Computed Tomography Score an Excellent Marker: Differentiates Eosinophilic and Non-eosinophilic Variants of Chronic Rhinosinusitis with Nasal Polyp

Eosinophilic and non-eosinophilic subtypes of chronic rhinosinusitis with nasal polyp (CRSwNP) have different clinical profile and management. Currently the 2 subtypes are differentiated based on tissue eosinophilic infiltration, which is identified after surgery by histopathological examination. Hence this study was conducted to compare utility of computed tomography (CT) scans, serum IgE levels, absolute eosinophil count (AEC) and Sino-nasal Outcome Test (SNOT)-20 score for discriminating the 2 subtypes. In this prospective study of 1 year duration, patients suspected of CRSwNP were recruited. Serum IgE levels and AEC estimation were performed by ELISA and standard numerical formula respectively, along with histopathological examination of nasal polyp biopsies. CT score and ratio of CT score for ethmoid sinus and maxillary sinus (E/M ratio) were calculated. Patients were asked to fill SNOT-20 questionnaire. Receiver-operating characteristic (ROC) curve analysis was performed. Out of 52 patients studied, 38 and 14 were no. of eosinophilic and non-eosinophilic CRSwNP cases respectively on the basis of histopathological examination. E/M ratio and overall CT score were found to be highly accurate with area under ROC curve of 0.990 and 0.964 respectively, while rest 3 parameters had low accuracy. Optimal cut-off of CT score and E/M ratio for eosinophilic CRSwNP were 6 and 2.065 respectively. This study demonstrated E/M ratio and total CT score as the most useful surrogate markers for preoperative differentiation of eosinophilic and non-eosinophilic CRSwNP, and hence can be used to predetermine postoperative management before surgery.