新一代多模型迭代算法在70 kVp成人副鼻窦CT扫描中的应用

探讨成人在70 kVp副鼻窦CT检查中降低有效辐射剂量的同时,获取最佳图像质量的新一代多模型迭代算法(Adaptive Statistical Iterative Reconstruction-V,Asir-V)的权重。本研究对20例成人患者进行副鼻窦Revolution CT检查,采用70 kVp、230 mA条件下进行螺旋CT扫描,扫描完成后对每例患者的原始数据采用不同权重(0,20%,40%,60%,80%,100%)的后置新一代多模型迭代算法(Adaptive Statistical Iterative Reconstruction-V,Asir-V)重建的方法,共获得120幅图像,并对每例6组图像进行客观评价及主观评分。客观评价包括噪声(standard deviations, SD)和对比噪声比(contrast noise ratio,CNR),主观评价由2名评价医生对图像质量评分并对两者的主观一致性进行评价。每例患者扫描完成后,记录其剂量长度乘积(dose-length product,DLP)和CT容积剂量指数(CT dose index volume,CTDI_vol),并计算其平均有效辐射剂量(effective dose,ED)。客观评价结果表明不同权重的Asir-V图像噪声随着Asir-V权重的提升而降低,CNR值随着Asir-V权重的提升而升高,且有效辐射剂量ED较常规头颈部CT检查的平均辐射剂量明显减少;主观评价结果表明不同权重的Asir-V图像评分不同,在Asir-V 60% 时评分最高,且2名医生主观评价一致性好。结合主客观评价结果,认为在70 kVp、230 mA成人副鼻窦Revolution CT检查中,Asir-V 60％的图像既可满足临床诊断的需要,也可明显降低有效辐射剂量。

Application of adaptive statistical iterative reconstruction-V and 70 kVp in adult paranasal sinus CT scan

To investigate the weight of the Adaptive Statistical Reconstruction-V( Asir-V) algorithm to obtain the best image quality while reducing the effective radiation dose in adult paranasal sinus Revolution CT examination of 70 kVp. Revolution CT was applied to perform paranasal sinus scans in 20 cases of adults. The scanning conditions were 70 k Vp,230 m A. The original projection data,a total of 120 images were obtained,were reconstructed by using different weights( 0,20%,40%,60%,80%,100%) of the Pos-Asir-V technique. Six groups of each case of pictures were subjective rated and objective evaluated. The objective evaluation included the evaluation of noise( standard deviations,SD) and contrast noise ratio( CNR). The subjective rating was evaluated by two evaluation physicians for image quality scores and for their subjective consistency. After each patient had completed the scan,its dose-length product( dose-length product,DLP) and CT volumetric dose index( CT dose indexvolume,CTDIvol) were recorded and their average effective radiation dose( effective dose,ED) was calculated. The objective evaluation results showed that the Asir-V image noise with different weights decreased with the Asir-V weight,the CNR increased with the Asir-V weight,and the effective radiation dose( ED) significantly decreased compared with the average radiation dose of the regular head and neck CT examination. The subjective evaluation results showed that the Asir-V image scores with different weights were different,with a high score of 60% at Asir-V,and the subjective evaluation of two doctors was good. Combined with the subjective and objective evaluation results,it is concluded that the image of Asir-V 60% in 70 kVp,230 m A adult paranasal sinus Revolution CT examination could meet the needs of clinical diagnosis and significantly reduce the effective radiation dose.