100kVp条件下碘克沙醇(270mgI/mL)应用于冠状动脉CTA检查的可行性研究

Coronary CT angiography with 100kVp and iodixanol(270mg I/mL) using iterative reconstruction:a feasibility study

目的：探讨100kVp条件下碘克沙醇（270mgI／mL）应用于冠状动脉CTA（CCTA）检查的可行性，比较不同比例自适应统计迭代重建（AsiR）的图像质量。方法：前瞻性收集临床疑诊冠状动脉病变、身体质量指数（BMI）20～25kg／m。的患者资料。所有患者行64排cCTA检查，采用前瞻性心电触发扫描模式，管电压100kVp，管电流600mA。使用对比剂碘克沙醇（270mgI／mL），共60mL。采用滤波反投影（FBP）算法及30％～40％、60％、80％、100％ASiR算法对原始数据进行重建，每位患者得到5组重建图像。由1名有经验的影像科医师分别对5组冠状动脉图像进行主观评分，并行统计学分析。测量冠状动脉各节段CT值和图像噪声，计算5组图像的信噪声比（SNR）和对比噪声比（cNR），并行统计学分析。结果：共45例受试者入组。冠状动脉各节段图像符合诊断要求的比例为95．6％（172／180）。60％和80％ASiR图像质量评分均高于100％ASiR，差异具有统计学意义（P〈0．05），其余FBP及ASiR图像质量评分之间差异均无统计学意义（P〉0．05）。所有冠脉节段平均cT值均〉300HU。ASiR重建的图像噪声低于FBP重建，且AsiR重建比例越高，噪声越低。ASiR重建图像中血管的SNR和CNR均显著高于FBP重建者（P〈0．001），且ASiR重建比例越高，SNR和CNR越高。结论：100kVp条件下碘克沙醇（270mgI／mL）应用于CCTA检查可以满足临床诊断需要，迭代重建能够提高图像质量，本组条件下推荐使用30％～40％ASiR进行重建。

Objective：To evaluate the image quality of coronary CT angiography （CCTA） using 100kVp and iterative reconstruction with contrast of iodixanol （270rag I/mL）. Methods：Patients suspected of coronary artery diseases were col lected prospectively,with body mass index （BMI） 20% 25kg/m2. Prospective ECG-triggered CCTA images were acquired with following parameters ： 100kVp, 600mA ; iodixanol（270mg I/mL）, total volume 60mL. The raw data were reconstructed with filtered back projection （FBP） and 30 %- 40 %, 60 %, 80 %, 100 % adaptive statistical iterative reconstruction （ASiR）, respectively. For subjective assessment,one experienced radiologist assessed the overall image impression of vessel demon- stration for each segment. For objective assessment, CT value, signal-to-noise ratio （SNR） and contrast-to-noise ratio （CNR） of the coronary lumen were measured by segment. Results：Forty-five cases were enrolled. The image quality of 95. 6 % （172/180） segments met clinical diagnostic criteria. Among the CCTA images with different reconstruction algorithm, images with 60% and 800/00 ASiR were considered to provide better image quality than that of the 100% ASiR. The average CT values of all segments were over 300HU. The image noise was significantly lower in ASiR images than that of FBP ima gesmeanwhile, SNR and CNR were significantly higher in ASiR images. Conclusion： CCTA with 100kVp and contrast of iodixanol （270mg I/mL） is feasible for CCTA study in patients with BMI of 20%25kg/m2. Image quality can be improved by iterative reconstruction, and 30 %-40 % ASiR is recommended.