Tissue eosinophilia in chronic sinusitis - Quantification techniques

Objective: To ascertain the reliability of a proposed method for quantifyin g tissue eosinophilia in sinus mucosa. Design: Prospective cohort study. Interventions and Outcome Measures: Pathology slides from patients undergoi ng endoscopic sinus surgery for chronic rhinosinusitis were independently a ssessed by 2 reviewers. Using a proposed systematic counting method, the de gree of tissue eosinophilia was quantified. Disease severity was assessed b y computed tomographic (CT) staging. Intrarater, interrater, and intrapatie nt reliability was determined using correlational reliability analysis. The degree of correlation between tissue eosinophilia and CT stage was determi ned. Results: One hundred thirty-two slides from 65 patients were reviewed. The mean (SD) eosinophil density was 23.4 (37.2) eosinophils per high-power fie ld. Only 12 patients (18%) had no eosinophils on histopathologic analysis. Strong intrarater (r greater than or equal to0.91 for each rater, P<.001) a nd interrater reliability (r<greater than or equal to>0.82 between raters, P<.001) was noted for the quantification method. A moderate degree of corre lation was found between CT scan stage and degree of tissue eosinophilia (S pearman <rho>=0.62, P<.001). Conclusions: The proposed method for quantifying tissue eosinophilia in sin us mucosa is reliable and valid. A relatively strong correlation exists bet ween CT scan stage and tissue eosinophilia in chronic rhinosinusitis.