title: Breast mass evaluation: factors influencing the quality of US elastography.
abstract: OBJECTIVE
  To investigate factors influencing the quality of ultrasonographic (US) elastography in the evaluation of suspicious breast masses.
  
  
  METHODS
  This prospective study was conducted with institutional review board approval; written informed consent was obtained. Between January 2009 and February 2009, real-time US elastography of 312 breast masses (245 benign, 67 malignant) was performed in 268 consecutive patients (mean age, 45.7 years ± 10.2 [standard deviation]) prior to US-guided core biopsy. Five breast radiologists who had performed the examinations assessed the quality of elasticity images as inadequate, low, or high without histologic information. Age, body mass index (BMI), mammographic density, lesion size, lesion depth, and breast thickness at US were analyzed for their association with image quality by using the χ(2) test, Student t test, and multivariate analysis. Sensitivities and specificities for the differentiation of benign from malignant masses on the basis of elastography were calculated and compared between groups of quality scores by using the logistic regression method.
  
  
  RESULTS
  The quality of elasticity images was assessed as inadequate in 21 (6.7%) cases, low in 134 (42.9%), and high in 157 (50.3%). According to univariate analysis, smaller lesion size (P = .001), shallower lesion depth (P = .005), less breast thickness where the lesion was located (P < .0001), and benign pathologic finding (P = .004) were significantly associated with higher image quality. There was no correlation of image quality with age (P = .213), BMI (P = .191), mammographic density (P = .091), or distance from the nipple (P = .100). Multivariable analysis showed that breast thickness at the location of target lesions was the most important factor influencing elasticity image quality (P = .001). There were significant differences in sensitivity between higher-quality and lower-quality images (87.0% vs 56.8%, respectively; P = .015) in the differentiation of benign from malignant masses.
  
  
  CONCLUSIONS
  Breast thickness at the location of the lesion was the most important factor influencing image quality at US elastography. Sensitivity for classification of benign and malignant masses improved with higher quality scores.
authors.affiliation: Department of Radiology and Clinical Research Institute, Seoul National University Hospital and the Institute of Radiation Medicine, Seoul National University Medical Research Center, 28 Yongon-dong, Chongno-gu, Seoul 100-744, Korea.
authors.forename: Jung Min
authors.initials: JM
authors.lastname: Chang
authors.forename: Woo Kyung
authors.initials: WK
authors.lastname: Moon
authors.forename: Nariya
authors.initials: N
authors.lastname: Cho
authors.forename: Seung Ja
authors.initials: SJ
authors.lastname: Kim
mesh_terms: D001943:Breast Neoplasms / Q000000981:diagnostic imaging* / Q000453:epidemiology*; D054459:Elasticity Imaging Techniques / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D008875:Middle Aged; D015203:Reproducibility of Results; D056910:Republic of Korea / Q000453:epidemiology; D018570:Risk Assessment; D012307:Risk Factors; D012680:Sensitivity and Specificity; D016217:Ultrasonography, Mammary / Q000706:statistics & numerical data*