title: Foci on breast magnetic resonance imaging in high-risk women: cancer or not?
abstract: OBJECTIVE
  To assess how frequently foci are identified on MRI in high-risk patients, and their association with malignancy, breast density, and background parenchymal enhancement (BPE).
  
  
  METHODS
  In this multicentric study, two readers, in consensus, retrospectively reviewed screening breast MRI of 245 high-risk women, performed between 2009 and 2014. Eligible patients had at least two consecutive screening MRI, and a follow-up of at least 1 year after a lesion was first detected; histology was available for all suspicious findings. Breast density, BPE (both using BI-RADS lexicon), presence, and changes at follow-up for foci were evaluated. Clinical history of the patients was reviewed. Chi-square test was used to define significant correlations.
  
  
  RESULTS
  166 women (mean age 43 years), who underwent a median of 4 MRI (range 2-6) during the study period, were included. 68 foci were found in 58 women [34.9 %, 95 % confidence interval (CI) 28.1-42.5 %]. Foci were more frequent in dense breasts (P = 0.079) and with moderate or marked BPE (P < 0.001). During follow-up, two foci increased in size (2.9 %, 95 % CI 0.8-10.1 %) and at biopsy, a cancer was found (1 high-grade ductal carcinoma in situ, 1 tubular carcinoma). Breast cancer was diagnosed in the other three cases, not initially appearing as foci, and it was more frequent in women with dense breasts (P = 0.04); no correlation between cancer and BPE was found (P = 0.145).
  
  
  CONCLUSIONS
  Foci are relatively frequent in screening MRI, and they are usually benign. An increase in size is the most reliable criteria to suspect malignancy.
authors.affiliation: Institute of Diagnostic Radiology, Department of Medical and Biological Sciences, University of Udine, P.le Santa Maria della misericordia, Udine, 33100, Italia. clauser.p@hotmail.it.|Department of Biomedical Imaging and Image-guided Therapy, Division of Molecular and Gender Imaging, Medical University of Vienna, Waehringer Guertel 18-20, 1090, Vienna, Austria. clauser.p@hotmail.it.
authors.forename: Paola
authors.initials: P
authors.lastname: Clauser
authors.affiliation: Division of Breast Radiology, European Institute of Oncology, Via G. Ripamonti 435, 20141, Milan, Italy.
authors.forename: Enrico
authors.initials: E
authors.lastname: Cassano
authors.affiliation: Institute of Diagnostic Radiology, Department of Medical and Biological Sciences, University of Udine, P.le Santa Maria della misericordia, Udine, 33100, Italia.|Radiology Department, APSS-Trento, Via Degasperi 79, 38123, Trento, Italy.
authors.forename: Arianna
authors.initials: A
authors.lastname: De Nicolò
authors.affiliation: Division of Breast Radiology, European Institute of Oncology, Via G. Ripamonti 435, 20141, Milan, Italy.
authors.forename: Anna
authors.initials: A
authors.lastname: Rotili
authors.affiliation: Division of Cancer Prevention and Genetics, European Institute of Oncology, Via G. Ripamonti 435, 20141, Milan, Italy.
authors.forename: Bernardo
authors.initials: B
authors.lastname: Bonanni
authors.affiliation: Institute of Diagnostic Radiology, Department of Medical and Biological Sciences, University of Udine, P.le Santa Maria della misericordia, Udine, 33100, Italia.
authors.forename: Massimo
authors.initials: M
authors.lastname: Bazzocchi
authors.affiliation: Institute of Diagnostic Radiology, Department of Medical and Biological Sciences, University of Udine, P.le Santa Maria della misericordia, Udine, 33100, Italia.
authors.forename: Chiara
authors.initials: C
authors.lastname: Zuiani
mesh_terms: D000328:Adult; D000368:Aged; D001943:Breast Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology; D003287:Contrast Media; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods; D008279:Magnetic Resonance Imaging / Q000706:statistics & numerical data*; D008403:Mass Screening; D008536:Meglumine / Q000031:analogs & derivatives; D008875:Middle Aged; D009942:Organometallic Compounds; D012189:Retrospective Studies; D018570:Risk Assessment / Q000379:methods*; D012307:Risk Factors
chemical_list: D003287:Contrast Media; D009942:Organometallic Compounds; C064572:gadobenic acid; D008536:Meglumine
keywords: BI-RADS; Breast; Cancer; High-risk; Magnetic resonance imaging