Friday, March 29, 2024

CT Scan of the Larynx

Overview

Direct examination via endoscopy remains the criterion standard for evaluation of laryngotracheobronchial pathologic conditions. Endoscopy allows for easy visualization and accurate diagnosis of mucosal and superficial submucosal lesions. However, the evaluation of deeper structures is capable only through computed tomography (CT) scanning or magnetic resonance imaging (MRI). CT scanning has become the most commonly used technique for general laryngeal imaging. It is readily available at most hospitals and even at some outpatient centers. The acquisition time for a CT image is extremely short (within a matter of seconds), which is quite useful for the laryngeal examination, as patients are generally required to hold their breath to reduce movement.

Nevertheless, small lesions may still be difficult to visualize. In these cases, active techniques such as the Valsalva maneuver and phonation can better delineate masses of the hypoglottis and vocal cords, respectively.

See the image below.

The tumor shown in the images above is seen in a p

The tumor shown in the images above is seen in a preoperative CT scan image. The posterior plate of the cricoid cartilage can be visualized. Also, a mass is seen eroding the thyroid cartilage and spreading into the soft tissue of the neck.

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MRI has also become more widely available in the past decade, although it has not surpassed CT scanning for conventional laryngeal imaging. Both techniques have advantages and disadvantages. For example, CT and MRI appear to be comparable in efficacy for defining the site and extent of disease in fat and muscle. MRI, however, is more sensitive for detecting pathologic involvement of cartilage (Glastonbury). CT imaging is best for evaluation of occult fractures and dislocations during laryngeal trauma. Furthermore, MRI seems to be the optimal method for examining cooperative patients, especially for preoperative larynx evaluation when partial laryngectomy is considered. CT imaging is more useful in patients who cannot lie still for the study (eg, inebriated, combative). The imaging study performed usually depends on the experience of the radiologist. Additionally, MRI avoids radiation exposure. For more information, please see the Medscape Reference articleMR Imaging of the Larynx.

This article focuses on the use of CT imaging in the evaluation of the larynx, with particular focus on laryngeal neoplasia, trauma, foreign bodies, and radiation-induced changes.

For excellent patient education resources, see eMedicineHealth’s patient education article CT Scan.

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