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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
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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 • 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/019852403x.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 Couinaudsegments • 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 • R/L femoral • Superior mesenteric • R/L renal • Left gastric • Splenic • 8 Couinaud segments • 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 • Wax mold or 3D printed mold • Apply silicone over mold • Heat/saturate mold for removal • Time constraint
Our Approach Create Vasculature Suspend within enclosure Mark/construct enclosure Return lines/ fluid manifold • Create holes at junctions • Adhere branches • Mimic spatial relation • Temporary attachment of vasculature to enclosure walls • 24” X 18” X 8” • Mark entrance and exit points • Drill exit and entrance holes • Attach quick disconnect fittings • Assemble enclosure walls • Attach return lines to fittings • Attach return lines to fluid manifold • Attach fluid manifold to pump
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 time-resolved 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 Semester 2 • Rough/working vascular model • Develop enclosure • Single speed using current flow pump • Safety and reliability testing • Usability testing with interventional radiologists • 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