title: Validation of phalanx bone three-dimensional surface segmentation from computed tomography images using laser scanning.
abstract: OBJECTIVE
  To examine the validity of manually defined bony regions of interest from computed tomography (CT) scans.
  
  
  METHODS
  Segmentation measurements were performed on the coronal reformatted CT images of the three phalanx bones of the index finger from five cadaveric specimens. Two smoothing algorithms (image-based and Laplacian surface-based) were evaluated to determine their ability to represent accurately the anatomic surface. The resulting surfaces were compared with laser surface scans of the corresponding cadaveric specimen.
  
  
  RESULTS
  The average relative overlap between two tracers was 0.91 for all bones. The overall mean difference between the manual unsmoothed surface and the laser surface scan was 0.20 mm. Both image-based and Laplacian surface-based smoothing were compared; the overall mean difference for image-based smoothing was 0.21 mm and 0.20 mm for Laplacian smoothing.
  
  
  CONCLUSIONS
  This study showed that manual segmentation of high-contrast, coronal, reformatted, CT datasets can accurately represent the true surface geometry of bones. Additionally, smoothing techniques did not significantly alter the surface representations. This validation technique should be extended to other bones, image segmentation and spatial filtering techniques.
authors.affiliation: Department of Biomedical Engineering, Center for Computer Aided Design, The University of Iowa, Iowa City, IA 52242, USA.
authors.forename: Nicole A
authors.initials: NA
authors.lastname: DeVries
authors.forename: Esther E
authors.initials: EE
authors.lastname: Gassman
authors.forename: Nicole A
authors.initials: NA
authors.lastname: Kallemeyn
authors.forename: Kiran H
authors.initials: KH
authors.lastname: Shivanna
authors.forename: Vincent A
authors.initials: VA
authors.lastname: Magnotta
authors.forename: Nicole M
authors.initials: NM
authors.lastname: Grosland
mesh_terms: D000368:Aged; D000465:Algorithms; D002102:Cadaver; D005260:Female; D050278:Finger Phalanges / Q000000981:diagnostic imaging*; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D021621:Imaging, Three-Dimensional / Q000379:methods*; D007834:Lasers; D012015:Reference Standards; D015203:Reproducibility of Results; D014057:Tomography, X-Ray Computed / Q000379:methods*