炎性和转移性淋巴结弥散加权成像b值选择的初探

Diffusion-weighted Imaging of Inflammatory and Metastatic Lymph Nodes:Primary research of b-value selection

目的对新西兰大白兔炎性和转移性腘窝淋巴结模型弥散加权成像图像质量定性和定量评价,选择合适的成像参数即b值。方法分别建立炎性和转移性淋巴结新西兰大白兔动物模型12只,分别选择b值=300、600、900对两组进行弥散加权成像,计算信噪比,进行非参Kruskal-WallisH检验。所有淋巴结经病理证实。结果肿瘤组当b=300、600、900三组的平均秩次分别为54.00、29.67、25.83,χ2值(即H值)为25.574,p=0.000,可认为三组信噪比(SNR)有差异。炎症组当b=300、600、900三组的平均秩次分别为54.13、37.04、18.33,χ2值(即H值)为35.574,p<0.05SNR有差异。结论选择合适的扩散梯度系数能够得到较佳的信号对比度,同时也能较准确地区分炎性和转移淋巴结。

Objective To select the appropriate b-value in order to qualitatively and quantitatively evaluate image quality on lymph node of New Zealand white rabbits which were inflammatory and metastatic by using diffusion-weighted imaging.Method We compared two groups of popliteal lymph nodes on 12 New Zealand white rabbits which were Inflammatory and metastatic,respectively.Diffusion-weighted imaging of the above two groups in which b value = 300,600,900 were operated to calculate the signal to noise ratio.Nonparametric Kruskal-Wallis H test were made to analyze the difference.All lymph nodes were pathologically confirmed.Results On tumor group,we got average rank of 54.00,29.67,and 25.83,respectively,according to the above three groups which b was equal to 300,600,900.Χ 2 value（i.e.,H value） were 25.574,p = 0.000.So that differences were considered to be significant.On inflammation group,average rank of three b value groups were 54.13,37.04,and 18.33,respectively.Χ 2 value（i.e.,H value） were 35.574,p 0.05.Significant differences were found on SNR.Conclusions Appropriate diffusion coefficient could lead to good signal to noise ratio and good image quality,which also accurately distinguish inflammatory lymph nodes from metastatic ones.