title: Autonomous virtual mobile robot for three-dimensional medical image exploration: application to micro-CT cochlear images.
abstract: OBJECTIVE
  In this paper, we present an autonomous virtual mobile robot (AVMR) for three-dimensional (3D) exploration of unknown tubular-like structures in 3D images.
  
  
  METHODS
  The trajectory planning for 3D central navigation is achieved by combining two neuro-fuzzy controllers, and is based on 3D sensory information; a Hough transform is used to locally fit a cylinder during the exploration, estimating the local radius of the tube. Nonholonomic constraints are applied to assure a smooth, continuous and unique final path. When applied to 3D medical images, the AVMR operates as a virtual endoscope, directly providing anatomical measurements of the organ. After a thorough validation on challenging synthetic environments, we applied our method to eight micro-CT datasets of cochleae.
  
  
  RESULTS
  Validation on synthetic environments proved the robustness of our method, and highlighted key parameters for the design of the AVMR. When applied to the micro-CT datasets, the AVMR automatically estimated length and radius of the cochleae: results were compared to manual delineations, proving the accuracy of our approach.
  
  
  CONCLUSIONS
  The AVMR presents several advantages when used as a virtual endoscope: the nonholonomic constraint guarantees a unique and smooth central path, which can be reliably used both for qualitative and quantitative investigation of 3D medical datasets. Results on the micro-CT cochleae are a significant step towards the validation of more clinical computed tomography (CT) studies.
authors.affiliation: Division of Image Processing, Department of Radiology, Leiden University Medical Center (LUMC), Albinusdreef 2, 2333 ZA Leiden, The Netherlands.
authors.forename: Luca
authors.initials: L
authors.lastname: Ferrarini
authors.forename: Berit M
authors.initials: BM
authors.lastname: Verbist
authors.forename: Hans
authors.initials: H
authors.lastname: Olofsen
authors.forename: Filiep
authors.initials: F
authors.lastname: Vanpoucke
authors.forename: Johan H M
authors.initials: JH
authors.lastname: Frijns
authors.forename: Johan H C
authors.initials: JH
authors.lastname: Reiber
authors.forename: Faiza
authors.initials: F
authors.lastname: Admiraal-Behloul
mesh_terms: D003051:Cochlea / Q000000981:diagnostic imaging*; D004724:Endoscopy / Q000379:methods; D017143:Fuzzy Logic; D006801:Humans; D021621:Imaging, Three-Dimensional; D012371:Robotics; D014057:Tomography, X-Ray Computed / Q000379:methods*