BACKGROUND AND PURPOSE: The round window niche veil (RWNV) is a potential anatomic barrier at the round window niche due to thickened middle ear mucosa or fibrosis that either partially or completely covers the niche and may prevent intratympanic medication efficacy. This study aimed to characterize the in vivo capability of photon-counting-detector (PCD) CT to visualize the RWNV. MATERIALS AND METHODS: 80 PCD-CT temporal bones were included in the study between April and June 2025. Two experienced neuroradiologists independently reviewed each scan and assigned each with one of the following scores: 1: partial veil seen with or without fluid, 2: complete veil seen with or without fluid, 3: no round window niche veil, and 4: not seen, complete round window niche opacification. RESULTS: PCD-CT visualized either partial or complete RWNV in 43.8% of ears. Further, the RWNV was not visualized in 48.8% of ears when the round window was clear. In 7.5% of ears, complete opacification of the round window niche was noted without visualization of a RWNV. The presence or absence of RWNV visualization demonstrated high inter-rater reliability with unweighted kappa of 0.81 (0.69, 0.92). CONCLUSIONS: PCD-CT may visualize the round window niche veil in vivo and may be helpful in determining if the round window niche is patent.
Neuberger et al. (2026) studied this question.