title: Role of quantitative pharmacokinetic parameter (transfer constant: K(trans)) in the characterization of breast lesions on MRI.
abstract: BACKGROUND
  The semi-quantitative analysis of the time-intensity curves in dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) has a limited specificity due to overlapping enhancement patterns after gadolinium administration. With the advances in technology and faster sequences, imaging of the entire breast can be done in a few seconds, which allows measuring the transit of contrast (transfer constant: K(trans)) through the vascular bed at capillary level that reflects quantitative measure of porosity/permeability of tumor vessels.
  
  
  OBJECTIVE
  Our study aims to evaluate the pharmacokinetic parameter K(trans) for enhancing breast lesions and correlate it with histopathology, and assess accuracy, sensitivity, and specificity of this parameter in discriminating benign and malignant breast lesions.
  
  
  METHODS
  One hundred and fifty-one women with 216 histologically proved enhancing breast lesions underwent high temporal resolution DCE-MRI for the early dynamic analysis for calculation of pharmacokinetic parameters (K(trans)) using standard two compartment model. The calculated values of K(trans) were correlated with histopathology to calculate the sensitivity, specificity, and accuracy.
  
  
  RESULTS
  Receiver operating characteristic (ROC) curve analysis revealed a mean K(trans) value of 0.56, which reliably distinguished benign and malignant breast lesions with a sensitivity of 91.1% and specificity of 90.3% with an overall accuracy of 89.3%. The area under curve (AUC) was 0.907.
  
  
  CONCLUSIONS
  K(trans) is a reliable quantitative parameter for characterizing benign and malignant lesions in routine DCE-MRI of breasts.
authors.affiliation: Department of MRI, Rajiv Gandhi Cancer Institute and Research Centre, New Delhi, India.
authors.forename: Jena
authors.initials: J
authors.lastname: Amarnath
authors.forename: Taneja
authors.initials: T
authors.lastname: Sangeeta
authors.forename: Shashi Bhushan
authors.initials: SB
authors.lastname: Mehta
keywords: Breast lesions; Ktrans; dynamic contrast-enhanced magnetic resonance imaging