title: Augmented Reality Using Transurethral Ultrasound for Laparoscopic Radical Prostatectomy: Preclinical Evaluation.
abstract: To guide the surgeon during laparoscopic or robot-assisted radical prostatectomy an innovative laparoscopic/ultrasound fusion platform was developed using a motorized 3-dimensional transurethral ultrasound probe. We present what is to our knowledge the first preclinical evaluation of 3-dimensional prostate visualization using transurethral ultrasound and the preliminary results of this new augmented reality.
  
  
  
  The transurethral probe and laparoscopic/ultrasound registration were tested on realistic prostate phantoms made of standard polyvinyl chloride. The quality of transurethral ultrasound images and the detection of passive markers placed on the prostate surface were evaluated on 2-dimensional dynamic views and 3-dimensional reconstructions. The feasibility, precision and reproducibility of laparoscopic/transurethral ultrasound registration was then determined using 4, 5, 6 and 7 markers to assess the optimal amount needed. The root mean square error was calculated for each registration and the median root mean square error and IQR were calculated according to the number of markers.
  
  
  
  The transurethral ultrasound probe was easy to manipulate and the prostatic capsule was well visualized in 2 and 3 dimensions. Passive markers could precisely be localized in the volume. Laparoscopic/transurethral ultrasound registration procedures were performed on 74 phantoms of various sizes and shapes. All were successful. The median root mean square error of 1.1 mm (IQR 0.8-1.4) was significantly associated with the number of landmarks (p = 0.001). The highest accuracy was achieved using 6 markers. However, prostate volume did not affect registration precision.
  
  
  
  Transurethral ultrasound provided high quality prostate reconstruction and easy marker detection. Laparoscopic/ultrasound registration was successful with acceptable mm precision. Further investigations are necessary to achieve sub mm accuracy and assess feasibility in a human model.
authors.affiliation: Urology Department, Grenoble University Hospital, Grenoble, France; Centre National de la Recherche Scientifique, Institut National de la Santé et de la Recherche Médicale, Techniques de l'Ingénierie Médicale et de la Complexité-Informatique, Mathématiques et Applications-Grenoble, Unité Mixte de Recherche 5525, Université Joseph Fourier-Grenoble 1, Grenoble, France.
authors.forename: Cecilia
authors.initials: C
authors.lastname: Lanchon
authors.affiliation: Centre national de la recherche scientifique, Techniques de l'Ingénierie Médicale et de la Complexité-Informatique, Mathématiques et Applications-Grenoble, Unité Mixte de Recherche 5525, Université Joseph Fourier-Grenoble 1, Grenoble, France.
authors.forename: Guillaume
authors.initials: G
authors.lastname: Custillon
authors.affiliation: Centre national de la recherche scientifique, Techniques de l'Ingénierie Médicale et de la Complexité-Informatique, Mathématiques et Applications-Grenoble, Unité Mixte de Recherche 5525, Université Joseph Fourier-Grenoble 1, Grenoble, France; Centre d'Investigation Clinique, Innovation Technologique, Institut National de la Santé et de la Recherche Médicale, Centre Hospitalier Universitaire de Grenoble, Université Joseph Fourier-Grenoble 1, Grenoble, France.
authors.forename: Alexandre
authors.initials: A
authors.lastname: Moreau-Gaudry
authors.affiliation: Urology Department, Grenoble University Hospital, Grenoble, France; Centre National de la Recherche Scientifique, Institut National de la Santé et de la Recherche Médicale, Techniques de l'Ingénierie Médicale et de la Complexité-Informatique, Mathématiques et Applications-Grenoble, Unité Mixte de Recherche 5525, Université Joseph Fourier-Grenoble 1, Grenoble, France.
authors.forename: Jean-Luc
authors.initials: JL
authors.lastname: Descotes
authors.affiliation: Urology Department, Grenoble University Hospital, Grenoble, France; Centre National de la Recherche Scientifique, Institut National de la Santé et de la Recherche Médicale, Techniques de l'Ingénierie Médicale et de la Complexité-Informatique, Mathématiques et Applications-Grenoble, Unité Mixte de Recherche 5525, Université Joseph Fourier-Grenoble 1, Grenoble, France.
authors.forename: Jean-Alexandre
authors.initials: JA
authors.lastname: Long
authors.affiliation: Urology Department, Grenoble University Hospital, Grenoble, France; Centre National de la Recherche Scientifique, Institut National de la Santé et de la Recherche Médicale, Techniques de l'Ingénierie Médicale et de la Complexité-Informatique, Mathématiques et Applications-Grenoble, Unité Mixte de Recherche 5525, Université Joseph Fourier-Grenoble 1, Grenoble, France.
authors.forename: Gaelle
authors.initials: G
authors.lastname: Fiard
authors.affiliation: Centre National de la Recherche Scientifique, Institut National de la Santé et de la Recherche Médicale, Techniques de l'Ingénierie Médicale et de la Complexité-Informatique, Mathématiques et Applications-Grenoble, Unité Mixte de Recherche 5525, Université Joseph Fourier-Grenoble 1, Grenoble, France. Electronic address: Sandrine.Voros@imag.fr.
authors.forename: Sandrine
authors.initials: S
authors.lastname: Voros
mesh_terms: D005240:Feasibility Studies; D006801:Humans; D021621:Imaging, Three-Dimensional; D010535:Laparoscopy / Q000379:methods*; D008297:Male; D008953:Models, Anatomic; D011467:Prostate / Q000000981:diagnostic imaging* / Q000601:surgery*; D011468:Prostatectomy / Q000379:methods*; D025321:Surgery, Computer-Assisted / Q000379:methods*; D018084:Ultrasonography, Interventional / Q000379:methods*
keywords: diagnostic imaging; laparoscopy; prostatic neoplasms; ultrasonography; urethra