Maximilian E H Wagner1, Nils-Claudius Gellrich2, Karl-Ingo Friese3, Matthias Becker4, Franz-Erich Wolter3, Juergen T Lichtenstein2, Marcus Stoetzer2, Majeed Rana2, Harald Essig5. 1. Department of Craniomaxillofacial Surgery, Hannover Medical School, Carl-Neubergstrasse 1, 30625, Hannover, Germany. m.e.h.wagner@icloud.com. 2. Department of Craniomaxillofacial Surgery, Hannover Medical School, Carl-Neubergstrasse 1, 30625, Hannover, Germany. 3. Institute for Man-Machine Communication, Leibniz University Hannover, Hannover, Germany. 4. MIRALab, University of Geneva, Geneva, Switzerland. 5. Department of Craniomaxillofacial Surgery, University Hospital Zürich, Zurich, Switzerland.
Abstract
PURPOSE: Objective determination of the orbital volume is important in the diagnostic process and in evaluating the efficacy of medical and/or surgical treatment of orbital diseases. Tools designed to measure orbital volume with computed tomography (CT) often cannot be used with cone beam CT (CBCT) because of inferior tissue representation, although CBCT has the benefit of greater availability and lower patient radiation exposure. Therefore, a model-based segmentation technique is presented as a new method for measuring orbital volume and compared to alternative techniques. METHODS: Both eyes from thirty subjects with no known orbital pathology who had undergone CBCT as a part of routine care were evaluated (n = 60 eyes). Orbital volume was measured with manual, atlas-based, and model-based segmentation methods. Volume measurements, volume determination time, and usability were compared between the three methods. Differences in means were tested for statistical significance using two-tailed Student's t tests. RESULTS: Neither atlas-based (26.63 ± 3.15 mm(3)) nor model-based (26.87 ± 2.99 mm(3)) measurements were significantly different from manual volume measurements (26.65 ± 4.0 mm(3)). However, the time required to determine orbital volume was significantly longer for manual measurements (10.24 ± 1.21 min) than for atlas-based (6.96 ± 2.62 min, p < 0.001) or model-based (5.73 ± 1.12 min, p < 0.001) measurements. CONCLUSION: All three orbital volume measurement methods examined can accurately measure orbital volume, although atlas-based and model-based methods seem to be more user-friendly and less time-consuming. The new model-based technique achieves fully automated segmentation results, whereas all atlas-based segmentations at least required manipulations to the anterior closing. Additionally, model-based segmentation can provide reliable orbital volume measurements when CT image quality is poor.
PURPOSE: Objective determination of the orbital volume is important in the diagnostic process and in evaluating the efficacy of medical and/or surgical treatment of orbital diseases. Tools designed to measure orbital volume with computed tomography (CT) often cannot be used with cone beam CT (CBCT) because of inferior tissue representation, although CBCT has the benefit of greater availability and lower patient radiation exposure. Therefore, a model-based segmentation technique is presented as a new method for measuring orbital volume and compared to alternative techniques. METHODS: Both eyes from thirty subjects with no known orbital pathology who had undergone CBCT as a part of routine care were evaluated (n = 60 eyes). Orbital volume was measured with manual, atlas-based, and model-based segmentation methods. Volume measurements, volume determination time, and usability were compared between the three methods. Differences in means were tested for statistical significance using two-tailed Student's t tests. RESULTS: Neither atlas-based (26.63 ± 3.15 mm(3)) nor model-based (26.87 ± 2.99 mm(3)) measurements were significantly different from manual volume measurements (26.65 ± 4.0 mm(3)). However, the time required to determine orbital volume was significantly longer for manual measurements (10.24 ± 1.21 min) than for atlas-based (6.96 ± 2.62 min, p < 0.001) or model-based (5.73 ± 1.12 min, p < 0.001) measurements. CONCLUSION: All three orbital volume measurement methods examined can accurately measure orbital volume, although atlas-based and model-based methods seem to be more user-friendly and less time-consuming. The new model-based technique achieves fully automated segmentation results, whereas all atlas-based segmentations at least required manipulations to the anterior closing. Additionally, model-based segmentation can provide reliable orbital volume measurements when CT image quality is poor.
Entities:
Keywords:
Cone beam computed tomography; Model segmentation; Orbital volume; Pseudoforamina
Authors: Christoph Zizelmann; Nils Claudius Gellrich; Marc Christian Metzger; Ralf Schoen; Rainer Schmelzeisen; Alexander Schramm Journal: Br J Oral Maxillofac Surg Date: 2005-08-10 Impact factor: 1.651
Authors: Robert A Mischkowski; Reinhard Pulsfort; Lutz Ritter; Jörg Neugebauer; Hans Georg Brochhagen; Erwin Keeve; Joachim E Zöller Journal: Oral Surg Oral Med Oral Pathol Oral Radiol Endod Date: 2007-07-05
Authors: M C Metzger; G Bittermann; L Dannenberg; R Schmelzeisen; N-C Gellrich; B Hohlweg-Majert; C Scheifele Journal: Int J Comput Assist Radiol Surg Date: 2013-02-17 Impact factor: 2.924
Authors: Robert P Bentley; Spyros Sgouros; Kalyan Natarajan; M Stephen Dover; Anthony D Hockley Journal: J Neurosurg Date: 2002-04 Impact factor: 5.115