640层螺旋CT低管电压技术结合低浓度对比剂在腹部扫描中的应用

目的探讨低管电压扫描技术结合低浓度对比剂在腹部CT扫描中的应用。方法选取体重指数18．5kg／m^2BMI≤24．9kg／m^2的患者60例，随机分成常规剂量组和低剂量组，每组各30例。常规剂量组管电压120KV，造影剂选用碘帕醇370mgI／ml；低剂量组管电压100kV，造影剂选用成视派克270mgI／ml。记录两组有效剂量及总碘量，比较两组平扫及动脉期的主动脉、肝脏、脾脏及竖脊肌的CT值、噪声及信噪比（SNR），并对图像质量进行评级。结果常规剂量组辐射剂量及总碘量显著高于低剂量组。差异有统计学意义（P〈0．05）。两组平扫及动脉期的主动脉、肝脏、脾脏及竖脊肌的CT值、噪声及信噪比（SNR）差异无统计学意义（P〉0．05）。两组图像质量评分差异无统计学意义（P〉0．05）。结论低剂量造影剂结合100KV管电压可以得到与常规120KV相当的强化效果。两组图像均能满足诊断的效果。

Objective To prospectively determine the feasibility of low tube voltage scanning technique combined with low concentration contrast agent in abdominal CT. Methods Institutional review board approval and verbal informed consent were obtained. 60 patients whose BMI were between 18.5kg/m^2 to 24.9kg/m^2 were selected and randomly divided into the conventional dose group and low dose group. There were 30 cases in each group. The patients of two groups underwent the protocol for abdomen dual phase CT imaging respectively： 120 kVp tube voltage combined with high iodine load （ Ultravist, 370 mgI/ml, 0.8ml contrast agent per kilogram of body weight ） , and 100 kVp combined with the low iodine load （ Visipaque, 270 mgI/ml, 0.8ml contrast agent per kilogram of body weight ） . The image quality of the two groups were graded. CT numbers of aorta, liver, spleen and musculus erector spinae were measured and compared with one-way analysis of variance. Results The radiation dose and the total amount of iodine in the low dose group were significantly lower than those in the conventional dose group （ P〈0.05 ） . There was no significant difference in the CT value, noise and signal to noise ratio （ SNR ） between the aorta, liver, spleen and the vertical spinal muscle of the two groups in non-enhance CT and arterial phase （ P〉0.05 ） . There was no significant difference in image quality between the two groups （ P〉0.5 ） . Conclusion Low dose contrast agent combined with 100 kVp tube voltage can be obtained nearly the same enhancement effect with the conventional 120kVp. The all images of two grouos can meet the diagnostic need.