颈部能谱CT与常规CT扫描辐射剂量与图像质量的对比研究  

Comparative study of radiation dose and image quality between spectral CT scanning and conventional scanning on neck

作　　者：郭锬[1] 周诚[1] 陈涓[1] 吴国庚[1] 杨正汉[1] 沈正寅 陈敏[1] 

机构地区：[1]卫生部北京医院放射科,100730

出　　处：《中华放射学杂志》2015年第4期279-282,共4页Chinese Journal of Radiology

摘　　要：目的探讨颈部能谱CT与常规CT扫描辐射剂量与图像质量的差异。方法回顾性分析行颈部增强CT扫描的60例患者，其中行能谱CT成像的30例作为能谱扫描组，行常规CT扫描的30例作为常规扫描组。能谱扫描组采用管电压80、140kVp瞬时切换，管电流为默认值630mA，转速0．5s/周；常规扫描组管电压120kVp，管电流采用自动毫安技术（100—600mA），转速0.6s/周。对2组患者上、中、下颈部图像进行客观评价[噪声、对比信噪比（CNR）]、主观评分，并记录辐射剂量。采用独立样本t检验比较2组患者的辐射剂量，采用独立样本t检验和秩和检验比较各部位65、55keV单能量图像与常规扫描组混合能量图像的客观评价指标和主观评分。结果能谱扫描组和常规扫描组的CT剂量指数分别为17．77、（17．26±2．18）mGy，差异无统计学意义（t=-1．26，P=0．218）。上、中、下颈部能谱扫描组65keV图像噪声分别为（4．5±0．8）、（4．5±0．9）、（5．2±1．0）HU，常规扫描组上述部位噪声分别为（4．5±1．1）、（4．1±1．0）、（5．0±1．7）HU，差异均无统计学意义（t值分别为0．102、-1．362、-0．621，P均〉0．05）。上、中、下颈部能谱扫描组65keV图像评分分别为（4．1±0．3）、（4．7±0．5）、（3．8±0．7）分，常规扫描组上述部位图像评分分别为（4．1±0．4）、（4．6±0．5）、（3．5±0．6）分，两组差异无统计学意义（Z值分别为-0．286、-0．531、-1．568，P均〉0.05）。上、中、下颈部能谱扫描组55keV图像噪声分别为（5．4±0．9）、（5．6±1．1）、（6．6±1．6）HU，均大于常规图像噪声，差异均有统计学意义（t值分别为-3．614、-5．560、-3．784，P均〈0．05）。上、中颈部能谱扫描组55keV图像评分分别为（3．7±0．5）、（4．2±0．4）分，低于常规组图像，差异有统计学意义（z值分别为-2．5Objective To investigate the radiation dose and image quality of spectral and conventional CT scan in neck. Methods Sixty patients with enhanced neck CT scan were analyzed retrospectively. The 30 patients with spectral CT scan were included in spectral CT group, and the 30 patients with conventional CT scan were included in conventional CT group. The tube voltage, tube current and rotation speed of the spectral CT group were fast switching with 80 and 140 kVp, 630 mA and 0.5 s, respectively. The scanning parameters of conventional CT group were 120 kVp, auto tube current （100 to 600 mA）, and 0.6 s, respectively. The objective evaluation [noise and （contrast to noise ratio） CNR] and subjective scores in the upper, middle and lower neck were evaluated. The radiation dose was also evaluated in the two groups. The independent-samples t test was used in comparison of the radiation dose. The independent-samples t test and the rank sum test were used to compare the objective and subjective image quality. Results The CT dose index of spectral and conventional scan in the neck were 17.77 mGy and （17.26±2.18） mGy, respectively without significant difference （t=-1.26, P=0.218）. The noises of 65 keV images in upper, middle and lower neck were （4.5 ± 0.8）, （4.5± 0.9）, （5.2± 1.0） HU, and the noises of conventional CT images in above-mentioned regions were （4.5± 1.1）, （4.1 ± 1.0）, （5.0± 1.7） HU. There was no significant differences （t=0.102, - 1.362, - 0.621; P〉0.05）. The subjective scores of 65 keV images in upper, middle and lower neck were （4.1 ± 0.3）, （4.7 ± 0.5）, （3.8 ± 0.7）, while the subjective scores of conventional CT images in associated region were （4.1 ±0.4）, （4.6 ±0.5）, （3.5 ±0.6）, wihtout significant differences （Z=- 0.286, - 0.531, - 1.568;P〉0.05）. The noises of 55 keV images in upper, middle and lower neck were （5.4±0.9）, （5.6±1.1）, （6.6± 1.6） HU, which were significandy higher than noise of conventional image

关 键 词：体层摄影术 x线计算机 辐射计量 对比研究 

分 类 号：R816[医药卫生—放射医学]