基于 Scout 的自动管电压选择技术（千伏辅助）在胸部增强计算机断层扫描中的应用：对辐射剂量和图像质量的影响

Scout-Based Automated Tube Potential Selection Technique (kV Assist) in Enhanced Chest Computed Tomography: Effects on Radiation Exposure and Image Quality.

作者信息

Li Meng, Feng Shichao, Wu Ning, Zhang Li

机构信息

From the *Department of Diagnostic Radiology, and †PET-CT Center, Cancer Hospital, Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing, People's Republic of China.

出版信息

J Comput Assist Tomogr. 2017 May/Jun;41(3):442-445. doi: 10.1097/RCT.0000000000000523.

DOI:10.1097/RCT.0000000000000523

PMID:27759600

Abstract

OBJECTIVE

The aim of our study was to assess radiation dose reduction and image quality for enhanced chest CT examinations with a scout-based automated tube potential selection technique (kV Assist) compared with a standard 120-kV protocol.

METHODS

Prospective study of enhanced chest CT examinations was performed in 100 consecutive patients with kV Assist and in 100 consecutive patients with conventional 120-kV protocol on a multislice CT (Discovery CT750 HD). The body mass index, CT dose index volume, and dose length product were recorded from the examination protocol. Image noise and CT value was measured on region of interest, signal-to-noise ratio, and contrast-to-noise ratio was calculated. The subjective image quality was assessed by two radiologists blinded to the respective protocol with the use of a 3-grade scale (3, superior quality; 2, moderate quality; 1, inferior quality).

RESULTS

With kV Assist, the percentages of patients being scanned using 80, 100, and 120 kV were 12.0%, 80.0%, and 8.0%, respectively. The kilovolt setting was related with body mass index (r = 0.565, P = 0.000). Compared with the conventional 120 kV protocol, kV Assist allowed for an overall average decrease of 30.6% in CT dose index volume (kV Assist, 11.05 ± 4.78 mGy; 120 kV, 15.92 ± 6.89 mGy) (P < 0.001) and 32.3% in dose length product (kV Assist, 386.41 ± 184.02 mGy cm; 120 kV, 571.14 ± 286.68 mGy cm) (P < 0.001). In the kV Assist, mean attenuation of regions of interest inside the aorta was significantly higher than that in 120-kV protocols (kV Assist, 310.27 ± 73.70 HU; 120 kV, 239.44 ± 47.65 HU) (P < 0.001), resulting in increased contrast-to-noise ratio (kV Assist, 26.69 ± 7.78; 120 kV, 21.38 ± 6.05) (P < 0.001). There was no significant difference in subjective image quality scores between the 2 groups.

CONCLUSIONS

The use of attenuation-based kV Assist technique enables significant dose reduction in enhanced chest CT scan while improving arterial enhancement and preserving image quality at adequate levels.

摘要

目的

我们研究的目的是评估与标准120 kV方案相比，基于定位像的自动管电压选择技术（kV Assist）在增强胸部CT检查中降低辐射剂量和图像质量的情况。

方法

对100例连续接受kV Assist检查的患者和100例连续接受传统120 kV方案检查的患者进行了增强胸部CT检查的前瞻性研究。在多排CT（Discovery CT750 HD）上，从检查方案中记录体重指数、CT剂量指数容积和剂量长度乘积。在感兴趣区域测量图像噪声和CT值，计算信噪比和对比噪声比。由两位对各自方案不知情的放射科医生使用3级评分量表（3分，优质；2分，中等质量；1分，劣质）评估主观图像质量。

结果

使用kV Assist时，分别以80 kV、100 kV和120 kV扫描的患者百分比为12.0%、80.0%和8.0%。管电压设置与体重指数相关（r = 0.565，P = 0.000）。与传统120 kV方案相比，kV Assist使CT剂量指数容积总体平均降低30.6%（kV Assist，11.05±4.78 mGy；120 kV，15.92±6.89 mGy）（P < 0.001），剂量长度乘积降低32.3%（kV Assist，386.4l±184.02 mGy cm；120 kV，571.14±286.68 mGy cm）（P < 0.001）。在kV Assist组中，主动脉内感兴趣区域的平均衰减显著高于120 kV方案组（kV Assist，310.27±73.70 HU；120 kV，239.44±47.65 HU）（P < 0.001），导致对比噪声比增加（kV Assist，26.69±7.78；120 kV，21.38±6.05）（P < 0.001）。两组主观图像质量评分无显著差异。