The central dot sign represents the telltale appearance of intrahepatic portal vein branches surrounded by severely dilated bile ducts, ...×ArticlesLogInCasesSignUpCoursesQuizDonateAbout×MenuSearchADVERTISEMENT:Radiopaediaisfreethankstooursupportersandadvertisers.BecomeaGoldSupporterandseenoads.ArticlesCasesCoursesLogInLoginSignup{"url":"/signup-modal-props.json?lang=us\u0026email="}ArticlesCasesCoursesQuizAboutRecentEditsGoad-freeSearchCentraldotsignDrMuhammadShoyabandDrBalintBotz◉etal.Thecentraldotsignrepresentsthetelltaleappearanceofintrahepaticportalveinbranchessurroundedbyseverelydilatedbileducts,whichcanbevisualizedbyeitherCT,MRI,orUS.PathologyThecentraldotsignisprimarilyencounteredincongenitalintrahepaticbileductdilatation(Carolisyndrome)1,2. Whileinitiallyconsideredspecificforthisdisease,laterresultshaveshownthatthecentraldotsignsporadicallyalsooccursinotherconditions(e.g.peribiliarycysts,periportallymphedema,andjaundiceduetobiliaryobstruction)3. Nevertheless,thesignaidsdifferentiatingCarolisyndromefromotherconditionsresultinginintrahepaticbileductdilatationsuchasprimarysclerosingcholangitisorrecurrentpyogeniccholangitis4.RadiographicfeaturesUltrasoundOnultrasonography,thecentraldotsignmanifestsasechogenicfociorbundles(dependingontheimagingplane)surroundedbythehypoechoiccysticbileductdilatations2.CT/MRIWhenusingcross-sectionalimagingthesignisusuallybestseenintheaxialimagingplane.The"dot"representsthecross-sectionofaportalveinbranch,completelysurroundedbytheabnormallydilatedbileducts.Ifintravenouscontrastisused,thecentralportalveinbranchesshowprofoundenhancementmakingtheappearanceevenmorestriking1.References1.BIChoi,KMYeon,SHKim,MCHan.Carolidisease:centraldotsigninCT.(1990)Radiology.174(1):161-3.doi:10.1148/radiology.174.1.2294544-Pubmed2.NeilU.Lall,MarkJ.Hogan.Carolidiseaseandthecentraldotsign.(2009)PediatricRadiology.39(7):754.doi:10.1007/s00247-009-1147-3-Pubmed3.AhmadiT,ItaiY,MinamiM.CentraldotsigninentitiesotherthanCarolidisease.(1997)Radiationmedicine.1