64排螺旋CT低剂量筛查肾上腺肿瘤的实验研究

Screening Adrenal Tumors with 64-Slice Spiral CT in Low Dose:an Experimental Study

目的探索适用于64层螺旋CT肾上腺成像筛查肾上腺肿瘤的低剂量扫描参数,以有利于该技术在临床上更广泛应用。方法选择2009年6月至2010年6月吉化集团公司总医院确诊的肾上腺肿瘤30例,男15例,女15例。平均年龄38岁,年龄范围在28岁-67岁之间。肾上腺肿瘤共36个,其中所有病例均经手术病理证实。对照组:健康自愿者10例。一同使用64层螺旋CT在自动管电流模式下以不同的扫描参数组合扫描:噪声指数(NI)分别采用8、121、5、18、21、24、273、0、33;管电压(TV)分别采用140 kV、120 kV、100 kV8、0 kV;球管旋转时间(RT)分别采用0.4 s和0.5 s。将所得数据经0.625 mm重建后传至GE ADW4.3工作站。运用肾上腺成像专用软件重组出肾上腺的图像,由1名有20年放射经验的医师对各扫描参数组合所得图像进行评分,记录各扫描参数组合的放射剂量(DLP),采用偏相关分析探讨放射剂量及图像质量与噪声指数、管电压、球管旋转时间的关系。结果 DLP与NI的偏相关系数为-0.613,P<0.0l;DLP与TV的偏相关系数为0.198,P>0.05;DLP与RT的偏相关系数为-0.054,P>0.05。结论自动管电流法模式下扫描,NI取值21,管电压120 KV,球管旋转时间0.4 s为64层螺旋CT筛查肾上腺肿瘤的最优剂量扫描参数组合,其放射剂量约为固定管电流法CT肾上腺成像的18.6%。上述扫描参数可作为64层螺旋CT筛查肾上腺肿瘤的低剂量扫描参数。

Objective The purpose of this study was to probe into the optimal scan parameters in low dose when screening adrenal tumors with 64-slice spiral CT,in order to make it more popular in clinical application.Materials and.Methods We had selected 30 adrenal tumors patients（15 male and 15 female;between 28 and 67 years old;mean age 38 years old） maken a definite diagnosis in general hospital of Jilin Chemical Industry from June 2009 to June 2010.All of the selected adrenal tumors patients were confirmed by surgical pathology.Control group;10 healthy volunteers.Both cases and controls were scanned on a 64-slice spiral CT under auto tube current modulation mode with combinations of serval parameters;noise index（NI）：8/12/15/18/21/24/27/30/33;tube voltage（TV）：140 kV/120 kV/100 kV/80 kV;rotation time（RT）： 0.4 s/0.5 s.The datum were reconstructed per 0.625mm and then transferred to the ADW4.3 workstation.Using adrenal imaging special software to reconstruct adrenal imaging.An radiologist who has more than 10 years work experience had scored the comprised imaging recorded doze length product（DLP）.The relations between DLP and NI/TV/RT and the relations between IQS and NI/DLP/TV/RT were analyzed through partial correlation.Results Coefficient of partial correlation between DLP and NI was-0.613（P0.0l）;Coefficient of partial correlation between DLP and TV was 0.198（P0.05）;Coefficient of partial correlation between DLP and RT was-0.054（P0.05）.Conclusion The optimal parameters of 64-slice spiral CT colonography was a combination of 120 kV（TV）,12（NI）,0.5s（RT） under the auto tube current modulation mode.The dose of screening adrenal tumors with with 64-slice spiral CT using the scan combinated parameters was about 18.6% of fixed tube current TV,NI and RT can be used as low dose scan parameters when screening adrenal tumors with 64-slice spiral CT.