title: Ultrasound elastography as a tool for imaging guidance during prostatectomy: initial experience.
abstract: BACKGROUND
  During laparoscopic or robotic assisted laparoscopic prostatectomy, the surgeon lacks tactile feedback which can help him tailor the size of the excision. Ultrasound elastography (USE) is an emerging imaging technology which maps the stiffness of tissue. In the paper we are evaluating USE as a palpation equivalent tool for intraoperative image guided robotic assisted laparoscopic prostatectomy.
  
  
  METHODS
  Two studies were performed: 1) A laparoscopic ultrasound probe was used in a comparative study of manual palpation versus USE in detecting tumor surrogates in synthetic and ex-vivo tissue phantoms; N=25 participants (students) were asked to provide the presence, size and depth of these simulated lesions, and 2) A standard ultrasound probe was used for the evaluation of USE on ex-vivo human prostate specimens (N=10 lesions in N=6 specimens) to differentiate hard versus soft lesions with pathology correlation. Results were validated by pathology findings, and also by in-vivo and ex-vivo MR imaging correlation.
  
  
  RESULTS
  In the comparative study, USE displayed higher accuracy and specificity in tumor detection (sensitivity=84%, specificity=74%). Tumor diameters and depths were better estimated using USE versus with manual palpation. USE also proved consistent in identification of lesions in ex-vivo prostate specimens; hard and soft, malignant and benign, central and peripheral.
  
  
  CONCLUSIONS
  USE is a strong candidate for assisting surgeons by providing palpation equivalent evaluation of the tumor location, boundaries and extra-capsular extension. The results encourage us to pursue further testing in the robotic laparoscopic environment.
authors.affiliation: Johns Hopkins University, Baltimore, MD, USA. inicola1@jhu.edu
authors.forename: Ioana Nicolaescu
authors.initials: IN
authors.lastname: Fleming
authors.forename: Carmen
authors.initials: C
authors.lastname: Kut
authors.forename: Katarzyna J
authors.initials: KJ
authors.lastname: Macura
authors.forename: Li-Ming
authors.initials: LM
authors.lastname: Su
authors.forename: Hassan
authors.initials: H
authors.lastname: Rivaz
authors.forename: Caitlin M
authors.initials: CM
authors.lastname: Schneider
authors.forename: Ulrike
authors.initials: U
authors.lastname: Hamper
authors.forename: Tamara
authors.initials: T
authors.lastname: Lotan
authors.forename: Russ
authors.initials: R
authors.lastname: Taylor
authors.forename: Gregory
authors.initials: G
authors.lastname: Hager
authors.forename: Emad
authors.initials: E
authors.lastname: Boctor
mesh_terms: D054459:Elasticity Imaging Techniques / Q000379:methods*; D006801:Humans; D010535:Laparoscopy; D008297:Male; D010173:Palpation; D019047:Phantoms, Imaging; D011467:Prostate / Q000000981:diagnostic imaging* / Q000473:pathology / Q000601:surgery*; D011468:Prostatectomy