Validation of a novel semi-automated method for three-dimensional surface rendering of condyles using cone beam computed tomography data.

Int J Oral Maxillofac Surg. 2013 Aug;42(8):1023-9. doi: 10.1016/j.ijom.2013.01.016. Epub 2013 Mar 23.

Xi T(1), van Loon B, Fudalej P, Bergé S, Swennen G, Maal T.

Author information:

(1) Department of Oral and Maxillofacial Surgery, Radboud University Nijmegen

Medical Centre, Nijmegen, The Netherlands.

Morphological changes of the condyles are often observed following orthognathic

surgery. In addition to clinical assessment, radiographic evaluation of the

condyles is required to distinguish the physiological condylar remodelling from

pathological condylar resorption. The low contrast resolution and distortion of

greyscale values in cone beam computed tomography (CBCT) scans have impeded an

accurate three-dimensional (3D) rendering of the condyles. The current study

proposes a novel semi-automated method for 3D rendering of condyles using CBCT

datasets, and provides a clinical validation of this method. Ten patients were

scanned using a standard CBCT scanning protocol. After defining the volume of

interest, a greyscale cut-off value was selected to allow an automatic

reconstruction of the condylar outline. The condylar contour was further

enhanced manually by two independent observers to correct for the under- and

over-contoured voxels. Volumetric measurements and surface distance maps of the

condyles were computed. The mean within-observer and between-observer

differences in condylar volume were 8.62 mm(3) and 6.13 mm(3), respectively. The

mean discrepancy between intra- and inter-observer distance maps of the condylar

surface was 0.22 mm and 0.13 mm, respectively. This novel method provides a

reproducible tool for the 3D rendering of condyles, allowing longitudinal

follow-up and quantitative analysis of condylar changes following orthognathic

surgery.

Copyright © 2013 International Association of Oral and Maxillofacial Surgeons.

Published by Elsevier Ltd. All rights reserved.

DOI: 10.1016/j.ijom.2013.01.016

PMID: 23528746 [Indexed for MEDLINE]