title: Conventional frequency ultrasonic biomarkers of cancer treatment response in vivo.
abstract: BACKGROUND
  Conventional frequency quantitative ultrasound in conjunction with textural analysis techniques was investigated to monitor noninvasively the effects of cancer therapies in an in vivo preclinical model.
  
  
  METHODS
  Conventional low-frequency (∼7 MHz) and high-frequency (∼20 MHz) ultrasound was used with spectral analysis, coupled with textural analysis on spectral parametric maps, obtained from xenograft tumor-bearing animals (n = 20) treated with chemotherapy to extract noninvasive biomarkers of treatment response.
  
  
  RESULTS
  Results indicated statistically significant differences in quantitative ultrasound-based biomarkers in both low- and high-frequency ranges between untreated and treated tumors 12 to 24 hours after treatment. Results of regression analysis indicated a high level of correlation between quantitative ultrasound-based biomarkers and tumor cell death estimates from histologic analysis. Applying textural characterization to the spectral parametric maps resulted in an even stronger correlation (r (2) = 0.97).
  
  
  CONCLUSIONS
  The results obtained in this research demonstrate that quantitative ultrasound at a clinically relevant frequency can monitor tissue changes in vivo in response to cancer treatment administration. Using higher order textural information extracted from quantitative ultrasound spectral parametric maps provides more information at a high sensitivity related to tumor cell death.
authors.affiliation: Imaging Research - Physical Sciences, Sunnybrook Research Institute, Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada ; Department of Radiation Oncology, Odette Cancer Centre, Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada ; Department of Medical Biophysics, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada ; Department of Radiation Oncology, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Ali
authors.initials: A
authors.lastname: Sadeghi-Naini
authors.forename: Omar
authors.initials: O
authors.lastname: Falou
authors.forename: Hadi
authors.initials: H
authors.lastname: Tadayyon
authors.forename: Azza
authors.initials: A
authors.lastname: Al-Mahrouki
authors.forename: William
authors.initials: W
authors.lastname: Tran
authors.forename: Naum
authors.initials: N
authors.lastname: Papanicolau
authors.forename: Michael C
authors.initials: MC
authors.lastname: Kolios
authors.forename: Gregory J
authors.initials: GJ
authors.lastname: Czarnota