背景:淋巴水肿是一种疾病,其中组织肿胀是由皮下组织中的间质液滞留引起的。它是由淋巴系统受损引起的。淋巴闪烁显像是用于评估淋巴系统功能障碍的当前和主要方式。超声弹性成像是用于评估淋巴水肿肢体组织硬度的补充工具。组织硬度意味着存在组织微观结构的变化。然而,在淋巴水肿肢体的临床评估中,与组织微观结构相关的超声特征被忽略。在这项研究中,我们旨在评估超声Nakagami和熵成像的淋巴水肿诊断价值,它们是,分别,基于模型和非模型的散射体特征后向散射统计分析方法。
方法:共纳入60例患者,和淋巴闪烁显像用于对患者的肢体淋巴水肿的临床严重程度进行评分(0:正常;1:部分淋巴阻塞;2:完全淋巴阻塞)。我们进行了超声检查以获取B模式的超声反向散射信号,Nakagami,和熵成像。包络振幅,Nakagami,和熵值,作为患者淋巴阻塞等级的函数,以它们的中位数和四分位数间距(IQR)表示。然后将这些值用于独立t检验和受试者工作特征(ROC)曲线分析。
结果:对于患者评分从0增加到2,包络幅度值为405.44(IQR:238.72-488.17),411.52(IQR:298.53-644.25),和476.37(IQR:348.86-648.16),分别。Nakagami参数为0.16(IQR:0.14-0.22),0.26(IQR:0.23-0.34),和0.24(IQR:0.16-0.36),分别,熵值为4.55(IQR:4.41-4.66),4.86(IQR:4.78-4.99),和4.87(IQR:4.81-4.97),分别。从B模式和Nakagami分析获得的正常对照组和淋巴水肿组之间的P值大于0.05;而熵成像的P值小于0.05。B模式的ROC曲线下的面积,Nakagami,和熵成像为0.64(灵敏度:70%;特异性:47.5%),0.75(灵敏度:70%;特异性:75%),和0.94(灵敏度:95%;特异性:87.5%),分别。
结论:目前的发现证明了超声Nakagami和熵成像技术的诊断价值。特别是,使用非基于模型的熵成像能够提高表征肢体淋巴水肿时的性能。
BACKGROUND: Lymphedema is a disease in which tissue swelling is caused by interstitial fluid retention in subcutaneous tissue. It is caused by a compromised lymphatic system. Lymphoscintigraphy is the current and primary modality used to assess lymphatic system dysfunction. Ultrasound elastography is a complementary tool used for evaluating the tissue stiffness of the lymphedematous limb. Tissue stiffness implies the existence of changes in tissue microstructures. However, ultrasound features related to tissue microstructures are neglected in clinical assessments of lymphedematous limbs. In this study, we aimed to evaluate the lymphedematous diagnostic values of ultrasound Nakagami and entropy imaging, which are, respectively, model- and nonmodel-based backscattered statistical analysis methods for scatterer characterization.
METHODS: A total of 60 patients were recruited, and lymphoscintigraphy was used to score the patient\'s clinical severity of each of their limb lymphedema (0: normal; 1: partial lymphatic obstruction; and 2: total lymphatic obstruction). We performed ultrasound examinations to acquire ultrasound backscattered signals for B-mode, Nakagami, and entropy imaging. The envelope amplitude, Nakagami, and entropy values, as a function of the patients\' lymphatic obstruction grades, were expressed in terms of their median and interquartile range (IQR). The values were then used in both an independent t test and a receiver operating characteristic (ROC) curve analysis.
RESULTS: For each increase in a patient\'s score from 0 to 2, the envelope amplitude values were 405.44 (IQR: 238.72-488.17), 411.52 (IQR: 298.53-644.25), and 476.37 (IQR: 348.86-648.16), respectively. The Nakagami parameters were 0.16 (IQR: 0.14-0.22), 0.26 (IQR: 0.23-0.34), and 0.24 (IQR: 0.16-0.36), respectively, and the entropy values were 4.55 (IQR: 4.41-4.66), 4.86 (IQR: 4.78-4.99), and 4.87 (IQR: 4.81-4.97), respectively. The P values between the normal control and lymphedema groups obtained from B-mode and Nakagami analysis were larger than 0.05; whereas that of entropy imaging was smaller than 0.05. The areas under the ROC curve for B-mode, Nakagami, and entropy imaging were 0.64 (sensitivity: 70%; specificity: 47.5%), 0.75 (sensitivity: 70%; specificity: 75%), and 0.94 (sensitivity: 95%; specificity: 87.5%), respectively.
CONCLUSIONS: The current findings demonstrated the diagnostic values of ultrasound Nakagami and entropy imaging techniques. In particular, the use of non-model-based entropy imaging enables for improved performance when characterizing limb lymphedema.