Evaluation of the Dynamic Patency of the Frontonasal Duct: Value of PNS CT Scan after Administration of anlsoosmolar Contrast Agent for Low lrritation into the Nasal Cavity

Chung, Jae Joon; Chung, Tae Sub; Jang, Tae Young; Yoon, Sang Wook; Kim, Kyung Soo

Abstract

PURPOSE
To evaluate the dynamic patency of the frontonasal duct(FND) on PNS CT scan after administration ofan iso-osmolar contrast agent (lsovist) into the nasal cavity.
MATERIALS AND METHODS
Coronal PNS CT scans from ten normal and 30 patients with symptoms of chronic sinusitis were obtained after administration of lsovist intothe nasal cavity, followed by Valsalva maneuver for the even distribution of the agent into the FND and sinuses. Atotal of 80 FNDs were evaluated for dynamic patency by examining the presence of the contrast agent in ducts.
RESULTS
The contrast agent was visualized in 34/37 FNDs(91.9%) without ipsilateral frontal sinus it is and was visualized in 18/43 FNDs(41.9%) in cases of ipsilateral frontal sinusitis. In addition, the contrast agent within the ipsilateral frontal sinus was visualized in 8/18 FNDs(44.4%). The major causes of ductal obstruction were mucoperiosteal thickening and polypoid lesions secondary to inflammation.
CONCLUSION
PNS CT scan together with the administration of lsovist, which caused minimal irritation, was useful for the evaluation of the relationship between the dynamic patency of the FND and frontal sinusitis, In addition, this study can provide the rhinologist with accurate anatomical and pathological information concerning the FND before a choice is made between endoscopic sinus surgery or medical treatment.