Vascular Patterns in Healthy and Diseased Sinonasal Mucosa: A Prospective i-Scan Image-Enhanced Endoscopy Study

Background and Objectives: Image-enhanced endoscopy improves visualization of mucosal and microvascular architecture and is well established in several head and neck subsites, whereas its application in the sinonasal region remains insufficiently explored. This study aimed to characterize the i-scan appearance of healthy and pathological sinonasal mucosa, identify disease-associated vascular features, and propose a preliminary classification of sinonasal vascular patterns. Materials and Methods: This prospective case–control study included 85 adults with at least one sinonasal diagnosis and 30 controls with healthy sinonasal mucosa recruited in western Croatia. Endoscopy was performed using a Pentax flexible video endoscope with i-scan enhancement. Standardized images were obtained from predefined bilateral anatomical sites and pathological lesions. After application of predefined exclusion and image-quality criteria, all eligible images were independently evaluated by four experienced otorhinolaryngologists blinded to the corresponding clinical and histopathological diagnoses. Vascular characteristics were assessed within a prespecified pattern framework derived from previously published image-enhanced endoscopy classifications, and final assignments were established by consensus. Results: i-scan enhanced visualization of sinonasal mucosal microvasculature, enabling recognition of distinct vascular patterns in healthy mucosa and pathological lesions. Inflammatory changes were generally associated with reduced visibility of the fine vascular network, vascular congestion, and a pale mucosal background, whereas polypoid and neoplastic lesions demonstrated different degrees of translucency, vascular density, congestion, and anastomotic organization. Several of the observed patterns showed similarities to previously described sinonasal vascular classifications. Conclusions: i-scan image-enhanced endoscopy provides detailed visualization of sinonasal microvascular architecture and supports descriptive characterization of healthy and pathological mucosa. The proposed vascular patterns should be regarded as a preliminary classification framework rather than a validated diagnostic tool. Diagnostic accuracy, interobserver and intraobserver agreement, and clinical utility for lesion discrimination or biopsy targeting were not established in this study and require prospective external validation in larger and more diverse cohorts.