Chronic sinusitis. In this axial plane CT of a patient with chronic sinusitis, radiographic evidence of inflammation can be seen. The right nasolacrimal duct (NL) mucosa is edematous. There is an air-fluid level and opacification of the right maxillary sinus (M). Source: Otolaryngology: Head & Neck Surgery, CURRENT Diagnosis & Treatment: Surgery, 14e Citation: Doherty GM. CURRENT Diagnosis & Treatment: Surgery, 14e; 2015 Available at: https://accesssurgery.mhmedical.com/DownloadImage.aspx?image=/data/books/1202/doh_ch15_f005.png&sec=71517795&BookID=1202&ChapterSecID=71517698&imagename= Accessed: October 23, 2017 Copyright © 2017 McGraw-Hill Education. All rights reserved