title: Parallel artery and vein: sign of benign nature of breast masses.
abstract: OBJECTIVE
  The purpose of this study was to assess the parallel artery and vein sign at color Doppler breast ultrasound as a predictor of the benign nature of breast masses.
  
  
  METHODS
  A prospective study was performed to identify evidence of a parallel artery and vein in breast lesions consecutively biopsied with a 14-gauge needle under ultrasound guidance. Sensitivity, specificity, positive and negative predictive values, likelihood ratios, and 95% CIs for the parallel artery and vein sign were calculated.
  
  
  RESULTS
  The parallel artery and vein sign was identified in 142 of the 1074 masses (13.2%). The specificity for benignity was 99.3% (CI 95%, 98.3-100.0%); sensitivity, 17.6% (CI 95%, 15.0-20.3%); positive predictive value, 99.0% (CI 95%, 96.7-100); negative predictive value, 30.0% (CI 95%, 27.0-32.9); positive likelihood ratio, 24.7 (CI 95%, 21.2-28.7); and negative likelihood ratio, 0.83 (CI 95%, 0.80-0.86). Among masses found to have the parallel artery and vein sign, all BI-RADS ultrasound category 3 and 95.1% of BI-RADS 4 lesions were determined to be benign.
  
  
  CONCLUSIONS
  Although the parallel artery and vein sign is an uncommon finding, it has a significant association with benign pathologic results (96.5%) with a positive likelihood ratio of 24.7. The presence of this color Doppler ultrasound finding in breast masses in BI-RADS ultrasound categories 3 and 4 reinforces the benign nature and may allow follow-up rather than biopsy in the care of some patients.
authors.affiliation: Departamento de Imagenes, Clinica Alemana de Santiago, Universidad Del Desarrollo, Av Vitacura 5951, Santiago, Chile. eleonora.horvath@gmail.com
authors.forename: Eleonora
authors.initials: E
authors.lastname: Horvath
authors.forename: Claudio
authors.initials: C
authors.lastname: Silva
authors.forename: Gerardo
authors.initials: G
authors.lastname: Fasce
authors.forename: Camillo
authors.initials: C
authors.lastname: Ferrari
authors.forename: Miguel-Angel
authors.initials: MA
authors.lastname: Pinochet
authors.forename: Cecilia
authors.initials: C
authors.lastname: Galleguillos
authors.forename: Eduardo
authors.initials: E
authors.lastname: Soto
mesh_terms: D000328:Adult; D001707:Biopsy, Needle; D001940:Breast / Q000098:blood supply*; D001941:Breast Diseases / Q000000981:diagnostic imaging*; D001943:Breast Neoplasms / Q000000981:diagnostic imaging; D018567:Breast Neoplasms, Male / Q000000981:diagnostic imaging; D016009:Chi-Square Distribution; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D016013:Likelihood Functions; D008297:Male; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012680:Sensitivity and Specificity; D018615:Ultrasonography, Doppler, Color; D018084:Ultrasonography, Interventional; D016217:Ultrasonography, Mammary