高浓度对比剂结合低剂量扫描方案降低头颅CTA辐射剂量
前瞻性研究纳入150例行头颅CTA患者，随机分三组，均接受总碘量21.6g、80kV扫描。A组用碘美普尔400、IDR 2.0g/s、90mAs；B组用碘普罗胺370、IDR 1.48g/s、164mAs；C组用碘普罗胺370、IDR 2.0g/s、90mAs。结果显示A、C组颅内血管SNR和CNR与B组无显著差异，但辐射剂量较B组分别降低46.53%和45.62%，A组注射流率更低。
要点
- 高碘浓度对比剂（碘美普尔400）可在较低注射流率下达到目标IDR，降低辐射剂量约46%。
- 在80kV管电压下，采用高IDR（2.0g/s）联合低mAs（90mAs）方案不降低颅内血管SNR和CNR。
- 低剂量方案下图像噪声增高，但CT衰减值也增高，需注意窗宽窗位调整。
关键影像表现/征象
- A组和C组颅内血管CT衰减值及图像噪声均高于B组，但三组间SNR和CNR无统计学显著差异。
- A组和C组辐射剂量较B组分别降低46.53%和45.62%。
- A组注射流率低于C组，仍能达到目标IDR 2.0g/s。
诊断标准与关键数值
- A组方案：碘美普尔400，IDR 2.0g/s，管电流时间乘积90mAs，管电压80kV，总碘量21.6g。
- B组方案：碘普罗胺370，IDR 1.48g/s，管电流时间乘积164mAs，管电压80kV，总碘量21.6g。
- C组方案：碘普罗胺370，IDR 2.0g/s，管电流时间乘积90mAs，管电压80kV，总碘量21.6g。
临床应用与阅片要点
- 在头颅CTA中可优先考虑高浓度碘对比剂（如碘美普尔400）联合低mAs（90mAs）和80kV方案，以降低辐射剂量。
- 使用低剂量方案时图像噪声增高，阅片时需适当调整窗宽窗位，注意评估小血管显示是否受影响。
- 高IDR（2.0g/s）可通过较低注射流率实现，有助于减少注射相关风险。
局限性
- 研究为单中心前瞻性设计，样本量150例，结论外推需谨慎。
- 未报告诊断准确性（敏感度、特异度、AUC）等临床效能指标。
- 仅评估了客观图像质量指标，未纳入主观图像质量评分。
以上解读依据论文摘要（全文未开放获取或许可不允许翻译转载）。
英文原文（摘要）· 点击展开
OBJECTIVES: To investigate whether high-concentration iodine contrast medium (HICM) combined with low-dose radiation scanning protocols can further reduce the radiation dose of cerebral computed tomography angiography (CTA) scans without compromising image quality.
MATERIALS AND METHODS: The prospective study included 150 eligible patients who underwent cranial CTA examinations. The patients were randomly divided into three groups (A, B, and C). All patients received a total iodine dose of 21.6 g and underwent scanning at tube voltage of 80 kV. Each group included 50 patients. Different protocols were applied as below. Group A: Iomeprol 400, iodine delivery rate (IDR) 2.0 g/s, tube current-time product (TCTP) 90 mAs; Group B: Iopromide 370, IDR 1.48 g/s, TCTP 164 mAs; Group C: Iopromide 370, IDR 2.0 g/s, TCTP 90 mAs. Radiation doses (Computer Tomography Dose Index Volume, Dose-Length Product, Effective Dose) were recorded, and CT attenuation values, image noise, Signal-to-Noise Ratio (SNR), and Contrast-to-Noise Ratio (CNR) were measured.
RESULTS: There were no statistically significant differences in the SNR and CNR of intracranial vessels among groups A, B, and C. Group A and C showed higher CT attenuation values and image noise, but lower radiation dose (reduced by 46.53% and 45.62% compared with Group B). The injection flow rate was lower in Group A.
CONCLUSION: A higher IDR is effective in reducing radiation dose. Moreover, higher iodine concentration (iomeprol 400) enables a lower injection flow rate to achieve a target IDR. A 46% reduction in radiation dose can be achieved using iomeprol 400 combined with a low-dose protocol, without compromising image quality, at an optimized injection flow rate.
引用
- Zheng W, Wu S, Zhang B, et al. Achieving lower radiation dose of cerebral computed tomography angiography: The role of high-concentration contrast medium. Eur J Radiol. 2026. PMID: 42150388. doi:10.1016/j.ejrad.2026.112933
供执业医师工作参考，不替代临床判断；数值与分级以指南原文为准。