Cone beam CT--anatomic assessment and legal issues: the new standards of care

Until the recent introduction of cone beam computed tomography scanners, standard 2-D imaging provided a moderate contribution to overall treatment planning when considering the diagnostic potential, costs of study and risks to the patient. Cone beam computed tomography-dedicated maxillofacial imaging scanners provide broader imaging tools for anatomic assessment and have become widely available. This article discusses the uses and benefits of 3-D imaging, as well as the impact on the standard of care. Many phases of patient care involve imaging to assist with diagnosis, treatment planning, risk assessment and treatment. Techniques employing X-rays, visible light, ultrasound, lasers and magnetic fields have been used in medicine and dentistry to create images. All forms of imaging require a coupled system of emitters and sensors. For example, a cephalometric image is produced using an X-ray emitter and film sensor. Imaging systems can be categorized in many different ways based upon emitter or output type (examples; film-based, digital, 2-D and 3-D images). The resultant images can be used to evaluate the anatomy of interest, including surface and subsurface. The ultimate quest of all forms of imaging is to reveal the anatomic truth; that is, to portray the anatomy as it exists in nature. Thoughtful clinical application of image acquisition requires matching the uses and limitations of the available imaging choices to achieve the desired diagnostic information (imaging goal) while keeping the risks and costs to the patient as low as possible. Imaging data must provide a benefit at an acceptable cost and risk. Two-dimensional representation of 3-D anatomies creates images that have poor spatial accuracy, are static in space and time, and contain information voids. These 2-D measurements have propagated legacy databases of inaccurate morphometric measurements. Current development in imaging technology for dentistry includes digital imaging and improved sensor technology. Multidimensional anatomical reconstruction can be performed through software applications. The ultimate reward of technological imaging advancements is the 3-D representations (digital volume) of anatomy as it exists in nature (anatomic truth). Analysis of the accurate digital volume can provide clinically relevant spatial information or data. Visualization and analysis of 3-D information can benefit a dental practice by providing data that will improve diagnosis, risk assessment, treatment outcome and treatment efficiency, and reduce treatment complications. This article discusses the uses and benefits of 3-D imaging (cone beam CT, CBCT) for diagnosis, treatment planning and the legal issues affecting the standard of care, as well as offering risk management tips and use guidance.