Diagnosing Eosinophilic Chronic Rhinosinusitis in Excised Tissue Using Optical Coherence Tomography

ABSTRACT Objectives There is currently no method of diagnosing eosinophilic chronic rhinosinusitis with nasal polyps (ECRSwNP) without histologic evidence of tissue eosinophilia. We aimed to quantify eosinophils in fresh sinonasal tissue using optical coherence tomography (OCT), a non‐contact imaging modality, and compare these counts with eosinophils per high‐power field (HPF) on histology. Methods Sinonasal tissue was collected from patients undergoing endoscopic sinus surgery for CRS. Half of each sample was sent for histologic processing, and eosinophils per HPF were quantified and averaged over three hematoxylin‐and‐eosin slides per sample. The other half of each tissue sample was imaged with high‐resolution OCT directly without histologic processing, and globules with the appearance of eosinophils were counted and averaged over three images per sample. Mean globule counts in OCT images and eosinophils per HPF on histology were correlated. Results Sinonasal tissue was collected from 14 patients including six with ECRSwNP (42.9%). Mean globules resembling eosinophils in tissue from patients with ECRSwNP were significantly greater than in other patients (101.9 ± 39.9 vs. 24.3 ± 17.1, p < 0.001). There was a statistically significant correlation between globule counts on OCT and eosinophils per HPF on histology across all samples ( ρ = 0.90, p < 0.001). A cutoff of 45 globules on OCT was 100% sensitive and 87.5% specific for diagnosing ECRSwNP using a cutoff of 55 eosinophils per HPF on histology. Conclusion OCT may be used to diagnose ECRSwNP in excised sinonasal tissue. These results may serve as a proof‐of‐concept for developing an intranasal OCT system to diagnose ECRSwNP non‐invasively. Level of Evidence 4