Imaging in head and neck oncology

Abstract

Evaluation of head and neck cancer with imaging is a topic that is far more extensive than can be covered in this article. The main reason for head and neck imaging is to evaluate the true extent of disease to best determine surgical and therapeutic options. This process includes evaluation of the size, location, and extent of tumor infiltration into surrounding vascular and visceral structures. Important anatomic variants must be pointed out so the surgeon can avoid potential intraoperative complications. These variant scan be evaluated with the appropriate multiplanar and three-dimensional images to provide as much information as possible to the surgeon preoperatively. Second, nodal staging should be assessed in an effort to increase the number of abnormal nodes detected by physical examination and, more important, to precisely define their location by a standard classification system that can be understood and consistently applied by the radiologist, surgeon, radiation oncologist, and pathologist. Although secondary to the previously described tasks, imaging frequently enables a limitation of the diagnostic and histologic possibilities based on lesion location and signal-attenuation characteristics, which may lead the clinical investigation along a different path. saving the patient unnecessary risk and shortening the time to diagnosis and ultimate treatment. This article has attempted to detail the current state of the controversy between CT, MRI, and other modalities, and has emphasized the constant evolution of this controversy because of the evolving imaging technology. Although CT and MRI are both well suited to evaluation of the deep spaces and submucosal spaces of the head and neck, each has some limitations.MRI has the advantages of higher soft tissue contrast resolution, the lack of iodine-based contrast agents, and high sensitivity for perineural and intracranial disease. The disadvantages of MRI include lower patient tolerance, contraindications in pacemakers and certain other implanted metallic devices, and artifacts related to multiple causes, not the least of which is motion. CT is fast, well tolerated, and readily available but has lower contrast resolution and requires iodinated contrast and ionizing radiation. The current authors' practice is heavily centered on CT for initial evaluation, preoperative planning, biopsy targeting, and postoperative follow-up. They reserve MRI for tumors that are suspicious for perineural,cartilaginous, or bony invasion on CT, or for tumors such as adenoid cystic carcinoma that are highly likely to spread by way of these routes. For patients who have head and neck cancer, a radiologist who is educated in the treatment options, patterns of tumor growth, and important surgical landmarks, and who has a well-established pattern of communication with the head and neck clinical services, including surgery, radiation oncology,and pathology, is key in providing accurate and useful image interpretation.