结合迭代重建算法的低剂量CT在颈部的应用研究

胡启云; 董越; 张瑞; 王菲菲; 董瑞彤; 罗娅红; 王长德

doi:10.15953/j.1004-4140.2018.27.04.04

摘要: 目的：探讨结合迭代重建算法的低剂量CT在颈部应用价值。方法：172例疑头颈部病变患者行CT检查，随机分为常规剂量组（86例，管电流125 mAs）和低剂量组（86例，40~110 mAs），分别采用滤波反投影和三维自适应迭代剂量降低（AIDR3D）重建。在下颌角及上纵隔水平分别测量不同组织的CT均值及标准差，由两位CT影像医师采用4分法标准对图像盲法评分；比较图像质量差异和不同扫描方式下患者的辐射剂量。结果：下颌角水平，低剂量组颈内静脉噪声高于常规剂量组（&lt;i&lt;P&lt;/i&lt;&lt;0.05），两组间胸锁乳突肌噪声、信噪比、对比噪声比及背景噪声无明显差异（&lt;i&lt;P&lt;/i&lt;&lt;0.05）；上纵隔水平，低剂量组上腔静脉、胸大肌及胸壁皮下脂肪噪声低于常规剂量组（&lt;i&lt;P&lt;/i&lt;&lt;0.05），信噪比更高（&lt;i&lt;P&lt;/i&lt;&lt;0.05），对比噪声比相仿（&lt;i&lt;P&lt;/i&lt;&lt;0.05）。常规剂量和低剂量组图像质量的评分一致性均良好，下颌角水平低剂量组图像质量评分与常规剂量组图像无明显差异（&lt;i&lt;P&lt;/i&lt;&lt;0.05）；上纵隔水平低剂量组图像评分优于常规剂量组（&lt;i&lt;P&lt;/i&lt;&lt;0.05）；与常规剂量组相比，低剂量组有效辐射剂量显著降低（&lt;i&lt;P&lt;/i&lt;&lt;0.05），剂量指数减低63.34%，有效辐射剂量减低63.16%。结论：结合三维自适应迭代剂量降低重建的低剂量CT技术可以用于颈部CT扫描，可以减少辐射剂量并提供优质的图像。

Abstract: Objective: Exploring the application value of iterative reconstruction algorithm in neck low-dose computed tomography (CT). Methods: 172 patients undergoing CT examination on a 640-slice CT system for suspected neck diseases, were randomly divided into routine-dose (86 cases, 125 m As) and low-dose (86 cases, 40-110 m As) groups, with using conventional filtered back projection construction and Auto-m A adaptive iterative dose reduction construction with three dimensional processing technology respectively. Mean attenuation values and standard deviation (SD) were measured and recorded on the level of mandible and mediastinum, image quality was assessed objectively at the level of mandible and superior mediastinum and by two independent readers using a four-point scale. The image quality and radiation dose were compared using with independent sample test and wilcoxon rank sum test. Results: On the level of mandible, the internal jugular vein (IJV) noise in low-dose group was significantly higher than that in routine-dose group (&lt;i&lt;P&lt;/i&lt;&lt;0.05), while there was not significantly different in noise, signal-to-noise-ratio (SNR), contrast-to-noise ratio (CNR) of sternocleidomastoid muscle (SCM) and background noise between the two groups (&lt;i&lt;P&lt;/i&lt;&lt;0.05). On the level of mediastinum, the noise in low-dose group was lower than that in routine-dose group (&lt;i&lt;P&lt;/i&lt;&lt;0.05), while the SNR was higher (&lt;i&lt;P&lt;/i&lt;&lt;0.05). There was not significant difference in CNR between the two groups (&lt;i&lt;P&lt;/i&lt;&lt;0.05). The agreement of the routine-dose and low-dose image quality was good. Both readers graded the similar score on the level of mandible for overall image quality (&lt;i&lt;P&lt;/i&lt;&lt;0.05), but the low-dose group graded higher score than routine-dose on the level of mediastinum (&lt;i&lt;P&lt;/i&lt;&lt;0.05). Comparing to the routine-dose group, the CT dose index (CTDIvol) and effective dose (ED) in low-dose group reduced about 63.34% and 63.16%. Conclusion: Low-dose CT with AIDR3 D can provide high quality image with the reduction of radiation dose, and it has application value in low-dose CT of neck.

结合迭代重建算法的低剂量CT在颈部的应用研究

The Study of Low-dose Computed Tomography with Iterative Reconstruction in Neck