From the Department of Diagnostic and Interventional Radiology, University Hospital Würzburg, Oberdürrbacher Strasse 6, 97080 Würzburg, Germany (H.H., A.S.K., T.S.P., S.P., P.G., J.F.H., T.A.B., J.P.G.); Department of Urology, Ludwig-Maximilians-University of Munich, Munich, Germany (T.W.); and Institute for Diagnostic and Interventional Radiology, Faculty of Medicine and University Hospital Cologne, Cologne, Germany (S.L.).
Radiology. 2024 Jul;312(1):e232453. doi: 10.1148/radiol.232453.
Background Contrast-unenhanced abdominal CT is the imaging standard for urinary calculi detection; however, studies comparing photon-counting detector (PCD) CT and energy-integrating detector (EID) CT dose-reduction potentials are lacking. Purpose To compare the radiation dose and image quality of optimized EID CT with those of an experimental PCD CT scan protocol including tin prefiltration in patients suspected of having urinary calculi. Materials and Methods This retrospective single-center study included patients who underwent unenhanced abdominal PCD CT or EID CT for suspected urinary caliculi between February 2022 and March 2023. Signal and noise measurements were performed at three anatomic levels (kidney, psoas, and obturator muscle). Nephrolithiasis and/or urolithiasis presence was independently assessed by three radiologists, and diagnostic confidence was recorded on a five-point scale (1, little to no confidence; 5, complete confidence). Reader agreement was determined by calculating Krippendorff α. Results A total of 507 patients (mean age, 51.7 years ± 17.4 [SD]; 317 male patients) were included (PCD CT group, 229 patients; EID CT group, 278 patients). Readers 1, 2, and 3 detected nephrolithiasis in 129, 127, and 129 patients and 94, 94, and 94 patients, whereas the readers detected urolithiasis in 113, 114, and 114 patients and 152, 153, and 152 patients in the PCD CT and EID CT groups, respectively. Regardless of protocol (PCD CT or EID CT) or calculus localization, near perfect interreader agreement was found (α ≥ 0.99; 95% CI: 0.99, 1). There was no evidence of a difference in reader confidence between PCD CT and EID CT (median confidence, 5; IQR, 5-5; ≥ .57). The effective doses were 0.79 mSv (IQR, 0.63-0.99 mSv) and 1.39 mSv (IQR, 1.01-1.87 mSv) for PCD CT and EID CT, respectively. Despite the lower radiation exposure, the signal-to-noise ratios at the kidney, psoas, and obturator levels were 30%, 23%, and 17% higher, respectively, in the PCD CT group ( < .001). Conclusion Submillisievert abdominal PCD CT provided high-quality images for the diagnosis of urinary calculi; radiation exposure was reduced by 44% with a higher signal-to-noise ratio than with EID CT and with no evidence of a difference in reader confidence. Published under a CC BY 4.0 license. See also the editorial by Nezami and Malayeri in this issue.
背景 对比增强腹部 CT 是检测尿路结石的影像学标准；然而，缺乏比较光子计数探测器（PCD）CT 和能量积分探测器（EID）CT 剂量减少潜力的研究。目的 比较优化 EID CT 和实验性 PCD CT 扫描方案的辐射剂量和图像质量，该方案包括对疑似尿路结石患者进行锡预过滤。材料与方法 本回顾性单中心研究纳入了 2022 年 2 月至 2023 年 3 月期间因疑似尿路结石而行增强腹部 PCD CT 或 EID CT 的患者。在三个解剖水平（肾脏、腰大肌和闭孔肌）进行信号和噪声测量。三位放射科医生独立评估肾结石和/或输尿管结石的存在，并在五分制上记录诊断信心（1，几乎没有信心；5，完全有信心）。读者间一致性通过计算 Krippendorff α 来确定。结果 共纳入 507 例患者（平均年龄，51.7 岁±17.4[标准差]；317 例男性患者）（PCD CT 组 229 例，EID CT 组 278 例）。读者 1、2 和 3 在 PCD CT 和 EID CT 组中分别检测到 129、127 和 129 例患者的肾结石和 94、94 和 94 例患者的肾结石，而 113、114 和 114 例患者的输尿管结石和 152、153 和 152 例患者的输尿管结石。无论使用哪种方案（PCD CT 或 EID CT）或结石定位，都发现了近乎完美的读者间一致性（α≥0.99；95%置信区间：0.99，1）。在 PCD CT 和 EID CT 之间，没有证据表明读者信心存在差异（中位数信心，5；IQR，5-5；≥0.57）。PCD CT 和 EID CT 的有效剂量分别为 0.79 mSv（IQR，0.63-0.99 mSv）和 1.39 mSv（IQR，1.01-1.87 mSv）。尽管辐射暴露较低，但 PCD CT 组的肾脏、腰大肌和闭孔肌水平的信噪比分别提高了 30%、23%和 17%（<0.001）。结论 亚毫西弗腹部 PCD CT 为尿路结石的诊断提供了高质量的图像；与 EID CT 相比，辐射暴露降低了 44%，信噪比更高，且没有证据表明读者信心存在差异。在 CC BY 4.0 许可下发布。请参阅本期内 Nezami 和 Malayeri 的社论。
