低浓度对比剂结合能谱CT最佳单能量成像对胆囊动脉的显示能力

目的 评价低浓度对比剂结合能谱CT最佳keV成像技术对胆囊动脉的显示能力。方法 前瞻性选取体质量指数为25.15~34.91 kg/m²的90例患者，按照扫描方式和对比剂浓度分为能谱扫描低浓度对比剂组（A组）和常规扫描高浓度对比剂组（B组）。对两组分别测量胆囊动脉、相同层面竖脊肌的CT值及竖脊肌CT值的标准差，计算胆囊动脉与竖脊肌间的CNR和SNR。对胆囊动脉行VR、MIP及CPR。由2名观察者分别独立评价两组重建后的图像质量。对以上指标进行统计学分析，并进行观察者间一致性检验。结果 能谱CT单能量成像显示胆囊动脉的平均最佳keV值为（60.62±5.85）keV。A组胆囊动脉CT值、竖脊肌CT值均高于B组（P均<0.05），但两组CNR及SNR差异均无统计学意义（P均>0.05）。两名观察者主观评分一致性良好（Kappa=0.804、0.773），主观评分差异无统计学意义（t=-0.243，P=0.808）。结论 低浓度对比剂结合能谱CT最佳单能量成像技术可提供良好的胆囊动脉的图像质量，并可显著降低对比剂用量。

Evaluation of quality of CT angiography on cystic artery with low concentration contrast medium optimizing gemstone spectral imaging technique with spectral CT

Objective To evaluate the image quality of spectral computed tomography for cystic CT angiography (CTA) with the best keV and low dose contrast media. Methods A total of 90 patients with body mass index (BMI) 25.15-34.91 kg/m² were divided into GSI group and control group according to the scanning protocol and concentration of contrast medium. CT values of cystic artery and erector spinae and standard deviation (SD) of erector spinae on both groups were measured. CNR and SNR were calculated. The overall image quality was evaluated using a five-point scale by two radiologists. All above indices were statistically analyzed, and inter-observer agreement in subjective image quality grading was assessed with Kappa statistics. Results The average best keV of 90 patients was (60.62±5.85)keV. CT values of cystic artery and erector spinae in group A were higher than those of group B (both P<0.05), while CNR and SNR of cystic artery-to erector spinae had no statistical difference between the two groups (both P>0.05). The consistency of two observers was good (Kappa=0.804, 0.773), and the subjective score had no significant difference (t=-0.243, P=0.808). Conclusion Cystic CTA with the best keV and low dose contrast media can provide satisfactory images with significant reduction of iodine administration.