title: Multiparametric 3D in vivo ultrasound vibroelastography imaging of prostate cancer: Preliminary results.
abstract: OBJECTIVE
  Ultrasound-based solutions for diagnosis and prognosis of prostate cancer are highly desirable. The authors have devised a method for detecting prostate cancer using a vibroelastography (VE) system developed in our group and a tissue classification approach based on texture analysis of VE images.
  
  
  METHODS
  The VE method applies wide-band mechanical vibrations to the tissue. Here, the authors report on the use of this system for cancer detection and show that the texture of VE images characterized by the first and the second order statistics of the pixel intensities form a promising set of features for tissue typing to detect prostate cancer. The system was used to image patients prior to radical surgery. The removed specimens were sectioned and studied by an experienced histopathologist. The authors registered the whole-mount histology sections to the ultrasound images using an automatic registration algorithm. This enabled the quantitative evaluation of the performance of the authors' imaging method in cancer detection in an unbiased manner. The authors used support vector machine (SVM) classification to measure the cancer detection performance of the VE method. Regions of tissue of size 5 × 5 mm, labeled as cancer and noncancer based on automatic registration to histology slides, were classified using SVM.
  
  
  RESULTS
  The authors report an area under ROC of 0.81 ± 0.10 in cancer detection on 1066 tissue regions from 203 images. All cancer tumors in all zones were included in this analysis and were classified versus the noncancer tissue in the peripheral zone. This outcome was obtained in leave-one-patient-out validation.
  
  
  CONCLUSIONS
  The developed 3D prostate vibroelastography system and the proposed multiparametric approach based on statistical texture parameters from the VE images result in a promising cancer detection method.
authors.affiliation: University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada.
authors.forename: Mehdi
authors.initials: M
authors.lastname: Moradi
authors.affiliation: British Columbia Cancer Agency, Vancouver, British Columbia V5Z 4E6, Canada.
authors.forename: S Sara
authors.initials: SS
authors.lastname: Mahdavi
authors.affiliation: University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada.
authors.forename: Guy
authors.initials: G
authors.lastname: Nir
authors.affiliation: University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada.
authors.forename: Omid
authors.initials: O
authors.lastname: Mohareri
authors.affiliation: Bristol Urological Institute, Brunel Building, Southmead Hospital, Bristol BS10 5NB, UK.
authors.forename: Anthony
authors.initials: A
authors.lastname: Koupparis
authors.affiliation: Vancouver General Hospital, Vancouver, British Columbia V5Z 1M9, Canada.
authors.forename: Louis-Olivier
authors.initials: LO
authors.lastname: Gagnon
authors.affiliation: Vancouver Prostate Center, Vancouver, British Columbia V6H 3Z6, Canada.
authors.forename: Ladan
authors.initials: L
authors.lastname: Fazli
authors.affiliation: Consultant Urologist, Essex Cancer Centre, Colchester University NHS Foundation Trust, Essex, CO62QL, UK.
authors.forename: Rowan G
authors.initials: RG
authors.lastname: Casey
authors.affiliation: University of Melbourne, Melbourne, Victoria 3010, Australia.
authors.forename: Joseph
authors.initials: J
authors.lastname: Ischia
authors.affiliation: Vancouver General Hospital, Vancouver, British Columbia V5Z 1M9, Canada.
authors.forename: Edward C
authors.initials: EC
authors.lastname: Jones
authors.affiliation: Department of Urologic Sciences, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada.
authors.forename: S Larry
authors.initials: SL
authors.lastname: Goldenberg
authors.affiliation: University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada.
authors.forename: Septimiu E
authors.initials: SE
authors.lastname: Salcudean
mesh_terms: D000465:Algorithms; D019540:Area Under Curve; D054459:Elasticity Imaging Techniques / Q000379:methods*; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods*; D008297:Male; D064847:Multimodal Imaging / Q000379:methods*; D011467:Prostate / Q000000981:diagnostic imaging / Q000473:pathology / Q000503:physiopathology; D011471:Prostatic Neoplasms / Q000175:diagnosis / Q000000981:diagnostic imaging* / Q000503:physiopathology* / Q000601:surgery; D012372:ROC Curve; D060388:Support Vector Machine; D014732:Vibration