Spectroscopic data of pleural effusion

Pleural effusion is a medical condition having its etiology in various primary diseases, eg. cardiological, pulmonological, and oncological. It is a side effect of diseases such as pneumonia, tuberculosis, cancer, heart failure, and inflammation which are responsible for causing inflammatory diseases of the pleura. Late detection of pleural effusion disturbs the respiratory function, heart operation or may cause bleeding into the pleural cavity. In such a case, there is an immediate requirement for medical intervention and drainage of the pleural space or execution of pleurodesis causing pleural plaques to fuse, which is an invasive and potentially life-threatening procedure. Therefore, patients with fluid in the pleural cavity, especially a group with recurrent pleural effusion should be continuously monitored. In a standard clinical procedure, the presence of pleural effusion is diagnosed by a physician with the use of chest radiography, ultrasonography, or computed tomography. Although ultrasound becomes portable and handheld the diagnosis is possible only in the clinics or medical centers so far. The monitoring of pleural effusion in outpatients is still an unsolved problem. So far, the use of near-infrared spectroscopy (NIRS) to test the amount of hydro-derivative fluids in various biomedical applications has been developed. For example, a method for assessing brain edema, water composition in rabbit meal, the water content in moisturizing creams or ceramic plasters has been published. In this work, the data form noninvasive NIRS measurement in patients with pleural effusion were collected. The method for noninvasive detection of pleural effusion using continuous-wave near-infrared spectroscopy is presented. The method has been developed based on numerical simulations of light transport in turbid media and validated on phantoms mimicking tissues and on patients with excess pleural fluid undergoing thoracocentesis. Numerical simulations consisted in modeling light propagation in an optically turbid, non-homogeneous medium with tissue properties of peripulmonary structures and for various amounts of pleural fluid. A three-layer model depicting pleural effusion was adopted. It was assumed that the outer surface layer consists of skin, fat and muscle. Fiber optics were connected to this layer during measurements. Two fiber optics were used: one guiding the light from the source (emitter) and the second delivering to the spectrometer (detector). The second layer, present only when pleural effusion is present, is water layer. The third layer is the lung tissue layer. The NIRS measurement was performed in a reflective scenario.胸腔积液（Pleural effusion）是一类病因源于多种原发性疾病的临床病症，涵盖心脏科、呼吸科及肿瘤科相关疾病。该病症是肺炎、肺结核、癌症、心力衰竭与炎症等疾病的并发症，上述疾病可引发胸膜炎症性病变。胸腔积液的延迟诊断会干扰呼吸功能、影响心脏手术开展，甚至可导致胸膜腔出血。此时需立即开展医疗干预，包括胸膜腔引流或实施胸膜固定术（pleurodesis）以促使胸膜斑融合，该操作属于侵入性且可能危及生命的手术方式。因此，存在胸腔积液的患者，尤其是复发性胸腔积液人群，需接受持续监测。 在标准临床流程中，医师通过胸部X线摄影（chest radiography）、超声检查（ultrasonography）或计算机断层扫描（computed tomography, CT）诊断胸腔积液。尽管超声设备已实现便携化与手持式操作，但截至目前，此类诊断仍仅能在诊所或医疗中心开展。门诊患者的胸腔积液监测仍是尚未解决的临床难题。 目前，近红外光谱（near-infrared spectroscopy, NIRS）已被开发用于多种生物医学应用中检测水性体液的含量，例如用于评估脑水肿、兔肌肉的水分组成、保湿霜或陶瓷石膏中的水分含量。本研究收集了胸腔积液患者的无创NIRS测量数据，并提出了一种基于连续波（continuous-wave）近红外光谱的无创胸腔积液检测方法。 该方法基于浑浊介质中的光传输数值模拟开发，并在模拟人体组织的体模（phantoms）以及接受胸腔穿刺术（thoracocentesis）的胸腔积液过量患者中得到验证。数值模拟工作包括对具有肺周围组织光学特性的浑浊非均匀介质，以及不同体积胸腔积液的光传播过程进行建模。本研究采用了描述胸腔积液的三层模型：假设外层为皮肤、脂肪与肌肉组织，测量过程中将光纤（fiber optics）连接至该层，共使用两根光纤：一根用于传输光源发出的光（发射器，emitter），另一根用于将光传导至光谱仪（spectrometer，探测器，detector）。仅当存在胸腔积液时才存在的第二层为水层，第三层为肺组织层。NIRS测量采用反射式检测构型。