THE HIDDEN TRAPS ON CBCT

We present a case of a metastatic malignancy seen on CBCT published in the Imaging Science in Dentistry Journal.

A 66 year old woman presents for pre-operative maxillary alveolar process implant placement assessment with history of kidney removal due to renal cancer. CBCT was obtained on CBCT with a field of view 80 x 80 x 80mm.

Images show complete opacification of the left sphenoid sinus with mass effect. No internal calcification. There is remodelling of the sinus septum with regions of complete septal loss and superiorly, there is evidence of cribriform plate erosion/base of skull erosion. These findings prompt the dental doctor to advise the patient for further investigation with their primary care provider. Following further investigation and biopsy, definitive diagnosis of metastatic renal cell carcinoma was made.

Studies show up to 41.6% of incidental findings on CBCT required further medical attention (cervical spine degeneration, sinusitis, carotid calcification) with approximately 1.4% representing a life threatening condition such as malignancy.

The extraordinary growth of radiology has benefitted dentistry, more particularly with the advent of 3D radiological exams CBCT. However the growing use, improved resolution and increasing field of view also results in more frequent occult/incidental findings, unrelated to the original diagnostic query, which raises issues of further investigation, diagnosis, referral and follow-up.

For example, carotid artery calcifications (CAC) detected during dental imaging examination range between 5.7 to 11.6% correlate to increased cardiovascular and cerebrovascular risk which may require specialist input. Calcified stylohyoid ligament (prevalence ranging from 3.1 to 26.7%) has been associated with symptoms such as cervicofacial, throat pain, or dysphagia. CBCT may reveal incidental findings in the upper airway, the presence and severity of obstructive sleep apnea. Most critically, CBCT may reveal cancer of the head and neck region during its early stages while patients are asymptomatic which carries significant prognostic life-saving impact if acted upon immediately.

Given the frequency of this type of imaging data and particularly the litigation risk associated, it is important that dental practitioners collaborate with imaging specialists to ensure best possible management and outcome for their patients.

a . Bilateral circumferential calcifications of the left and right carotid arteries. b . MIP reconstruction demonstrating the same calcifications at the level of C3C4 
Carotid calcification – moderate stenosis of the left internal carotid artery

Ossifi cation of anterior longitudinal ligament is seen in sagittal section  
Ossification of the anterior longitudinal ligament of cervical spine
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