Qin Evelyn S, Bowen Mindy J, Chen Wei F
Division of Plastic and Reconstructive Surgery, Department of Surgery, University of Iowa Hospitals and Clinics, Iowa City, Iowa, USA.
Division of Plastic and Reconstructive Surgery, Department of Surgery, University of Iowa Hospitals and Clinics, Iowa City, Iowa, USA.
J Plast Reconstr Aesthet Surg. 2018 Jul;71(7):1041-1050. doi: 10.1016/j.bjps.2018.02.012. Epub 2018 Apr 9.
Bioimpedance spectroscopy (BIS) is used by healthcare specialists to diagnose lymphedema. BIS measures limb fluid content by assessing tissue resistance to the flow of electric current. However, there is debate regarding the validity of BIS in diagnosing early lymphedema. Indocyanine green (ICG) lymphography has been established as the most accurate diagnostic modality to date for lymphedema diagnosis. In this retrospective study, we test the sensitivity, specificity, and diagnostic accuracy of BIS in diagnosing lymphedema by referencing its results with ICG lymphography.
Patients presented to the University of Iowa Lymphedema Center from 2015 to 2017 were evaluated with a standardized protocol that included history and physical examination, a validated lymphedema-specific quality-of-life assessment (LYMQOL), circumference -measurement-based index, BIS, and ICG lymphography. Diagnostic accuracy of BIS was assessed using ICG lymphography as a reference test.
Fifty-eight patients had positive ICG lymphography results, which confirmed the diagnosis of lymphedema. ICG lymphographic findings consistently correlated with clinical examination, LYMQOL evaluation, and lymphedema indices. By contrast, BIS demonstrated a false-negative rate of 36% - 21 out of 58 patients had normal BIS readings, but a positive ICG lymphography result. The 21 false-negative results occurred in patients with early-stage disease. Sensitivity and specificity for BIS were 0.64 and 1, respectively.
BIS carries an excessively high rate of false-negative results to be dependably used as a diagnostic modality for lymphedema. ICG lymphography highly correlates with other tracking modalities, and it remains the most reliable tool for diagnosing lymphedema.
医疗保健专家使用生物电阻抗光谱法（BIS）诊断淋巴水肿。BIS通过评估组织对电流流动的阻力来测量肢体液体含量。然而，关于BIS在诊断早期淋巴水肿方面的有效性存在争议。吲哚菁绿（ICG）淋巴造影已被确立为迄今为止淋巴水肿诊断最准确的诊断方法。在这项回顾性研究中，我们通过将BIS的结果与ICG淋巴造影进行对比，测试BIS在诊断淋巴水肿时的敏感性、特异性和诊断准确性。
对2015年至2017年就诊于爱荷华大学淋巴水肿中心的患者，采用标准化方案进行评估，该方案包括病史和体格检查、经过验证的淋巴水肿特异性生活质量评估（LYMQOL）、基于周长测量的指数、BIS和ICG淋巴造影。以ICG淋巴造影作为参考测试，评估BIS的诊断准确性。
58例患者ICG淋巴造影结果呈阳性，确诊为淋巴水肿。ICG淋巴造影结果与临床检查、LYMQOL评估和淋巴水肿指数始终相关。相比之下，BIS的假阴性率为36%——58例患者中有21例BIS读数正常，但ICG淋巴造影结果呈阳性。这21例假阴性结果出现在早期疾病患者中。BIS的敏感性和特异性分别为0.64和1。
BIS的假阴性率过高，不能可靠地用作淋巴水肿的诊断方法。ICG淋巴造影与其他跟踪方法高度相关，仍然是诊断淋巴水肿最可靠的工具。
