title: Role of quantitative magnetic resonance imaging parameters in the evaluation of treatment response in malignant tumors.
abstract: OBJECTIVE
  To elaborate the role of quantitative magnetic resonance imaging (MRI) parameters in the evaluation of treatment response in malignant tumors.
  
  
  METHODS
  Data cited in this review were obtained mainly from PubMed in English from 1999 to 2014, with keywords "dynamic contrast-enhanced (DCE)-MRI," "diffusion-weighted imaging (DWI)," "microcirculation," "apparent diffusion coefficient (ADC)," "treatment response" and "oncology."
  
  
  METHODS
  Articles regarding principles of DCE-MRI, principles of DWI, clinical applications as well as opportunity and aspiration were identified, retrieved and reviewed.
  
  
  RESULTS
  A significant correlation between ADC values and treatment response was reported in most DWI studies. Most quantitative DCE-MRI studies showed a significant correlation between K trans values and treatment response. However, in different tumors and studies, both high and low pretreatment ADC or K trans values were found to be associated with response rate. Both DCE-MRI and DWI demonstrated changes in their parameters hours to days after treatment, showing a decrease in K trans or an increase in ADC associated with response in most cases.
  
  
  CONCLUSIONS
  Combinations of quantitative MRI play an important role in the evaluation of treatment response of malignant tumors and hold promise for use as a cancer treatment response biomarker. However, validation is hampered by the lack of reproducibility and standardization. MRI acquisition protocols and quantitative image analysis approaches should be properly addressed prior to further testing the clinical use of quantitative MRI parameters in the assessment of treatments.
authors.forename: Qing-Gang
authors.initials: QG
authors.lastname: Xu
authors.affiliation: Department of Radiology, Beijing Tongren Hospital, Capital Medical University, Beijing 100730, China.
authors.forename: Jun-Fang
authors.initials: JF
authors.lastname: Xian
mesh_terms: D003287:Contrast Media; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D009369:Neoplasms / Q000175:diagnosis*; D015203:Reproducibility of Results
chemical_list: D003287:Contrast Media