50%碘剂量降低至 40keV 重建的单源双能量全身体 CT 血管造影的优缺点。
Advantages and disadvantages of single-source dual-energy whole-body CT angiography with 50% reduced iodine dose at 40 keV reconstruction.
机构信息
Department of Radiology, Gifu University, Gifu, Japan.
Department of Radiology, Frontier Science for Imaging, Gifu University, Gifu, Japan.
出版信息
Br J Radiol. 2021 May 1;94(1121):20201276. doi: 10.1259/bjr.20201276. Epub 2021 Feb 22.
OBJECTIVES
To assess the feasibility of whole-body dual-energy computed tomographic angiography (DECTA) at 40 keV with 50% reduced iodine dose protocol.
METHODS
Whole-body CTA was performed in 65 patients; 31 of these patients underwent 120 kVp single-energy computed tomographic angiography (SECTA) with standard iodine dose (600 mgI/kg) and 34 with 40 keV DECTA with 50% reduced iodine dose (300 mgI/kg). SECTA data were reconstructed with adaptive statistical iterative reconstruction of 40% (SECTA group), and DECTA data were reconstructed with adaptive statistical iterative reconstruction of 40% (DECTA-40% group) and 80% (DECTA-80% group). CT numbers of the thoracic and abdominal aorta, iliac artery, background noise, signal-to-noise ratio (SNR), and arterial depiction were compared among the three groups. The CT dose index volumes (CTDI) for the thorax, abdomen, and pelvis were compared between SECTA and DECTA protocols.
RESULTS
The vascular CT numbers and background noise were found to be significantly higher in DECTA groups than in the SECTA group ( < 0.001). SNR was significantly higher in the order corresponding to DECTA-80%, SECTA, and DECTA-40% ( < 0.001). The arterial depiction was comparable in almost all arteries; however, intrapelvic arterial depiction was significantly worse in DECTA groups than in the SECTA group ( < 0.0001-0.017). Unlike the pelvic region ( = 0.055), CTDI for the thorax ( < 0.0001) and abdomen ( = 0.0031) were significantly higher in the DECTA protocol than in the SECTA protocol.
CONCLUSION
DECTA at 40 keV with 50% reduced iodine dose provided higher vascular CT numbers and SNR than SECTA, and almost comparable arterial depiction, but had a degraded intrapelvic arterial depiction and required a larger radiation dose.
ADVANCES IN KNOWLEDGE
DECTA enables 50% reduction of iodine dose while maintaining image quality, arterial depiction in almost all arteries, vascular CT numbers, and SNR; however, it does not allow clear visualization of intrapelvic arteries, requiring a slightly larger radiation dose compared with SECTA with standard iodine dose.
目的
评估 40keV 双能 CT 血管造影（DECTA）以 50%降低碘剂量方案的可行性。
方法
对 65 例患者进行全身 CTA 检查；其中 31 例患者接受 120kVp 单能 CT 血管造影（SECTA），标准碘剂量（600mgI/kg），34 例患者接受 40keV DECTA，碘剂量降低 50%（300mgI/kg）。SECTA 数据采用 40%的自适应统计迭代重建（SECTA 组）重建，DECTA 数据采用 40%（DECTA-40%组）和 80%（DECTA-80%组）的自适应统计迭代重建重建。比较三组患者的胸主动脉、腹主动脉、髂动脉、背景噪声、信噪比（SNR）和动脉显影情况。比较 SECTA 和 DECTA 方案中胸、腹、盆腔 CT 剂量指数容积（CTDI）。
结果
DECTA 组的血管 CT 值和背景噪声明显高于 SECTA 组（<0.001）。SNR 依次为 DECTA-80%、SECTA 和 DECTA-40%，均明显升高（<0.001）。几乎所有动脉的动脉显影都相当，但盆腔内动脉显影 DECTA 组明显差于 SECTA 组（<0.0001-0.017）。与盆腔区域（=0.055）不同，DECTA 方案的胸（<0.0001）和腹（=0.0031）CTDI 明显高于 SECTA 方案。
结论
40keV 时，50%降低碘剂量的 DECTA 可提供比 SECTA 更高的血管 CT 值和 SNR，以及几乎相当的动脉显影，但盆腔内动脉显影较差，辐射剂量较大。
知识进步
DECTA 可在保持图像质量、几乎所有动脉的动脉显影、血管 CT 值和 SNR 的同时，降低 50%的碘剂量；然而，与标准碘剂量的 SECTA 相比，它不能清晰地显示盆腔内的动脉，需要略大的辐射剂量。
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