MRI signal distribution within the intervertebral disc as a biomarker of adolescent idiopathic scoliosis and spondylolisthesis

Abstract

BackgroundEarly 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.MethodsThis 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.ResultsThere 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.ConclusionsThis 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.

T1ρ and T2 Mapping of the Intervertebral Disk: Comparison of Different Methods of Segmentation

“…15,21 In cases of severe scoliosis, disk degeneration may occur unevenly in different regions of the disk. [22][23][24] The presence of volunteers with scoliosis could potentially affect our results of comparison between different segmentation techniques, but it did not occur because we had no case of scoliosis. Panoramic radiographs were available for each case due to another research project in progress from our group.…”

“…The presence of osteophytes should also be considered carefully so that the segmentation does not encompass these regions. 25 Other accentuated postural changes, vertebral fractures, listhesis, or extruded disk herniation could also result in uneven disk degeneration, 24,26 so that using only central sagittal sections for data extraction could result in a different composition assessment of the disk. Our sample had no volunteer with deformities, fractures, or disk herniation.…”

Adolescent idiopathic scoliosis: evidence for intrinsic factors driving aetiology and progression

“…It is currently unclear whether these changes are a secondary response to spinal curvature and altered loading. However, changes to the intervertebral disc in AIS have been reported to occur early in the disease process, as detected by differences in magnetic resonance imaging (MRI) signal intensity [17]. In addition, MRI studies have detected central as well as concave and convex vertebral growth plate abnormalities to be frequently located near the apex of the curve [14], which could indicate that these abnormalities are a primary event.…”

Matrix metalloproteinase 12 is an indicator of intervertebral disc degeneration co-expressed with fibrotic markers

“…Due to the difficulty in obtaining IVD specimen from healthy individuals, this study used scoliotic IVD as the non-degenerated control. While IVDs from scoliosis patients may be subjected to abnormal load due to the deformity, scoliotic NP has been suggested to retain high water and proteoglycan content, as documented by MRI signal intensity 39 . It is also worth noting that although scoliotic IVDs may not be regarded as a true non-degenerated control, they were reported to represent accelerated ageing and are proposed to be analogous to IVD of 20 years older 40 .…”