摘要
目的分析肝脏CT增强扫描中不同噪声指数(NI)联合迭代重组算法对肥胖患者CT图像质量的影响。方法选取2016年5月至2018年6月我院拟行肝脏CT增强扫描的84例肥胖(BMI指数≥21828kg/m2)患者为研究对象,依据自动管电流调制技术(ATCM)设定N1组(NI=11)、N2组(NI=13)、N3组(NI=15)、N4组(NI=17)四组各21例,均行肝脏三期CT增强扫描,以权重为50%的迭代重组算法进行重组,对四组图像质量进行主观评分及客观评价(信噪比、对比噪声比),记录其辐射剂量[容积剂量指数(CTDIvol)、剂量长度乘积(DLP)、有效剂量(ED)]。结果随NI增加,患者在肝脏三期CT增强扫描中图像质量评分均减少,N4组评分最低,N1组评分最高,N4组动脉期、静脉期、延迟期的图像质量评分与N1组、N2组、N3组差异均有统计学意义(P<0.05),N2组、N3组动脉期图像质量评分低于N1组(P<0.05);动脉期N1组、N2组信噪比、对比噪声比差异无统计学意义(P>0.05),其余组差异有统计学意义(P<0.05),N4组静脉期、延迟期的信噪比、对比噪声比低于N1组、N2组、N3组(P<0.05),且同组内,静脉期与延迟期的信噪比、对比噪声比均高于动脉期(P<0.05);随NI增加,CTDIvol、DLP、ED有下降趋势,N3组CTDIvol、DLP低于N1组,N4组CTDIvol、DLP低于N2组(P<0.05),N1组ED高于N2组、N3组、N4组(P<0.05),N2组、N3组、N4组的ED分别较N1组下降25.39%、28.04%、30.53%,N2组、N3组、N4组的ED比较差异无统计学意义(P>0.05)。结论肝脏CT增强扫描中,在保证图像质量前提下,设置不同NI指数联合应用迭代重组算法可有效降低辐射剂量。
Objective To analyze the effect of different noise index(NI) combined with iterative recombination algorithm in liver CT enhanced scan on CT image quality in obese patients. Methods 84 patients with obesity(BMI index not less than 28 kg/m2) undergoing liver CT enhanced scan in the hospital from May 2016 to June 2018 were enrolled in the study. The N1 group(NI=11), N2 group(NI=13), N3 group(NI=15) and N4 group(NI=17) were established according to the automatic tube current modulation technique(ATCM), 21 cases in each group. The liver CT three-phase enhanced scan was performed for all patients, recombining with iterative recombination algorithm at a weight of 50%. Subjective and objective evaluation was performed on the image quality in the four groups(signal-to-noise ratio, contrast-to-noise ratio), the radiation dose [volume dose index(CTDIvol), dose length product(DLP), effective dose(ED)] was recorded. Results With the increase of NI, the image quality scores of the patients in the threephase CT enhanced scan were reduced, the N4 group had the lowest score, the N1 group had the highest score. There were significant differences in image quality scores at the arterial, venous and delayed phases among the N4, N1, N2 and N3 group(P<0.05). The image quality scores of N2 group and N3 group at the arterial phase were lower than those of N1 group(P<0.05). There was no statistical significance in the signal-to-noise ratio and contrast noise ratio between N1 group and N2 group at arterial phase(P>0.05). The difference in the other groups was statistically significant(P<0.05). The signal-to-noise ratio and contrast-to-noise ratio at the venous phase and the delayed phase of the N4 group were lower than those of the N1 group, the N2 group and the N3 group(P<0.05). In the same group, the signal-to-noise ratio and contrast-to-noise ratio at venous phase and delayed phase were higher than those at arterial phase(P<0.05). with NI increasing, CTDIvol, DLP, ED showed a downward trend, CTDIvol and DLP in N3 group were lower than those in N1 group, CTDIvol and DLP were lower in N4 group than N2 group(P<0.05), ED in N1 group was higher than that in N2 group, N3 group and N4 group(P<0.05), ED in N2 group, N3 group and N4 group decreased 25.39%, 28.04%, 30.53% compared with that in N1 group. There were no significant differences in ED among the N2 group, the N3 group and the N4 group(P>0.05). Conclusion In the liver CT enhanced scan, under the premise of ensuring image quality, setting different NI index combined with the iterative recombination algorithm can effectively reduce the radiation dose.
作者
陈雷
李高宏
虎支
马盖珺
张伟红
CHEN Lei;LI Gao-hong;HU Zhi(Department of Radiology,Qingdao Central Hospital,Qingdao 266042,Shandong Province,China)
出处
《中国CT和MRI杂志》
2020年第7期78-81,共4页
Chinese Journal of CT and MRI
关键词
肝脏
CT
增强扫描
噪声指数
迭代重组算法
肥胖
图像质量
Liver
CT
Enhanced Scan
Noise Index
Iterative Recombination Algorithm
Obesity
Image Quality
