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

To compare image-quality and radiation dose between photon-counting CT (PCD CT) and cone-beam CT (CBCT) for postoperative cochlear implantation (CI) imaging.

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.

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.

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.