摘要
目的 探讨不同管电压及不同噪声指数（NI）指导管电流自动调节对脑CTA图像质量及辐射剂量的影响,确定头颅CTA最优扫描条件.方法 采用PH3头颅CTA仿真体模,行头颅CTA检查.扫描方案：按管电压不同分为120、100、80 kV共3组,每组分别采用固定毫安（300、400 mA）和NI为3、4、5、6、7、8、9、10的自动管电流调节技术行头颅CTA扫描,管电压和管电流参数组合共30种扫描方案.记录辐射剂量[容积剂量指数（CTDIvol）、剂量长度乘积（DLP）和有效剂量（ED）]、图像客观评价指标（血管CT值和噪声、脑组织CT值和噪声、信噪比和对比噪声比）和五级血管的主观评分.采用单因素方差分析比较不同管电压间和管电流参数间血管CT值、血管噪声、脑组织CT值、脑组织噪声、信噪比和对比噪声比的差异.结果 管电压一定时,NI从3增加至10,CTDIvol、DLP和ED均呈下降趋势.100 kV、300 mA组与120 kV、300 mA组比较,CTDIvol下降35.32%（12.22/34.59）;100 kV、NI=6组与120 kV、300 mA组相比,CTDIvol下降46.72%（16.16/34.59）;100 kV、NI=6组与100 kV、300 mA组相比,CTDIvol下降17.61%（3.94/22.37）.管电压一定时,采用不同的管电流和NI,血管CT值、脑组织CT值差异无统计学意义（P〉0.05）,血管噪声、脑组织噪声、SNR、CNR差异有统计学意义（P均〈0.05）;管电流和NI一定时,不同管电压下上述客观评价指标的差异均有统计学意义（P均〈0.05）.100 kV、NI=6组与120 kV、300 mA组比较,SNR、CNR分别高6.31%（2.69/42.66）和7.18%（2.64/36.78）.管电压、NI和管电流对一级和二级血管主观评分无影响,四级和五级血管评分差异较大.结论 在头颅CTA扫描中,采用NI=6指导管电流自动调节联合100 kV低管电压技术,能够获得较好的图像质量,并降低辐射剂量.
Objective To study the impacts of different tube voltage and different noise index（NI） guided automatic tube current modulation on the image quality and radiation dose in cerebrovascular imaging and determine the optimal scanning condition. Methods PH3 angiographic CT head phantom was used for head CTA examination. Scanning protocols： all the scanning objectives were divided into three groups according to the different tube voltages of 80, 100 and 120 kV. Each group applied certain tube current（300,400 mA）and automatic tube current modulation technique with NI from 3 to 10 to perform head CTA. There were 30 scanning proposals with different parameter combinations of tube voltage and tube current. The radiation dose [ CT dose index volume （CTDIvol）, dose length product （DLP） and effective dose （ED）], objective indicators of images（CT value of the blood vessels and its noise, CT value of brain tissue and its noise, signal-to-noise ratio , contrast-to-noise ratio） and the subjective scores of the five cerebrovascular segments were recorded. Differences of CT value of the blood vessels and its noise, CT value of brain tissue and its noise, signal-to-noise ratio and contrast-to-noise ratio between different tube voltages and tube currents were analyzed by One-Way ANOVA. Results When the tube voltage was certain, the CTDIvol, DLP and ED were all dropped while NI was increased from 3 to 10. Compared with group（120 kV, 300 mA）, CTDIvol of group with 100 kV, 300 mA decreased 35.32%（12.22/34.59）, CTDIvol of group（100 kV, NI=6） decreased 46.72%（16.16/34.59）. Compared with group（100 kV, 300 mA）, CTDIvol of group （100 kV, NI=6） decreased 17.61%（3.94/22.37）. When the tube voltage was certain and the tube current and NI were not certain, there is no statistical difference （P〉0.05） between CT values of blood vessel and brain, while blood vessel noise, noise of brain, SNR and CNR showed statistical difference （P〈0.05）. When tube current and NI were certain while tu
作者
胡婷婷
刘成佳
王鑫宏
余忠强
孙建忠
章伟敏
余日胜
Hu Tingting Liu Chengjia Wang Xinhong Yu Zhongqiang Sun Jianzhong Zhang Weimin Yu Risheng(Department of Radiology, The Second Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou 310009, China)
出处
《中华放射学杂志》
CAS
CSCD
北大核心
2017年第10期794-799,共6页
Chinese Journal of Radiology
基金
浙江省医药卫生科技计划（2014KYB114）
