Zhang Mengyuan, Nie Kehui, Yuan Dian, Zhang Yicun, Qi Ke, Zhang Weiting, Gu Yanbo, Chen Yan, Gao Jianbo, Liu Jie
Department of Radiology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou 450052, China (M.Z., D.Y., Y.Z., K.Q., W.Z., Y.G., Y.C., J.G., J.L.).
Siemens Healthineers Digital Technology (Shanghai) Co., Ltd, Shanghai, China (K.N.).
Acad Radiol. 2025 Jul 28. doi: 10.1016/j.acra.2025.07.020.
This study evaluated the image quality of photon-counting detector computed tomography (PCD-CT) for head and neck vascular imaging using the "Quadruple Low" strategy (ultra-low contrast dose, low contrast concentration, low injection rate, and low radiation dose). The results were compared with those from conventional energy-integrating detector computed tomography (EID-CT) performed using routine scanning parameters.
This retrospective cohort study included 50 patients with cerebrovascular disease who underwent EID-CT with a standard contrast protocol (contrast dose: body weight × 0.6 mL/kg), serving as the control group (CG). Two prospective cohorts, each comprising 50 patients, underwent PCD-CT with an optimized contrast protocol (contrast dose: body weight × 0.4 mL/kg; injection rate: contrast dose/[delay time + scan duration]), forming the experimental groups (EG1 and EG2). In EG2, the radiation dose was further reduced relative to that in EG1. Objective image quality was assessed by measuring vascular attenuation, image noise, signal-to-noise ratio (SNR), and contrast-to-noise ratio (CNR). Subjective image quality was evaluated using a 5-point Likert scale.
This study included 150 patients (86 men; mean age, 56.03 ± 11.10 years; mean body mass index[BMI], 24.28 ± 3.03 kg/m²). Compared with the CG, the optimized contrast protocol in EG1 and EG2 reduced the median contrast volume by >30%, decreased the contrast concentration by 9%, and lowered the injection flow rate by 10% (all p < 0.001). The effective radiation dose in EG2 was reduced by 28% (p < 0.001) while maintaining image quality comparable to that of other groups (p > 0.05). EG2 exhibited a greater potential for radiation dose reduction. EG1 and EG2 exhibited significant improvements in vascular attenuation, reduced image noise, and enhanced SNR and CNR. Subjective image quality was consistently rated as high across all groups, with a median Likert score of 4 (IQR: 4-5), and excellent interobserver agreement (κ = 0.814-0.934), indicating consistently high diagnostic confidence.
PCD-CT using the "Quadruple Low" strategy enables neurovascular imaging with substantially reduced contrast media and radiation exposure, while maintaining image quality comparable to conventional EID-CT. This protocol may serve as a safer alternative in routine cerebrovascular evaluation.
本研究采用“四低”策略（超低对比剂剂量、低对比剂浓度、低注射速率和低辐射剂量）评估了光子计数探测器计算机断层扫描（PCD-CT）对头颈部血管成像的图像质量。将结果与使用常规扫描参数进行的传统能量积分探测器计算机断层扫描（EID-CT）的结果进行比较。
这项回顾性队列研究纳入了50例脑血管疾病患者，他们接受了采用标准对比剂方案（对比剂剂量：体重×0.6 mL/kg）的EID-CT检查，作为对照组（CG）。两个前瞻性队列，每个队列包括50例患者，接受了采用优化对比剂方案（对比剂剂量：体重×0.4 mL/kg；注射速率：对比剂剂量/[延迟时间+扫描持续时间]）的PCD-CT检查，形成实验组（EG1和EG2）。在EG2中，相对于EG1进一步降低了辐射剂量。通过测量血管衰减、图像噪声、信噪比（SNR）和对比噪声比（CNR）来评估客观图像质量。使用5点李克特量表评估主观图像质量。
本研究共纳入150例患者（86例男性；平均年龄56.03±11.10岁；平均体重指数[BMI]24.28±3.03kg/m²）。与CG相比，EG1和EG2中的优化对比剂方案使对比剂体积中位数减少了>30%，对比剂浓度降低了9%，注射流速降低了10%（均p<0.001）。EG2中的有效辐射剂量降低了28%（p<0.001），同时保持了与其他组相当的图像质量（p>0.05）。EG2在降低辐射剂量方面具有更大的潜力。EG1和EG2在血管衰减、图像噪声降低以及SNR和CNR提高方面均有显著改善。所有组的主观图像质量均持续被评为高分，李克特评分中位数为4（四分位距：4-5），观察者间一致性良好（κ=0.814-0.934），表明诊断信心始终很高。
采用“四低”策略的PCD-CT能够在大幅减少对比剂和辐射暴露的情况下进行神经血管成像，同时保持与传统EID-CT相当的图像质量。该方案可作为常规脑血管评估中更安全的替代方案。
