Topical contrast agents to improve soft-tissue contrast in the upper airway using cone beam CT: a pilot study

Abstract

The purpose of this study is to explore the topical use of radiographic contrast agents to enhance soft-tissue contrast on cone beam CT (CBCT) images. Different barium sulphate concentrations were first tested using an airway phantom. Different methods of barium sulphate application (nasal drops, syringe, spray and sinus wash) were then tested on four volunteers, and nebulized iodine was tested in one volunteer. CBCT images were performed and then assessed subjectively by two examiners for contrast agent uniformity and lack of streak artefact. 25.0% barium sulphate presented adequate viscosity and radiodensity. Barium sulphate administered via nasal drops and sprays showed non-uniform collection at the nostrils, along the inferior and/or middle nasal meatuses and posterior nasal choana. The syringe and sinus wash showed similar results with larger volumes collecting in the naso-oropharynx. Nebulized iodine failed to distribute into the nasal cavity and scarcely collected at the nostrils. All methods of nasal application failed to adequately reach or uniformly coat the nasal cavity beyond the inferior nasal meatuses. The key factors to consider for optimum topical radiographic contrast in the nasal airway are particle size, flow velocity and radio-opacity.

Volumetric upper airway changes after rapid maxillary expansion: a systematic review and meta-analysis

“…There is much debate over the validity of CT and CBCT volumetric analysis in the measurement of function airway spaces. Topical contrast agents have been suggested to improve accuracy in defining soft tissue surfaces (73), an alternative that was not used in any of the included studies. Only a few studies that use CBCT for airway volume calculation describe using any form of standardization of patient positioning and protocol during image capture.…”

Optimized imaging of the midface and orbits

“…The use of contrast agents in DVT examinations to improve soft tissue contrast is still experimental [ 27 ]. Alsufyani et al showed that the mucosal surface of the paranasal sinuses is best opacified by using 25% barium sulfate, while iodine-containing contrast agents are not suitable [ 28 ]. However, even with this approach, the authors failed to reliably opacify soft tissues cranial to the middle turbinate [ 28 ].…”

Optimierte Bildgebung des Mittelgesichtes und der Orbita

“…Abb 28. MRT einer 66-jährigen Patientin mit einem Karzinom der Nase und Übergreifen des Tumors auf den Nasenrachen.…”