低剂量造影剂结合低管电压在食管癌CT增强扫描中应用的可行性研究

Feasibility Study on the Application of Low Dose Contrast Agent and Low KV Photography on CT Enhancement Scanning of Esophageal Cancer

目的探讨低剂量造影剂结合低管电压在食管癌CT增强扫描中应用的可行性。方法选取2013年5—9月在本院行胸部CT增强扫描的食管癌患者100例,将其随机分为两组:常规剂量造影剂组(A组,造影剂用量为1.5 ml/kg体质量,管电压为120 kV,采用反投影滤过重建算法)和低剂量造影剂组(B组,造影剂用量为1.0 ml/kg体质量,管电压为80 kV,采用迭代重建算法),各50例。记录患者的造影剂用量和辐射剂量,测量两组图像中胸主动脉、正常食管、食管癌病变的平均CT值及噪声,计算信噪比(SNR)和对比噪声比(CNR)。对图像质量进行评级评分。结果 B组的造影剂用量低于A组〔(52.5±13.4)ml与(80.5±15.4)ml,P<0.05〕;B组的辐射剂量低于A组〔容积剂量指数(CTDIvol):(2.3±1.1)mGy与(6.5±1.5)mGy,剂量长度乘积(DLP):(75.3±22.6)mGy·cm与(220.5±35.1)mGy·cm;P<0.05〕。两组图像中胸主动脉、正常食管、食管癌病变平均CT值、噪声、SNR、CNR间无差异(P>0.05);两组的图像质量评分间无差异(P>0.01)。结论低剂量造影剂结合低管电压及迭代重建算法可得到质量满意的食管癌CT增强扫描图像。

Objective To investigate the feasibility of application of low dose contrast agent and low KV photography on CT enhancement scanning of esophageal cancer. Methods 100 patients with esophageal cancer who underwent contrast-enhanced chest CT in our hospital from May 2013 to September 2013,were randomly divided into two groups：conventional dose contrast agent group（ group A,contrast agent dosagea was 1. 5 ml/kg body weight,tube voltage was 120 kV,images were reconstructed with filter back projection）and low dose contrast agent group（ group B,contrast agent dosage was 1. 0 ml/kg body weight,tube voltage was 80 kV,iterative reconstruction algorithm was used）,50 cases in each group. The contrast agent dosage and radiation dose were recorded,the mean CT numbers and noise of two groups of images on thoracic aorta,normal esophagus and esophageal cancer were measured,SNR and CNR were calculated,and image quality was rated and scored. Results The contrast agent dosage in group B was significantly less than that in group A〔（52. 5 ± 13. 4） ml vs. （80. 5 ± 15. 4） ml,P〈0. 05〕. The radiation dose in group B was significantly less than that in group A〔CTDIvol：（ 2. 3 ± 1. 1 ） mGy vs. （ 6. 5 ± 1. 5） mGy;DLP：（75. 3 ± 22. 6） mGy·cm vs. （220. 5 ± 35. 1） mGy·cm;P〈0. 05〕. There was no significant difference in mean CT numbers,noise,SNR and CNR of images on thoracic aorta,normal esophagus and esophageal cancer between two groups（P〉0. 05）. There was no significant difference in the image quality score between two groups（P〉0. 01）. Conclusion The high-quality enhancement scanning images of esophageal cancer can be achieved by using low dose contrast agent with low KV photography and iterative reconstruction algorithm.