BI - RADSUpdateCecilia L. Mercado,MDINTRODUCTIONTheAmericanCollegeof Radiology(ACR) BreastImaging Reporting and Data System(BI-RADS)has undergone revision. The main objectives of thenew BI-RADS edition remain the same: to diminishconfusionin theinterpretation ofimagingfindings,tostandardizereporting, andtosimplifyoutcomemonitoring.1The overall changes made to the ACRBI-RADShavebeendesignedtogive more flexibilityfor situations where the previous edition of BI-RADSin the past had given much confusion.2The new edition of BI-RADS has made changestoits 3components, theBI-RADS breastimaginglexicon,thestandardizedreportinglanguage,andthemedical audit andoutcomemonitoring. Themammography, ultrasound, andmagnetic reso-nanceimaging(MRI) lexicons have beenmademore compatible with each other by using thesame descriptors for a lesion across wheneverpossible all 3 imaging modalities. An increase num-ber of mammographyimageshavebeenaddedtotheneweditionreplacingmanyof thefeatureillustrationsinthepreviousedition.Alsoaddedinthis new edition isan increase in number ofrefer-ence citations, which provides evidence-basedjustification to the lexicon and managementrecommendations.3BREASTIMAGINGLEXICONSeveral changes to the mammography, ultrasound,andMRI lexicon terminology have been made in thenewedition.2Inconsistenciesinsomedescriptiveterms have been addressed, and terms have beendeleted,added,orrevisedinanefforttoenhanceclarification of appropriate usage.MammographyLexiconVariousdescriptorsinthemammographylexiconwerechangedtoimproveclarificationof termi-nology. The previous BI-RADS mammographylexicon usedthe terms groupedor clusteredfor calcificationslessthan1ccinvolume, andthetermregionalforcalcificationsgreaterthan2 cc. These terms did not address the group of cal-cificationsmeasuring1ccto2ccinvolume.Thenew edition has resolved this inconsistency by ex-pandingthedefinitionof groupedtoavolumeextending up to 2 cc. In addition, the terms groupor clustered, whichcouldbeusedinterchange-ably with the previous BI-RADS edition, are beingphasedout andhavebeenchangedtothetermgrouped (historicallyclustered) withtheinten-sion of ultimately changing it to grouped in a laterrevision.2Increasedsimplificationhasledtosometermsintheneweditiontobeconsolidated, suchasthe descriptors lucent-centered, egg-shell,and rim used to describe types of benign calcifi-cations.These are now under one single descrip-tiveterm, rim (Fig. 1). Another termthat hasbeeneliminatedisthedescriptorformassshapelobular, whichhasbeenreplacedbythetermDepartment of Radiology, New York University School of Medicine, NYU Cancer Institute, 160 East 34th Street,3rdFloor,NewYork,NY10016, USAE-mailaddress: cecilia.mercado@nyumc.orgKEYWORDS

Breast Breastimaging BI-RADS BI-RADSatlas LexiconKEYPOINTS The newedition of BI-RADS has been updated to provide further clarification of lesion interpretationand standardization of lesion terminology and reporting. The BI-RADS revision provides a uniformity of terminology in the lexicon across all 3 imaging mo-dalities, mammography, ultrasound, and magnetic resonance imaging. Introduction of newdescriptive terms in the updated BI-RADS is reflective of newavailable technol-ogies and evidence provided from current publications.Radiol Clin N Am 52 (2014) 481487http://dx.doi.org/10.1016/j.rcl.2014.02.0080033-8389/14/$ see front matter 2014 Elsevier Inc. All rights reserved.radiologic.theclinics.comovaltostandardizedescriptorsacrossimagingmodalities. These changes have been summarizedin Box 1. Other terms such as intermediateconcern, used for amorphous and coarse hetero-geneous calcifications and the term higher prob-abilityof malignancyusedfor finepleomorphic,finelinear,and fine-linearbranchingcalcificationshavealsobeendeletedfromthemammographylexicon. Newpublishedevidencesuggests thatsome of the descriptive terms used to characterizecalcifications may not impart the level of suspicionpreviously believed, and therefore the revisedBI-RADShaschangedtoonlyusingdescriptorsfor lesion characterization.4There are some descriptive terms in the updatedBI-RADSthat havebeenexpanded, suchasthetermsthatdescribeanasymmetryoftenrepre-sentssummationartifact.Inaddition,anewtermdevelopingasymmetry,which describesafocalasymmetry that is new, growing, or more conspic-uous, has beenaddedtotheexistingtypes ofasymmetries in the mammography lexicon.Increasedclarificationhas beenprovidedas tothedifferent management recommendations forthe 4 types of asymmetries (Box 2).UltrasoundLexiconThe terminology in the ultrasound lexicon has beenexpanded in the newBI-RADS edition. Descriptorsfortissuecompositionascharacterizedonultra-sound have been revised to correlate to themammographicbreast densities. Theseareho-mogeneous-fat, homogeneous-fibroglandular,andheterogeneous tissue composition. As inthe previous edition, there are primary descriptorstocharacterizetheshapeandmarginof massesimagedonultrasound. Similar tothemammog-raphy and MRI lexicon, the ultrasound descriptorswere updated to maintain consistency among the3modalities. Therewill becertaintermsthatwillbedefinedsuchasthat for acomplicatedcyst,whichisdefinedasacircumscribed, oval, massparallel orientation containing low-level echoesthroughout (Fig. 2).Along with descriptors for the additional section,which include echo pattern and posterioracoustic features, there is a new subsection titledAssociated Features, which will include descrip-tors for architectural distortion, vascularity, andelastography (tissue stiffness). The descriptiveterms for elastography are new and includesoft, intermediate, andhard. It is empha-sized that the features of elastography do nottrump the primary features of morphology, shape,margin, and orientation.3These changes havebeen summarized in Box 3.MagneticResonanceImagingLexiconSeveral changes were also introducedintotheMRIlexicon.AlthoughpreviouslyintroducedasaFig. 1. Updatedmammographylexiconterminology.Spotmagnificationmammographyshowsrimcalcifi-cationnear lumpectomysite. Thedescriptors egg-shellandlucent-centeredusedtodescribetypesof benign calcifications have been consolidated undertheterm rim.Box 1Summary of changes to the BI-RADSmammography lexiconLexicon Terminology Updated BI-RADSGroupedhistoricallyclusteredReplaces grouped orclusteredRim Replaces lucent-centered, egg-shellOval Replaces lobularDeveloping asymmetryNewBox 2Descriptors for types of asymmetry in themammography lexicon and appropriateassessment categoryTypes of Asymmetry Assessment CategoryAsymmetry BI-RADS 1Global asymmetry BI-RADS 2Focal asymmetry BI-RADS 3Developing asymmetry BI-RADS 4Mercado 482concept,backgroundparenchymal enhancement(BPE) has beenofficially addedtothenewBI-RADSMRIlexiconandtheMRIreport.Thereare4termsthatdescribetheamountof BPE: mini-mal, mild, moderate, and marked.5It isimportant torecognizethat theamount of BPEdoes not directly correlate with the amount of fibro-glandular tissue seen on mammography. However,the amount of BPEdepends on the amount of fibro-glandular tissue present, and inclusion of terminol-ogy that characterizes the amount of fibroglandulartissueasassessedonthenoncontrast, nonsub-tractedT1sequencehasbeenaddedtotheBI-RADS revision. These terms are meant to correlatewith the amount of fibroglandular parenchymaseen on mammography. The descriptors todescribe fibroglandular parenchymal tissue onMRI are almost entirely fat, scatteredfibrogland-ular tissue, heterogeneous fibroglandular tissue,and extreme fibroglandular tissue.2,5,6Several descriptors have also been changedor deleted from the MRI lexicon to increasesimplification. Terms used to describe mass shaperound, oval, andirregularremain. However,the descriptor lobularfor mass shape, has beendeleted and incorporated in the term oval(Fig.3).Massmargindescriptorshavealsobeenrevised. Thetermcircumscribed hasreplacedsmooth, and the term irregular is now adescriptor of mass shape and margin. In addition,termsusedtodescribetheinternal enhancementof a mass, central enhancement, and enhancinginternal septations,havebeenremovedfromthelexicon due to lack of usage. Similarly, descriptorsusedfor nonmassenhancement, reticular anddendritic, have also been removed from the lexi-confor underutilization. Another descriptor elimi-natedfromthe MRIlexiconisductal, whichhasbeen consolidated under the term linear (Fig. 4).Other terms multiple foci and stippled, descrip-tors for nonmass enhancement have been removedfromthelexiconasitisnowrecognizedthattheyrepresent normal enhancement of fibroglandulartissueandwill bedescribedas part of BPE.5,6Thesechanges have been summarized in Box 4.A new term to describe nonmass enhancementhasbeenintroducedintotheMRILexicon,clus-teredringenhancement. Thisfinding, althoughnot often seen, has been shown to have ahigh positive predictive value (PPV) for ductal car-cinoma in situ.7,8Another newimaging featureintroducedintothelexicondescribesthecharac-teristics of masses andnonmass enhancementon the T2 noncontrast sequence.5This featureassesses the T2 signal intensity of lesions, asincreased T2 signal intensity has been mostlyassociated with benign lesion such as cysts and fi-broadenomas,9,10andmuchlesswithmalignantlesionssuchasmucinouscarcinoma. Inadditionto the changes regarding the morphologic de-scriptors for mass andnonmass enhancement,therevisededitionincludesasectiononkineticdescriptors, newsections listing nonenhancingfindings, and associated findings as well as anew implants section.5,6REPORTINGSYSTEMThe new BI-RADS edition has made severalchangestothestandardizedreportinglanguageaswell. AsintheBreast ImagingLexicon, sometermshavebeendeleted,added,orclarified.Thenewedition has eliminated the percent rangesfor the breast density categories found in themammography lexicon. These had been intro-duced in previous editions in an attempt to providean equal distribution of breast density assignmentsthroughout all studiesperformed. However, theywere not found to be helpful and were deleted.Fig. 2. Ultrasound lexicon terminology updated. Ultra-soundimages of complicatedcysts showa circum-scribed, oval mass with parallel orientation containinghomogeneous low-level echoes throughout.Box 3Summary of changes to BI-RADS ultrasoundlexiconLexicon TerminologyUpdatedBI-RADSTissue composition descriptors NewAssociative features section NewElastography descriptors NewBI-RADS Update 483The newBI-RADSalso provides clarificationof terms used to describe lesion location onmammography. Previously, in cases where alesionwaslocatedinthecentral breastoratthe12:00location, aspecificquadrant couldnot beassigned. ThenewBI-RADShasexpandedtheterminology for lesionlocationbyaddingtermssuch as upper/lower/outer/inner central. Thisterminology has been added to the mammographylexiconandallowsfordirectcorrelationof lesionlocationonultrasoundandMRI.Increasedclarifi-cation has alsobeen providedtodescribe theuse of subcategories for the BI-RADS assessmentCategory4. ThenewBI-RADSprovidesspecificPPVcut-offpointsforBI-RADS4A/4B/4C,whichmatchcertainspecificimagingfindings. Theuseof these cut-off points remains optional in thenew edition but is strongly encouraged.4OneofthemajorchangesinthenewBI-RADSeditionhas beentheseparationof assessmentcategories and management recommendationsthathadbeenlinkedinthepreviousedition. Inmost cases, the assessment and managementhave been paired up appropriately. However,there are some instances where the managementrecommendations did not go along with theBI-RADS assessment. This is the case in theBI-RADS Category 3/follow-up at 1-year manage-ment recommendation given at the third follow-uprecommendation for a probably benign finding.The newedition provides flexibility for discor-dances between the assessment and the manage-ment. It alsoincludessituationswhereabenignfinding may require an intervention or surgicalmanagement: when a patient presents with apalpable mass without imaging findings stillrequiring surgical management, or cases of thera-peuticcystaspirationsduetopatientdiscomfort.The new BI-RADS edition addresses thesediscrepancies.Other specific situations leading to discrep-anciesthat havebeenaddressedincludecasesof ruptured silicone implants, abscesses, new he-matoma,andunexplainededema.Inthesesitua-tions, theimagingfindingsarebenignappearingandleadtoabenignrecommendationbut withFig.3. RevisedMRIlexiconterminologyformassshape.Axialpost-contrastT1-weighted(A)andsagittalpost-contrast subtractedT1-weighted(B) images showanoval enhancingmass inthecentral right breast. Thedescriptor formassshapelobular hasbeendeletedandreplaced withtheterm oval.Fig. 4. UpdatedMRI lexiconterminologyfornonmassenhancement. Axial post-contrastT1-weighted(A) andsagittal post-contrast subtracted T1-weighted (B) images demonstrate linear enhancement in the inferior lateralright breast. The term ductal has been eliminated from the lexicon and replaced with the descriptor for non-massenhancementlinear.Mercado 484surgical/clinical managementrequired.Byunlink-ingthe assessment fromthe management, theBI-RADS assessment category then appropriatelyreflects the imaging finding providing a concordantmanagement recommendation for the assess-ment. Thisisthenfollowedbytheadditionof aseparatesentencethatexplainsthediscordanceand provides the additional management.AUDITINGTheauditingsectionhasalsobeenexpandedinthenewBI-RADSedition.Newandupdatedper-formance benchmarks based on more recent pub-lished literature have been incorporated in the newedition,as the previousoneswere outdated.Oneof thebenchmarksthathasbeenupdatedistherecallrate.Halfofallradiologistsdonot meetthe10%benchmarkfor recall rate, andthereforeithasbeenchangedtoamorerealisticnumberof12%asmorethan75%of radiologistsareableto meet it.11,12Thedefinitionforscreeningintervalhasbeenre-evaluatedinthenewedition. TherevisedBI-RADS editionrecognizes thatthe screening inter-val may differ fromcountry to country and insome countries it may be 1 year or 2- to 3-year in-tervals. As the definition of cancer for purpose ofoutcome monitoring is cancer diagnosis within thescreeninginterval,theimportanceofdefiningtheexactlengthof thescreening intervalis apparent.A longer screening interval results in a larger num-ber of falsenegativesascancersareallowedtogrowfor alonger periodof timebeforetheyarediscovered.Theneweditionalsoaddressesthedifferencebetween the 2 types of cyst aspirations: diagnosticversus therapeutic. A diagnostic cyst aspiration isperformedtoevaluateif alesionis acyst andshouldbeaccompaniedbyasuspiciousassess-ment with a recommendation for tissue diagnosis.Atherapeuticcyst aspirationisperformedonasimplecystforsymptomaticreliefandshouldbeaccompaniedbyabenignassessment(Category2)withanadditional phraseaddedtotherecom-mendationstatingwhyit wasperformed. Thera-peuticcystaspirationsshouldnotbeincludedasbiopsies when auditing the practice.2ASSESSMENTCATEGORIESChangeshavebeenmadetotheBI-RADSman-agementterminology,whichincludeexplanationsfor each BI-RADS assessment category on its us-age. Added explanations provide guidance onhoweachassessment categoryshouldbeusedand for which specific circumstance. The BI-RADS assessment Category 0 (Incomplete) isusedwhenadditional imagingworkupisrequiredto make a final assessment, primarily fromscreeningexaminationsandrarelyfromadiag-nosticstudy. It canalsobeusedincaseswhenoneis awaitingprior studies for comparison. Itstates that when used in this situation,re-assessment needs to be performed within30daysastoavoiddelayinreporting. BI-RADSCategory1(Negative) shouldbeusedonlywhenthemammographyreport describesnospecificbenignfinding, andBI-RADSCategory2(Benignfinding)shouldonlybeusedwhenthemammog-raphyreportdescribesabenignfinding.Forbothcategories, therecommendationremainsroutinescreening.For BI-RADS Category 3 (Probably benignfinding), anexplanationisprovidedonwhentheassessment category should be used, that is,forlesionsthathavealessthan2%likelihoodofmalignancy. Arecommendationof short-intervalfollow-up should be given for lesions assessed asCategory 3. The revised BI-RADS edition providesadditionalguidanceastowhichparticularlexicondescriptor leads to a concordant assessmentCategory3assupportedintheliterature; theseinclude a group of tiny round/oval calcifications, anoncalcified circumscribed solid mass, and a focalasymmetry.13,14ACategory3assessmentshouldbe given only after a full diagnostic imaging evalu-ation has been performed, almost never if previousexaminations areavailablefor comparison, andnever from a screening study.Theterminologyfor recommendationsassoci-atedwiththeBI-RADSassessmentcategories4,5, and6havechangedinthenewedition. ForCategories4and5, therecommendationshaveBox 4Summary of changes to BI-RADS MRI lexiconLexicon TerminologyUpdatedBI-RADSBPE NewAmount of fibroglandulartissueNewCentral enhancement DeletedEnhancing internal septations DeletedLinear, linear branching ReplacesductalMultiple foci DeletedStippled DeletedReticular DeletedDendritic DeletedClustered ring NewNonenhancing lesion section NewImplant section NewBI-RADS Update 485changed to tissue diagnosis with a directive thatstates Biopsy should be performed in theabsenceofclinical contraindication.Therecom-mendationappropriateactionshouldbetakenfor Category 6 has also been changed to Surgicalexcision when clinically appropriate. The changesto the wording reflect the importance of conveyingthe appropriate management recommendationwhen tissue diagnosis is required.TheBI-RADSassessment Category 4(Suspi-ciousabnormality) isassignedtoall findingsthatare betweenCategory 3(>2% risk ofmalignancy)andCategory5(95%riskofmalignancy).Mostrecommendationsfor tissuediagnosisareCate-gory 4, ranging fromaspiration of newcomplicatedcysts tobiopsy of very suspicious pleomorphiccalcifications.1The subdivisions of Category4(4A/4B/4C) havebeenbetter delineatedinthenew edition with well-defined cut-off points(Box 5). The terminology for Category 4Bhaschangedfromintermediatetomoderateandfor Category 4C has changed from moderate tohightoreflect newevidencefrommorerecentpublished literature.4The assessment Category5(Highlysuggestiveofmalignancy) isassignedtofindings that are almost always malignant withmorethan95%riskofcancer.Ithasbeenrecog-nized that not one single imaging feature can impartsucha highrisk of malignancy, but rather acombina-tion of findings is required to lead to the assessmentCategory 5.2BI-RADS Category 6 (Known biopsy proven malignancy) is given when the findings havealreadybeenconfirmedas malignant by biopsy,and the imaging has been performed before surgicalexcision. Category6lesionsshouldbeexcludedfromthemedical audit, asthey wouldinappropriatelyinflate the cancer detection rate and PPVs.1SUMMARYTheneweditionof BI-RADSprovidesincreasedclarificationof thelexiconterminology byintro-ducing new terms and deleting others whenappropriate. It also leads to improved standar-dization of the reporting language andimprovedimageinterpretation. Therevisionalsoprovidesin-creased guidance in the usage of the BI-RADS man-agement terminology, providing explanations on howtheassessment categoriesshouldbeusedandinwhichspecificcircumstances.Overall,thechangesmade in the new BI-RADS give increased uniformityof terminology across the mammography, ultra-sound, andMRI lexicons; addcompatibilityacrossthe lexicons; and promote usage of the samedescriptors across all 3 modalities ultimately leadingto improved patient diagnosis and patient care.ADDENDUMThe below is the reference to the new ACRBI-RADSAtlas, 5thEditionwhichwaspublishedlatertowritingthisarticle.DOrsi CJ,SicklesEA,MendelsonEB, et al. Breast ImagingReportngand Data System: ACR BI-RADS Atlas. Re-ston(VA): American College of Radiology; 2013.REFERENCES1. DOrsi CJ, MendelsonEB, IkedaDM, et al. Breastimaging reporting and data system: ACR BI-RADSbreast imagingatlas. Reston(VA): Amer-icanCollegeof Radiology; 2003.2. DestaunisSV, SicklesEA, MendelsonEB, et al. BI-RADSUpdateandchallenge(aninteractive ses-sion).RefresherCoursethe99thAnnual MeetingoftheRadiological Societyof NorthAmerica, RSNA.Chicago,December4,2013.3. HansenB. InsidetheNewBI-RADS. ACRBulletin2011;66(6):22.4. Torres-Tabanera M, Ca rdenas-Rebollo JM, Villar-Castan oP, et al. Analysisof thepositivepredictivevalue of the subcategories of BI-RADS() 4 lesions:preliminaryresultsin880lesions. Radiologia2012;54(6):52031.5. EdwardsSD, LipsonJA, IkedaDM, et al. UpdatesandrevisionstotheBI-RADSmagneticresonanceimaginglexicon. MagnResonImagingClinNAm2013;21:48393.6. Available at: http://www.auntminnieeurope.com/index.aspx?sec5sup&sub5wom&pag5dis&ItemID5605318. AccessedDecember 27, 2012.7. UematsuT, Kasami M. High-spatial-resolution3-Tbreast MRI of nonmasslike enhancement lesions:an analysis of their features as significant predictorsof malignancy. AJRAmJRoentgenol 2012;198(5):122330.8. Tozaki M, FukudaK. High-spatial-resolutionMRI ofnon-masslike breast lesions: interpretation modelbased on BI-RADS MRI descriptors. AJR AmJRoentgenol2006;187(2):3307.Box 5Subdivision of category 4 (suspiciousabnormality)Category 4A Low suspicion for malignancy(>2%10% likelihood ofmalignancy)Category 4B Moderate suspicion formalignancy (>10%50%likelihood of malignancy)Category 4C High suspicion for malignancy(>50% but