ISSN 1004-4140
CN 11-3017/P

深度学习重建算法的图像质量体模研究

Image Quality Assessment for Deep Learning Image Reconstruction Algorithm: A Phantom Study

  • 摘要: 目的:使用体模比较CT深度学习重建算法和迭代重建算法的图像质量。方法:使用GE Revolution Apex扫描ACR质量控制体模Gammex 464,分别测量module 1~module 4的5种物质CT值准确性、低对比度分辨率、图像均匀性和高对比度分辨率。通过指标比较高剂量下(20 mGy)深度学习重建算法TrueFedelity<sup<TM</sup<(TFI)3种等级(DL、DM及DH)和自适应统计迭代重建算法V(AV)3种等级(30%、60% 及90%)的图像质量。两种算法的各指标比较采用单因素方差分析。结果:所有6组图像的高/低分辨率均一致(高对比度分辨率:10 lp/cm;低对比度分辨率:6 mm);两种算法都轻微高估聚乙烯、空气以及丙烯酸的CT值,各物质间CT值差异不具有统计学意义。两种算法均低估骨和固态水的CT值,其中,TFI算法对固态水的CT值较AV更接近真实值,但各组图像间不具有统计学差异。6组图像中,TFIDH的图像均匀性最佳;同等级条件下,深度学习重建算法相较IR算法的图像均匀性更佳。结论:深度学习重建算法在高剂量水平下可以在保持图像空间分辨率和CT值准确性的基础上,进一步降低图像噪声。

     

    Abstract: Objective: To compare the image quality between the deep learning image reconstruction (DLIR) and iterative reconstruction (IR) algorithms via the dedicated phantom. Method: ACR quality assurance phantom (Gammex 464) was scanned by GE Revolution Apex. The CT value accuracy, low contrast resolution, image uniformity and high contrast resolution of five substances from module 1 to module 4 were measured respectively. Through the above indicators, the image quality of three levels (DL, DM and DH) of Truefedelitytm (TFI) and three levels (30%, 60% and 90%) of adaptive statistical iterative reconstruction-V (asir-V, hereinafter referred to as AV) under high dose (20 mgy) were compared. The comparison between the two algorithms for each parameter was tested by One-Way Anova. Results: The high/low-contrast resolution of the six image series were consistent (high-contrast resolution: 10 lp/cm; low-contrast resolution: 6 mm). The two algorithms both slightly overestimated the CT value of polyethylene, air and acrylic, and no statistically significant difference was found among the difference of CT values of the substances. Both algorithms underestimated the CT value of bone and the solid water; TFI showed better performance in evaluating the solid water which was closer to the real value, though statistical difference was not found between each group of images. Among the 6 groups of images, TFI DH showed the best image uniformity and at the same reconstruction level, TFI showed better uniformity than AV. Conclusion: DLIR can further reduced image noise while maintaining image spatial resolution and CT value accuracy at high dose level.

     

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