Radiographic Distribution of Drops and Sprays within the Sinonasal Cavities

Background Topical nasal sprays are commonly prescribed for sinonasal disease. Nasal drops applied in a head-down position are described alternatively to sprays. Multiple research methods have investigated the deposition pattern of intranasal medications, each with limitations. This pilot study analyzed the use of a conebeam computed tomography (CBCT) scanner to study deposition patterns of intranasal sprays and drops using radiopaque contrast solution. Methods Nine volunteers participated in this two-trial study. In trial 1, participants instilled 3 sprays of contrast into each nostril. After 3 minutes a CBCT scan was performed. In trial 2, 3 drops of contrast were instilled into the participants’ nostrils in the “vertex-to-floor” position. Again, after 3 minutes a CBCT scan was performed. Two otolaryngologists and a neuroradiologist reviewed the images and scored 21 sites within the sinonasal cavity for the presence of contrast. Results Contrast was detected in the nasal vestibule and inferior nasal vault in nearly every trial with the spray and drops. Nasal spray was more diffusely distributed within the nasal cavity and was detected at a greater proportion on the floor of the nose, inferior meatus, anterior inferior nasal cavity, and nasopharynx. Neither spray nor drops were consistently detected in spaces superior to the middle turbinate. Conclusion Radiopaque contrast delivered by nasal spray and drops were detected by the CBCT scanner, with a significant difference at one subsite. Neither spray nor drops were detected in superior nasal spaces. The CBCT scan provides an alternative to conventional CT scans in future studies using this technique.