Bogdan DzyubakJoe HelfenbergerNick BalgeMatt ParlatoClients: Dr. Reeder, Dr. Block, Catherine HinesAdvisor: Dr. Cheslerwww.mritutor.org/mriteach/5000/ct2.jpgOutline Project Description Problem Statement Motivation Design Criteria Design Basic Description and Layout Outer Water-filled Case Honeycomb Inner Structure Material Selection Emulsions Basics Liquid vs. Solid Phase Future Work Semester Goals Long-term Goals ConclusionProblem Statement Client has developed an MRI procedure to quantitatively measure liver fat Needs a way to evaluate procedure performance MRI ―Phantom‖ is required Phantom — Device used to simulate object of interest in an imaging procedure. Many times used for training and/or performance evaluation. A phantom is needed to simulate liver fat, allowing evaluation of this techniqueFatty Liver Disease Abnormal presence of fat in liver Causes/Associations Alcohol Obesity Fat Distribution Problems Impedes normal function Prevents nutrient deliveryhttp://www.abc.net.au/science/news/img/health/liver031007.jpgDiagnosis of Fatty Liver Disease Currently: biopsy required for diagnosis No early symptoms Dr. Scott Reeder Advanced Algorithm Detects Fat%http://www.pathguy.com/lectures/fatty_liver.jpgRelevant Fat Percentages Normal Liver Fat: 0% Abnormal Liver Fat: Range: 5-30% Maximum Observed: 50% Adipose Tissue: 90-95%http://www.hartnell.cc.ca.us/faculty/aedens/Bio6L/tissue-adiposeB.jpghttp://media.photobucket.com/image/normal%20liver%20cells/jondopics/drugbio/liver6-1.jpghttp://www.uic.edu/com/dom/gastro/fac.banner.nafld.gifhttp://en.wikipedia.org/wiki/File:Liver_steatosis_fatty_change.jpghttp://en.wikipedia.org/wiki/File:Non-alcoholic_fatty_liver_disease1.jpgAdipose TissueFat Accumulation in Liver CellsNormal Liver CellsDesign Criteria 1. Realistically simulate liver fat conditions2. Be MRI compatible No metal or other magnetic materials Nothing that significantly distorts MR images Physically fit within an MRI 1-channel head coil3. Easy to use, transport, and store Shelf-life of greater than 3 years4. Highly reproducible Every time the phantom is imaged, it must appear the same (error tolerance ± 0.3%) If more are manufactured, they all must behave the same in MRIGeneral Phantom Structure Samples enclosed in glass vials Airtight and transparent Vials housed in plastic ―honeycomb‖ Honeycomb submerged in acrylic water-tank No sample-air interfaces Water is doped with Gd to simulate liver conditionsDimensions (cm) Fits 20 vials – 5 wide by 4 tall Separated by 7.2 mm (4 pixels) Vials are 2.8 cm diameter by 7.6 cm long7.2 mm 7.2 mm3.6 mm7.6 cm2.8 cmMore Dimensions (cm)Material SelectionOuter Case – Acryilic Transparent Watertight sealInner Structure – Plastic Machineable High densityMixture Containers – Glass Water impermeable TransparentNo Metal!http://www.ospreyco.com/images/acrylic-sheet-.jpghttp://www.tradevv.com/TradevvImage/productimages/PTFE-teflon-rod-A3e4d7.jpghttp://www.sks-science.com/images/986491LRG.jpgSamples 20 vials total Fat fraction distribution: 0.3% intervals in 0% to 10% range Sparsely sampled above 10%0 5 10Fat Fractions (0-10%)Oil-in-water Emulsion Water and fat are immiscible Emulsifier/surfactant required to mix IvoryTMhand soap Density difference causes eventual separation Stabilizer is needed to maintain the mixture Liquid Phase Solid Phasehttp://openlearn.open.ac.uk/file.php/3592/T356_3_003i.jpgEmulsion StabilizersLiquid Phase Increases viscosity Air bubbles are mobile Easier to create and work with post-addition of stabilizerSolid Phase Creates a cross-linked matrix Air stays in a fixed position Generally longer lastingLiquid Phase Solid PhaseMixture Duration (50) 25 40Workability (20) 20 5Ability to Manipulate Air (25) 5 25Previously Tested (5) 0 5Total (100) 50 75Goals for this SemesterPrototype Construction Prototype Testing Construction of prototype Honeycomb Outer Case Create fat-water solutions using standard analytical chemistry techniques Verify that method used to make phantom is highly reproducible and accurate Perform several MRI scans of the phantom Run client’s fat quantification procedure Evaluate ease of use, transport, and storage of current designFuture Work Correct unforeseen problems Include different emulsion additives Addition of Fe2+ ions Addition of physiological materials Include useful extras: Handles Water spigots Case coverConclusion Overall Goal: Construct a phantom for MRI fat-quantification calibration Honeycomb design submerged in water-filled outer case Glass vials filled with solid-phase oil-in-water emulsionhttp://www.sutterbuttesimaging.com/images/mri_scannerlg.jpgAcknowledgementsWe would like to extend thanks to:Our Advisor: Dr. CheslerOur Clients: Dr. Reeder, Dr. Block, and Catherine HinesAnd helpful collaborator: Gary FrankBibliography (references) Fabbrini, E, Magkos, F, Selma, BM, Terry, P, Abumrad, N, Patterson, B, Okunade, A, Klein, S. 2009. Intrahepatic fat, not visceral fat, is linked with metabolic complications of obesity. PNAS vol. 106:36 (15430-15435) Nonalcoholic Steatohepatitis 2006. The National Digestive Diseases Information Clearinghouse (NDDIC). NIH Publication No. 07–4921 http://digestive.niddk.nih.gov/ddiseases/pubs/nash/ Woodward P and Freimarck R (eds) 1995 MRI for Technologists (New York:
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