【摘要】 目的评估应用128层螺旋CT(u CT 760)结合Karl 3D迭代技术进行低管电压、低对比剂碘摄入量冠状动脉CTA检查在老年群体的临床应用价值。方法前瞻性连续选取身体质量指数(BMI)在20～25 Kg/m~2临床怀疑或已知冠心病拟行冠状动脉CTA检查的200例老年患者。按随机数字表法选取60例为对照组(A组),其余140例为试验组(B组)。2组均行冠状动脉CTA检查,A组采用管电压120 kVp,碘对比剂浓度350 mgI/mL。B组再根据管电压和碘对比剂不同分为2个亚组,低剂量组B1组(60例)采用80 kVp、350 mgI/mL碘对比剂,双低剂量组B2组(80例)采用70 kVp、300 mgI/mL碘对比剂。并分别采用滤波反投影法(FBP)(A组)和Karl 3D迭代重建技术(B组)进行图像重建。对各组CT图像的辐射剂量[CT剂量容积指数(CTDIvol)和有效剂量(ED)]以及图像噪声(SD)、图像信噪比(SNR)、冠状动脉近段的对比噪声比(CNR)、对比剂碘摄入量进行系统测量。每例患者的冠状动脉CTA图像质量由2名放射科医师采用双盲法进行4分法主观评分。应用ANOVA单因素方差分析比较3组辐射剂量(CTDIvol和ED)、SD、SNR和冠状动脉近段CNR。采用秩和检验比较各组图像的主观评价指标差异。用Kappa检验评价2名观察者冠状动脉图像质量评分的一致性。结果 A组、B1组、B2组的CTDIvol分别为(17.81±0.92)mGy、(5.99±0.60)mGy和(4.87±1.35)mGy,ED分别为(3.59±0.15)m Sv、(1.21±0.13)m Sv和(0.97±0.29)m Sv,3组间两两比较差异有统计学意义(P<0.05)。A组、B1组、B2组在主、客观图像质量评分上差异无统计学意义(P>0.05)。双低剂量B2组较常规剂量A组对比剂碘摄入量减少了21.4%。结论 128层螺旋CT采用低管电压、低对比剂碘摄入量在老年群体中行冠状动脉CTA检查,通过结合Karl 3D迭代技术,在保证图像质量的前提下,可以有效降低辐射剂量及对比剂碘摄入量,从而达到老年群体低剂量冠状动脉成像的目的。更多还原

【Abstract】 Objective To investigate the clinical application value of dual low dose coronary computed tomography angiography(CCTA) on 128 slices CT(u CT 760)using Karl 3 Diterative reconstruction technique(IRT)in elderly population. Methods Two hundred sequential patients with normal BMI(20-25 kg/m~2) who were suspected coronary heart disease(CHD)or had been diagnosed CHD underwent coronary CT angiography. Two hundred patients were divided into 2 groups at random:controlgroup(groupA) and experimental group(groupB).The tube voltage/Iodine contrast agent concentration was 120 kVp/350 mg/mL ingroup A. Group B was divided into the following two subgroups according to different tube voltage and Iodine contrast agent concentration:group B1(80 kVp/350 mg/mL),group B2(70 kVp/300 mg/mL).The imaging data were reconstructed by FBP(group A)or Karl IRT(group B). Two blinded readers graded image quality on a 4-point Likert scale. The differences in image noise,signal-tonoise ratio(SNR) contrast-to-noise ratio(CNR),CT dose volume index(CTDIvol),effective dose(ED),and image quality between the groups were compared by using ANOVA or ranks test. Results The CTDIvol and ED were respectively(17.81 ±0.92)mGy,(5.99 ±0.60)mGy,(4.87±1.35)mGy and(3.59±0.15)m Sv,(1.21±0.13)m Sv,(0.97±0.29)m Sv. There were significant differences of the CTDIvol and EDbetween group A,group B1 and group B2(P<0.05). There was no significant difference in subjective and objective image quality scores among the three groups(P>0.05). Compared with the conventional dose group,the dose of iodine contrast agent in low-dose group B2 decreased by 21.4%. Conclusion Dual low dose CCTA on 128 slices CT,by usingKarl 3 DIRT,can effectively reduce the radiation dose and contrast agent iodine intake without compromise of image quality,and achieve the purpose of low-dose coronary angiography in the elderly population.更多还原