低速对比剂注射方案在儿童腹部实体瘤增强CT扫描中的应用

Application of low speed contrast injection scheme in abdominal enhanced CT for children with solid tumors

目的采用低速对比剂注射方案联合单期相CT能谱扫描技术进行儿童腹部增强CT检查,探讨低速对比剂注射方案在儿童腹部增强CT检查中的可行性。方法收集腹部肿瘤化疗后CT复诊需评估瘤灶的患儿45例,首诊检查数据设为A组,采用常规对比剂注射方案及常规腹部CT三期增强扫描方案;化疗后接受增强CT扫描的数据为B组,采用低速对比剂注射方案结合增强CT能谱单期扫描模式。记录对比剂注射速度、注射完成时间、注射过程中血管内最大注射压力、患者接受的辐射剂量。由2名高年资影像医师采用盲法对B组40keV和60keV序列的能谱CT图像的动、静脉及腹部实质脏器显像质量进行4分制及5分制的主观评分,评分≥3分认为可用于临床诊断。结果 A组的对比剂注射速度、注射时最大压力及辐射剂量均明显大于B组(P均<0.001);2名医生对两组血管和腹部实质脏器的主观评分均≥3分,且诊断一致性好(κ分别为0.89和0.75)。结论使用低速对比剂注射方案联合单期相CT能谱扫描技术进行儿童腹部肿瘤增强CT检查具有可行性。

Objective To study the feasibility of using low speed contrast injection scheme in abdominal enhanced CT scans with single-phase, dual energy spectral CT mode for children with solid tumors. Methods Totally 45 children with solid tumor who had initial （group A） and follow up CT （group B） after chemotherapy were enrolled. The initial diagnostic scan （Group A） was performed using the standard 3 enhanced phases CT and the follow up scan was a single enhanced phase with spectral mode. The contrast injection speed, maximum injection pressure and volume CT dose index （CTDIvol） were compared between the two groups. The imaging quality of artery, vein phase and abdominal organs of 40 keV and 60 keV spectral CT images of Group B were subjectively and blindly evaluated by two senior radiologists using a 4-grade and 5-grade scale, and scores greater than or equal to 3 were considered diagnostic. Results The injection speed, maximum injection pressure, radiation dose in group A were higher than those in B group （all P〈0.001）. The subjective evaluation results for the abdominal arteries, portal veins, vena cava and abdominal organs were≥3. The two readers had excellent agreements for the quality scores （κ=0.89 for vascular scores, κ=0.75 for organs scores）. Conclusion Low speed contrast injection scheme with single enhanced phase, dual energy spectral imaging is feasibility with clinically acceptable image quality in abdominal enhanced CT scan for children with solid tumors.