Background Photon-counting computed tomography (PCCT) is an emerging technique under evaluation for temporal bone imaging. Its capacity for radiation dose reduction while maintaining diagnostic image quality (IQ) requires further study. Purpose To evaluate how PCCT compares to energy-integrating CT (EICT) in temporal bone imaging in terms of IQ and visualization of anatomical landmarks, at a clinically relevant, reduced radiation dose. Material and Methods An anthropomorphic phantom with exchangeable fresh frozen human temporal bone specimens was scanned. Nine specimens were scanned on a PCCT system with clinical protocol settings, followed by stepwise dose reductions for one specimen. Ten specimens were scanned on a EICT system with clinical protocol settings. Three readers assessed overall IQ and visualization of 10 important anatomical landmarks on a 4-point scale. Results PCCT was preferred by readers for most landmarks and ranked higher in overall IQ compared with EICT. At clinical protocol, PCCT provided statistically significant better results for all landmarks and overall IQ compared to EICT with dose reduction of almost 70%. With stepwise dose reduction PCCT maintained good to excellent IQ for most landmarks, suboptimal for the ossicular chain landmarks at lower doses, and overall poor image quality at the lowest dose level. PCCT at clinical and several reduced dose levels demonstrated statistically significant difference in overall image quality and visualization of landmarks, compared to EICT ( P <0.05). Conclusion PCCT provides improved diagnostic image quality compared to EICT at clinical protocols, with lowered radiation dose, indicating its suitability for temporal bone imaging.
Pellby et al. (Fri,) studied this question.