The "T sign" is really the absence of a twin-peak sign (or lambda (λ) sign) and is used in ultrasound assessment of a multifetal pregnancy.×ArticlesLogInCasesSignUpCoursesQuizDonateAbout×MenuSearchADVERTISEMENT:Radiopaediaisfreethankstooursupportersandadvertisers.BecomeaGoldSupporterandseenoads.ArticlesCasesCoursesLogInLoginSignup{"url":"/signup-modal-props.json?lang=us\u0026email="}ArticlesCasesCoursesQuizAboutRecentEditsGoad-freeSearchTsign(obstetrics)AssocProfCraigHacking◉◈andAssocProfFrankGaillard◉◈etal.The"Tsign"isreallytheabsenceofatwin-peaksign (orlambda(λ) sign)andisusedinultrasoundassessmentofamultifetalpregnancy.Itreferstothelackofchorionextendingbetweenthelayersoftheintertwinmembrane,denotingamonochorionicpregnancy.TheintertwinmembranecomestoanabrupthaltattheedgeinaTconfiguration.Quizquestions{"containerId":"expandableQuestionsContainer","displayRelatedArticles":true,"displayNextQuestion":true,"displaySkipQuestion":true,"articleId":2142,"mcqUrl":"https://radiopaedia.org/articles/t-sign-obstetrics/questions/2175?lang=us"}References1.WeisslederR,WittenbergJ,HarisinghaniMMet-al.PrimerofDiagnosticImaging,ExpertConsult-OnlineandPrint.Mosby.(2011)ISBN:0323065384.ReaditatGoogleBooks-FinditatAmazon2.NybergDA,McGahanJP,PretoriusDH.Diagnosticimagingoffetalanomalies.LippincottWilliams&Wilkins.(2003)ISBN:0781732115.ReaditatGoogleBooks-FinditatAmazon3.TropI.Thetwinpeaksign.Radiology.2001;220(1):68-9.Radiology(fulltext)-Pubmedcitation4.MerzE,BahlmannF.Ultrasoundinobstetricsandgynecology.ThiemeMedicalPublishers.(2005)ISBN:1588901475.ReaditatGoogleBooks-FinditatAmazonRelatedRadiopaediaarticlesUltrasound-obstetricultrasound(introduction)obstetricultrasoundfirsttrimester andearlypregnancygestationalsacdoubledecidualsacsignintradecidualsacsignmeansacdiameteremptygestationalsacpseudogestationalsacyolksacembryo/fetuscrownrumplength(CRL)fetalheartratefetaltachycardiafetalbradycardiafetalbradyarrhythmia(s)gestationalagephysiologicgutherniationembryonicrhombencephalonamnionchori