Development of measurement of water content in articular cartilage using near infrared spectroscopy for diagnosis of osteoarthritis

本研究的目的是建立一种通过测量软骨含水量来测定退变软骨力学性能的方法。为此，使用了近红外（NIR）光谱法，其可以根据吸光度定量测量水含量。先前的研究发现正常关节软骨之间的渗透性存在差异（透明软骨）和OA（骨关节炎）软骨（纤维软骨），因此，在压痕测试之后，这两种软骨之间预期具有不同的时间依赖性含水量。首先，本研究涉及人体软骨的吸光度恢复与退化之间的详细关系的两个方面，即，1）人关节软骨的退化与去除压痕载荷后相对于时间的吸光度模式之间的关系，2）通过Mankin评分分级的人关节软骨的退化与吸光度变化之间的关系 ...更多信息 其次，本研究探讨软骨与高耶豆腐在压缩过程中吸光度的降低。压痕后吸光度的恢复分为3种模式。观察到吸光度的初始降低和随后的增加（模式1）、在去除压痕载荷之后吸光度的立即增加（模式2）和吸光度没有恢复（模式3）。在大多数分级为“正常”的标本中，吸光度的恢复模式为“模式1”。在“模式1”的样本中，Mankin评分能够与吸光度具有最小值的时间相关。在“模式2”的样本中，平均值± S.D. Mankin评分为3.6±2.0。软骨在压缩过程中表现出吸光度的增加，而koya-tofu在压缩过程中表现出吸光度的减少。因此，近红外光谱使我们能够进行低侵入性，无损和定量测量的水含量在关节软骨，这可以应用于骨关节炎的程度的诊断。少

The objective of this study is to develop the method for the determination of mechanical properties of the degenerated articular cartilage through the measurement of water content. To this end, near infrared (NIR) spectroscopy which can measure water content quantitatively in terms of absorbance was used. Previous studies found differences in permeability between normal articular cartilage (hyaline cartilage), and OA (osteoarthritis) cartilage (fibrocartilage), and therefore different time-dependent water content after indentation testing was expected between these two cartilages.First, this study deals with the two aspects of the detailed relations between recovery of absorbance and degeneration of human cartilage, that is, 1) relation between the degeneration of human articular cartilage and pattern of absorbance with respect to time after removal of indentation load, 2) relation between the degeneration of human articular cartilage graded by Mankin Score and variation of absorbance … More with time after removal indentation load.Second, this study discusses the decreases of absorbance for cartilages and koya-tofu during compression. The recoveries of absorbance after indentation were classified into 3 patterns. Initial decrease and the subsequent increase of absorbance (pattern 1), immediate increase of absorbance after removal of indentation load (pattern 2), and no recovery of absorbance (pattern 3) were observed. In the most of specimens graded as "normal", the recovery pattern of absorbance was "pattern 1". In the specimens of "pattern 1", the Mankin Score was able to be related to the time when absorbance had the minimum value. In the specimens of "pattern 2", the mean ± S.D. of Mankin Score was 3.6±2.0. Cartilages showed the increase of absorbance during compression, while koya-tofu showed the decrease of absorbance during compression.It is concluded that NIR spectroscopy enables us to perform the low-invasive, nondestructive and quantitative measurement of water content in articular cartilage, and this can be applied to the diagnosis of the extent of osteoarthritis. Less