Emergency imaging assessment of deep neck space infections

Deep neck space infection may lead to severe and potentially life-threatening complications, such as airway obstruction, mediastinitis, septic embolization, dural sinus thrombosis, and intracranial abscess. The clinical presentation is widely variable, and often early symptoms do not reflect the disease severity. The complication risk depends on the extent and anatomical site: diseases that transgress fascial boundaries and spread along vertically oriented spaces (parapharyngeal, retropharyngeal, and paravertebral space) have a higher risk of complications and require a more aggressive treatment compared with those confined within a nonvertically oriented space (peritonsillar, sublingual, submandibular, parotid, and masticator space). Imaging has 5 crucial roles: (1) confirm the suspected clinical diagnosis, (2) define the precise extent of the disease, (3) identify complications, (4) distinguish between drainable abscesses and cellulitis, and (5) monitor deep neck space infection progression. Ultrasonography is the gold standard to differentiate abscesses from cellulitis, for the diagnosis of lymphadenitis. and to identify internal jugular thrombophlebitis in the infrahyoid neck. However, field-of-view limitation and poor anatomical information confine the use of ultrasonography to the evaluation of superficial lesions and to image-guided aspiration or drainage. Computed tomography (CT) combines fast image acquisition and precise anatomical information without field-of-view limitations. For these reasons, it is the most reliable technique for the evaluation of deep and multicompartment lesions and for the identification of mediastinal and intracranial complications. Contrast agent administration enhances the capability to differentiate fluid collections from cellulitis and allows the detection of vascular complications. Magnetic resonance imaging is more time-consuming than CT, limiting its use to selected indications. It is the technique of choice for assessing the epidural space involvement in pre- and paravertebral space infections and complements CT in the evaluation of the infections reaching the skull base.