Low-dose ultra-high-resolution temporal bone imaging using Sn100 kVp photon-counting CT: A comparative study with...

To evaluate the clinical impact of low-dose ultra-high-resolution temporal bone imaging using photon-counting detector CT (PCD-CT) with 100 kVp tin filtration (Sn100 kVp), focusing on radiation dose reduction and image quality compared with conventional energy-integrating detector CT (EID-CT).

Patients with suspected or confirmed temporal bone lesions were prospectively enrolled and underwent PCD-CT scanning. Their prior EID-CT scans were retrospectively retrieved for comparison. PCD-CT was performed at Sn100 kVp, and images were reconstructed at 0.2 mm (PCD-0.2) and 0.6 mm (PCD-0.6) slice thicknesses. The EID-CT scans were acquired at 120 kVp with 0.6 mm reconstruction (EID-0.6). Quantitative parameters including CT attenuation, image noise, signal-to-noise ratio (SNR), and contrast-to-noise ratio (CNR) were measured. In addition, qualitative assessment of six normal anatomical structures, preference ranking and radiation dose metrics were performed for comparison.

A total of 46 patients (24 females; mean age, 40.37 ± 15.89 years) contributed 55 temporal bone CT image datasets. Compared with EID-CT, PCD-CT achieved a 53 % reduction in radiation dose (effective dose: 0.35 ± 0.05 vs. 0.75 ± 0.12 mSv; p < 0.001). PCD-0.6 demonstrated significantly lower image noise (55.51 ± 7.66 vs. 79.70 ± 13.04 HU; p < 0.001) and higher CNR of vestibule, muscle and bone than in EID-0.6 (all p < 0.001). PCD‑0.2 was preferred over PCD‑0.6, and both PCD reconstructions were preferred over EID‑0.6 for visualization of six anatomical structures and overall image quality (all p < 0.05).

In this comparison of real-world clinical protocols with multiple varying parameters, the low-dose Sn100 kVp PCD-CT protocol reduced dose by 53 % and improved image quality versus EID-CT. Ultra-thin 0.2 mm reconstruction, despite higher noise, leveraged PCD-CT's high spatial resolution to better depict fine temporal bone details.