However, MRI has unique advantages compared to CT, including higher contrast resolution, detection sensitivity for detecting head and neck abscesses, 4, 5 and a tendency for less image quality degradation due to metal artifacts associated with dental treatment. 3 MRI is not used as the first or only imaging modality in emergency situations due to some disadvantages such as limited availability, relatively long scan times, and patient access related to implantable devices and claustrophobia. In addition, dual-energy CT can produce noncontrast CT-like virtual unenhanced images that are useful for the detection of sialoliths. 2 Various state-of-the-art techniques including virtual monochromatic imaging derived from dual-energy CT, subtraction CT technique, and artifact reduction algorithm described later in this article can be useful to mitigate these artifacts. Although CT has many of these advantages, metal artifacts associated with dental treatment can degrade image quality and obscure the depiction of infectious diseases of the oral cavity or oropharynx. 1 CT with a bone reconstruction kernel is an excellent imaging modality for the temporal bone and paranasal sinuses. Contrast-enhanced CT is also well suited for identifying the origin of infection and its extension into the deep neck spaces. Its advantages include immediate availability, cost-effectiveness, short examination time with rapid data acquisition, and thus minimal motion artifacts that are potentially caused by swallowing and eye movements. Delayed clinical intervention increases the risk of complications and the spread of infection, which can compromise critical anatomical structures such as the airway, blood vessels, optic nerves, and intracranial structures.Ĭontrast-enhanced CT is the first and standard imaging modality of choice in head and neck infections. Radiological imaging plays a critical role in depicting the location and extent of the disease, identifying the origin of infection, and detecting associated complications. Head and neck infections require rapid diagnosis and intervention due to their proximity to critical neurovascular structures including the brain and spinal cord. This article provides a region-based approach to the imaging evaluation of head and neck infections, using both conventional and advanced imaging techniques. Subtraction CT techniques are used to detect progressive bone-destructive changes and to reduce dental amalgam artifacts. Dual-energy CT is helpful in reducing metal artifacts, evaluating deep neck abscess, and detecting salivary stones. MR bone imaging may be of additional value in evaluating bony structures of the skull base and jaw. Dynamic contrast-enhanced MRI perfusion may be useful in assessing the activity of skull base osteomyelitis. Apparent diffusion coefficient derived from diffusion-weighted imaging is useful for differential diagnosis and treatment response of head and neck infections in various anatomical sites. Both CT and MRI are useful in the evaluation of abscesses and thrombophlebitis, while MRI is especially useful in the evaluation of intracranial inflammatory spread/abscess formation, differentiation of abscess from other conditions, evaluation of the presence and activity of inflammation and osteomyelitis, evaluation of mastoid extension in middle ear cholesteatoma, and evaluation of facial neuritis and labyrinthitis. While contrast-enhanced CT is the standard imaging modality for evaluating head and neck infections, MRI can better characterize the skull base, intracranial involvement, and osteomyelitis, implying that these are complementary techniques for a comprehensive assessment. When head and neck infection is suspected, appropriate imaging contributes to treatment decisions and prognosis.
0 Comments
Leave a Reply. |