In vivo characterisation of 3D intervertebral disc strains

腰痛是全球残疾的主要原因，据估计，NHS每年要花费5亿英镑。已经发现腰椎间盘退变和下腰痛之间的联系，这表明退变可能是一个促成因素。在这种情况下，确定患者并不是直接的，特别是因为有可能出现退变的椎间盘而不经历任何疼痛。最初，下腰痛的患者接受保守治疗，但对于需要手术的患者，椎体融合是最常见的手术，尽管越来越多的完全或部分椎间盘置换技术被认为是为了保持关节的运动。这些手术的结果相对较差，在10年内接受腰椎融合术的患者中，多达20%的患者需要进行翻修手术。改善患者选择对于使用这些治疗方法获得良好的临床结果非常重要，然而，目前可用的工具(通常是磁共振成像(MRI)或X射线)在做出临床决定之前提供的关于椎间盘功能的信息很少。定量评估椎间盘内变形的能力将提供一种独特的工具，使治疗能够针对适当的患者，从而改善结果。通过结合数字体积相关(DVC)技术和高分辨率研究扫描仪(9.4T)采集的MR图像，在测量人体身体标本的椎间盘变形方面取得了最新进展。这项技术的工作原理是获得同一标本的两组图像，一组未加载，另一组加载。然后在两组图像之间跟踪图像内的三维图案，从而可以计算变形和应变。这项研究的结果显示出巨大的潜力，但当该工具可以用于临床时，将会出现真正的突破，这在目前是不可能的，因为研究中的MRI扫描仪的直径不到10厘米。本研究将在临床MRI扫描仪(即每家医院使用的扫描仪为患者成像)中使用DVC，以创建一种非侵入性的临床方法来测量椎间盘变形。这一新的诊断工具将允许在治疗中更好地分层。它还将为健康和退变的椎间盘的复杂机制提供新的见解，这些信息将指导未来的手术治疗和医疗器械设计。

Low back pain is the leading cause of disability worldwide and is estimated to cost the NHS £500 million annually. A link has been found between degeneration of the intervertebral discs and low back pain, suggesting degeneration may be a contributing factor. Identifying patients where this is the case is not straight forward, particularly as it is possible to have degenerate discs without experiencing any pain at all.Initially, patients with low back pain are treated conservatively, but for those who require surgery, fusion of the vertebrae is the most common procedure, although increasingly total or partial disc replacement technologies are considered to preserve motion at the joint. Outcomes from these procedures are relatively poor, with revision surgeries required in as many as 20% of patients who undergo a lumbar fusion within 10 years. Improving patient selection is important for good clinical outcomes using these treatments, however the tools currently available (usually Magnetic Resonance Imaging (MRI) or X-ray) provide little information of how the disc is functioning before a clinical decision is made. The ability to assess quantitatively the deformations within discs would provide a unique tool to allow treatments to be targeted towards appropriate patients and therefore improve outcomes. Recent advances have been made in measuring disc deformations in human cadaveric specimens by combining a technique called Digital Volume Correlation (DVC) and MR images captured with a high-resolution research scanner (9.4T). The technique works by obtaining two sets of images of the same specimen, one unloaded, and one loaded. Three dimensional patterns within the images are then tracked between the two sets of images such that deformations and strains can be calculated. Results from this study show huge potential but a real breakthrough will come when the tool can be used clinically, this is not currently possible because the bore of research MRI scanners is less than 10cm in diameter.This study will utilise DVC in clinical MRI scanners (that is, scanners used in every hospital to image patients) to create a non-invasive clinical method of measuring intervertebral disc deformations. This novel diagnostic tool will allow better stratification in treatment. It will also provide fresh insight into the intricate mechanics of healthy and degenerate discs, information that will guide future surgical treatments and medical device designs.