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MRI Liver Phantom for
Transarterial Chemoembolization
Simulation
Team Leader – Benjamin Engel
Communicator – Eric Printz
BWIG – Ryan Carroll
BSAC – Justin Schmidt
Client – Dr. Wally Block, Ph.D
Departments of Biomedical Engineering & Medical Physics
Advisor – Dr. Bill Murphy, Ph.D
Department of Biomedical Engineering
Overview
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Research Motivation
Background Information
Project Requirements
General Design Approach
Vascular Network Options
Next Steps
Research Motivation
• Hepatic metastases are a major cause of
mortality
– Colorectal cancer and breast carcinoma
– Primary liver tumors
• Systemic chemotherapy treatment ineffective
– Response rate of 20%
– 20% of tumors are surgically operable
• Targeted techniques improve results
– TACE procedures
X-Ray Guided Technique
• Current procedure involves two step
process
– Preoperative CT or MRI scan
– X-ray guided catheterization
• X-ray disadvantages
– Incomplete tumor location
– Not tolerated by patients with
compromised kidney function
– Ionizing radiation
– 2 dimensional projections
http://content.answers.com/main/content/img/oxford/Oxford_Body/01985240
3x.x-rays.3.jpg
MRI Guided Technique
• High contrast, cross-sectional imaging technique
• Contrast enhancement + under sampling techniques make
real-time, dynamic images possible
• Active catheter tracking
Block, WF. 3D Real-Time MRI Imaging Grant. PHS 398/2590.
Result: Improved tumor localization without the need to
deliver high doses of radiation to the patient
Liver Anatomy
• Eight Couinaud segments
– Branch from hepatic
arteries
• 75% venous circulation
• 25% arterial circulation
• TACE focuses on arterial
vasculature
Block, WF. 3D Real-Time MRI Imaging Grant. PHS 398/2590.
Current Phantom
Left/Right Hepatic Arteries Connect to Liver
Aorta
Right Renal Artery
• Does not model liver
• Surrounded with opaque gel
• Artifacts caused by proximity of
phantom edges to vasculature
• Connected to constant flow pump
Right Femoral Artery
Block, WF. 3D Real-Time MRI Imaging Grant. PHS 398/2590.
Project Specifications
• Vasculature
– 8 couinaud segments
– Key abdominal arteries
• Material compatible with MRI
– Minimize image artifacts
– Four inches between enclosure and vasculature
• Port for catheter entrance into vasculature
• Active flow through vasculature
• Maneuverable by one person
General Approach
Plexiglas Enclosure
Fluid Manifold
Vascular
Network
Flow Pump
Catheter insertion
port
1 Entrance Point
15 Exit Points
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R/L femoral
Superior mesenteric
R/L renal
Left gastric
Splenic
8 Couinaud segments
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Aorta
Vascular Network Design Ideas
• Limitless variation
• Tygon tubing using plastic connectors
– Vascular junctions using barbed plastic connectors
– Limitation on achievable angles
• Tygon tubing using adhesive
– Silicone based epoxy
– Precise placement of branches
• Silicone wrapped mold
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Wax mold or 3D printed mold
Apply silicone over mold
Heat/saturate mold for removal
Time constraint
Liver Model
Our Approach
Create
Vasculature
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Create holes at
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junctions
Adhere branches
Mimic spatial relation
Suspend within
enclosure
Temporary attachment
of vasculature to
enclosure walls
Mark/construct
enclosure
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24” X 18” X 8”
Mark entrance and exit
points
Drill exit and entrance
holes
Attach quick
disconnect fittings
Assemble enclosure
walls
Return lines/
fluid manifold
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Attach return lines to
fittings
Attach return lines to
fluid manifold
Attach fluid manifold
to pump
Questions?
References
Block, WF. 3D Real-Time MRI Imaging Grant. PHS 398/2590.
Vigen KK, Peters DC, Grist TM, Block WF, Mistretta CA. Undersampled projection reconstruction imaging for timeresolved contrast-enhanced imaging. Magnetic Resonance in Medicine. 2000;43:170-176.
Longmire WP, Tompkins RK, Manual of Liver Surgery, Springer-Verlag, 1981
Shelley Medical Imaging Technologies. Rigid Abdominal Aorta Product Details. Product Number: A-R-N-001.
X-Ray Angiograph. http://content.answers.com/main/content/img/oxford/Oxford_Body/019852403x.x-rays.3.jpg
Liver Model. Mevis-Distant Services. http://www.mevis-distant-services.com/index.php?id=23
Project Scope
Semester 1
• Rough/working vascular
model
• Develop enclosure
• Single speed using current
flow pump
• Safety and reliability testing
• Usability testing with
interventional radiologists
Semester 2
• Improvement of 3D vascular
network
• Integration of pulsatile flow
through current flow pump
• Upgrade flow pump
• Development of gel/liquid
that mimics T1/T2 relaxation
times
• Continued usability testing