低浓度对比剂、低辐射剂量婴幼儿腹部CT扫描

目的探讨使用低浓度对比剂(270mgI/ml)、低辐射剂量(管电压100kV)增强CT扫描在婴幼儿腹部CT检查的可行性。方法收集因腹部实体肿瘤或外伤需接受CT增强检查的婴幼儿90例,将其分为3组:A组为平扫与实质期管电压120kV、对比剂碘克沙醇(320mgI/ml);B组为平扫与实质期管电压100kV、对比剂碘克沙醇(320mgI/ml);C组为平扫与实质期管电压100kV、对比剂碘克沙醇(270mgI/ml)。采用4分制主观评价实质期图像质量。测量实质期的皮下脂肪标准差(SD),以及肝实质、脾实质、肾皮质、肾静脉和腹主动脉SNR和CNR,记录容积CT剂量指数(CTDI_(vol))、剂量长度乘积(DLP),并计算有效剂量(ED)。对3组数据进行统计学分析。结果 3组实质期肝实质、脾实质、肾皮质、肾静脉和腹主动脉的SNR、CNR及主观评分差异均无统计学意义(P均0.05)。3组CTDI_(vol)、DLP、ED差异有统计学意义(P均0.01)。A组CTDI_(vol)(P=0.001、0.002)、DLP(P=0.013、0.004)、ED(P=0.003、0.001)与B组、C组比较差异均有统计学意义,B、C组CTDI_(vol)、DLP、ED差异无统计学意义(P均0.05)。结论采用低浓度对比剂(270mgI/ml)联合100kV管电压进行CT增强扫描,可保证婴幼儿腹部图像的CNR,并满足临床诊断要求。

Low concentration contrast medium and low radiation dose for infants and young children abdominal CT scanning

Objective To assess the feasibility of low concentration contrast medium (270 mgI/ml) and low radiation dose (100 kV) for enhanced CT scanning in infants and young children abdominal CT examination. Methods Ninety children with abdomen tumors or abdominal injuries who underwent contrast-enhanced CT examination were selected. The patients were divided into 3 groups (each n=30):Group A with tube voltage of 120 kV for non-contrast enhanced and parenchymal phase scanning and iodixanol contrast-medium (320 mgI/ml); group B with tube voltage of 100 kV for non-contrast enhanced and parenchymal phase scanning and iodixanol contrast-medium (270 mgI/ml); group C with tube voltage of 100 kV for non-contrast enhanced and parenchymal phase scanning and iodixanol contrast-medium (270 mgI/ml). The 4-point scale was used to evaluate the quality of parenchymal phase imaging. The standard difference (SD) of CT value in subcutaneous fat, SNR and CNR of liver parenchyma, splenic parenchyma, renal cortical, renal vein, and abdominal aorta were measured at parenchymal phase, and CT dose index of volume (CTDI_vol), dose length product (DLP) and effective dose (ED) were recorded. The data were statistically analyzed among 3 groups. Results There was no significant difference of SNR, CNR nor objective scores of liver parenchyma, splenic parenchyma, renal cortical, renal vein and abdominal aorta among 3 groups (all P>0.05). The differences of CTDI_vol, DLP and ED among 3 groups were statistically significant (all P<0.01). The CTDI_vol had no statistical difference between group B and group C (P=0.001, 0.002), DLP (P=0.013, 0.004) and ED (P=0.03, <0.001) of group A had statistical difference with those of group B and C. Conclusion CNR of the abdominal image can be guaranteed using low concentration contrast medium (270 mgI/ml) combined with 100 kV tube voltage for CT scanning of infants and young children, therefore satisfying clinical diagnostic requirements.