NON-INVASIVE MEASUREMENT OF INTERVERTEBRAL DISC OSMOTIC PRESSURE WITH T1P MRI

这个子项目是许多研究子项目中的一个 由NIH/NCRR资助的中心赠款提供的资源。子项目和 研究者（PI）可能从另一个NIH来源获得了主要资金， 因此可在其他CRISP条目中表示。所列机构为 研究中心，而研究中心不一定是研究者所在的机构。 椎间盘退变是一种常见的，有时使人衰弱的疾病， 占人口的很大比例。椎间盘退变的最早阶段涉及 髓核区域的蛋白多糖的分解和随后的消耗 阀瓣，这导致阀瓣中的流体静压力降低。钠MRI以前曾被 用于计算细胞核组织的固定电荷密度，随后可以 用于计算由钠阳离子吸引的渗透压， 蛋白聚糖上的固定电荷。椎间盘的渗透压与 流体静压是椎间融合器的重要生物力学特性， disc.目前用于评估椎间盘压力的临床技术是 椎间盘造影术，这是一种侵入性手术，已被证明可以启动和加剧 椎间盘退变在这项研究中，我们打算首先优化一个协议， 钠MRI测量完整椎间盘样品中的渗透压。但由于 由于其低信噪比效率，钠MRI的临床应用受到限制。与此相反的是， T1 <$MRI已被证明是一种测量固定电荷密度的准确技术， 纤维软骨如关节软骨和椎间盘。此外，由于T1目标 与常规MRI技术一样，它具有相对较高的信噪比 与钠MRI相比，其效率更高，这使得其更容易在临床环境中应用。 因此，本研究的目的是将使用钠MRI测量的渗透压与 到椎间盘的T1 <$弛豫时间常数。这样，我们就可以证明T1？ MRI无创测量椎间盘渗透压的临床应用价值。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Intervertebral disc degeneration is a common and sometimes debilitating condition affecting a significant percentage of the population. The earliest stage of disc degeneration involves the breakdown and subsequent depletion of proteoglycans in the nucleus pulposus region of the disc, which results in decreased hydrostatic pressure in discs. Sodium MRI has previously been used to calculate the fixed-charge-density of the nucleus tissue, which can subsequently be used to calculate the osmotic pressure generated by the sodium cations attracted by the fixed-charge on proteoglycans. The osmotic pressure of intervertebral disc is linearly related to the hydrostatic pressure, which is an importantly biomechanical property of the intervertebral disc. The current clinical technique for the assessment of intervertebral disc pressure is discography, which is an invasive procedure that has been shown to initiate and exacerbate intervertebral disc degeneration. In this study, we intend to first optimize a protocol to use sodium MRI to measure osmotic pressure in intact intervertebral disc samples. However, due to its low signal-to-noise ratio efficiency, sodium MRI's clinical applicability is limited. In contrast, T1¿ MRI has been shown to be an accurate technique for measuring fixed-charge-density in fibrocartilage such as articular cartilage and intervertebral disc. In addition, since T1¿ targets proton nuclei like conventional MRI techniques, it has comparatively higher signal-to-noise ratio efficiency compared to sodium MRI, which makes it more readily to be applied in clinical setting. Therefore the purpose of this study is to correlate osmotic pressure measured using sodium MRI to T1¿ relaxation time constant of intervertebral discs. In doing so, we can demonstrate T1¿ MRI's clinical utility in the non-invasive measurement of intervertebral disc osmotic pressure.