SAFIRE重建联合CARE kV技术在主动脉CT低剂量成像中的临床应用

The Clinical Application of SAFIRE Reconstruction Combined with CARE kV in Aortic Low-Dose CT Angiography

目的与常规扫描及滤波反投影法（FBP）比较,探讨SAFIRE迭代重建联合CARE kV技术在主动脉CT低辐射剂量成像中的临床应用价值。方法将拟行全主动脉CT成像的226例患者采用128层螺旋CT扫描,分别按如下进行检查：常规扫描组（A组）：113例,固定120 kV,FBP重建; Care kV扫描组：113例患者采用CARE kV技术CTA检查,根据扫描千伏值不同分为3组（机器按照患者体型自动选择扫描千伏）：B组（80 kV,30例）,C组（100 kV,69例）,D组（120 kV,14例）,CARE kV组的每位患者CTA数据同时进行FBP重建（B1、C1、D1组）和SAFIRE重建（B2、C2、D2组）。记录患者的BMI指数及辐射剂量各项指标,测量并计算主动脉图像的噪声、信噪比（SNR）、对比噪声比（CNR）,采用5分法对图像质量进行主观评分。比较各组间及组内各项指标,P 〈0. 05为差异有统计学意义。结果与常规扫描A组相比,B组和C组的辐射剂量各项指标均明显降低（P 〈0. 05）,其中有效辐射剂量分别降低为63. 7%和38. 1%,D组与A组差异无统计学意义（P〉 0. 05）。B1组的主动脉噪声和CNR明显高于A组,主观评分低于A组（P 〈0. 05）,两者间SNR差异无统计学意义（P〉 0. 05）; B2组的主动脉CT噪声、SNR及CNR高于A组（P 〈0. 05）,评分低于A组（P 〈0. 05）; C1组的噪声高于A组,评分低于A组（P 〈0. 05）,而SNR及CNR无差异（P〉0. 05）; C2组的噪声、SNR及CNR高于A组（P 〈0. 05）,评分无差异（P〉 0. 05）; D1组的噪声高于A组,评分低于A组（P 〈0. 05）,SNR及CNR无差异（P〉 0. 05）; D2的噪声、SNR及CNR高于A组（P 〈0. 05）,评分无差异（P〉 0. 05）。B2、C2及D2组的噪声分别低于B1、C1及D1,而SNR、CNR及评分均高于B1、C1及D1组（P 〈0. 05）。结论与常规剂量扫描FBP重建相比,CARE kV技术联合SAFIRE重建在进行主动脉CT成像时,能够个性化降低患者的辐射剂量,同时保证主动脉图像质量。

Objective To investigate the clinical value of combining Sinogram Affirmed Iterative Reconstruction（ SAFIRE） with automatic tube potential selection（ CARE k V） in the CT angiography（ CTA） of aorta compared with conventional scan method and Filtered Back Projection（ FBP）. Methods A total of 226 patients who intended to take the aortic CTA examination were included this experimentation,scanned by 128 slice spiral CT. 113 patients who were scanned by fix120 kV and reconstructed by FBP were set as the Conventional scan group（ group A）. The other 113 patients scanned with CARE k V which could automatically select different tube voltage according to the patient ＇s shape were set as the Care k V group. Based on the value of tube voltage,the patients of the CARE k V group were divided into three groups： group B（ 80 k V,30 cases）,group C（ 100 kV,69 cases）,group D（ 120 k V,14 cases）. All images had been taken by both FBP（ B1、C1、D1 group） and SAFIRE（ B2、C2、D2 group） reconstruction algorithm. The BMI and the radiation dose of all patients were recorded. The noise,the SNR（ Signal-to-Noise Ratio） and CNR（ Contrast-to-Noise Ratio） of aorta were evaluated. Based on a 5-point subjective scale,the image quality was evaluated. Compared this indexes in each group,there was statistical significance when P〈0. 05. Results Compared to group A,the radiation doses of the group A and group B were reduced,among them the ED value was reduced by 63. 7%（ group B） and 38. 1%（ group C）,but the radiation dose of group D was similar to group A. The noise and CNR of group B1 was higher than group A,the score was lower than group A（ P〈0. 05）,but there was no significant difference in SNR; The noise,SNR and CNR of group B2 was higher than group A,but the score was lower than group A（ P〈0. 05）. The noise of group C1 was higher than group A,the scores were lower than group A（ P〈0. 05）,but there was no significant difference in SNR and CNR（ P〉0. 05）. The noise,SNR and CNR of group C2 was higher than group A（ P〈0. 05）,but there was no significant difference in the score（ P〉0. 05）; The noise of group D1 was higher than group A,the score was lower than group A（ P〈0. 05）,but there was no significant difference in SNR and CNR（ P〈0. 05）; The noise,SNR and CNR of group D2 was higher than group A（ P〈0. 05）,but there was no significant difference in the score（ P〉0. 05）. The SNR,CNR and the score of aorta in the subgroup B2,C2 and D2 were higher than group B1,C1 and D1,respectively,but,the noise was lower（ P〈0. 05）. Conclusion Compared with conventional scan method and Filtered Back Projection（ FBP）,SAFIRE combined the CARE k V used in aortic CTA could obviously reduce the patient radiation dose. Further more,the image quality of aorta could be guaranteed.