Cone beam imaging: is this the ultimate imaging modality?

Abstract

This review article provides an overview of cone beam (CB) imaging technology and its role in orofacial imaging, including comparison with two-dimensional (2D) radiography and multislice computed tomography (MCT). The radiation dose levels of CB systems are discussed, with reference to those delivered by MCT and common dental 2D views. The large variation in dose levels delivered by CB systems and the importance of using ultra low-dose CB units are emphasized. Low-dose MCT protocols can be used. CB and MCT image quality are compared. CB is an essential technique that all dental and orofacial clinicians must be familiar with. Where ultra low-dose systems and protocols are used, CB imaging should be considered in day-to-day clinical practice. However, CB imaging is not the technique of choice in many clinical scenarios. Rather than replacing other modalities, CB imaging complements intraoral 2D radiography, panoramic radiography, MCT and other techniques including magnetic resonance imaging, ultrasound and nuclear medicine. MCT is a much more powerful and flexible modality and presently remains the technique of choice over CB imaging in many clinical scenarios. All radiologic examinations, including CB and MCT, should be comprehensively evaluated in entirety. The responsibilities and the radiological skill levels of clinicians involved in imaging as well as the associated ethical and medico-legal implications require consideration.

The basic principles of radiological interpretation

“…The radiations dose levels delivered vary substantially between cone beam machines, some of which can be higher than multislice CT (when appropriate protocols are employed). 4 The significant differences of the strengths and limitations of all these modalities are not within the scope of this paper. However, of note are the substantial limitations of the commonly used panoramic radiograph.…”

“…Persons engaged in the interpretation of these scans must be thoroughly familiar with the limitations of this modality, including beam hardening, noise, low signal, metal artefact and poor soft tissue contrast resolution and the effect of motion artefact. 4 The effects of the various protocols using the same equipment must also be understood.…”

Cone beam computed tomography and obstructive sleep apnoea

“…Many of the currently available CBCT machines available to dental practitioners have a field of view (FOV) that can include the paranasal sinuses, pharyngeal air spaces, skull base, cervical spine and upper neck in addition to the oral and perioral structures. 48 Therefore, it is incumbent on the clinician to decide whether they are fluent in interpreting the data from the entire volume and not just their anatomical area of interest (Fig. 7).…”

How to Interpret Cone Beam Computed Tomography Scans

“…The optimal protocol should be based ultimately on the clinician's judgment, anatomy accurately and to identify incidental findings (Koong, 2010;Jacobs, 2011;Scarfe et al, 2012). This chapter presents a sequential and logical approach to navigating three-dimensional (3D) volumes in order to distinguish normal from abnormal anatomy and to identify pathologies and incidental findings.…”