Department of Mechanical Engineering, Ecole Polytechnique, Montreal, Canada.
BMC Musculoskelet Disord. 2012 Dec 3;13:239. doi: 10.1186/1471-2474-13-239.
Early stages of scoliosis and spondylolisthesis entail changes in the intervertebral disc (IVD) structure and biochemistry. The current clinical use of MR T2-weighted images is limited to visual inspection. Our hypothesis is that the distribution of the MRI signal intensity within the IVD in T2-weighted images depends on the spinal pathology and on its severity. Therefore, this study aims to develop the AMRSID (analysis of MR signal intensity distribution) method to analyze the 3D distribution of the MR signal intensity within the IVD and to evaluate their sensitivity to scoliosis and spondylolisthesis and their severities.
This study was realized on 79 adolescents who underwent a MRI acquisition (sagittal T2-weighted images) before their orthopedic or surgical treatment. Five groups were considered: low severity scoliosis (Cobb angle ≤50°), high severity scoliosis (Cobb angles >50°), low severity spondylolisthesis (Meyerding grades I and II), high severity spondylolisthesis (Meyerding grades III, IV and V) and control. The distribution of the MRI signal intensity within the IVD was analyzed using the descriptive statistics of histograms normalized by either cerebrospinal fluid or bone signal intensity, weighted centers and volume ratios. Differences between pathology and severity groups were assessed using one- and two-way ANOVAs.
There were significant (p < 0.05) variations of indices between scoliosis, spondylolithesis and control groups and between low and high severity groups. The cerebrospinal fluid normalization was able to detect differences between healthy and pathologic IVDs whereas the bone normalization, which reflects both bone and IVD health, detected more differences between the severities of these pathologies.
This study proves for the first time that changes in the intervertebral disc, non visible to the naked eye on sagittal T2-weighted MR images of the spine, can be detected from specific indices describing the distribution of the MR signal intensity. Moreover, these indices are able to discriminate between scoliosis and spondylolisthesis and their severities, and provide essential information on the composition and structure of the discs whatever the pathology considered. The AMRSID method may have the potential to complement the current diagnostic tools available in clinics to improve the diagnostic with earlier biomarkers, the prognosis of evolution and the treatment options of scoliosis and spondylolisthesis.
脊柱侧凸和脊椎滑脱的早期阶段涉及椎间盘（IVD）结构和生物化学的变化。目前临床上使用的磁共振 T2 加权图像仅限于视觉检查。我们的假设是，T2 加权图像中 IVD 内的 MRI 信号强度分布取决于脊柱病理学及其严重程度。因此，本研究旨在开发 AMRSID（磁共振信号强度分布分析）方法来分析 IVD 内的 3D 磁共振信号强度分布，并评估其对脊柱侧凸和脊椎滑脱及其严重程度的敏感性。
本研究共纳入 79 名青少年，他们在接受矫形或手术治疗前接受了 MRI 采集（矢状 T2 加权图像）。考虑了五个组：低严重度脊柱侧凸（Cobb 角≤50°）、高严重度脊柱侧凸（Cobb 角>50°）、低严重度脊椎滑脱（Meyerding 分级 I 和 II）、高严重度脊椎滑脱（Meyerding 分级 III、IV 和 V）和对照组。使用直方图的描述性统计信息分析 IVD 内的 MRI 信号强度分布，这些直方图通过脑脊液或骨信号强度进行归一化，加权中心和体积比。使用单因素和双因素方差分析评估病理学和严重程度组之间的差异。
在脊柱侧凸、脊椎滑脱和对照组之间以及在低严重度和高严重度组之间，指数存在显著差异（p<0.05）。脑脊液归一化能够检测到健康和病理性 IVD 之间的差异，而反映骨和 IVD 健康的骨归一化则能够检测到这些病理学严重程度之间的更多差异。
本研究首次证明，脊柱矢状 T2 加权磁共振图像上肉眼不可见的椎间盘变化，可以通过描述 MRI 信号强度分布的特定指数来检测。此外，这些指数能够区分脊柱侧凸和脊椎滑脱及其严重程度，并提供有关无论考虑何种病变，椎间盘组成和结构的重要信息。AMRSID 方法可能有潜力补充当前临床可用的诊断工具，通过早期生物标志物改善诊断，预测疾病进展，并为脊柱侧凸和脊椎滑脱提供治疗选择。
