双低剂量联合迭代重建技术在急性脑梗死容积CT全脑灌注成像中的可行性应用

Application feasibility of double-low dose combined with iterative reconstruction technique in the whole brain perfusion imaging

目的:探讨低浓度对比剂、低管电压联合迭代重建技术在急性脑梗死患者全脑灌注成像(CTP)中的可行性应用。方法:选取2014年9月-2015年3月在徐州医学院徐州临床学院行全脑CTP检查、临床拟诊为急性脑梗死患者59例,随机分为A、B两组,A组28例[管电压100kV,对比剂为碘海醇(350mg I/mL),滤波反投影重建法(FBP)重建];B组31例[管电压80kV,对比剂为碘克沙醇(270mg I/mL),迭代重建算法(ART)重建]。测量并计算A、B两组的大脑中动脉CT值、信噪比(SNR)、对比噪声比(CNR)、剂量长度乘积(DLP)、有效辐射剂量(ED)及碘摄入量,并对两组间上述指标进行统计学分析;2名医师对两组图像质量评价的一致性采用kappa分析;两组间图像质量主观评价差异采用χ2检验。结果:A、B两组间的CT值、SNR、CNR、CTP及CTA的图像主观质量评价差异均无统计学意义(P均>0.05);两组间梗死灶的检出率无统计学差异;而B组(双低剂量组)的ED、碘摄入量较A组低。结论:联合低管电压和迭代重建技术时,使用低浓度对比剂(270mg I/mL)进行全脑CTP检查,在不降低图像质量的同时,还能减少ED及碘摄入量,从而降低对比剂肾病(CIN)的风险。

Objective：To evaluate the influence of low tube voltage and low iodine-concentration contrast material on the image quality,the degree of blood vessels enhancement and radiation dose in the whole brain perfusion imaging（CTP）.Methods：From September 2014 to March 2015,59 patients with clinical suspicion of acute cerebral infarction were enrolled in our center.They were randomly divided into two groups,and they all underwent CTP.Twenty-eight patients（group A）underwent examination with 100 kV,350mg I/mL contrast medium and filter back-projection（FBP）reconstruction.Thirtyone patients（group B）underwent examination with 80 kV,270mg I/mL contrast medium and algebraic reconstruction technique（ART）.The middle cerebral artery CT value was measured.The CT value,signal-to-noise ratio（SNR）,contrast-tonoise ratio（CNR）,dose length product（DLP）,effective radiation dose（ED）,and iodine intake of the two groups were compared and analyzed.Results：There was no significant difference in the CT value,subjective image quality score,SNR and CNR between the 2groups.The ED and total iodine intake in group B were lower than that in group A.Conclusion：Low tube voltage,low concentration of contrast agent（270mg I/mL）combined with ART in the CTP do not reduce the quality of image.They can reduce the ED and the the risk of contrast induced nephropathy（CIN）.