Comparison and optimization of sheep in vivo intervertebral disc injury model.

Background The current standard of care for intervertebral disc (IVD) herniation, surgical discectomy, does not repair annulus fibrosus (AF) defects, which is partly due to the lack of effective methods to do so and is why new repair strategies are widely investigated and tested preclinically. There is a need to develop a standardized IVD injury model in large animals to enable comparison and interpretation across preclinical study results. The purpose of this study was to compare in vivo IVD injury models in sheep to determine which annulus fibrosus (AF) defect type combined with partial nucleus pulposus (NP) removal would better mimic degenerative human spinal pathologies. Methods Six skeletally mature sheep were randomly assigned to one of the two observation periods (1 and 3 months) and underwent creation of 3 different AF defect types (slit, cruciate, and box-cut AF defects) in conjunction with 0.1 g NP removal in three lumbar levels using a lateral retroperitoneal surgical approach. The spine was monitored by clinical CT scans pre- and postoperatively, at 2 weeks and euthanasia, and by magnetic resonance imaging (MRI) and histology after euthanasia to determine the severity of degeneration (disc height loss, Pfirrmann grading, semiquantitative histopathology grading). Results All AF defects led to significant degenerative changes detectable on CT and MR images, produced bulging of disc tissue without disc herniation and led to degenerative and inflammatory histopathological changes. However, AF defects were not equal in terms of disc height loss at 3 months postoperatively; the cruciate and box-cut AF defects showed significantly decreased disc height compared to their preoperative height, with the box-cut defect creating the greatest disc height loss, while the slit AF defect showed restoration of normal preoperative disc height. Conclusions The tested IVD injury models do not all generate comparable disc degeneration but can be considered suitable IVD injury models to investigate new treatments. Results of the current study clearly indicate that slit AF defect should be avoided if disc height is used as one of the main outcomes; additional confirmatory studies may be warranted to generalize this finding

The value of magnetic resonance imaging and computed tomography in the study of spinal disorders

Computed tomography (CT) and magnetic resonance imaging (MRI) have replaced conventional radiography in the study of many spinal conditions, it is essential to know when these techniques are indicated instead of or as complementary tests to radiography, which findings can be expected in different clinical settings, and their significance in the diagnosis of different spinal conditions. Proper use of CT and MRI in spinal disorders may facilitate diagnosis and management of spinal conditions. An adequate clinical approach, a good understanding of the pathological manifestations demonstrated by these imaging techniques and a comprehensive report based on a universally accepted nomenclature represent the indispensable tools to improve the diagnostic approach and the decision-making process in patients with spinal pain. Several guidelines are available to assist clinicians in ordering appropriate imaging techniques to achieve an accurate diagnosis and to ensure appropriate medical care that meets the efficacy and safety needs of patients. This article reviews the clinical indications of CT and MRI in different pathologic conditions affecting the spine, including congenital, traumatic, degenerative, inflammatory, infectious and tumor disorders, as well as their main imaging features. It is intended to be a pictorial guide to clinicians involved in the diagnosis and treatment of spinal disorders

Diagnostic Imaging in Intervertebral Disc Disease

Imaging is integral in the diagnosis of canine intervertebral disc disease (IVDD) and in differentiating subtypes of intervertebral disc herniation (IVDH). These include intervertebral disc extrusion (IVDE), intervertebral disc protrusion (IVDP) and more recently recognized forms such as acute non-compressive nucleus pulposus extrusion (ANNPE), hydrated nucleus pulposus extrusion (HNPE), and intradural/intramedullary intervertebral disc extrusion (IIVDE). Many imaging techniques have been described in dogs with roles for survey radiographs, myelography, computed tomography (CT), and magnetic resonance imaging (MRI). Given how common IVDH is in dogs, a thorough understanding of the indications and limitations for each imaging modality to aid in diagnosis, treatment planning and prognosis is essential to successful case management. While radiographs can provide useful information, especially for identifying intervertebral disc degeneration or calcification, there are notable limitations. Myelography addresses some of the constraints of survey radiographs but has largely been supplanted by cross-sectional imaging. Computed tomography with or without myelography and MRI is currently utilized most widely and have become the focus of most contemporary studies on this subject. Novel advanced imaging applications are being explored in dogs but are not yet routinely performed in clinical patients. The following review will provide a comprehensive overview on common imaging modalities reported to aid in the diagnosis of IVDH including IVDE, IVDP, ANNPE, HNPE, and IIVDE. The review focuses primarily on canine IVDH due to its frequency and vast literature as opposed to feline IVDH

Spinal degeneration is associated with lumbar multifidus morphology in secondary care patients with low back or leg pain

Associations between multifidus muscle morphology and degenerative pathologies have been implied in patients with non-specific low back pain, but it is unknown how these are influenced by pathology severity, number, or distribution. MRI measures of pure multifidus muscle cross-sectional area (CSA) were acquired from 522 patients presenting with low back and/or leg symptoms in an outpatient clinic. We explored cross-sectional associations between the presence, distribution, and/or severity of lumbar degenerative pathologies (individually and in aggregate) and muscle outcomes in multivariable analyses (beta coefficients [95% CI]). We identified associations between lower pure multifidus muscle CSA and disc degeneration (at two or more levels): − 4.51 [− 6.72; − 2.3], Modic 2 changes: − 4.06 [− 6.09; − 2.04], endplate defects: − 2.74 [− 4.58; − 0.91], facet arthrosis: − 4.02 [− 6.26; − 1.78], disc herniations: − 3.66 [− 5.8; − 1.52], and when > 5 pathologies were present: − 6.77 [− 9.76; − 3.77], with the last supporting a potential dose–response relationship between number of spinal pathologies and multifidus morphology. Our findings could hypothetically indicate that these spinal and muscle findings: (1) are part of the same degenerative process, (2) result from prior injury or other common antecedent events, or (3) have a directional relationship. Future longitudinal studies are needed to further examine the complex nature of these relationships

A deep learning pipeline for automatized assessment of spinal MRI

Background This work evaluates the feasibility, development, and validation of a machine learning pipeline that includes all tasks from MRI input to the segmentation and grading of the intervertebral discs in the lumbar spine, offering multiple different radiological gradings of degeneration as quantitative objective output. Methods The pipelines’ performance was analysed on 1′000 T2-weighted sagittal MRI. Binary outputs were assessed with the harmonic mean of precision and recall (DSC) and the area under the precision-recall curve (AUC-PR). Multi-class output scores were averaged and complemented by the Top-2 categorical accuracy. The processing success rate was evaluated on 10′053 unlabelled MRI scans of lumbar spines. Results The midsagittal plane selection achieved an DSC of 74,80% ± 2,99% and an AUC-PR score of 81.71% ± 2.72% (96.91% Top-2 categorical accuracy). The segmentation network obtained a DSC of 91.80% ± 0.44%. The Pfirrmann grading of intervertebral discs in the midsagittal plane was classified with a DSC of 64.08% ± 3.29% and an AUC-PR score of 68.25% ± 6.00% (91.65% Top-2 categorical accuracy). Disc herniations achieved a DSC of 61.57% ± 3.39% and an AUC-PR score of 66.86% ± 5.03%. The cranial endplate defects reached a DSC of 49.76% ± 3.45% and 52.36% ± 1.98% AUC-PR (slightly superior predictions of caudal endplate defect). The binary classifications for the caudal Schmorl's nodes obtained a DSC of 91.58% ± 2.25% with an AUC-PR metric of 96.69% ± 1.58% (similar performance for cranial Schmorl's nodes). Spondylolisthesis was classified with a DSC of 89.03% ± 2.42% and an AUC-PR score of 95.98% ± 1.82%. Annular Fissures were predicted with a DSC of 78.09% ± 7.21% and an AUC-PR score of 86.31% ± 7.45%. Intervertebral disc classifications in the parasagittal plane achieved an equivalent performance. The pipeline successfully processed 98.53% of the provided sagittal MRI scans. Conclusions The present deep learning framework has the potential to aid the quantitative evaluation of spinal MRI for an array of clinically established grading systems. + Graphical abstrac

Comparison of T2-weighted Magnetic Resonance Imaging findings with histological findings in degenerated lumbar discs in patients with lumbar disc herniation

Diagnosis of disc degeneration and herniation largely depends on Magnetic Resonance Imaging (MRI) and X-rays which fails to detect early disc degeneration. This study was conducted to compare the degenerative changes seen in histological assessment with T2-weighted MRI findings. The study recruited 104 patients with lumbar disc herniation undergoing lumbar discectomy. Excised lumbar disc fragments were taken for histology and T2-weighted MRI was conducted prior to the surgery. Excised disc fragments were subjected to routine histology procedure and van Gieson stain for collagen was performed on each specimen.  Disc degeneration was assessed by histological parameters and T2-weighted MRI findings. The majority of subjects (94.2%) showed degenerative changes of the excised portion of the lumbar discs in histological assessment of the disc. However, T2-weighted MRI findings of degenerative changes of the discs were comparatively less (35.6%). According to the histological assessment, higher percentage (61.5 %) of discs were moderately degenerated while 7.7 % had severely degenerated discs. All patients who were confirmed for disc degeneration with T2-weighted MRI (n=37) had confirmed degenerative changes in the histological assessment as well. Histological degenerative alterations were observed in the majority of patients when compared to detectable degenerative changes in T2-weighted MRI suggesting the importance of histological assessment of degeneration in the excised intervertebral disc fragments. As early degenerative changes are not detected by the standard T2weighted MRI technique, if neglected, can progress to severe stages resulting in more discomfort and pain to the patients. KEYWORDS:    Disc degeneration, Histology, Magnetic Resonance Imaging &nbsp

Lumbar disk 3D modeling from limited number of MRI axial slices

This paper studies the problem of clinical MRI analysis in the field of lumbar intervertebral disk herniation diagnosis. It discusses the possibility of assisting radiologists in reading the patients MRI images by constructing a 3D model for the region of interest using simple computer vision methods. We use axial MRI slices of the lumbar area. The proposed framework works with a very small number of MRI slices and goes through three main stages. Namely, the region of interest extraction and enhancement, inter-slice interpolation, and 3D model construction. We use the Marching Cubes algorithm to construct the 3D model of the the region of interest. The validation of our 3D models is based on a radiologist’s analysis of the models. We tested the proposed 3D model construction on 83 cases and We have a 95% accuracy according to the radiologist evaluation. This study shows that 3D model construction can greatly ease the task of the radiologist which enhances the working experience. This leads eventually to more accurate and easy diagnosis process

Paraspinal muscle gene expression across different aetiologies in individuals undergoing surgery for lumbar spine pathology

PURPOSE The purpose of this study was to understand potential baseline transcriptional expression differences in paraspinal skeletal muscle from patients with different underlying lumbar pathologies by comparing multifidus gene expression profiles across individuals with either disc herniation, facet arthropathy, or degenerative spondylolisthesis. METHODS Multifidus biopsies were obtained from patients (n = 44) undergoing lumbar surgery for either disc herniation, facet arthropathy, or degenerative spondylolisthesis. Diagnostic categories were based on magnetic resonance images, radiology reports, and intraoperative reports. Gene expression for 42 genes was analysed using qPCR. A one-way analysis of variance was performed for each gene to determine differences in expression across diagnostic groups. Corrections for multiple comparisons across genes (Benjamini-Hochberg) and for between-group post hoc comparisons (Sidak) were applied. RESULTS Adipogenic gene (ADIPOQ) expression was higher in the disc herniation group when compared to the facet arthropathy group (p = 0.032). Adipogenic gene (PPARD) expression was higher in the degenerative spondylolisthesis group when compared to the disc herniation group (p = 0.013), although absolute gene expression levels for all groups was low. Fibrogenic gene (COL3A1) had significantly higher expression in the disc herniation group and facet arthropathy group when compared to the degenerative spondylolisthesis group (p < 0.001 and p = 0.038, respectively). When adjusted for multiple comparisons, only COL3A1 remained significant (p = 0.012). CONCLUSION Individuals with disc herniation and facet arthropathy demonstrate higher COL3A1 gene expression compared to those with degenerative spondylolisthesis. Future research is required to further understand the biological relevance of these transcriptional differences

Improving radiologists’ and orthopedists’ QoE in diagnosing lumbar disk herniation using 3D modeling

This article studies and analyzes the use of 3D models, built from magnetic resonance imaging (MRI) axial scans of the lumbar intervertebral disk, that are needed for the diagnosis of disk herniation. We study the possibility of assisting radiologists and orthopedists and increasing their quality of experience (QoE) during the diagnosis process. The main aim is to build a 3D model for the desired area of interest and ask the specialists to consider the 3D models in the diagnosis process instead of considering multiple axial MRI scans. We further propose an automated framework to diagnose the lumber disk herniation using the constructed 3D models. We evaluate the effectiveness of increasing the specialists QoE by conducting a questionnaire on 14 specialists with different experiences ranging from residents to consultants. We then evaluate the effectiveness of the automated diagnosis framework by training it with a set of 83 cases and then testing it on an unseen test set. The results show that the the use of 3D models increases doctors QoE and the automated framework gets 90% of diagnosis accuracy

A Quantitative Study of Intervertebral Disc Morphologic Changes Following Plasma‐Mediated Percutaneous Discectomy

Objective To quantitatively evaluate interval magnetic resonance imaging ( MRI ) changes in disc morphology following plasma‐mediated percutaneous discectomy. Design/Setting A retrospective comparison of pretreatment and posttreatment MRIs at a single university spine clinic. Subjects From a group of 60 consecutively treated patients, 15 met the study inclusion and exclusion criteria. All had either failed treatment or had other clinical reasons for a posttreatment MRI . Methods Two independent physicians electronically measured disc protrusion size and disc height at the treatment discs and adjacent discs on pre‐ and posttreatment MRI scans. Additionally, images were compared for gross anatomic changes including disc degeneration by P firrman classification, new disc herniations, high intensity zone ( HIZ ), vertebral endplate changes, post‐contrast enhancement, and changes in segmental alignment. P earson r correlation was used to determine interobserver reliability between the two physicians' MRI measurements. Paired t ‐tests were calculated for comparisons of pre‐ and posttreatment MRI measurements, and an ANOVA was performed for comparison of pre‐ to posttreatment changes in disc height measurements at treatment levels relative to adjacent levels. Results Correlation was high for measurement of disc height change ( r  = 0.89; P  < 0.0001) and good for anteroposterior protrusion size change ( r  = 0.51; P  = 0.0512). Disc height at treated discs demonstrated a small but statistically significant mean interval reduction of 0.48 mm ( P  = 0.0018). This remained significant when compared with the adjacent control discs ( P  < 0.0001). Pretreatment mean disc protrusion size (4.74 mm; range 3.75–6.55 mm) did not differ significantly ( P  = 0.1145) from posttreatment protrusion size (4.42 mm; range 2.55–7.95 mm). Gross anatomic changes at treatment levels included reduced disc protrusion size (N = 6), enlarged protrusion (N = 3), resolution of HIZ (N = 3), and improvement in endplate signal changes (N = 1). Also, 11/15 posttreatment MRIs included post‐contrast images that showed epidural fibrosis (N = 1), rim enhancement (N = 2), and enhancement of the posterior annulus (N = 4). Conclusions Based on MRI examinations, subtle anatomic changes may occur following plasma‐mediated percutaneous discectomy. Further study is required to determine the clinical relevance of these changes.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/109360/1/pme12525.pd