History: 45 year old female with congestion and headache.
Axial CT of the head in bone window shows areas of sinus mucosal thickening as well as a fluid level in the left maxillary sinus and bubbly secretions in the right sphenoid sinus (yellow arrows).
This is the appearance of acute sinusitis on CT. Sinusitis is inflammation of the sinuses as a result of infection with a virus, bacteria, or fungus. Usually patients do not need imaging for diagnosing sinusitis as it is diagnosed clinically by history and physical exam. However, sinusitis is frequently an incidental finding on head and maxillofacial imaging studies. On CT, features that suggest acute versus chronic sinusitis include air fluid levels and bubbly secretions, with a lack of underlying bony changes. Chronic sinusitis is diagnosed in the presence of underlying sclerosis of the bony walls of the sinuses.
The differential for this appearance includes a “pseudo” fluid level (a mucus retention cyst), a blood level in the setting of trauma, and postobstructive secretions. If chronic sinusitis is considered, the differential diagnosis includes fungal sinusitis, fungal mycetoma, Wegner’s granulomatosis, sarcoidosis, and sinonasal polyposis.
Periapical tooth abscess: Coronal CT image of the face reveals a periapical lucency near one of the right maxillary molars (yellow arrow). Note the mucosal thickening in the right maxillary sinus (green arrow) as a result of the adjacent inflammation.
This is an example of a tooth abscess, or periapical abscess. The lucency in the maxilla indicated by the yellow arrow is somewhat nonspecific and may be secondary to tooth loosening, however, the adjacent maxillary sinus mucosal thickening argues for the case of an abscess. Click the following link to learn about Odontogenic Sinusitis.
Tooth #5, the upper right first premolar, after extraction. The two single-headed arrows point to the CEJ, which is the line separating the crown (in this case, heavily decayed) and the roots. The double headed arrow (bottom right) shows the extent of the abscess that surrounds the apex of the palatal root. (Photo credit: Wikipedia)
History: 40 year old male with incidental finding on head CT done for minor head trauma.
Single axial CT of the head without contrast shows a well defined, calcified mass within the left frontal sinus.
This is the typical appearance for a Sinonasal Osteoma. Classically they are asymptomatic, and thus are incidental findings on imaging studies done for other reasons. Sinonasal osteomas are the most common benign tumor of the sinuses. They can be associated with Gardner syndrome, an autosomal dominant transmitted familial adenomatous polyposis syndrome.