Imaging of mandible invasion by oral squamous cell carcinoma using computed tomography, cone-beam computed tomography and bone scintigraphy with SPECT

The objective of this paper is to evaluate the predictability of preoperative tumour bone invasion of the mandible by squamous cell carcinoma of the oral cavity using CT, cone-beam CT and bone scintigraphy with SPECT. Eighty-four patients who had received CT, SPECT or cone-beam computed tomography (CBCT), as well as a further 48 patients who undergone all these investigations for preoperative evaluation of bone invasion were included in the study. A case-control analysis and the receiver operating characteristics were performed. Histological results of bone specimens served as the gold standard for assessment of bone invasion. CBCT and SPECT showed a comparable sensitivity for bone invasion (93 % [CI 0.816-0.972] and 96 % [CI 0.867-0.990], respectively) which was significantly higher than that of CT (63 % [CI 0.488-0.752]). Further, CBCT obtained higher specificity than SPECT (62 % [CI 0.478-0.743] and 48 % [CI 0.342-0.614], respectively), whereas CT showed the best specificity among the investigation methods (81 % [CI 0.677-0.896]). CT scan provides by its high specificity and positive predictive value a precise imaging technique for clinical routine. However, CBCT shows a much higher sensitivity for cortical bone invasion and a better negative predictive value. With a significantly lower exposure dose it can rule out this invasion effectively and prevent overtreatment. Considering the high-resolution images delivered by CBCT along with minimized artefacts in the mandible it provides an alternative imaging technique, which could be combined and accomplished with another soft-tissue imaging modality like MRI to obtain optimal hard and soft-tissue visualisation in patients with squamous cell carcinoma of the oral cavity.