Accuracy of sonographic findings in breast cancer: correlation between BI-RADS categories and histological findings*

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1 Origial Article Artigo Origial Soographic accuracy i breast cacer Accuracy of soographic fidigs i breast cacer: correlatio betwee BI-RADS categories ad histological fidigs* Acurácia dos achados ultrassoográficos do câcer de mama: correlação da classificação BI-RADS e achados histológicos José Hermes Ribas do Nascimeto 1, Viicius Duval da Silva 2, Atoio Carlos Maciel 3 Abstract Resumo OBJECTIVE: The mai purpose of the preset study is to evaluate the accuracy of ultrasoography (BI-RADS) i the diagosis of breast cacer whereas the additioal specific objectives are to describe the frequecy of differet soographic fidigs ad evaluatig iterobserver agreemet. MATERIALS AND METHODS: Images of patiets who had bee referred for biopsy with previous diagosis of breast odules were idepedetly reviewed by two specialists accordig to the BI-RADS classificatio. Histological fidigs were utilized as a gold-stadard. The accuracy of fidigs was determied. The chi-squared test for categorical variables was utilized i the aalysis of the differeces resultig from the groups compariso, ad the iterobserver agreemet was calculated with kappa (κ) statistics. RESULTS: Amog breast masses evaluated by ultrasoography, (69%) were beig ad 34 (30.9%) were maligat. Accordig to the radiologists, the sesitivity raged from 70.5% to 82.3%, egative predictive value, from 81.1% to 87.5%, positive predictive value, from 42.1% to 45.1%, specificity from 56.58% to 55.2%, ad accuracy from 60.9% to 63.6%. The global iterobserver agreemet was cosidered as moderate (κ = 0.50). CONCLUSION: The fourth editio of BI- RADS provides radiologists with a accurate cliical decisio support system for the diagosis ad maagemet of breast disease. Keywords: Breast cacer; Ultrasoography; BI-RADS; Aatomopathological; Accuracy. OBJETIVO: O objetivo geral do estudo é avaliar a acurácia da ultrassoografia (BI-RADS) o diagóstico do câcer de mama, e os objetivos específicos, descrever a frequêcia de apresetação dos diferetes achados ultrassoográficos e a avaliação da cocordâcia etre observadores. MATERIAIS E MÉTODOS: Exames de pacietes ecamihados para biópsia, com diagóstico prévio de ódulos, foram reaalisados idepedetemete por dois médicos especialistas utilizado a omeclatura do BI-RADS. Os achados histológicos foram utilizados como padrão-ouro. A acurácia dos achados foi determiada. As difereças os grupos de comparação foram aalisadas com teste qui-quadrado para variáveis categóricas e a cocordâcia etre os médicos foi calculada por meio da estatística kappa (κ). RESULTADOS: Ceto e dez massas mamárias foram avaliadas pelo ultrassom, sedo que (69%) foram beigas e 34 (30,9%), maligas. Foram observados, etre os radiologistas, sesibilidade variado etre 70,5% e 82,3%, valor preditivo egativo etre 81,1% e 87,5%, valor preditivo positivo etre 42,1% e 45,1%, especificidade etre 56,58% e 55,2% e acurácia etre 60,9% e 63,6%. Na avaliação etre observadores foi obtida cocordâcia global cosiderada moderada (κ = 0,50). CONCLUSÃO: O BI-RADS 4ª edição é um acurado sistema para auxiliar os médicos a descrição das lesões mamárias e a tomada de codutas. Uitermos: Câcer de mama; Ultrassoografia; BI-RADS; Aatomopatológico; Acurácia. Nascimeto JHR, Silva VD, Maciel AC. Accuracy of soographic fidigs i breast cacer: correlatio betwee BI-RADS categories ad histological fidigs. Radiol Bras. 2009;42(4): * Study developed at Potifícia Uiversidade Católica do Rio Grade do Sul (PUCRS), Porto Alegre, RS, Brazil. 1. Master, MD, Radiologist, Potifícia Uiversidade Católica do Rio Grade do Sul (PUCRS), Porto Alegre, RS, Brazil. 2. PhD, MD, Pathologist, Associate ProfessorProfessor, Potifícia Uiversidade Católica do Rio Grade do Sul (PUCRS), Porto Alegre, RS, Brazil. 3. Head for the Uit of Radiology Sata Casa de Misericórdia de Porto Alegre, MD, Radiologist Hospital de Clíicas de Porto Alegre, Porto Alegre, RS, Brazil. Mailig address: Dr. José Hermes Ribas do Nascimeto. Rua Marechal Floriao, 774, Meller Sul. Sato Âgelo, RS, Brazil, josehermesribas@hotmail.com Received December 27, Accepted after revisio April 22, INTRODUCTION Ultrasoography as a adjuvat to cliical examiatio ad mammography is cosidered as the most effective method for the diagosis of breast lesios (1). This is due to the techological developmet of ultrasoography devices such as real-time trasducers with high digital frequecy of 7.5 MHz, 10 MHz ad 13 MHz, ad harmoic imagig. These multi-frequecy trasduc- ers provide high-resolutio images, depth peetratio ad a high umber of scaig lies (2,3). Although breast ultrasoography has bee historically utilized for differetiatig solid from liquid lesios, there is a icreasig iterest i the utilizatio of this method for differetiatig maligat from beig masses. Additioally, ultrasoography has become a valuable tool i the characterizatio of odules foud at mammog Colégio Brasileiro de Radiologia e Diagóstico por Imagem 235

2 Nascimeto JHR et al. raphy, thus avoidig uecessary biopsies ad elimiatig the ecessity of follow-up mammography (4 6). The breast ultrasoography sesitivity has bee reported as superior to that of mammography (7,8) i premeopausal wome ad, recetly, soographic screeig has also bee recommeded for evaluatio of dese breasts (9). Studies have demostrated the usefuless of ultrasoography for detectio of cliically ad mammographically occult, opalpable breast carciomas (10,11). The Breast Imagig Reportig ad Data System (BI-RADS ) lexico for ultrasoography was developed by the America College of Radiology (ACR) aimig at icreasig the cliical efficacy of the method ad at stadardizig the reports orgaizatio ad wordig. There is a specific vocabulary for describig each lesio, ad, at the ed of the report, the lesio is classified ito categories ragig from 0 to 6 accordig to the fidigs suspicio degree based o the positive predictive value (PPV) of the study for breast cacer (12 14). The BI-RADS lexico icludes a soographic descriptio of breast odules or masses cosiderig cotours, orietatio, margis, lesios limits, iteral echoes patter, characterizatio of posterior acoustic shadowig, borders ad abormalities i adjacet tissues. At the ed of the descriptio, the lesio is assiged to a BI- RADS category (13,15). The preset study primarily proposes a evaluatio of the soographic BI-RADS classificatio accuracy for differetiatig beig lesios from maligat masses. The secodary objectives were the descriptio of the frequecy of differet soographic fidigs ad the evaluatio of the iterobserver agreemet. MATERIALS AND METHODS Two physicias specialized i breast imagig diagosis idepedetly reviewed studies of patiets referred to a cliic i the Northwester regio of the Rio Grade do Sul state (Brazil) for core biopsy. Previously, all of them had bee soographically diagosed with breast odules or masses classified ito BI-RADS categories 3, 4 or 5. Each specialist, with more tha te years of professioal experiece, course of residecy i radiology, specialist title ad/or course of specializatio i mammography by Colégio Brasileiro de Radiologia e Diagóstico por Imagem (CBR), blidly reviewed the soographic studies, utilizig the BI-RADS termiology, evaluatio ad recommedatios icluded i the most recet lexico for echography. Later, the reviewed studies were compared with the aatomopathological results. The ultrasoography studies were performed with a high-resolutio Soolie G50 (Siemes Medical Solutios; Berli, Germay) equipmet with 7.5 MHz ad 10 MHz liear array trasducers. The accuracy of the BI-RADS classificatio i ultrasoography was evaluated by calculatig sesitivity, specificity, PPV ad egative predictive value (NPV) for each of the described characteristics, ad i the differetiatio betwee beig ad maligat lesios. Histological fidigs were utilized as stadard criteria. The iterobserver agreemet for the fial categories ad separately for each category was aalyzed by the kappa test (κ) ad the differeces betwee groups were aalyzed through the chi-square test for categorical variables. The BI-RADS lexico for ultrasoography cosiders the followig terms for describig breast odules: shape, margis, orietatio of the odule i relatio to the ski axis, lesio borders, iteral echoes patter, posterior acoustic characteristics ad alteratios i adjacet tissues. After their descriptio i compliace with the BI-RADS criteria, all the lesios were classified ito categories 3, 4 or 5 (Chart 1). Category 3 icluded the well-defied lesios, ovoid or rouded i shape (cotour), with a parallel orietatio i relatio to the ski axis, circumscribed margis, abset posterior acoustic shadowig or presece of posterior acoustic ehacemet, ad absece of alteratios i adjacet tissues. Lesios associatig at least three sigs of maligacy were classified ito BI-RADS category 5 icludig irregular cotour, oparallel orietatio i relatio to the ski axis, ocircumscribed margis, presece of hyperechogeic halo, posterior acoustic shadowig ad alteratio i the adjacet tissues. BI-RADS category 4 icluded the lesios that did ot met the beigity criteria either combied three sigs of maligacy, so beig classified as idetermiate. The patiet s age, the site ad size of the lesio were also take ito cosideratio. Histological fidigs were compared with soographic characteristics. BI-RADS lexico diagostic accuracy, sesitivity, specificity, PPV ad NPV for ultrasoography were calculated, icludig category 3 i the beig group, ad uifyig categories 4 (probably beig) ad 5 i the maligat lesios group. VPPs ad NPVs for each category ad descriptio were obtaied. RESULTS Chart 1 Fial cliical coduct accordig to BI-RADS classificatio (12). The preset study icluded breast odules, 108 i female patiets ad 2 i male patiets. All the lesios were assessed by ultrasoography ad later submitted to histological study. The patiets mea age was ± years. Based o the soographic BI-RADS classificatio, the lesios were distributed as follows: observer A 53 (48.18%) category 3, 39 (35.46%) category 4, ad 18 (16.4%) category 5; observer B 48 Icomplete evaluatio Category 0 (zero): requires additioal imagig evaluatio Complete evaluatio Category 1: egative Category 2: egative fidigs Category 3: probably beig fidigs suggestig short iterval follow-up Category 4: suggestive of abormality biopsy should be cosidered (idetermiate) Category 5: highly suggestive of maligacy a appropriate coduct should be adopted Category 6: biopsy-proved maligat disease 236

3 Soographic accuracy i breast cacer (43.64%) category 3, 44 (40%) category 4 ad 18 (16.4%) category 5. No lesio was classified as categories 0, 1, 2 ad 6. Amogst all the cases icluded i the preset study, (69%) were beig, ad 34 were maligat at the aatomopathological study. Accordig to the observer A, NPV was 81.1%, PPV, 42.10%, sesitivity, 70.0%, specificity, 56.5%, ad accuracy, 60.9%. O the other had, accordig to the observer B, NPV was 87.5%, PPV, 46.6%, sesitivity, 82%, specificity, 55.2% ad accuracy, 63.6% (Tables 1 ad 2). Soographic odules characteristics Soographically, the odules demostrated the followig morphological characteristics: lesios cotour, margis, iteral echoes patter, orietatio i relatio to the ski axis, posterior acoustic characteristics, borders ad alteratios i adjacet tissues (14). a) Evaluatio of the lesios shape Accordig to the observer A, the lesios were roud-shaped i 71 cases, ovoid i 13 cases, ad irregular i 25 cases. Amog the 71 roud-shaped lesios, 83.1% were beig, ad 16.9% maligat. Amog the irregular odules, 21 were maligat, ad four were beig for a PPV de 84%. The NPV for ovoid lesios was 42.9%,ad for roud-shaped lesios, 83.1%. Accordig to the observer B, roudshaped was described i 67 masses, ovoid i 22, ad irregular i 21. Amog the 67 rouded-shaped lesios,.1% were beig ad 23.9%, maligat. The NPV for rouded-shaped lesios was.1%, ad 77.3% for ovoid lesios. Amog the irregular lesios, 14 were maligat for a PPV of 65%. b) Evaluatio of the lesios margis Accordig to the observer A, the margis were circumscribed i 68 cases, ad Table 1 Distributio of false- ad true-positive results ad false- ad true-egative results based o pathological ad discrimiate diagoses observer A. Test result T+ (category 4, 5) T (category3) Parameters Sesitivity Specificity Positive predictive value Negative predictive value Accuracy Positive disease Negative disease 24 (42.11) TP 10 (18.87) FN 34 (30.9) Formula TP/(TP + FN) TN/(TN + FP) TP/(TP + FP) TN/(TN + FN) (TP + TN)/ (57.89) FP (81.13) TN (69.1) % (with disease ad positive test) (without disease ad egative test) T+, positive test (lesio rated as category 4 or 5); T, egative test (lesio rated as category 3); TP, true-positive; FP, false-positive; TN, true-egative; FN, false-egative. Table 2 Distributio of false- ad true-positive results ad false- ad true-egative results based o pathological ad discrimiate diagoses observer B. Test result T+ (category 4, 5) T (category 3) Parameters Sesitivity Specificity Positive predictive value Negative predictive value Accuracy Positive disease Negative disease 28 (45.16) TP 6 (12.5) FN 34 (30.9) Formula TP/(TP + FN) TN/(TN + FP) TP/(TP + FP) TN/(TN + FN) (TP + TN)/ (54.84) FP (87.5) TN (69.1) % 82.3 (with disease ad positive test) 55.2 (without disease ad egative test) T+, positive test (lesio rated as category 4 or 5); T, egative test (lesio rated as category 3); TP, true-positive; FP, false-positive; TN, true-egative; FN, false-egative. ocircumscribed i 42. Oly 12 (17.6%) of the 68 lesios with circumscribed margis were maligat. Oly four (6%) amog the cases with circumscribed margis were classified i category 5 (Table 3). Out of 42 masses, 22 with ocircumscribed margis were maligat. The PPV for ocircumscribed margis was of 52.4%, ad the NPV for circumscribed margis was of 82.4%. Sesitivity was 64.7%, ad specificity, 73.7%. Accordig to the observer B, margis were circumscribed i 61 cases ad ocircumscribed i 49. Oly 12 (19.7%) of the 61 lesios with circumscribed were maligat. Oly three cases (4.9%) with circumscribed margis were classified as category 5 (Table 4). It was observed that 22 of 49 cases with ocircumscribed margis were cosidered as maligat. The PPV for ocircumscribed margis was of 44.9%, ad the Table 3 Distributio of margis ad relatioship with the BI-RADS classificatio for ultrasoography observer A. Category 3 Category 4 Category 5 Distributio Circumscribed Nocircumscribed 37 (84.1) 6 (66.7) 43 7 (15.9) 3 (33.3) (85.0) 12 (63.2) 29 3 (15.0) 7 (36.8) 10 2 (50.0) 2 (14.3) 4 2 (50.0) 12 (85.7) (82.4) 20 (47.6) 12 (17.6) 22 (52.4)

4 Nascimeto JHR et al. Table 4 Distributio of margis ad relatioship with the BI-RADS classificatio for ultrasoography observer B. Category 3 Category 4 Category 5 Distributio Circumscribed Nocircumscribed 34 (87.2) 8 (88.9) 42 5 (12.8) 1 (11.1) 6 14 (73.7) 17 (68.0) 31 5 (26.3) 8 (32.0) 13 1 (33.3) 2 (13.3) 3 2 (66.7) 13 (86.7) (80.3) 27 (55.1) 12 (19.7) 22 (44.9) NPV for circumscribed margis was of 80.3%. Sesitivity was 64.7%, ad specificity, 64.5%. c) Evaluatio of iteral echoes patters Iteral echoes patters were observed as follows: hypoechoic i 85 cases, isoechoic i two, hyperechoic i two, ad complex i 14 cases. All the hyperechoic lesios were beig, ad 71.4% of lesios with complex patter were beig. Amog the 85 (77.3%) hypoechoic odules, 26 were maligat, with PPV of 30.6%. Accordig to the observer B, the iteral echoes patter were hypoechoic i 79 cases, isoechoic i two, hyperechoic i five, ad complex i 17 cases. Particularly, the complex patter represeted 15 (92.8%) of the odules classified as categories 4 ad 5. All the hyperechoic lesios were beig, ad 58.8% of lesios with complex patter were beig. Amog the 79 (71.8%) hypoechoic odules, 22 were maligat, with PPV of 27.8%. d) Evaluatio of odule orietatio i relatio to the ski axis For both observers, the mea size of the lesios parallel to the ski axis was 14.2 ± 9.9 mm, ad 9.4 ± 4.5 mm i the lesios with vertical orietatio, with prevalece i the upper breast quadrats. Parallel orietatio i relatio to the ski axis was preset i 101 cases (28 maligat, ad 73 beig lesios) for a NPV of 72.3%. Atiparallel orietatio was preset i seve cases (four maligat ad three beig lesios) for a PPV of 72.3%. e) Descriptio of the posterior acoustic characteristic Accordig to the observer A, the absece of posterior acoustic characteristic preseted a NPV of 46.7%. Out of the lesios, 49 preseted posterior acoustic ehacemet ad, amog them, 40 were beig, with NPV of 81.6%; ad posterior acoustic shadowig was described i 13 cases, of which two were maligat, with PPV of 15%. Accordig the observer B, the absece of posterior acoustic characteristic preseted a NPV of 58.6%. Out of the lesios, 34 preseted posterior acoustic ehacemet ad, amog them, 29 were beig, with NPV of 85.3%; ad posterior acoustic shadowig was described i 11 cases, of which four were maligat, with PPV of 36.4%. f) Descriptio of lesios borders Accordig to the observer A, 38 (34.5%) of cases preseted abrupt iterface ad 65 (59.0%) demostrated echogeic halo. Echogeic halo was described i 27 cases classified as category 3, with NPV of 72.3%. Abrupt iterface preseted NPV of 68.4%. Accordig to the observer B, 31 (28.1%) of cases preseted abrupt iterface, ad 66 (60%) of the cases demostrated echogeic halo. Echogeic halo was described i 24 cases classified as category 3, with NPV of 72.1%. Abrupt iterface preseted NPV of 61.2%. g) Adjacet tissues appearace Accordig the observer A, 96 of the described masses did ot preset alteratio i adjacet tissues ad, amog them 52 were classified as category 3, with NPV of.6%. Out of 24 maligat lesios, 11 (45%) preseted alteratio i adjacet tissues, with PPV of 45%. Ski thickeig was ot observed i ay case. Accordig the observer B, 96 of the described masses did ot preset alteratio i adjacet tissues ad, amog them 45 were classified as category 3, with NPV of 72.6%. Out of 34 maligat lesios, 26 (%) preseted alteratio i adjacet tissues, with PPV of %. Ski thickeig was ot observed i ay case. h) Iterobserver agreemet (Table 5) As far as the soographic descriptio is cocered, a moderate iterobserver agreemet was observed i the evaluatio of odules orietatio (κ = 0.52), that was described as parallel or atiparallel i relatio to the ski axis. A moderate agreemet was observed i the evaluatio of the lesios cotour (κ = 0.50). Low iterobserver agreemet (κ = 0.29) was observed i the evaluatio of the lesio borders. Moderate agreemet was also observed i the evaluatio of the lesio margis (κ = 0.53) ad i the descriptio of iteral echoes patter (κ = 0.56). The differet terms utilized for describig posterior acoustic characteristic has also determied a moderate iterobserver agreemet (κ = 0.51). A moderate iterobserver agreemet (κ = 0.51) was also observed i the evaluatio of adjacet tissues, especially i cases where o alteratio was foud. The κ value, for uified categories 4 ad 5 was The prevalece of breast cacer i the preset study was of 34 (30.9%). DISCUSSION The BI-RADS classificatio for mammography was the first attempt to stadard- Table 5 Iterobserver variability i the descriptio of soographic lesios. Masses descriptio Lesios cotour Lesios margis Iteral echoes patter Lesios borders Orietatio i relatio to the ski axis Posterior acoustic patter Adjacet tissues appearace BI-RADS κ values

5 Soographic accuracy i breast cacer ize imagig fidigs i descriptive terms, costitutig a importat tool for aidig physicias both i the suspicio of maligacy ad i the decisio makig about the strategy to be adopted (16 18). I 2003, the BI-RADS lexico was updated, with a refiemet i the descriptio of microcalcificatios ad the iclusio of topics regardig breast ultrasoography ad magetic resoace imagig. Because of the frequecy of overlappig betwee radiological ad echographic fidigs ad the great PPV variability amog BI-RADS categories 3, 4 ad 5 i mammography (18), breast lesios idicative of maligacy detected at mammography ad ultrasoography have bee evaluated by biopsy to prove their maligacy or beigity (4,8,19). A high umber of biopsies is performed for beig lesios because of several factors; amog them the patiets dread; physicias ucertaity or eve the stadard protocols utilized (1,20). Ultrasoography should ot be utilized oly for differetiatig cystic from solid odules ad i the evaluatio of dese breasts. This method must be exploited with a accurate iterpretatio of the characteristics of each suspicious lesio i order to reduce the umber of biopsies i beig lesios (21). Improvemets i the soographic diagosis have bee achieved with the itroductio by the America College of Radiology, of the BI-RADS classificatio to aid radiologists i the descriptio of soographic fidigs ad that defie the fial classificatio ito categories associated with a better cliical maagemet of the cases (12). I the preset study, both observers foud a sesitivity ragig betwee 70% ad 80% (idetificatio of maligat lesios patiets with breast cacer) ad high NPV, betwee 81% ad 87% (idetificatio of egative fidigs i cacer-free patiets), i relatio to characteristics described i the BI-RADS with 18% FN. However, BI-RADS preseted a low specificity, betwee 55% ad 56% (cacer-free patiets with egative studies) because of the high umber of false-positive fidigs. The PPV (umber of cacers for soographic characteristics) raged betwee 45.1% ad 42.1%. I the preset study, the soographic accuracy raged from 60.9% to 63.6% i the differetiatio betwee beig ad maligat lesios with the utilizatio of the BI- RADS. The NPV for the category 3 raged from 81.1% to 87.5% betwee the observers, with a PPV ragig betwee 42.1% ad 45.1%, similarly to the studies developed by Costatii et al. (15) ad Roveda Jr et al. (20), who have demostrated a NPV ragig betwee, respectively, 92.3% ad 70.58% for category 3. Thus, the utilizatio of the category 3, as probably beig, is a tool utilized by radiologists to avoid uecessary biopsies, cosiderig that the risk for maligacy of lesios described i this category correspods to less tha 2% (12). If a icrease i the lesios dimesios were observed i the follow-up, there would be a tred towards chagig to BI-RADS category 4, so that the biopsy could be appropriate. The classificatio of breast odules ito category 4 presets the same cliical impact ad meaig as those described for category 5, sice i both cases biopsy would be idicated. I the preset study, the PPV for categories 4 ad 5 was o, respectively, 45.2% ad 42.2%, similarly to the study developed by Roveda Jr et al. (20), with a 50% PPV i category 4. The aalysis of the soographic characteristics associated with the classificatio ito categories 4 ad 5 demostrated that lesios with proved maligacy were frequetly associated with hypoechogeicity, irregular cotours, ocircumscribed margis, ad atiparallel orietatio i relatio to the ski axis, although may of the beig odules classified as BI-RADS categories 4 ad 5 were hypoechoic, eve beig associated with circumscribed margis ad parallel orietatio i relatio to the ski axis. It could be observed that with the presece of three of the followig fidigs, such as posterior acoustic shadowig, irregular cotours, ocircumscribed margis, hypoechoic halo ad atiparallel orietatio i relatio to the ski axis, the lesios were ormally classified ito categories 4 ad 5, i accordace with the fidigs described by Che et al. (22). Masses demostratig more tha three characteristics suggestive of maligacy were classified ito category 5 by both observers. Nodule margis represeted a relevat criterio i the differetiatio betwee beig ad maligat lesios, with a NPV ragig betwee 82.4% ad 80.3% for circumscribed margis, ot very differet from the fidigs reported by Calas et al. (23), who had observed a NPV of 97% for circumscribed lesios. I the preset study, the PPV for ocircumscribed margis raged betwee 52.4% ad 44.9%, differetly from the NPV described by Calas et al. (23), correspodig to 70.4%. Rouded cotour (shape) was associated with high NPV that raged betwee 83.3% ad.1%; ad irregular cotour, with high PPV, that raged betwee 84% ad 65% for both observers. Hypoechoic halo demostrated a lower PPV tha irregular cotour ad ocircumscribed margis. Echogeic halo preseted a NPV ragig betwee 72.3% ad 72.1%, ad abrupt iterface preseted a NPV ragig from 68.4% to 61.2% betwee the observers. Atiparallel odule orietatio i relatio to the ski axis preseted a high PPV (72.3%). I the study developed by Calas et al. (23) a PPV of 57.6% has bee observed. The posterior acoustic characteristic is a result of the soud atteuatio. The posterior acoustic ehacemet presets a NPV betwee 81% ad 85%, for both observers. Posterior acoustic shadowig preseted a low PPV, ragig betwee 15% ad 35% i the BI-RADS categories 4 ad 5. Although posterior acoustic shadowig is a soographic characteristic of maligat lesios (15), this fidig was ot cofirmed i the preset study, beig also observed i beig lesios. Fie bilateral shadowig was cosidered as a sig of beig lesio. I the aalysis of the iterobserver variability, a moderate agreemet was observed for the evaluatio of the lesios orietatio i relatio to the ski axis (κ = 0.52), evaluatio of cotours (κ = 0.50), margis (κ = 0.53), posterior acoustic characteristic (κ = 0.51), iteral echoes patter (κ = 0.56) ad evaluatio of adjacet tissues (κ = 0.51); ad low iterobserver agreemet was obtaied for the evaluatio of the lesios borders (κ = 0.29) (Table 5). 239

6 Nascimeto JHR et al. CONCLUSION The soographic evaluatio of breasts utilizig the BI-RADS classificatio is a accurate method, with the iterobserver variability ragig betwee 60.9% ad 63.3% i the differetiatio of maligat from beig lesios. The most frequet soographic fidigs of eoplasms were irregular odules with ocircumscribed margis ad atiparallel orietatio. I the preset study, complex or hypoechoic iteral echoes patter, the hypoechoic borders of the lesios, ad posterior acoustic shadowig preseted low PPV. The overall iterobserver variability was moderate. It is believed that the practice, the systematic follow-up periods, the double-readig techique, ad BI-RADS traiig courses for physicias should be implemeted to improve eve more the accuracy i the diagosis of breast diseases, thus reducig the umber of uecessary ad expesive ivasive procedures. REFERENCES 1. Chala LF, Barros N. Avaliação das mamas com métodos de imagem [editorial]. Radiol Bras. 2007;40(1):iv vi. 2. Guiseppetti GM, Giuliai F, Baldassarre S, et al. Metodologia e semiologia. I: Veroesi U, editor. Mastologia ocológica. Rio de Jaeiro: Medsi; p Baker JA, Soo MS. Breast US: assessmet of techical quality ad image iterpretatio. Radiology. 2002;223: Parker SH, Stavros AT, Deis MA. Needle biopsy techiques. Radiol Cli North Am. 1995;33: Stavros AT, Thickma D, Rapp CL, et al. Solid breast odules: use of soography to distiguish betwee beig ad maligat lesios. Radiology. 1995;196: Bassett LW, Kim CH. Breast imagig: mammography ad ultrasoography. Mag Reso Imagig Cli N Am. 2001;9: Schroeder RJ, Bostajoglo M, Rademaker J, et al. Role of power Doppler techiques ad ultrasoud cotrast ehacemet i the differetial diagosis of focal breast lesios. Eur Radiol. 2003;13: Lecote I, Feger C, Galat C, et al. Mammography ad subsequet whole-breast soography of opalpable breast cacers: the importace of radiologic breast desity. AJR Am J Roetgeol. 2003;180: Kolb TM, Lichy J, Newhouse JH. Occult cacer i wome with dese breasts: detectio with screeig US diagostic yield ad tumor characteristics. Radiology. 1998;207: Kolb TM, Lichy J, Newhouse JH. Compariso of the performace of screeig mammography, physical examiatio, ad breast US ad evaluatio of factors that ifluece them: a aalysis of 27,825 patiet evaluatios. Radiology. 2002; 225: Saaremaa I, Salmie T, Geiger U, et al. The effect of age ad desity of the breast o the sesitivity of breast cacer diagostic by mammography ad ultrasoography. Breast Cacer Res Treat. 2001;67: America College of Radiology. BI-RADS: ultrasoud, 1st ed. I: Breast Imagig Reportig ad Data System: BI-RADS atlas, 4th ed. Resto: America College of Radiology; Colégio Brasileiro de Radiologia. BI-RADS Sistema de laudos e registro de dados de imagem da mama. São Paulo: Colégio Brasileiro de Radiologia; Miller AB, To T, Baies CJ, et al. Caadia Natioal Breast Screeig Study-2: 13-year results of a radomized trial i wome aged years. J Natl Cacer Ist. 2000;92: Costatii M, Belli P, Lombardi R, et al. Characterizatio of solid breast masses: use of the soographic breast imagig reportig ad data system lexico. J Ultrasoud Med. 2006;25: Melhado VC, Alvares BR, Almeida OJ. Correlação radiológica e histológica de lesões mamárias ão-palpáveis em pacietes submetidas a marcação pré-cirúrgica, utilizado-se o sistema BI- RADS. Radiol Bras. 2007;40: Liberma L, Abramso A, Squires FB, et al. The breast imagig report ad data system: positive predictive value of mammographic features ad fial assessmet categories. AJR Am J Roetgeol. 1998;171: Kestelma FP, Souza GA, Thuler LC, et al. Breast Imagig Reportig ad Data System BI- RADS : valor preditivo positivo das categorias 3, 4 e 5. Revisão sistemática da literatura. Radiol Bras. 2007;40: Fleury EFC, Rialdi JF, Piato S, et al. Apresetação das lesões mamárias císticas à ultra-soografia utilizado a elastografia. Radiol Bras. 2008; 41: Roveda Jr D, Piato S, Oliveira VM, et al. Valores preditivos das categorias 3, 4 e 5 do sistema BI- RADS em lesões mamárias odulares ão-palpáveis avaliadas por mamografia, ultra-soografia e ressoâcia magética. Radiol Bras. 2007;40: Ciatto S, Houssami N, Apruzzese A, et al. Reader variability i reportig breast imagig accordig to BI-RADS assessmet categories (the Florece experiece). Breast. 2006;15: Che SC, Cheug YC, Su CH, et al. Aalysis of soographic features for the differetiatio of beig ad maligat breast tumors of differet sizes. Ultrasoud Obstet Gyecol. 2004;23: Calas MJG, Koch HA, Dutra MVP. Ultra-soografia mamária: avaliação dos critérios ecográficos a difereciação das lesões mamárias. Radiol Bras. 2007;40: