双源CT对正常胃部结构图像质量优化的可行性研究

摘要

目的：探讨双源CT（dual source CT，DSCT）对正常胃部结构图像质量优化的临床应用价值。方法：收集62例经胃镜证实无胃部疾病患者的腹部CT平扫和3期增强扫描的资料。其中32例完成双能（dual energy，DE）序列扫描作为实验组（DE组），30例完成常规序列扫描作为对照组（NDE组）。 ROI选择：胃壁1区：胃底小弯侧；胃壁2区：胃体大弯侧；胃壁3区：胃窦小弯侧。选择上述3个ROI附近脂肪，分别为脂肪1区、2区和3区。比较2组间SNR、主观评分、容积CT剂量指数（CTDIvol）和剂量长度乘积（DLP）、有效辐射剂量（ED）。结果：①DE组动脉期管电压100 kV与140 kV图像相比，前者胃壁1区和3区的SNR优于后者（P<0.05）；胃壁2区存在测量误差较大，2组比较差异无统计学意义（P>0.05）；前者脂肪1区和2区的SNR优于后者（P<0.05）；脂肪3区存在测量误差较大，两者比较差异无统计学意义（P>0.05）。②DE组管电压100 kV动脉期和静脉期图像相比，前者胃壁1区和3区的SNR优于后者（P<0.05）；胃壁2区存在测量误差较大，两者比较差异无统计学意义（P>0.05）；前者的脂肪1区、2区和3区的SNR与后者比较差异均无统计学意义（均P>0.05）。③DE组和NDE组基线特征和主观评分比较差异无统计学意义，前组的辐射剂量较后组明显减少（t=-12.58，P=0.000）。结论：通过对正常胃壁和胃周脂肪的不同ROI的主客观评价，证明DSCT可以从参数量化水平评估胃癌的T分期，具有可行性。低电压成像可使图像质量提高，辐射剂量降低。%Objective:To investigate the clinical value of dual-source CT (DSCT) in optimizing normal gastric images. Methods:62 patients without gastric diseases confirmed by endoscopy underwent abdominal plain scan and enhanced scan. Among them ,a total of 32 cases underwent DSCT scanning was regarded as an experimental group (DE group). 30 patients underwent conven-tional scanning were treated as a control group (NDE group). The lesser curvature of fundus was chosen as gastric ROI 1,the greater curvature of stomach as gastric ROI 2,the lesser curvature of antrum as gastric ROI 3. And the three fat regions near to the gastric ROIs were chosen as fat ROI 1,fat ROI 2,fat ROI 3,respectively. The differences of signal to noise ratio (SNR), contrast to noise ratio (CNR),subjective scoring,volume CT dose index,the dose length product (DLP) and effective dose (ED) between DE group and NDE group were compared. Results:①In DE group,the images in 100 kV compared with those in 140 kV, SNR of the former of gastric ROI 1 and 3 were higher than that in 140 kV ,and there were statistically significant differences (P<0.05). Gastric ROI 2 existed large measurement error,there was no statistically significant differences (P>0.05). SNR in 100 kV of fat ROI 1 and 2 were higher than that in 140 kV,and there were statistically significant differences (P<0.05). Fat ROI 3 exist-ed large measurement error,there was no statistically significant difference (P>0.05). ②In DE group,the images of arterial phase compared with those of venous phase,SNR in 100 kV of gastric ROI 1 and 3 were higher than that in 140 kV (P<0.05),while there was no significant difference for SNR of ROI 2 (P>0.05). SNR in 100 kV of fat ROI 1,2 and 3 were compared with that in 140 kV,there were no significant differences (P>0.05). ③The baseline characteristics and subjective scores between DE group and NDE group had no statistically significant differences. The radiation dose in 100 kV significantly reduced than that in 140 kV (t=-12.58,P=0.000). Conclusions:This study shows that DSCT can assess the T staging of gastric cancer from parameter quan-tization through different objective and subjective evaluation of the gastric ROI and fat ROI. Low-voltage imaging can improve the image quality,reduce the radiation dose,so that optimize the image.