Low-Contrast and Low-Radiation Dose Protocol in Cardiac Computed Tomography: Usefulness of Low Tube Voltage and Knowledge-Based Iterative Model Reconstruction Algorithm
Low-Contrast and Low-Radiation Dose Protocol in Cardiac Computed Tomography: Usefulness of Low Tube Voltage and Knowledge-Based Iterative Model Reconstruction Algorithm
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DOI：
10.1097/rct.0000000000000440
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发表时间：
2016-05
影响因子：
1.3
通讯作者：
Yuji Iyama;T. Nakaura;Koichi Yokoyama;M. Kidoh;K. Harada;S. Oda;Shinichi Tokuyasu;Y. Yamashita
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文献类型：
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作者：
Yuji Iyama;T. Nakaura;Koichi Yokoyama;M. Kidoh;K. Harada;S. Oda;Shinichi Tokuyasu;Y. Yamashita
目的应用基于知识的迭代模型重建(IMR)技术，评价80峰值千伏(KVP)低对比度、低辐射剂量(KVP)与前瞻性心电门控心脏CT(CT)的可行性。方法30例患者接受80kVp前瞻性心电门控CT扫描，低对比剂剂量(222 mg碘/公斤体重)。我们还招募了30名连续接受120kVP心脏CT扫描的患者作为历史对照组，使用标准对比剂剂量(每公斤体重370毫克碘)进行过滤反投影扫描。我们评估了两组的辐射剂量。采用滤波反投影(A方案)、混合迭代重建(HIR，B方案)和IMR(C方案)重建80kVP图像。我们比较了120-KVP方案、A方案、B方案和C方案的CT数目、图像噪声和对比度噪声比。此外，我们还比较了HIR和IMR的降噪率。两个独立的阅读器对4种协议的图像对比度、图像噪声、图像清晰度、不熟悉的图像纹理和整体图像质量进行了比较。结果80-KVP方案的估计有效剂量(ED)比120-KVP方案低74%(1.4比5.4mSv)。C组的对比噪声比明显高于A组，IMR组的降噪率明显高于HIR组(P<；0.01)。除图像对比度外，120-KVP方案与C方案在几乎所有定性图像质量上均无显著差异。结论与120-KVP方案相比，80-KVP方案结合IMR具有更高的图像质量，辐射剂量减少74%，对比剂剂量减少40%，同时与80-KVP方案结合HIR相比，图像噪声降低更多。
Objective This study aimed to evaluate the feasibility of a low contrast, low-radiation dose protocol of 80-peak kilovoltage (kVp) with prospective electrocardiography-gated cardiac computed tomography (CT) using knowledge-based iterative model reconstruction (IMR). Methods Thirty patients underwent an 80-kVp prospective electrocardiography-gated cardiac CT with low-contrast agent (222-mg iodine per kilogram of body weight) dose. We also enrolled 30 consecutive patients who were scanned with a 120-kVp cardiac CT with filtered back projection using the standard contrast agent dose (370-mg iodine per kilogram of body weight) as a historical control group. We evaluated the radiation dose for the 2 groups. The 80-kVp images were reconstructed with filtered back projection (protocol A), hybrid iterative reconstruction (HIR, protocol B), and IMR (protocol C). We compared CT numbers, image noise, and contrast-to-noise ratio among 120-kVp protocol, protocol A, protocol B, and protocol C. In addition, we compared the noise reduction rate between HIR and IMR. Two independent readers compared image contrast, image noise, image sharpness, unfamiliar image texture, and overall image quality among the 4 protocols. Results The estimated effective dose (ED) of the 80-kVp protocol was 74% lower than that of the 120-kVp protocol (1.4 vs 5.4 mSv). The contrast-to-noise ratio of protocol C was significantly higher than that of protocol A. The noise reduction rate of IMR was significantly higher than that of HIR (P < 0.01). There was no significant difference in almost all qualitative image quality between 120-kVp protocol and protocol C except for image contrast. Conclusions A 80-kVp protocol with IMR yields higher image quality with 74% decreased radiation dose and 40% decreased contrast agent dose as compared with a 120-kVp protocol, while decreasing more image noise compared with the 80-kVp protocol with HIR.