Predictive Value of Computed Tomographic Ethmoid-to-Maxillary Ratio in Patients with Chronic Rhinosinusitis and Nasal Polyp

Different types of inflammation in the sinuses require different treatments. Ethmoid dominance was proposed as an indicator on computed tomography (CT) images for type 2 chronic rhinosinusitis with nasal polyp (CRSwNP). This study evaluated the predictive value of the ethmoid-to-maxillary (E/M) ratio based on different CT scoring systems in type 2 CRSwNP. Adult patients with bilateral CRSwNP planning to undergo sinus surgery were prospectively recruited. CT images were evaluated using the Lund-Mackay (L-M) and Zinreich scoring systems which involved a more meticulous quantification of opacification on CT images. Tissue eosinophil count (TEC) was determined by histopathological analysis. The expression levels of type 2 cytokines in nasal polyps, including IL-5, IL-13, and eosinophil cationic protein (ECP), were measured using real-time PCR. A total of 174 participants were enrolled. Eighty of these participants exhibited an E/M ratio >1, 49 presented with E/M ratio=1, and 45 showed an E/M ratio <1 based on L-M CT scores. Twenty of the 49 (40.8%) patients with E/M ratio=1 on L-M score turned to E/M ratio >1 after re-evaluation by Zinreich scoring system. The E/M ratio based on the L-M and Zinreich scoring systems both exhibited correlation with the tissue markers of type 2 inflammation, including TEC, interleukin (IL)-5, IL-13, and ECP expression levels, although the Zinreich E/M ratio showed a higher correlation coefficient. The E/M ratio based on the L-M and Zinreich scoring systems correlated with tissue markers of type 2 inflammation. A scale with an E/M ratio of 1 in the L-M system should be further investigated using a more detailed scoring system to determine the presence of an ethmoid-dominant shadow. This could help clinicians better evaluate CT images to determine the severity of type 2 inflammation in patients with CRSwNP and provide optimal therapeutic strategies.