Diagnostic Imaging of the Larynx

Serving in a supportive role to laryngoscopy, diagnostic radiology provides key information in the evaluation of laryngeal pathology in both children and adults. Findings detected on imaging can both lead to a specific diagnosis and influence patient management. Computed tomography (CT), magnetic resonance (MR) imaging, and positron emission tomography-computed tomography (PET-CT) have become the main modalities in imaging of the larynx. With any of these modalities, knowledge of cross-sectional anatomy lays a foundation on which crucial imaging findings can be identified. In this manner, radiology plays a foremost role in diagnosing inflammatory conditions, detecting vocal cord paralysis, imaging laryngeal carcinoma both pretherapy and post-therapy, pinpointing traumatic injuries, and identifying foreign objects. Depending on the site of inflammation within the larynx, characteristic imaging features are often appreciated. For instance, a rounded, thumb-like density in place of the normal epiglottis is seen in epiglottitis, and “penciling” of the subglottic airway is visualized in croup. Vocal cord paralysis presents with a variety of imaging finding such as a paramedian position of the vocal cord, anteromedial displacement of the arytenoid cartilage, ipsilateral dilation of the piriform sinus, and enlargement of the laryngeal ventricle. As the deep structures cannot be analyzed with laryngoscopy, imaging is crucial in the staging of laryngeal cancers because involvement of the preepiglottic and paraglottic spaces, cartilages, and lymph nodes can be determined. In the traumatic setting, CT permits for the rapid evaluation of laryngeal cartilage damage and airway compromise. Both plain film radiography and CT are useful in the assessment for radiopaque foreign objects.