Earlyexperienceofnovelbiliarytreemagneticresonancecholangiopancreatography (MRCP)analysis

SiddharthVikal,Nassim Parvizi,MichaelBrady,Rajarshi Banerjee

Motivation

MRCPEnhancementwithoutcontrast

Needforobjectivequantitativemeasures

• MRCProutinelyusedinevaluationof:gallbladderanatomy,stones,cholestatic diseasesincludingPSC,choledocholithiasis,pancreatitis,hepatobiliary-pancreatictumours,andsurgicalplanning

• Non-invasive,increasesdiagnosticconfidenceandreducesfrequencyofinvasivefollow-upprocedures

• Stillhaslimitations:variableimagequality,intra-hepaticbileductsdepictedpoorlyascomparedtoinvasiveERCP

• NostandardmethodforinterpretingMRCPdata• ConventionalMaximalIntensityProjections(MIP)aredifficulttointerpretsince2Drepresentationsuffersfromocclusionproblemsandlackofdepthinformation

• Analysis/interpretationisqualitative,withlargeinterratervariation

• Objective,quantitativetools/measuresneededforaccuratediagnosisandmonitordiseaseprogression

• Weproposeanovelsynthesisofimageprocessingtechniquesforenhancementand3DvisualizationofbiliarytreefromMRCP

• Hessianbasedtubularstructureenhancement,followedbyOtsuthresholding,andinteractive3Dvisualization

• Postprocessingtechnique,nocontrastrequired

Axial,Coronal,Sagittalviews MIP Thresholded,3Dvisualization

Enhanced,thresholded,

3Dvisualization

Quantitativemodellingofbiliarytree

MRCPdata

Extractedbiliarytree,interactive3Dvisualization

Computedquantitativemodelthatshowsindividualductcenterlines,widths,cross-sectionorientationsandbranchingtopology

AutomaticidentificationandquantificationofstricturesanddilatationsBileductunderreviewin3D• Colorcodedwithdiameter• Redarrowsindicatestrictures• Bluearrowsindicatedilatations• Sizeofarrowproportionaltoamountofstricturing/dilatation•Unfoldtheconvolutedbileductandshowitin2Dwithdiametermeasurements

Registrationandco-viewingofMRCPwithanatomicalMRIin3D

Clinicalimpactstudy Caseexamples

Healthyindividual

SmallductPSCpatient

Biliaryreconstructionpatient

• Doubleblindedstudytoassessclinicalusefulnessofthetoolsdeveloped

• 10originalpatientdatasets,10correspondingenhanceddatasetsà 20differentdatasetsforradiologisttoreportfindingson

• Radiologistrecordsfindings• Findingscombinedanddecodedintooriginal

(unenhanced)vsenhanced

Result:Enhancementallowstoseegreaterlevelofbranchingofintra-hepaticductsandhelpsfindingstrictureswithease

Conclusions

• Analyticalenhancementtechniquesdevelopedhelpseefaintintra-hepaticductsclearlywithoutanycontrastagent

• Quantitativemodelingtoolsallowforanobjectiveandaccurateassessment

• Postprocessingtechniquesallowforretrospectiveevaluationandprospectivevalidationaswell

• InformationfusionofanatomicalMRIwithMRCP• Robustandrepeatablemethods