Imaging Diagnosis in the Subglottic Extension of the Laryngeal Carcinoma

Abstract

Computed tomography (CT) is still the mainstay of imaging diagnosis for laryngeal carcinoma. Presented herein are the typical CT protocols for laryngeal carcinoma, the normal CT imaging of subglottis and a CT diagnosis of the subglottic extension of the laryngeal carcinoma, respectively.
CT images are usually obtained after the administration of an intravenous contrast material with a slice thickness of 2 mm, intersection gap of 1-3mm and a field of view (FOV) of 14-16cm to evaluate the primary site of the laryngeal carcinoma. It is most important to obtain CT images parallel to the plane of the true cord for the accurate evaluation of the subglottic extension. The air-density lucency of the laryngeal ventricle, C4/5 or 5/6 intervertebral disc space, and the hyoid bone on the lateral scout view can be reference of the plane parallel to the true cord. Air-attenuation in the subglottic lumen directly abuts upon the internal surface of the cricoid cartilage on axial CT images of the normal larynx. Any soft tissue swelling adjacent to the cricoid cartilage is abnormal. The coronal and/or sagittal images on the multi-planar reformation well demonstrated the extent of tumor spread in the selected cases.