Photon-counting detector CT versus cone-beam CT for postoperative cochlear implant imaging.

PURPOSE: To compare image-quality and radiation dose between photon-counting CT (PCD CT) and cone-beam CT (CBCT) for postoperative cochlear implantation (CI) imaging. METHODS AND MATERIALS: This retrospective study included 224 postoperative CI datasets from July 2019 to February 2026, including 112 PCD CT scans using three dosage protocols (regular dose [RD], low dose [LD], ultra-low dose [ULD]) and 112 120-kV CBCT scans. Two radiologists independently assessed image-quality using 5-point Likert scales. Objective image-quality was assessed using contrast-to-noise ratio (CNR). Groups were compared using Mann-Whitney U and Kruskal-Wallis tests. Predictors of image-quality were analyzed with linear mixed-effects models. RESULTS: Among 224 datasets from 196 patients (mean age, 58.8 ± 16.5 years; 118 women), PCD CT showed higher subjective overall image-quality than CBCT (median: 4.5 vs. 2.5; p < 0.001; r = 0.82) and higher ratings across all other imaging parameters (p < 0.001; r ≤ 0.66-0.84). Image-quality differed between PCD CT protocols (H = 13.05; p = 0.0015; η2_H = 0.10), with higher ratings for RD, while LD and ULD did not differ. CNR was higher across all PCD CT protocols than for CBCT (p < 0.001). Estimated effective dose was 0.3 mSv for RD, 0.24 mSv for LD and 0.16 mSv for ULD, and 0.15 mSv for CBCT. ULD showed improved image-quality with an estimated effective dose close to that of CBCT. CONCLUSION: PCD CT was associated with higher image-quality and fewer artifacts than CBCT. ULD PC DCT retained higher image-quality ratings at a numerically similar dose, and may be advantageous for more precise postoperative evaluation, personalized device adjustments, and follow-up for radiosensitive or immobile patients.