Power Doppler and B-mode sonography of nasal mucosa

Abstract

Anatomy and perfusion of the nasal septum and inferior turbinate mucosa can be visualized with B-mode and power-Doppler ultrasound. The transducer is placed externally on the nasal ala parallel to the pyriform crest and directed towards the head of the inferior turbinate of the opposite side. An individually prepared dental splint keeps the transducer in position and allows assessment of dynamic changes in mucosal swelling and perfusion. Perfusion changes are evaluated by computerized quantification of power-Doppler color pixels. Coupling of ultrasound across the nasal lumen is achieved by introducing gel into one nasal vestibule and flooding the anterior nasal cavity of the side to be visualized with isotonic aqueous solutions. Perfusion could be visualized in 23 of 30 subjects, while B-mode sonographic anatomy was visualized in 16 subjects. The effect of isotonic saline solution (10 healthy subjects), naphazoline (10 patients with chronic nasal obstruction) and allergen extracts (10 patients with allergic rhinitis) on mucosal perfusion and swelling was studied. Isotonic saline solution induced a maximum drop in power-Doppler color pixel density by 10% and a maximum increase by 27%, but no change was seen in mucosal swelling. Naphazoline induced a 10-57% decrease in power-Doppler pixel density and decongestion of the inferior turbinate and septum mucosa by 17-43% and 4-27%, respectively. Allergen extracts induced an increase in power-Doppler color pixel density by 24-181% and an increase in mucosal thickness by 4-31%. These preliminary results encourage further studies of nasal mucosal perfusion changes using power-Doppler sonography after pharmacologic and allergen provocations.