不同重建方法对PET/CT肺内病灶SUV值及图像质量的影响

The influence of different reconstruction methods on standardized uptake value and image quality of PET/CT pulmonary lesions

  • 摘要:
    目的 研究PET/CT不同重建方法对肺内病灶标准摄取值(SUV)与图像质量的影响。
    方法 回顾性收集2023年3月至7月于江苏省中医院行PET/CT全身显像且有肺内病灶SUV摄取升高的44例患者的影像资料,其中男性33例、女性11例,年龄(69.8±11.0)岁,范围56~83岁。采用西门子Biograph vision 450 型PET/CT内置不同重建方法对病例图像进行图像质量分析研究。主要使用的重建方法包括反投影法(BP)、BP+时间飞行(TOF)、迭代(IT)、IT+TOF,分别对4组图像进行图像质量评估及定量分析。采用5级评分法进行图像视觉质量评估;分别测量各组图像病灶、肝血池以及纵隔血池的定量参数:最大标准摄取值(SUVmax)、平均标准摄取值(SUVmean)、SUV的标准差(SUVSD)、信噪比(SNR)以及相对SNR进行定量分析,以评估加入TOF后的重建方法对图像质量的影响。视觉评分的一致性分析采用Kappa检验进行评估。符合正态分布的图像参数等数据的组间比较,采用独立样本t检验;不符合正态分布的计量资料的组间比较,采用Mann-Whitney U检验(秩和检验)进行分析。
    结果 2名医师对44例患者图像的视觉评分结果具有高度一致性(Kappa=0.862,95%CI:0.745~0.979,P<0.001)。定量分析BP与IT加入TOF后均能降低噪声、提高SNR。BP加入TOF后,SNR由22.470(95%CI:14.003~35.827)提升至28.835(95%CI:19.417~45.341),P=0.007;IT加入TOF后SNR由76.880(95%CI:37.416~101.554)提升至126.593(95%CI:52.256~177.317),P=0.001。从相对SNR来看,IT+TOF的图像相对SNR>1的比例为97.7%,BP+TOF的图像相对SNR>1的比例为81.8%,TOF对于IT的提升更大。
    结论 进行PET/CT全身显像时对肺内病灶的观察使用BP与IT进行重建可加入TOF来提高图像质量。

     

    Abstract:
    Objective To investigate the influence of different reconstruction methods embedded in Siemens Biograph Vision 450 PET/CT on the image quality and standardized uptake value (SUV) of pulmonary lesions.
    Methods Analyzing retrospective collection of patients who underwent whole body imaging in our department from March to July 2023. Total patients: 44, 33 males, 11 females, average age of 69 years old from 56 to 83. Image quality analysis of the patient images was conducted using different reconstruction methods embedded in Siemens Biograph Vision 450 PET/CT. The main reconstruction methods used are as follows: Backproject, Backproject+ Time of Flight (TOF), Iterative, Iterative+TOF. The influence of adding TOF to different reconstruction methods on image quality SUVSD, signal-to-noise ratio (SNR) and realative SNR and related SUVs is analyzed and compared using kappa and rank-sum test
    Results The visual assessment of image quality scores shows a high degree of consistency, (Kappa=0.862, 95%CI: 0.745−0.979, P<0.001). Both Backprojection and Iterative can reduce noise and improve SNR after adding TOF, for Backprojection the SNR raised from 22.470(95%CI: 14.003−35.827) to 28.835(95%CI: 19.417−45.341) P=0.007 and for Iterative the SNR raised from 76.880(95%CI: 37.416−101.554) to 126.593(95%CI: 52.256−177.317) P=0.001. In terms of relative SNR, TOF method has a greater improvement on Iterative.
    Conclusion When using the Iterative or Backprojection built-in in Siemens Biograph Vision 450 PET/CT for reconstruction of the pulmonary lesions, TOF can be added as needed. Iterative is more recommended to use.

     

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