能谱CT低电压低对比剂浓度结合ASIR技术对胆囊动脉图像质量影响的研究  

A Preliminary Study of Improving Quality of CT Angiography on Cystic Artery with Low Concentration Contrast Medium Spectral CT Combination ASIR

作　　者：刘静红[1] 刘爱连[1] 浦仁旺[1] 吕婷婷[1] 田士峰[1] 李烨[1] 刘晓峰[1] 刘义军[1] 

机构地区：[1]大连医科大学附属第一医院放射科,116011

出　　处：《临床放射学杂志》2015年第8期1310-1313,共4页Journal of Clinical Radiology

摘　　要：目的评价能谱CT低电压低对比剂浓度结合50%自适应统计迭代重建（ASIR）技术对胆囊动脉图像质量的影响。方法前瞻性研究BMI〈22 kg/m2的患者共116例,年龄25~90岁,BMI 15.79~21.99 kg/m2,按照扫描电压和对比剂浓度分为低电压低对比剂浓度组（A组）和常规电压高对比剂浓度组（B组）。采用GE Discovery HD 750能谱CT机。A组为低电压80 kV p,50%ASIR技术,NI为14;B组采用120 kV p,NI为10。采用高压注射器于肘静脉注射碘对比剂,A组注射威视派克270 mgI/ml,B组注射欧乃派克350 mgI/ml,剂量均为100 ml,注射流率5 ml/s。对两组数据分别测量胆囊动脉、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对比噪声比（CNR）和信噪比（SNR）。记录CT剂量指数（CTDI）。对胆囊动脉行容积重建、最大密度投影及曲面重组。分别由两位工作7年及3年的放射科医师独立对两组重建后的图像质量进行评价,采用5分评分标准。采用独立样本t检验分析两组的胆囊动脉CT值、竖脊肌CT值、竖脊肌SD值、胆囊动脉-竖脊肌的CNR、胆囊动脉-竖脊肌的SNR、扫描的CTDI及主观评分,P〈0.05为差异有统计学意义。两位医师对胆囊动脉的评分主观一致性评估采用Kappa检验。Kappa值〉0.75为一致性良好,0.40~0.75为一般,〈0.40为一致性差。结果 A组胆囊动脉的CNR（4.22±2.16）明显高于B组（3.41±1.63）（P=0.036）;A组胆囊动脉的SNR（8.31±2.14）明显高于B组（5.41±1.76）（P=0.000）。A组和B组胆囊动脉的评分一致性Kappa值分别为0.809和0.758,一致性良好。A组的CTDI（6.44±1.43）mG y明显低于B组（9.28±2.87）mG y（P=0.000）。A组胆囊动脉图像质量的主观评分为（3.46±1.06）分,高于B组[（2.86±1.08）分]图像质量评分（t=2.272,P=0.023）。结论利用低电压80kV p,采用50%ASIR技术,结合低对比剂浓度能够提高胆囊动脉的图像质量。Objective To evaluate image quality and radiation dose of spectral computed tomography for cystic CT angiography（ CTA） with low kV p and low dose contrast media. Methods A total of 116 patients with the BMI 〈 22 kg / m2 were divided into two groups includes low group（ group A） and the control group（ group B） according to the scanning voltage and concentration of contrast medium. Cystic CTA was performed in 74 patients（ group A） with 80 kV p and 50% ASIR and low dose contrast media（ 270 mgI / ml）. Cystic CTA was performed in another 42 patients（ group B） with 120 kV p and normal dose contrast media（ 350 mgI / ml）. CT values and standard deviation of cystic artery,erector spinae on two groups were measured. CNR and SNR were calculated. Results The CNR of cystic artery in group A（ 4. 22 ± 2. 16） was higher than that of group B（ 3. 41 ± 1. 63）,P = 0. 002. The SNR of cystic artery in group A（ 8. 31 ± 2. 14） was higher than that of group B（ 5. 41 ± 1. 76）,P = 0. 000. CTDI of group A（ 6. 44 ± 1. 43） mG y was lower than that of group B（ 9. 28 ± 2.87） mG y,P = 0. 000. Conclusion Cystic CTA with 80 kV p and low dose contrast mediacan provide satisfactory images with significant reduction of radiation exposure and iodine administration simultaneously.

关 键 词：胆囊动脉 能谱CT 对比噪声比 信噪比 自适应统计迭代重建 

分 类 号：R816.5[医药卫生—放射医学] R657.4[医药卫生—临床医学]