Editing Sinusitis (section)

===Chronic===
For sinusitis lasting more than 12 weeks, a [[CT scan]] is recommended.<ref name="pmid17761281" /> On a CT scan, acute sinus secretions have a [[radiodensity]] of 10 to 25 [[Hounsfield unit]]s (HU), but in a more chronic state they become more [[Viscosity|viscous]], with a radiodensity of 30 to 60 HU.<ref>[https://books.google.com/books?id=FxUgUBVBmUUC&pg=PA674 Page 674] {{webarchive|url=https://web.archive.org/web/20170216044325/https://books.google.com/books?id=FxUgUBVBmUUC&pg=PA674 |date=2017-02-16 }} in: {{cite book|title=Cummings Otolaryngology – Head and Neck Surgery, 3-Volume Set| vauthors = Flint PW, Haughey BH, Niparko JK, Richardson MA, Lund VJ, Robbins KT, Lesperance MM, Thomas JR | author-link3 = John Niparko |publisher=Elsevier Health Sciences|year=2010|isbn=9780323080873}}</ref>

Nasal [[endoscopy]] and clinical symptoms are also used to make a positive diagnosis.<ref name="pmid18206715"/> A tissue sample for [[histology]] and [[cultures]] can also be collected and tested.<ref>Harrison's Manual of Medicine 16/e</ref> Nasal endoscopy involves inserting a flexible [[fiber-optic]] tube with a light and camera at its tip into the nose to examine the nasal passages and sinuses.

Sinus infections, if they result in tooth pain, usually present with pain involving more than one of the upper teeth, whereas a toothache usually involves a single tooth. Dental examination and appropriate radiography aid in ruling out pain arises from a tooth.<ref name="Burket-2014">{{cite book|title=Burket's oral medicine|publisher=Burket's oral medicine|last=Glick|first=Michael|date=30 June 2014 |isbn=978-1-60795-280-0|edition=12th|location=Shelton, Connecticut|pages=341|oclc=903962852}}</ref>

<gallery mode="packed" widths="360px" heights="220">
Image:Sinuses and Sinusitis (5937085231).jpg|CT of chronic sinusitis
File:CT of chronic sinuitis.jpg|[[CT scan]] of chronic sinusitis, showing a filled right maxillary sinus with sclerotic thickened bone
File:Brain MRI 112010 rgbca.png|MRI image showing sinusitis. Edema and mucosal thickening appears in both maxillary sinuses.
File:RtmaxobitinfectteethCT.png|Maxillary sinusitis caused by a dental infection associated with [[periorbital cellulitis]]
File:FrontalSinusitisMark.png|Frontal sinusitis
File:Maxilar sinusites.jpg|[[Projectional radiography|X-ray]] of left-sided maxillary sinusitis marked by an arrow. There is lack of the air transparency indicating fluid in contrast to the other side.
</gallery>