双低剂量联合迭代重建在不同BMI患者CTA的应用
Low Contrast Dose and Low Tube Voltage Combined with Adaptive Iterative Reconstruction in Abdominal CT Angiography in Patients with Different BMI
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摘要: 目的:探讨低浓度对比剂和低管电压联合迭代重建技术在不同BMI患者腹部CTA的图像质量和辐射剂量。方法:选取2017年1月至2018年6月在我院行腹部CTA检查的患者90例,随机分为A组、B组,按照BMI进一步分组:A1组与B1组:BMI<24kg/m2为正常或偏瘦;A2组与B2组:24kg/m2 ≤ BMI<28kg/m2为超重或偏胖患者;A3组与B3组:BMI ≥ 28kg/m2为肥胖患者。A组(常规剂量组)的扫描方案为120kV,对比剂浓度370mgI/mL,采用FBP法重建;B组(低剂量组)的扫描方案为100kV,对比剂浓度270mgI/mL,采用SAFIRE法(strength 3)重建。对比剂用量为:100mL,注射速率为:4.0mL/s,追加生理盐水20mL。采取团注追踪法,兴趣区(ROI)定在降主动脉,阈值设为100HU,达到阈值后延迟2s开始扫描。图像质量采取主观评价和客观评价方法。使用SPSS16.0软件进行数据分析。结果:各组患者腹主动脉干、肝总动脉、脾动脉、肠系膜上动脉、右肾动脉等的CT值与CNR无统计学差异(P>0.05);在辐照剂量方面,双低组比常规组低,差异有统计学差异(P<0.05);低剂量组患者CNR与BMI呈负相关,常规组无显著性差异。结论:采用双低剂量联合迭代技术进行腹部CTA检查,图像质量与常规组没有显著性差异,可用于临床诊断,且降低了辐照剂量与对比剂用量。Abstract: Objective: To investigate the image quality and radiation doses resulting from abdominal CTA when using low concentration contrast combined with low kV. Methods: 90 patients from our hospital during 2017 Jan. to 2018 Jun. were chosen for our study. The patients were divided into two groups: Group A: normal doses (120kV, 370mgI/mL), Group B: low doses group (100kV, 270mgI/mL). Group A and Group B were subdivided into three subgroups according to their BMI: A1, B1 (BMI<24), A2, B2 (24
28). 100mL contrast medium was injected at the speed of 4mL/s, after then, 20mL saline was added. The CT value and CNR of abdominal aorta, common hepatic artery, splenic artery, superior mesenteric artery and right renal artery, were evaluated by both doctors and system. The data were analyzed by SPSS16.0 software. Results: no significant difference were found in CT value or CNR of abdominal aorta, common hepatic artery, splenic artery, superior mesenteric artery and right renal artery (P>0.05). However, the radiation doses were much lower in low dose group compared with normal group (P<0.05). We also found a negative correlation between CNR and BMI value in low dose group, but not in normal group. Conclusion: There is no difference in image quality or CT value between normal group and low group. Radiation doses were significantly reduced in low doses group.