Diagnosis of Crystalopathies via Raman Spectroscopy

描述（由申请人提供）：关节间隙中晶体物质的存在和身份的误诊通常会导致关节病状况的不正确治疗。现有的偏振成像诊断标准缺乏特异性和敏感性，并且在很大程度上限于显微镜下可见的双折射晶体。在目前的研究中，我们提出了拉曼光谱作为一种替代诊断技术，以提高识别的晶体物种在联合空间。在拉曼光谱中，分子振动通过激光激发而触发，并且反射光保持关于观察区域中的种类的身份以及数量的信息。该技术目前用于关节镜下体内诊断其他疾病;因此，基于这种临床潜力，值得探索其分析和临床可行性，以评估关节病条件中涉及的晶体种类。拟议的探索性研究的第一阶段将揭示可以通过拉曼光谱检测的各种晶体的识别阈值。将不同浓度的尿酸盐、焦磷酸钙二水合物、羟基磷灰石、磷酸八钙、磷酸三钙、草酸钙、胆固醇、胱氨酸和黄嘌呤的合成类似物与健康滑液样品混合，并在宏观水平上分析这些混合物，以检测晶体发出的累积信号。我们将尝试通过采用表面增强拉曼光谱和光谱数据的主成分分析来降低识别阈值。在第二阶段，将从患者中采集滑液样本，并通过补偿偏光显微镜、X射线衍射和茜素染色确认晶体的存在或不存在。将对这些样品的等分试样进行拉曼分析，以确定拉曼分析是否可以检测临床样品中晶体的存在和鉴别。如果该探索性研究证明拉曼分析的分析限度足以涵盖晶体物质的临床浓度，则可以进行全面的临床研究以评估该技术的特异性和灵敏度，最终导致关节镜拉曼器械的开发。

DESCRIPTION (provided by applicant): Misdiagnosis of the presence and the identity of crystal species in joint space are often penalized with the incorrect treatment of the arthropathic condition. The existing diagnostic standard of polarized imaging lacks specificity and sensitivity and it is largely limited to microscopically visible birefringent crystals. In the current study we propose Raman spectroscopy as an alternative for diagnostic technology for improved identification of crystal species in joint spaces. In Raman spectroscopy molecular vibrations are triggered through laser excitation and the reflected light holds information on the identity as well as on the amount of species in the observed region. The technique is currently utilized for arthroscopic in vivo diagnosis of other diseases; thus, based on this clinical potential it would be worthwhile to explore its analytical and clinical feasibility towards the assessment of crystal species involved in arthropathic conditions. The first phase of the proposed exploratory study will reveal the identification thresholds of various crystals that can be detected by Raman spectroscopy. Synthetic analogs of monosodium urate, calcium pyrophosphate dihydrate, hydroxyapatite, octacalcium phosphate, tricalcium phosphate, calcium oxalate, cholesterol, cystine and xanthine will be mixed with healthy synovial fluid samples at various concentrations and these mixtures will be analyzed at the macro level to detect the cumulative signal emanating from crystals. We will attempt to lower the identification thresholds by employing surf ace-enhanced Raman spectroscopy and by principal component analysis of the spectral data. During the second phase synovial fluid samples will be taken from patients and the presence or absence of crystals will be confirmed via compensated polarized microscopy, X-ray diffraction and alizarin staining. Aliquots of these samples will be subjected to Raman analysis to determine whether Raman analysis can detect the presence and identity of crystals in clinical samples. If this exploratory study demonstrates that the analytical limits of Raman analysis suffice to cover clinical concentrations of crystal species than comprehensive clinical studies can be conducted to assess the specificity and the sensitivity of the technique finally leading to the development of an arthroscopic Raman device.