Diagnostic accuracy of cone beam computed tomography and conventional multislice spiral tomography in sheep mandibular condyle fractures

Abstract

Objectives: the aim of this study was to compare diagnostic accuracy of cone beam CT (CBCT) and multislice CT in artificially created fractures of the sheep mandibular condyle.

Methods: 63 full-thickness sheep heads were used in this study. Two surgeons created the fractures, which were either displaced or non-displaced. CBCT images were acquired by the NewTom 3G CBCT scanner (NIM, Verona, Italy) and CT imaging was performed using the Toshiba Aquillon multislice CT scanner (Toshiba Medical Systems, Otawara, Japan). Two-dimensional (2D) cross-sectional images and three-dimensional (3D) reconstructions were evaluated by two observers who were asked to determine the presence or absence of fracture and displacement, the type of fracture, anatomical localization and type of displacement. The naked-eye inspection during surgery served as the gold standard. Inter- and intra-observer agreements were calculated with weighted kappa statistics. The receiver operating characteristics (ROC) curve analyses were used to compare statistically the area under the curve (AUC) of both imaging modalities.

Results: kappa coefficients of intra- and interobserver agreement scores varied between 0.56 - 0.98, which were classified as moderate and excellent, respectively. There was no statistically significant difference between the imaging modalities, which were both sensitive and specific for the diagnosis of sheep condylar fractures.

Conclusions: this study confirms that CBCT is similar to CT in the diagnosis of different types of experimentally created sheep condylar fractures and can provide a cost- and dose-effective diagnostic option.

Figure 1

Three-dimensional CT view of an anterior condyle displacement

Figure 2

Axial CT and cone beam CT views of bilateral condyle fractures with displacement. Right side (R): medial displacement, left side (L): lateral displacement

Figure 3

Oblique CT view of a comminuted fracture (left) and a sham operated condyle (right)

Figure 4

Three-dimensional reconstruction of a posteriorly displaced condyle fracture in cone beam CT

Figure 5

Cone beam CT of bilateral fractured condyles from the coronal plane. Medial displacement on the left and a fracture without displacement on the right side are clearly visible

Figure 6

Cone beam CT imaging from the sagittal plane, note the posterior displacement of the condyle fracture

Figure 7

Schematic presentation of the condylar fracture types and the distribution of experimental groups. TMJ, temporomandibular joint