Accuracy of linear measurement in the Galileos cone beam computed tomography under simulated clinical conditions

Abstract

Objectives: The aim of this study was to determine the geometric accuracy of cone beam CT (CBCT)-based linear measurements of bone height obtained with the Galileos CBCT (Sirona Dental Systems Inc., Bensheim, Hessen, Germany) in the presence of soft tissues.

Methods: Six embalmed cadaver heads were imaged with the Galileos CBCT unit subsequent to placement of radiopaque fiduciary markers over the buccal and lingual cortical plates. Electronic linear measurements of bone height were obtained using the Sirona software. Physical measurements were obtained with digital calipers at the same location. This distance was compared on all six specimens bilaterally to determine accuracy of the image measurements.

Results: The findings showed no statistically significant difference between the imaging and physical measurements (P > 0.05) as determined by a paired sample t-test. The intraclass correlation was used to measure the intrarater reliability of repeated measures and there was no statistically significant difference between measurements performed at the same location (P > 0.05).

Conclusions: The Galileos CBCT image-based linear measurement between anatomical structures within the mandible in the presence of soft tissues is sufficiently accurate for clinical use.

Figures

Figure 1

Cone beam CT images showing the plane of measurement on the left side of the specimen. Top window: reconstructed panoramic image with the slicing window placed over the plane of measurement. Bottom left window: cross-sectional image corresponding to the slicing window on top. The image shows a cross-section of the mandible with spherical radiopaque markers placed over buccal and lingual alveolar ridges. A measurement tool was used to draw tangents along the superiormost and inferiormost points of the bone. Vertical distance was measured between the two tangents which depicted the height of bone at this location. Bottom right window: axial image showing the focal trough and the axial plane corresponding to the plane of measurement

Figure 2

Specimen mounted on a base, demonstrating the mandible surrounded by intraoral and extraoral soft tissues. The proposed plane of dissection, corresponding to the plane of measurement, is indicated by arrows

Figure 3

Tangent locater for determining the superiormost and inferiormost points of the cross-section of mandible on the specimen (indicated by arrows)

Figure 4

Physical measurement of bone height with calipers between the superiormost and inferiormost points of the cross-section of mandible

Figure 5

Cone beam CT (CBCT) vs physical measurements. Figure represents mean values of bone height using CBCT and calipers as measured on the right side, left side and overall (both)