Accuracy of three-dimensional measurements obtained from cone beam computed tomography surface-rendered images for cephalometric analysis: influence of patient scanning position

Abstract

The aims of this study were to assess the accuracy of linear measurements on three-dimensional (3D) surface-rendered images generated from cone beam computed tomography (CBCT) in comparison with two-dimensional (2D) slices and 2D lateral and postero-anterior (PA) cephalometric projections, and to investigate the influence of patient head position in the scanner on measurement accuracy. Eight dry human skulls were scanned twice using NewTom 3G CBCT in an ideal and a rotated position and the resulting datasets were used to create 3D surface-rendered images, 2D tomographic slices, and 2D lateral and PA projections. Ten linear distances were defined for cephalometric measurements. The physical and radiographic measurements were repeated twice by three independent observers and were compared using repeated measures analysis of variance (P=0.05). The radiographic measurements were also compared between the ideal and the rotated scan positions. The radiographic measurements of the 3D images were closer to the physical measurements than the 2D slices and 2D projection images. No statistically significant difference was found between the ideal and the rotated scan measurements for the 3D images and the 2D tomographic slices. A statistically significant difference (P<0.001) was observed between the ideal and rotated scan positions for the 2D projection images. The findings indicate that measurements based on 3D CBCT surface images are accurate and that small variations in the patient's head position do not influence measurement accuracy.

Accuracy of CBCT Measurements of a Human Skull

“…A study comparing linear measurement of the temporomandibular joint using CBCT and digital cephalometric radiography obtained similar results [22]. Moreover, skull orientation during CBCT scanning has not been found to affect accuracy or reliability of measurements [23][24][25].…”

Evaluating Dimensional Accuracy and Reliability of "Stitched" Small Field of View (SSFOV) Cone Beam Computed Tomography (CBCT) Datasets for Use in Proprietary Dental Implant Guided Surgery Software

“…The mandible was positioned with the aid of laser lights with the inferior border of the mandible parallel with the horizontal plane and the mid-sagital plane aligned perpendicular to the horizontal plane. This altered positioning, inferior border versus the occlusal plane being parallel to the horizontal plane, allows for the capture of the entire mandible and all associated reference points despite the SFOV (37mm) and will not affect scanning accuracy per Berco et al (2009) and Hassan et al (2009). The scan was performed with the following reduced exposure settings: mA 6, KvP 80, 0.018 s and 0.2 Voxels (resolution), accounting for the lack of soft tissue density.…”

“…Berco et al (2009) and Hassan et al (2009) insist skull orientation during CBCT scanning does not affect the accuracy or the reliability of the measurements.…”

“…Many studies are found in the literature verifying the dimensional accuracy of CBCT imaging; most of which using osteologic landmarks on dry human skulls as reference points for measurement (Lascala et al 2004;Hilgers et al 2005;Morishi et al 2007;Lagrave et al 2008;Loubele et al 2008;Periago et al 2008;Berco et al 2009;Hassan et al 2009;Moriera et al 2009). …”

Acurácia de medidas lineares em softwares de planejamento de implantes sobre imagens de mandibulas atróficas obtidas por tomografias computadorizadas de feixe cônico com diferentes protocolos de aquisição

“…O estudo atual confirma os resultados anteriores que demonstraram alta precisão de imagens obtidas com TCFC por meio de medidas lineares (Kobayshi et al, 2004;Lascala et al, 2004;Ludlow et al, 2007;Suomalainen et al, 2008;Loubele et al, 2008;Periago et al, 2008;Stratemann et al, 2008;Hassan et al, 2009;Lund et al, 2009;Brown et al, 2009;Damstra et al, 2010;Maloney et al, 2011;El-Beialy et al, 2011;Tomasi et al, 2011;Panzarella et al, 2011;Al-Ekrish, Ekran 2011;Timock et al, 2011;Engelbrecht et al, 2013;Waltrick et al, 2013;Kosalagood et al, 2014). Contribuindo para a consolidação da precisão das imagens de TCFC, análises geométricas das medidas também foram analisadas em alguns estudos (Marmulla et al, 2005;Baltrick et al, 2008;Primo et al, 2012) obtendo significativos resultados.…”