Relationship between low tube voltage (70 kV) and the iodine delivery rate (IDR) in CT angiography: An experimental in-vivo study.
Relationship between low tube voltage (70 kV) and the iodine delivery rate (IDR) in CT angiography: An experimental in-vivo study.
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DOI：
10.1371/journal.pone.0173592
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发表时间：
2017
期刊：
影响因子：
3.7
通讯作者：
Jost G
中科院分区：
文献类型：
--
作者：
Lell MM;Fleischmann U;Pietsch H;Korporaal JG;Haberland U;Mahnken AH;Flohr TG;Uder M;Jost G
CTA中非常短的采集时间和低kV协议的使用要求对造影剂（CM）注射方案进行修改。本研究旨在优化猪模型胸腹CTA中CM输送参数的使用。采用动态CTA方案（454 mm扫描长度，2.5 s时间分辨率，70 s总采集时间）检查6头猪（55-68 kg）。以随机顺序应用四种CM注射方案。120 kV CTA方案：（A）300 mg碘/kg体重（bw），IDR = 1.5 g/s（流速= 5 mL/s），注射时间（ti）12 s（60 kg bw）。70 kV CTA协议：150 mg碘/kg体重：（B）IDR = 0.75 g/s（流量= 2.5 mL/s），ti = 12 s（60 kg体重）;（C）IDR = 1.5 g/s（流量= 5 mL/s），ti = 12 s（60 kg体重）;（D）IDR = 3.0 g/s（流量= 10 mL/s），ti = 3 s（60 kg体重）。通过在不同血管区域中创建时间衰减曲线（TAC）来监测完整的CM团形状。根据TAC，确定达峰时间（TTP）和峰值增强。计算诊断窗口（相对增强> 300 HU），并与相应CTA数据集的目视检查进行比较。基线校正后的平均相对动脉峰值增强为358.6 HU（A）、356.6 HU（B）、464.0 HU（C）和477.6 HU（D）。TTP随IDR增加和ti降低而降低，方案A和B无显著差异（体动脉，p = 0.843;肺动脉，p = 0.183）。对于方案A和B（3.9，4.3 s）以及C和D（2.4，2.0 s），单相CTA的团注跟踪延迟时间（触发水平100 HU;目标增强300 HU）相当。通过目视检查不同CTA数据集和分析TAC，不同方案的扫描窗口时间范围具有可比性。所有方案均提供了充分的动脉增强。建议使用70 kV CTA方案，因为在维持团注曲线的同时，总CM体积减少50%，流速减少50%。与肺动脉增强相反，由于非常短的团注（3s）在肺中的团注分散，全身动脉增强仅略微改善，IDR从1.5 g/s增加到3 g/s。
Very short acquisition times and the use of low-kV protocols in CTA demand modifications in the contrast media (CM) injection regimen. The aim of this study was to optimize the use of CM delivery parameters in thoraco-abdominal CTA in a porcine model. Six pigs (55–68 kg) were examined with a dynamic CTA protocol (454 mm scan length, 2.5 s temporal resolution, 70 s total acquisition time). Four CM injection protocols were applied in a randomized order. 120 kV CTA protocol: (A) 300 mg iodine/kg bodyweight (bw), IDR = 1.5 g/s (flow = 5 mL/s), injection time (ti) 12 s (60 kg bw). 70 kV CTA protocols: 150 mg iodine/kg bw: (B) IDR = 0.75 g/s (flow = 2.5 mL/s), ti = 12 s (60 kg bw); (C) IDR = 1.5 g/s (flow = 5 mL/s), ti = 12 s (60 kg bw); (D) IDR = 3.0 g/s (flow = 10 mL/s), ti = 3 s (60 kg bw). The complete CM bolus shape was monitored by creating time attenuation curves (TAC) in different vascular territories. Based on the TAC, the time to peak (TTP) and the peak enhancement were determined. The diagnostic window (relative enhancement > 300 HU), was calculated and compared to visual inspection of the corresponding CTA data sets. The average relative arterial peak enhancements after baseline correction were 358.6 HU (A), 356.6 HU (B), 464.0 HU (C), and 477.6 HU (D). The TTP decreased with increasing IDR and decreasing ti, protocols A and B did not differ significantly (systemic arteries, p = 0.843; pulmonary arteries, p = 0.183). The delay time for bolus tracking (trigger level 100 HU; target enhancement 300 HU) for single-phase CTA was comparable for protocol A and B (3.9, 4.3 s) and C and D (2.4, 2.0 s). The scan window time frame was comparable for the different protocols by visual inspection of the different CTA data sets and by analyzing the TAC. All protocols provided sufficient arterial enhancement. The use of a 70 kV CTA protocol is recommended because of a 50% reduction of total CM volume and a 50% reduced flow rate while maintaining the bolus profile. In contrast to pulmonary arterial enhancement, the systemic arterial enhancement improved only slightly increasing the IDR from 1.5 g/s to 3 g/s because of bolus dispersion of the very short bolus (3s) in the lungs.