.
Pre-Op
Multi-Scale Demons Algorithm
Intra-Op CBCT
(PRE-Incision)
Endoscopy
RIGID
Deformation Field
CBCT C-Arm
3D Deformable Image Registration
Surgical Planning
DEFORMABLE
Image Cross-Correlation
Intra-Op
Integration of Image Guidance Systems
18 sec52 sec
Diff
0.99 (I1 – I0Rigid)
?
12 sec
0.98
11 sec
0.97
0.96
Bin x1
0.95
Bin x2
Bin x4
0.94
Bin x8
1
0
Diff
0.93 (I – I Deformable)
0
5
10
15
20
Iteration #
25
30
Registration Performance (TRE)
Demons Reg
Performance Evaluation
10 Patients
Rigid vs. Demons
6 Anatomical Targets
Target Registration Error (mm)
Rigid Reg
3D Deformable Image Registration:
“Demons” Algorithm
8
7
6
5
4
3
2
1
0
Real-Time Tracking and Navigation
Optimal fiducial arrangements
Automatic registration of image and tracking systems
Stereoscopic IR Camera
(NDI Polaris)
Fiducials
Centroid
Target
Infrared
Reflective Sphere
(5.8 mm radius)
Tungsten BB
(1.0 mm radius)
Multi-Modality Marker
(IR-Xray)
Rigid
Rigid
Demons
Demons
L
R
Temporal
Bone
L
R Spine Soft
Mandible
Tissue
Automatic Tracking Registration
Target Registration Error (TRE)
Manual Registration
TRE = (1.29 ± 0.34) mm
Automatic Registration
TRE = (1.14 ± 0.20) mm
Comparable accuracy
Improved reproducibility
Markers fixed to cranium surface
TRE = (0.83±0.20) mm
Markers off-surface
(better arrangement for H&N)
TRE = (1.24±0.20) mm
NSS (p=0.79)
Workflow
Manual Registration: minutes
Automatic Registration: seconds, automatic with each CBCT scan
Integrated CBCT + Endoscopy
Application in Sinus and Skull Base Surgery
Pre-Clinical Studies
• Tomosynthesis
- Image quality and dose
- Localization accuracy
3D Visualization
+ Video Endoscopy
Polaris
Vicra
• Temporal Bone
- Image quality (spatial resolution)
- Visualization of cochlear implants
• Sinus ablation
- Identification of CSF leak
- Frontal recess, ethmoid, sphenoid
• Skull base
C-Arm
Tracked Endoscope
Pointer
Cadaver
Head
CBCT-Guided Sinus Surgery
- Completeness of target ablation
- Avoidance of critical structures
- Quantitative analysis of surgical
performance under CBCT guidance
CBCT-Guided Sinus Surgery
No CSF Breach
1 mm Breach
2 mm Breach
4 mm Breach
• Identification of CSF Leak
Cadaver specimen
Total sinus ablation
Coronal CBCT
• Breach introduced
Diameter: 1, 2, 4 mm
1-2:
3-4:
5-6:
7-8:
Cribriform
Lateral lamella
Fovea ethmoidalis
Planum
• Observer study
5 surgeons, 1 radiologist
5-point detectability scale
Min detectable breach
Ethmoid Air Cell Ablation
in proximity to
Fovea Ethmoidalis
Skull Base Surgery:
Target Abation in the Clivus
CBCT-Guided Sinus Surgery
Detection of CSF Leak
5=
4=
3=
2=
1=
Perfectly obvious
Visible
Visible, but challenging
Could be overlooked
Unable to identify
Score
(Detectability)
O bserve
r S core
Rating Scale:
Intra-Operative CBCT
Defect Size (mm)
5
(d) Planum
4
Y = 0.68x + 2.02
3
2
Confident detection
>~1.5 - 2 mm breach
1
Critical
0
0
1
2
3
4
5
Defect Size (mm)
TARGET volume
NORMAL volume
Skull Base Surgery:
Target Abation in the Clivus
Intra-Operative CBCT
Critical
TARGET volume
NORMAL volume
Quantification of Surgical Performance
Hypothesis-testing framework for evaluation of surgical performance
Post-Operative CBCT
Critical
TARGET Remaining
NORMAL Remaining
Fraction of
Tumor = Sensitivity =
Excised
TP
TP + FN
Positive
Predictive = PPV =
Value
TP
TP + FP
Fraction of
Normal = Specificity =
Remaining
TN
FP + TN
Negative
Predictive = NPV =
Value
TN
TN + FN
CBCT-Guided Skull Base Surgery
Sensitivity
(Fraction of Target Excised)
1.0
Translation to Clinical Trials
CBCT-Guided
Unguided
(conventional)
0.8
0.6
0.4
0.2
0.0
0.0
0.2
0.4
0.6
0.8
1-Specificity
(Fraction of Normal Excised)
1.0
Normal Tissue
Target Volume (excised)
Target Volume (residual)
Scan 1
C-Arm Trials: Invasive Tumor
Scan 2
Plan Cut
Scan
Scan 3
Scan 4
Resection
Plates
Scan
Scan 44
Pl
an
Craniotomy
Fibula
Reconstruction
Target
(Radionecrosis)
Scan
Scan 3
Scan 22
Scan
C
ut
Scan 1
C-Arm Trials: Mandibulectomy
Tumor Packing
resection
Chondrosarcoma
Tumor
margins
Closure
Looking Ahead:
Opportunities in IGI
Multi-Modality Intra-Operative Imaging
- Essential to ‘closing the loop’ in image-guided surgery
ORs of the Future
Currently characterized by conglomeration of technology
- For example: MR/CT/US + Robot
- Engineering challenge is beyond simple integration
Rather, a re-engineering effort (or new system altogether)
is required according to the surgical task
MR / US / CT / Cone-beam CT
- More than simple translation from Dx to Tx
New development for the task of surgical guidance
Integration of Guidance Systems
- Essential to preserving / improving surgical workflow
Intraoperative imaging
Image registration
Planning and real-time navigation
3D visualization
Therapeutic delivery (e.g., robotics)
Demonstrating True Benefit
Such IG systems and ORs will need to meet new standards
of performance: comparative effectiveness
- Within technology (intra-metrics):
Optimal implementation of ‘Technology X’
- Between technologies (inter-metrics):
Performance of ‘Technology X’ vs ‘Technology Y’
- Clinical justification:
Effectiveness of therapy under ‘Tech X’ vs standard of care
Quantification of surgical performance is key
- Short of randomized clinical trials, approaches like
hypothesis-testing could be valuable
- Rigorous computerized planning
- Quantitative evaluation of planned (and delivered) Tx
ORs of the (more distant) future
- Hopefully exceed conglomerate “IGORs” of the present
Technologies created specifically for the OR
Streamlined integration with surgical workflow
An inter-disciplinary approach to new technologies in the
operating theatre
- (Surgeons, Nurses, Anesthesia) + (Physicists, Engineers)
- Radiation therapy offers a successful model example
Acknowledgements
University Health Network
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JC Irish, MD – Surgical Oncology
G Bachar, MD
E Barker, MD
H Chan, PhD
MJ Daly, MSc
M Rafferty, MD
A Vescan, MD
University of Toronto
• N Hamming, MHSc
• S Nithiananthan
Funding Support
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NIH R01-CA112163
NIH R01-CA127444
Siemens Healthcare (SP, Erlangen)
Princess Margaret Hospital Foundation
Thank you.
Cone-Beam CT
Projection data
Multiple projections
over ~180o
Volume reconstruction
Sub-mm spatial resolution
+ soft tissue visibility
Applications in IG Surgery
•
•
•
•
•
•
•
•
•
Orthopedic Surgery
Spine Surgery
Brachytherapy
Ear Surgery
Interventional Radiology
Urology
Lung Surgery
Breast Surgery
Head and Neck Surgery
Platform for optimizing /
integrating imaging and
navigation
Applications in IG Surgery
•
•
•
•
•
•
Orthopedic Surgery
Spine Surgery
Brachytherapy
Ear Surgery
Interventional Radiology
Urology
In vivo studies
of image quality and
geometric precision
• Lung Surgery
• Breast Surgery
• Head and Neck Surgery
Applications in IG Surgery
•
•
•
•
•
•
Orthopedic Surgery
Spine Surgery
Brachytherapy
Ear Surgery
Interventional Radiology
Urology
Lung Surgery
Breast Surgery
Head and Neck Surgery
Soft-tissue visualization
and real-time planning
• Lung Surgery
• Breast Surgery
• Head and Neck Surgery
Applications in IG Surgery
•
•
•
•
•
•
•
•
•
Orthopedic Surgery
Spine Surgery
Brachytherapy
Ear Surgery
Interventional Radiology
Urology
Resection of
sub-palpable lesions
Applications in IG Surgery
•
•
•
•
•
•
•
•
•
Orthopedic Surgery
Spine Surgery
Brachytherapy
Ear Surgery
Interventional Radiology
Urology
Lung Surgery
Breast Surgery
Head and Neck Surgery
Maximal target ablation
and critical structure
avoidance
Skull Base Surgery:
Target Abation in the Clivus
Skull Base Surgery:
Target Abation in the Clivus
Intra-Operative CBCT
Intra-Operative CBCT
Critical
Critical
TARGET volume
NORMAL volume
TARGET volume
NORMAL volume
Scan 1
C-Arm Trials: Maxillectomy
Scan 4
Scan 3
Scan 2
Adenoid Cystic
Carcinoma
Resection
Dental
Prosthesis
Post-Operative CBCT
Critical
TARGET Remaining
NORMAL Remaining