低管电压联合低剂量对比剂扫描方案用于MSCT门静脉成像

目的探讨低管电压联合低对比剂扫描方案用于MSCT门静脉成像(MSCTP)的可行性。方法纳入接受MSCTP、体质量指数25kg/m2的患者118例,随机分为两组:双低组(n=59),管电压90kVp,管电流395mAs,对比剂用量1.2ml/kg体质量;常规组,管电压120kVp,管电流200mAs,对比剂用量1.5ml/kg体质量。比较两组门静脉期图像质量评分、肝实质CT值(CTH)、门静脉CT值(CTP)、图像噪声(SD),肝实质SNR(SNRH)、门静脉与肝实质CNR(CNRP)及有效剂量(ED)差异。结果双低组图像质量评分(4.53±0.32)高于常规组(3.71±0.32,P0.05);双低组CTH[(101.11±16.65)HU]、CTP[(186.94±29.29)HU]、SNRH(6.92±2.28)和CNRP(5.71±2.00)均明显高于常规组[CTH:(83.61±13.94)HU,CTP:(141.85±26.89)HU,SNRH:6.05±1.58,CNRP:4.23±1.65;P均0.05],两组图像SD差异无统计学意义[(16.32±9.21)HU vs(14.33±2.32)HU,P0.05];双低组ED[(3.81±0.44)mSv]明显低于常规组[(5.77±0.52)mSv,P0.05)。结论采用低管电压结合低剂量对比剂扫描方案进行MSCTP可提高图像质量,并降低辐射剂量。

Application of low tube voltage combined with low dosage of contrast agent in multi-slice spiral CT portography

Objective To investigate the feasibility of low tube voltage combined with low dosage of contrast media in MSCT portography（MSCTP）.Methods Totally 118 patients with body mass index25kg/m2 underwent MSCTP.The patients were randomly divided into double-low group（n=59）with tube voltage of 90 kVp,tube current of 395 mAs,contrast agent of 1.2ml/kg and regular group（n=59）with tube voltage of 120 kVp,tube current of 200 mAs,contrast agent of 1.5ml/kg.The score of image quality,CT value of hepatic parenchyma（CTH）and portal vein（CTP）,the noise of image（SD）,SNR of hepatic parenchyma（SNRH）,CNR of portal vein（CNRP）and effective dose（ED）at portal vein period were compared between the two groups.Results The score of image quality in double-low group（4.53±0.32）was higher than that in regular group（3.71±0.32,P〈0.05）.CTH（[101.11±16.65]HU）,CTP（[186.94±29.29]HU）,SNRH（6.92±2.28）and CNRP（5.71±2.00）in double-low group were all higher than those in regular group（CTH：[83.61±13.94]HU,CTP：[141.85±26.89]HU,SNRH：6.05±1.58,CNRP：4.23±1.65,all P〈0.05）.There was no significant difference of SD between the two groups（[16.32±9.21]HU vs[14.33±2.32]HU,P〈0.05）.ED in double-low group[（3.81±0.44）mSv]was significantly lower than that in regular group[（5.77±0.52）mSv,P〈0.05].Conclusion In MSCTP,the quality of image is improved,at the same time,the radiation dose is reduced using low tube voltage combined with low dose of contrast media scanning program.