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 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 Result: Improved tumor localization without the need to deliver high doses of radiation to the patient Block, WF. 3D Real-Time MRI Imaging Grant. PHS 398/2590.

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 Does not model liver Surrounded with opaque gel Artifacts caused by proximity of phantom edges to vasculature Connected to constant flow pump Left/Right Hepatic Arteries Connect to Liver Aorta Right Renal Artery 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

Plexiglas Enclosure General Approach Vascular Network Fluid ManifoldFlow Pump 1 Entrance Point 15 Exit Points R/L femoral Superior mesenteric R/L renal Left gastric Splenic 8 Couinaud segments Aorta Catheter insertion port

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

Liver Model

Our Approach Create holes at junctions Adhere branches Mimic spatial relation Create Vasculature Suspend within enclosure Mark/construct enclosure Return lines/ fluid manifold 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

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 time- resolved contrast-enhanced imaging. Magnetic Resonance in Medicine. 2000;43: 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. Liver Model. Mevis-Distant Services.

Project Scope Semester 1Semester 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