Diagnostic Imaging in Intervertebral Disc Disease

Animal Models of Intervertebral Disc Diseases: Advantages, Limitations, and Future Directions

Animal models are valuable tools for studying the underlying mechanisms of and potential treatments for intervertebral disc diseases. In this review, we discuss the advantages and limitations of animal models of disc diseases, focusing on lumbar spinal stenosis, disc herniation, and degeneration, as well as future research directions. The advantages of animal models are that they enable controlled experiments, long-term monitoring to study the natural history of the disease, and the testing of potential treatments. However, they also have limitations, including species differences, ethical concerns, a lack of standardized protocols, and short lifespans. Therefore, ongoing research focuses on improving animal model standardization and incorporating advanced imaging and noninvasive techniques, genetic models, and biomechanical analyses to overcome these limitations. These future directions hold potential for improving our understanding of the underlying mechanisms of disc diseases and for developing new treatments. Overall, although animal models can provide valuable insights into pathophysiology and potential treatments for disc diseases, their limitations should be carefully considered when interpreting findings from animal studies.

Development of a deep learning model for automatic detection of narrowed intervertebral disc space sites in caudal thoracic and lumbar lateral X-ray images of dogs

Intervertebral disc disease is the most common spinal cord-related disease in dogs, caused by disc material protrusion or extrusion that compresses the spinal cord, leading to clinical symptoms. Diagnosis involves identifying radiographic signs such as intervertebral disc space narrowing, increased opacity of the intervertebral foramen, spondylosis deformans, and magnetic resonance imaging findings like spinal cord compression and lesions, alongside clinical symptoms and neurological examination findings. Intervertebral disc space narrowing on radiographs is the most common finding in intervertebral disc extrusion. This study aimed to develop a deep learning model to automatically recognize narrowed intervertebral disc space on caudal thoracic and lumbar X-ray images of dogs. In total, 241 caudal thoracic and lumbar lateral X-ray images from 142 dogs were used to develop and evaluate the model, which quantified intervertebral disc space distance and detected narrowing using a large-kernel one-dimensional convolutional neural network. When comparing veterinary clinicians and the deep learning model, the kappa value was 0.780, with 81.5% sensitivity and 95.6% specificity, showing substantial agreement. In conclusion, the deep learning model developed in this study, automatically and accurately quantified intervertebral disc space distance and detected narrowed sites in dogs, aiding in the initial screening of intervertebral disc disease and lesion localization.

Effects of age on accuracy of advanced imaging modalities in identifying intervertebral disc extrusions in Dachshunds

OBJECTIVE

The aim of this study was to ascertain whether patient age was a significant factor for the accurate identification of compressive intervertebral disc extrusions (IVDE) in Dachshunds using non-contrast computed tomography (CT).

METHODS

This retrospective analysis encompassed 150 Dachshunds evaluated for suspected IVDE at a referral hospital in south-eastern Queensland, Australia. Each case underwent diagnostic evaluation by CT, either with or without myelography, or magnetic resonance imaging (MRI), followed by surgical intervention for an intervertebral disc extrusion.

RESULTS

In the <9-year dog cohort, 94.7% (71/75) were diagnosed with IVDE via non-contrast CT and proceeded to surgery. In contrast, the ≥9-year dog cohort, only 56% (42/75) were diagnosed via non-contrast CT, with the remaining 44% (33/75) necessitating CT myelography or MRI for diagnosis. The odds of requiring CT myelography or MRI increased 13.95-fold (95% CI, 4.62-42.13) in Dachshunds aged 9 years or older. Furthermore, each additional year of age was associated with a 0.60 increase in the odds of undergoing these advanced imaging modalities (CT myelography or MRI) (95% CI, 0.49-0.74).

CONCLUSIONS

Age significantly affected the efficacy of non-contrast CT in diagnosing IVDE in Dachshunds. Dogs aged 9 years and above were substantially more likely to require CT myelography or MRI due to the reduced visibility of disc extrusions on non-contrast CT. Veterinarians performing advanced imaging on older Dachshunds for suspected IVDE should be aware of the limitations of non-contrast CT in obtaining an accurate diagnosis and localisation of IVDE, and be prepared to perform either CT myelography or MRI if required.

Case series: Cervical far-lateral and combined cervical far lateral/foraminal intervertebral disk extrusions in 10 dogs

Far-lateral intervertebral disk extrusions (IVDEs) have been reported infrequently in dogs in veterinary literature, mostly affecting the caudal lumbar intervertebral disks. We describe the clinical findings, computed tomography (CT) and magnetic resonance imaging (MRI) findings, treatment, and outcome in 10 dogs with cervical far-lateral IVDEs. Patient databases of 3 small animal hospitals and 1 veterinary teleradiology service were retrospectively searched for patients in which imaging studies (CT or MRI) identified the presence of intervertebral disk material outside the limits of the intervertebral foramen. Presenting clinical signs included: episodic signs of cervical pain (6/10, 30%), persistent signs of cervical pain (3/10, 50%), nerve root signature or lameness (5/10, 50%), and abnormal cervical posture only (excluding nerve root signature) (1/10, 10%). Affected IVD spaces (for 11 IVDEs in 10 dogs) included: C3-4 (6/11, 55%), C5-6 (3/11, 27%), and C2-3 (2/11, 18%). Nerve root signature was not reported for C2-3 IVDEs. All cases were managed medically (without surgery). The top 3 used medications were gabapentinoids (10/10, 100%), non-steroidal anti-inflammatory drugs (NSAIDs) (10/10, 100%), and paracetamol (3/10, 30%). Median treatment duration was 25 days (range 10-84). Short-term outcome (<3 months) was recorded in 9/10 (90%) cases. Resolution of clinical signs was reported in 7/9 (78%) cases. Long-term follow-up was available for 6/10 (60%) cases (median 11.5 months, range 5.5-30 months); 5/6 (83%) showed resolution of clinical signs. Recurrence of clinical signs was reported in 1 case (9 months later), managed medically again, with successful outcome. In conclusion, cervical far-lateral disk extrusions are a rare clinical entity in dogs, but can result in severe, persistent or episodic, pain. Medical management is associated with a positive short- and long-term outcome in most cases.

Evaluation of Intervertebral Disc Space Width Between 10th and 11th Thoracic Vertebrae in Cats Using Radiography and Magnetic Resonance Imaging

BACKGROUND

It is well known that the T10-T11 intervertebral disc space is usually narrower than the adjacent intervertebral disc spaces in most dogs. However, whether the T10-T11 disc space is narrower than the adjacent disc spaces is not well-established in cats.

OBJECTIVES

To measure the intervertebral disc space width of the T10-T11 disc space and to compare it with that of the adjacent disc spaces using radiography and magnetic resonance imaging (MRI).

METHODS

In Groups 1 (101 clinically normal cats) and 2 (32 cats without spinal diseases from T8 to T13), dorsal width (DW), central width (CW) and ventral width (VW) of the T8-T13 disc spaces were measured by radiography or MRI. Significant differences of the DW, CW and VW among disc spaces measured by radiography and MRI were evaluated. Intra- and interobserver reliabilities were measured by intraclass correlation coefficient.

RESULTS

In Groups 1 and 2 using radiography, the DW and CW of the T10-T11 disc space were significantly narrower than those of adjacent disc spaces (p < 0.05). The DW of the T8-T12 disc spaces was significantly narrower than that of the T12-T13 disc space in Group 1 using radiography. In Groups 1 and 2 using radiography, the CW and VW of the T8-T11 disc spaces were significantly narrower than those of the T11-T13 disc spaces. In Group 2 using MRI, the DW of the T10-T11 disc space was significantly narrower than that of the T11-T13 disc spaces. The VW of the T8-T11 disc spaces was significantly narrower than that of the T11-T13 disc spaces.

CONCLUSION

The T10-T11 intervertebral disc space on radiography is statistically narrower than the adjacent intervertebral disc spaces in normal cats. The cranial thoracic intervertebral disc spaces (T8-T11) are usually narrower than the caudal thoracic intervertebral disc spaces (T11-T13) on radiography and MRI.

Double Cervical Adjacent Hydrated Nucleus Pulposus Extrusion (HNPE) in a Yorkshire Terrier

A 9-year-old Yorkshire terrier was brought to the emergency department for inability to maintain the correct station with acute onset. Neurological examination showed a non-ambulatory tetraparesis, spontaneous proprioceptive deficit in all limbs, and decreased flexor reflex in the forelimbs. The neurological symptoms suggested a cranial cervical spinal cord with suspicion of spinal shock. The clinical differential diagnoses included degenerative (intervertebral disc extrusion), vascular, inflammatory, or neoplastic disease. No pathological findings were evident in the hematobiochemical tests or in the radiograph examination. MRI examination of the cervical spine showed the presence of two adjacent hydrated nucleus pulposus extrusions at C3-C4 and C4-C5 tracts. Treatment included analgesic and non-steroidal anti-inflammatory therapy; movement restriction was initially necessary, followed by physiotherapy. Follow-up at 4 weeks showed complete recovery. A telephone follow-up after 3 months with the owner confirmed the absence of symptoms. This article reports the first double cervical HNPE case in a dog, adding the possibility that the disease may present in this form and the success of conservative treatment as described in the literature.

Prevalence and classification of congenital thoracic vertebral body abnormalities in neurologically normal brachycephalic 'screw-tail' dog breeds in referral practice in Australia

OBJECTIVE

To evaluate the prevalence, type, site and breed predisposition of thoracic congenital vertebral malformations (CVM) in neurologically normal brachycephalic 'screw-tail' dog breeds.

STUDY DESIGN

Retrospective case series.

ANIMALS

Neurologically normal French Bulldogs (n = 63), British Bulldogs (n = 42), Boston Terriers (n = 4) and Pugs (n = 86) presenting for brachycephalic obstructive airway syndrome treatment.

METHODS

Either a plain computer tomography scan of the thorax or lateral and dorso-ventral digital radiographs of the thoracic vertebral column of each dog were assessed for any vertebral malformations and classed according to the Modified McMaster vertebral abnormality classification scheme proposed by Guiterrez et al. RESULTS: The prevalence of dogs with one or more abnormal vertebrae was 96.82% in French Bulldogs, 90.47% in British Bulldogs, and 76.74% in Pugs. Pugs had significantly lower instances of CVMs than French Bulldogs. The four Boston Terriers all had vertebral malformations, but the results were not considered to be statistically significant due to their small sample size. In French Bulldogs and British Bulldogs, ventral hypoplasia (Type 3) occurred at greater rates than all other types, followed by ventral and median hypoplasia (Types 7) and symmetrical hypoplasia (Type 8). In Pugs, symmetrical hypoplasia (Type 8) was the most common and then ventral hypoplasia (Type 3). The most affected vertebrae were T6-T9 in Pugs and T5-T10 in French Bulldogs and British Bulldogs.

CONCLUSIONS

The majority of neurologically normal brachycephalic 'screw-tail' dogs assessed in this paper possessed one or more congenital thoracic vertebral malformations. Dogs with vertebral malformations were found to be more likely to have more than one affected vertebra. Sex had no effect on the prevalence of CVM.

CLINICAL RELEVANCE

A substantial number of neurologically normal brachycephalic 'screw-tail' dogs suffer from congenital vertebral malformations. Thus, the need for selective breeding programmes to eliminate this hereditary condition is crucial.

Seeing the unseen: The role of bioimaging techniques for the diagnostic interventions in intervertebral disc degeneration

Intervertebral Disc Degeneration is a pathophysiological condition that primarily affects the spinal discs, causing back pain and neurological deficits. It is caused by the contribution of several factors such as genetic predisposition, age-related degeneration, and lifestyle choices like obesity and physical activity. Even though there are medications to treat pain, there is a lack of medicines for a complete cure. The main difficulty lies in poor diagnosis of the morphological and functional changes in the disc. With the ever-increasing research on bioimaging techniques, new techniques are being developed and repurposed to evaluate disc shape and composition, and their defects like thinning or deformities on the disc, leading to the proper diagnostic intervention in intervertebral disc degeneration. In this review, we aim to present a comprehensive overview of the imaging techniques used in the pre-clinical and clinical stages for the diagnosis of intervertebral disc degeneration. First, we will discuss about patho-anatomy and the pathophysiology of degenerative disc disease with the significance and a brief description of various dyes and tracers utilized for bioimaging. Then we will shed light on the latest advancements in diagnostic modalities in intervertebral disc degeneration; concluded by an analysis of the repercussions of the methodologies and experimental systems employed in identifying mechanisms and developing therapeutic strategies in intervertebral disc degeneration.

Equine intervertebral disc disease with dorsal protrusion and spinal cord compression: A computed tomography, myelography, MRI, and histopathologic case study

A 3-year-old American Saddlebred gelding presented for progressive tetraparesis, ataxia, and cervical hyperaesthesia. Radiographic myelography identified spinal cord compression at C6-7 in neutral, extended, and flexed positions and at C4-5 in the flexed position. CT myelography and postmortem MRI identified severe vertebral canal stenosis/compression at C6-7. MRI further identified severe intervertebral disc herniation at C6-7 with intramedullary changes. Disc protrusion was confirmed macroscopically at postmortem. Lesions consistent with compressive myelopathy were confirmed microscopically at C6-7. This is the first report of equine disc protrusion and myelocompression confirmed by multiple advanced imaging modalities and postmortem examination.

Clinical presentation, magnetic resonance imaging findings, and outcome of 80 Dachshunds with cervical intervertebral disc extrusion

Introduction

Large clinical studies regarding cervical intervertebral disc extrusion (IVDE) in Dachshunds are lacking. This retrospective multicentric study therefore aims to describe the clinical features, magnetic resonance imaging (MRI) findings and outcomes of Dachshunds diagnosed with cervical IVDE.

Methods

Medical records of Dachshunds with cervical IVDE were reviewed for signalment, onset of clinical signs, neurological examination, MRI features, treatment and outcome.

Results

Eighty Dachshunds were included in the study, mostly ambulatory (55% grade 1 and 33% grade 2) and without nerve root signature (85% of cases) on presentation. Information on coat type was available for 56% of dogs; specifically, 41% were smooth-haired, 9% were long-haired and 6% were wire-haired Dachshunds. There were 29 (36%) neutered female, 27 (34%) male entire, 15 (19%) male neutered and 9 (11%) entire female dogs. The onset of clinical signs was most often >48 h (84%). The most common intervertebral disc space affected was C2-C3 (38%) and foraminal IVDEs were reported in 14% of dogs. A foraminal IVDE was diagnosed in only 25% of dogs presented with nerve root signatures. Most dogs (77.5%) were treated surgically. In this group, a higher body condition score on presentation and a higher mean spinal cord compression ratio calculated on MRI were directly and moderately associated with a longer hospitalization time (r = 0.490 p = 0.005 and r = 0.310 p = 0.012, respectively). The recovery time was longer in dogs with an onset of clinical signs <24 h or 24-48 h compared to those with an onset of clinical signs >48 h (3.1 ± 6.5 days versus 1.6 ± 6.2, p < 0.001) in both medically and surgically treated groups. Data about the outcome was available for 83% of dogs. Eighty percent of the entire population of dogs was considered to have completely returned to normal. There was no association between the therapeutic choice (surgical versus medical management) and the outcome of the dogs included in this study.

Thoracolumbar hydrated nucleus pulposus extrusion and intervertebral disc extrusion in dogs: Comparison of clinical presentation and magnetic resonance imaging findings

Thoracolumbar hydrated nucleus pulposus extrusion (TL-HNPE) is an increasingly recognised pathology with a substantial lack of literature describing its features. The aim of this retrospective case-control study was to analyse the clinical and magnetic resonance imaging (MRI) features of dogs with TL-HNPE compared to dogs affected with thoracolumbar intervertebral disc extrusion (TL-IVDE). Data from dogs diagnosed with TL-HNPE and TL-IVDE via MRI at two referral hospitals, were retrospectively collected and compared in terms of clinical signs and MRI features. Cases diagnosed with TL-IVDE were deemed controls. The MRI features of the affected IVD space, herniated IVD material, affected overlying spinal cord and local epaxial musculature were evaluated for each group. Fifty-one cases with TL-HNPE and 105 randomly selected cases of TL-IVDE were included. Several signalment and neurological signs were identified as statistically distinct between groups in univariate analysis. Multivariate analysis identified that dogs affected with TL-HNPE were typically older, less likely to be chondrodystrophic (62.2 % vs. 91 %), more frequently experiencing a peracute onset (90.2 % vs. 61.9 %) often attributed to a suspected trauma linked with exercise (37.3 % vs. 10.5 %), being less frequently progressive (41.2 % vs. 86.5 %) and with herniated disc material less frequently lateralised (72.6 % vs. 89.5 %) than cases with TL-IVDE. MRI-identifiable intervertebral disc degeneration was found in every TL-IVDE case but only in 60 % of TL-HNPE cases. TL-HNPEs were associated to significantly less spinal cord compression and less hyperalgesia than TL-IVDE.

Exploring deep learning strategies for intervertebral disc herniation detection on veterinary MRI

Intervertebral Disc Herniation (IVDH) is a common spinal disease in dogs, significantly impacting their health, mobility, and overall well-being. This study initiates an effort to automate the detection and localization of IVDH lesions in veterinary MRI scans, utilizing advanced artificial intelligence (AI) methods. A comprehensive canine IVDH dataset, comprising T2-weighted sagittal MRI images from 213 pet dogs of various breeds, ages, and sizes, was compiled and utilized to train and test the IVDH detection models. The experimental results showed that traditional two-stage detection models reliably outperformed one-stage models, including the recent You Only Look Once X (YOLOX) detector. In terms of methodology, this study introduced a novel spinal localization module, successfully integrated into different object detection models to enhance IVDH detection, achieving an average precision (AP) of up to 75.32%. Additionally, transfer learning was explored to adapt the IVDH detection model for a smaller feline dataset. Overall, this study provides insights into advancing AI for veterinary care, identifying challenges and exploring potential strategies for future development in veterinary radiology.

Evidence of MRI image features and inflammatory biomarkers association with low back pain in patients with lumbar disc herniation

BACKGROUND CONTEXT

While MRI image features and inflammatory biomarkers are frequently used for guiding treatment decisions in patients with lumbar disc herniation (LDH) and low back pain (LBP), our understanding of the connections between these features and LBP remains incomplete. There is a growing interest in the potential significance of MRI image features and inflammatory biomarkers, both for quantification and as emerging therapeutic tools for LBP.

PURPOSE

To investigate the evidence supporting MRI image features and inflammatory biomarkers as predictors of LBP and to determine their relationship with pain intensity.

STUDY DESIGN

Prospective cohort study.

PATIENT SAMPLE

All consecutive patients with LDH who underwent discectomy surgery at our institution from February 2020 to June 2023 at the author's institution were included.

OUTCOME MEASURES

MRI image features in discogenic, osseous, facetogenic, and paraspinal muscles, as well as inflammatory biomarkers in serum (including CRP (C-reactive protein), ESR (erythrocyte sedimentation rate), PCT (procalcitonin), TNF (tumor necrosis factor), interleukin-1 beta (IL-1β), and IL-6), and paraspinal muscles (including TNF, IL-1β, IL-6, IL-10, and transforming growth factor beta 1 (TGF-β1)).

METHODS

A series of continuous patients diagnosed with LDH were categorized into acute LBP (<12 weeks), chronic LBP (≥12 weeks), and nonLBP groups. MRI image features and inflammatory biomarkers relation to pain intensity was assessed using the independent t-test, Chi-squared tests, Spearman rank correlation coefficient, and logistic regression test.

RESULTS

Compared to the nonLBP group, the chronic LBP group exhibited a higher incidence of intervertebral disc (IVD) degeneration (≥ grade 3) and high-fat infiltration in paraspinal muscles, alongside a significant reduction in the cross-sectional area (CSA) and fatty degeneration of the multifidus muscle. Furthermore, there was a greater expression of IL-6 in serum and TNF in paraspinal muscles in the chronic LBP group and a greater expression of CRP and IL-6 in serum and TNF in paraspinal muscles in the acute LBP group. CSA and fatty degeneration of multifidus muscle were moderately negatively correlated with chronic LBP scores. The expression of TNF and IL-6 in serum and the expression of TNF in the multifidus muscle were moderately correlated with preoperative LBP. IVD degeneration and high-fat infiltration were identified as risk factors for chronic LBP.

CONCLUSION

The results provide evidence that IVD degeneration, high-fat infiltration, and the reduction of CSA in paraspinal muscles were associated with the development of chronic LBP in patients with LDH, and these associations are linked to inflammatory regulation. This deepens our understanding of the etiology and pathophysiology of LBP, potentially leading to improved patient stratification and more targeted interventions.

Case report: Double adjacent ventral slot in two medium-sized breed dogs

Two medium-sized, 7-year-old dogs, with no previous history of pain, presented with acute neurologic symptoms consistent with intervertebral disk disease. Both cases had CT, where cervical pathology was identified. In one dog, the diagnosis was singular extensive cervical disk herniation with possible epidural hemorrhage and in the other, the diagnosis was multiple-site cervical disk herniation. The first dog, a Shar-Pei, underwent treatment with two standard adjacent ventral slots between the C4-C5 and C5-C6 intervertebral disk spaces and a fenestration between the C3 and C4 intervertebral disk spaces. The second case, a beagle, underwent a double adjacent standard ventral slot between the C5-C6 and C6-C7 intervertebral disk spaces. Both dogs recovered uneventfully after the surgery and showed no signs of recurrence during a 2-year follow-up period. This is the first detailed report of the use of a double adjacent ventral slot as a treatment for spinal decompression in medium-sized dogs with multiple-site spinal cord compression.

Myelo-CT imaging findings in 15 dogs with surgically-treated cervical acute compressive hydrated nucleus pulposus extrusion

Compressive hydrated nucleus pulposus extrusion (HNPE) is a sudden extrusion of hydrated, nondegenerated nucleus pulposus material with well-known characteristic MRI findings. The appearance of compressive HNPE during contrast-enhanced CT has already been described, but never its myelo-CT characteristics. The aim of this retrospective multicenter case series is to describe the myelo-CT findings in 15 dogs with compressive HNPE confirmed with gross surgical findings. A distinctive and consistent myelo-CT appearance of cervical compressive HNPE in dogs that included a focal extradural "seagull"-shaped extradural compression dorsal to the annulus fibrosus combined with a narrowing of the affected intervertebral disc space was found. The extruded material was hypoattenuating in the soft tissue algorithm. Myelo-CT could be a useful diagnostic tool and influence the clinical decision to address cervical compressive HNPE conservatively or surgically when MRI is not available.

Morphometric Evaluation of Thoracolumbar Spinal Canal and Cord by Magnetic Resonance Imaging in Normal Small-Breed Dogs

Thoracolumbar intervertebral disc disease (IVDD) is the most common cause of spinal injury in dogs. MRI has been considered the gold standard for neurologic diagnosis, but studies focusing on the thoracolumbar spinal canal and spinal cord using MRI in small-breed dogs are limited. Therefore, this study aimed to establish an MRI reference range for the spinal cord and canal measurements (height, width, cord-to-canal ratio of height, width, cross-sectional area (CSA)) of each intervertebral disc level from T11 to L5 (total of seven levels) on transverse T2-weighted images in normal small-breed dogs. We hypothesized that the spinal cord and spinal canal measurements might vary according to the body weight and age. The width and height of the spinal cord and canal increased as the body weight increased at all levels (p < 0.05). The cord-to-canal ratio of the width showed a negative correlation to the body weight at all levels. The cord-to-canal ratio of the height did not show any correlation to the body weight at all levels. All measurements (height, width, cord-to-canal ratio of height, width, CSA) did not show any statistical correlation between the groups subdivided by age. These measurements could serve as a morphometric baseline for thoracolumbar spinal diseases and clinical research in small-breed dogs.

Outcome of the Use of Clinical Reasoning Alone in Dogs with Acute Thoracolumbar Myelopathy and/or Pain

Acute thoracolumbar myelopathy is a common neurological presentation in dogs. Although certain spinal conditions present with characteristic clinical pictures, managing such cases with clinical reasoning alone (i.e., without cross-sectional imaging) has never been explored. The aim of this study was to define the outcome of patients with suspected intervertebral disc extrusion (IVDE), ischaemic myelopathy (IM) or acute non-compressive nucleus pulposus extrusion (ANNPE) that were managed with clinical reasoning alone. The database of the Queen's Veterinary School Hospital (Cambridge) was searched for paraparetic or paraplegic dogs with suspected IVDE or IM/ANNPE that were initially managed medically without undergoing imaging. Clinical presentation and outcome were recorded. If cross-sectional imaging was subsequently performed, information about the final diagnosis was collected and compared with the initially suspected diagnosis. A total of 123 IVDE cases were collected: 81% had a successful outcome with no imaging performed; 16% had IVDE confirmed with imaging and successful outcome with surgery or medical management; and just 3% were found to have an alternative diagnosis or were euthanised without imaging. A total of 16 IM/ANNPE cases were collected: 94% had a successful outcome, and one dog was euthanised. Successful outcomes can be obtained by using clinical reasoning alone in most dogs with suspected IVDE or IM/ANNPE.

Modic changes in the lumbar vertebral column of chondrodystrophic and non-chondrodystrophic dogs with intervertebral disc disease

Introduction

Modic changes (MC) are signs of vertebral pathology visible on magnetic resonance (MR) images that have been associated with low back pain (LBP) and disc degeneration in people. Multiple breeds of dogs also develop MCs and coincident back pain. However, the association between breed, MC, and spinal pathologies has yet to be fully elucidated. This study aimed to identify the prevalence of MC that occur spontaneously in the lumbar vertebral column of dogs diagnosed with intervertebral disc disease (IVDD) and examine their association with demographic criteria and the disc width index (DWI).

Methods

Medical records and lumbar vertebral column MR images were examined from 104 dogs (831 intervertebral disc spaces and adjacent vertebrae), which were divided into three groups: chondrodystrophic dogs (CD; n =54) and non-chondrodystrophic dogs (NCD; n =30) with IVDD as the primary diagnosis, and control dogs (n =20) with other spinal diseases as their primary diagnosis.

Results

Increasing age and a diagnosis of IVDD were significantly associated with MC in dogs (p <  0.001 and p = 0.0062, respectively). In CD dogs with IVDD, Type 2 MC were most prevalent, whereas, in NCD dogs, Type 3 MC were the most prevalent type. Type 2 MC were distributed nearly equally across the lumbar vertebral column, while Type 3 MC were primarily detected at the level of L7-S1.

Discussion

This study demonstrated that MC developed spontaneously in dogs, are common in dogs diagnosed with IVDD, and the type observed varies by breed. Further research is needed to understand the pathogenesis of MC; however, the increased presence of Type 2 MC in CD dogs, similar to what is found in people with disc degeneration, suggests that CD dogs could serve as models for MC in people.

Evaluation of differences in expression pattern of three isoforms of the transforming growth factor beta in patients with lumbosacral stenosis

The study investigates molecular changes in the lumbosacral (L/S) spine's yellow ligamentum flavum during degenerative stenosis, focusing on the role of transforming growth factor beta 1-3 (TGF-β-1-3). Sixty patients with degenerative stenosis and sixty control participants underwent molecular analysis using real-time quantitative reverse transcription reaction technique (RTqPCR), enzyme-linked immunosorbent assay (ELISA), Western blot, and immunohistochemical analysis (IHC). At the mRNA level, study samples showed reduced expression of TGF-β-1 and TGF-β-3, while TGF-β-2 increased by only 4%. Conversely, at the protein level, the study group exhibited significantly higher concentrations of TGF-β-1, TGF-β-2, and TGF-β-3 compared to controls. On the other hand, at the protein level, a statistically significant higher concentration of TGF-β-1 was observed (2139.33 pg/mL ± 2593.72 pg/mL vs. 252.45 pg/mL ± 83.89 pg/mL; p < 0.0001), TGF-β-2 (3104.34 pg/mL ± 1192.74 pg/mL vs. 258.86 pg/mL ± 82.98 pg/mL; p < 0.0001), TGF-β-3 (512.75 pg/mL ± 107.36 pg/mL vs. 55.06 pg/mL ± 9.83 pg/mL, p < 0.0001) in yellow ligaments obtained from patients of the study group compared to control samples. The study did not establish a significant correlation between TGF-β-1-3 concentrations and pain severity. The findings suggest that molecular therapy aimed at restoring the normal expression pattern of TGF-β-1-3 could be a promising strategy for treating degenerative stenosis of the L/S spine. The study underscores the potential therapeutic significance of addressing molecular changes at the TGF-β isoforms level for better understanding and managing degenerative spinal conditions.

Residual volume of extruded disc material and residual spinal cord compression measured on postoperative MRI do not predict neurological outcomes in dogs following decompressive surgery for thoracolumbar intervertebral disc extrusion

Published studies on the validity of using quantitative MRI measures of pre- and postoperative spinal cord (SC) compression as prognostic indicators for dogs undergoing surgery for intervertebral disc extrusion (IVDE) are currently limited. The aim of this retrospective analytical study was to describe the volume of postoperative residual extradural material (VREM) and the ratio of the cross-sectional area (CSA) of maximum SC compression to the CSA of SC in a compression-free intervertebral space as MRI measures of preoperative and postoperative compression (residual spinal cord compression, RSCC), and to compare these measures between the neurological outcome in a group of dogs. Inclusion criteria were dogs that underwent surgery for thoracolumbar IVDE, were imaged pre- and immediately postoperatively by MRI, and had a neurological follow-up examination 2 to 5 weeks postoperatively. Two blinded observers independently performed measurements in pre- and postoperative MRI studies. Dogs were classified into positive outcome (PO) and negative outcome (NO) groups based on follow-up neurologic examination scores. Seventeen dogs were included (12 PO, 5 NO). Interobserver agreement for MRI measurements was good to excellent (ICCs: 0.76-0.97). The prevalence of residual extradural material in postoperative MRI studies was 100%. No significant differences in mean preoperative SC compression, mean RSCC, mean SC decompression, or VREM were found between outcome groups (P = .25; P = .28; P = .91, P = .98). In conclusion, neither postoperative VREM nor RSCC could predict successful neurological outcomes.

Detection of spondylosis deformans in thoracolumbar and lumbar lateral X-ray images of dogs using a deep learning network

Introduction

Spondylosis deformans is a non-inflammatory osteophytic reaction that develops to re-establish the stability of weakened joints between intervertebral discs. However, assessing these changes using radiography is subjective and difficult. In human medicine, attempts have been made to use artificial intelligence to accurately diagnose difficult and ambiguous diseases in medical imaging. Deep learning, a form of artificial intelligence, is most commonly used in medical imaging data analysis. It is a technique that utilizes neural networks to self-learn and extract features from data to diagnose diseases. However, no deep learning model has been developed to detect vertebral diseases in canine thoracolumbar and lumbar lateral X-ray images. Therefore, this study aimed to establish a segmentation model that automatically recognizes the vertebral body and spondylosis deformans in the thoracolumbar and lumbar lateral radiographs of dogs.

Methods

A total of 265 thoracolumbar and lumbar lateral radiographic images from 162 dogs were used to develop and evaluate the deep learning model based on the attention U-Net algorithm to segment the vertebral body and detect spondylosis deformans.

Results

When comparing the ability of the deep learning model and veterinary clinicians to recognize spondylosis deformans in the test dataset, the kappa value was 0.839, indicating an almost perfect agreement.

Conclusions

The deep learning model developed in this study is expected to automatically detect spondylosis deformans on thoracolumbar and lumbar lateral radiographs of dogs, helping to quickly and accurately identify unstable intervertebral disc space sites. Furthermore, the segmentation model developed in this study is expected to be useful for developing models that automatically recognize various vertebral and disc diseases.

Association between periodontitis and disc structural failures in patients with cervical degenerative disorders

OBJECTIVE

Recent studies have shown that the mouth-gut-disc axis may play a key role in the process of disc structural failures (including intervertebral disc degeneration (IDD) and endplate change) in the cervical spine and neck pain. However, the potential mechanisms underlying the mouth-gut-disc axis remain elusive. Therefore, we explored whether periodontal disease is associated with disc structural failures in patients with cervical degeneration disorders and clinical outcomes.

METHODS

Adults (aged > 18 years) who met open surgery criteria for cervical spine were enrolled in this prospective cohort study. Participants were allocated into two groups based on periodontal examinations before surgery: no/mild periodontitis group and moderate/severe periodontitis group. Data were evaluated using an independent t test and Pearson's correlation analysis.

RESULTS

A total of 108 patients were enrolled, including 68 patients in the no/mild periodontitis group and 40 patients in the moderate/severe periodontitis group. The number of common causes of missing teeth (P = 0.005), plaque index (PLI) (P = 0.003), bleeding index (BI) (P = 0.000), and probing depth (PD) (P = 0.000) significantly differed between the two groups. The incidence rate of endplate change (P = 0.005) was higher in the moderate/severe periodontitis group than in the no/mild periodontitis group. A moderate negative association was found between the neck disability index (NDI) score and periodontal parameters (PLI: r = - 0.337, P = 0.013; BI: r = - 0.426, P = 0.001; PD: r = - 0.346, r = - 0.010).

CONCLUSIONS

This is the first study to provide evidence that severe periodontitis is associated with a higher occurrence rate of disc structural failures and poor clinical outcomes in patients with cervical degenerative disorders.

The Role of Mesenchymal Stem Cell Secretome (Extracellular Microvesicles and Exosomes) in Animals' Musculoskeletal and Neurologic-Related Disorders

The advances in regenerative medicine are very important for the development of medicine and the discovery of stem cells has shown a greater capacity to raise the level of therapeutic quality while their use becomes more accessible, especially in their mesenchymal form. In veterinary medicine, it is not different. The use of those cells, as well as recent advances related to the use of their extracellular vesicles, demonstrates a great opportunity to enhance therapeutic methods and ensure more life quality for patients, which can be in clinical or surgical treatments. Knowing the advances in these modalities and the growing clinical and surgery research and demands for innovations in orthopedic and neurology medicines, this paper aimed to review the literature about the methodologies of use and applications such as the pathways of action and the advances that were postulated for microvesicles and exosomes derived from mesenchymal stem cells in veterinary medicine, especially for musculoskeletal disorders and related injuries.

Relation of lumbar intervertebral disc height and severity of disc degeneration based on Pfirrmann scores

Background

Disc height (DH) change is considered one of the most critical factors in assessing intervertebral disc degeneration (IVD). Pfirrmann et al. developed a scoring system for disc degeneration evaluation based on changes in DH in magnetic resonance imaging (MRI). While the relationship between DH measurements and Pfirrmann scores for disc degeneration has been explored, the validity of different DH measuring techniques or their connection with disc degeneration is yet uncertain. The present study investigates intra-rater and inter-rater agreement and reliability of different DH measurement methods on MRI and evaluates the relationship between different DH measurement methods and Pfirrmann scores of IVD degeneration, as well as between different Pfirrmann scores and clinical outcomes.

Methods

Adult patients with MRI scans of the lumbar spine were recruited. Eight DH measuring techniques were tested for intra-rater and inter-rater agreement and reliability. Bland and Altman's Limits of Agreement (LOA) was used to evaluate intra-rater and inter-rater agreements. Intra-rater and inter-rater reliability were evaluated using intra-class correlations (ICC) with 95 % confidence intervals (95 % CI). The association between DH and Pfirrmann scores was examined using one-way ANOVA.

Results

Excellent intra-rater reliability was reported for 332 participants on DH (ranging from 0.912 (0.901, 0.923) to 0.973 (0.964, 0.981) and from 0.902 (0.892, 0.915) to 0.975 (0.962, 0.985) by two independent raters). All measuring methods had high intra-rater agreement, except for methods 4 and 5. All methods had good-to-excellent of inter-rater reliability on DH (ICCs ranging from 0.812 (0.795, 0.828) to 0.995 (0.994, 0.995)) except for the posterior disc material length of method 5 (ICC 0.740 (0.718, 0.761)). Methods 1 to 6 for evaluating DH in patients with spondylolisthesis had poor inter-rater reliability. The IVD levels with grades IV and V in Pfirrmann scores had significantly lower DH than the IVD levels with grades I to III in Pfirrmann scores. IVD levels with grades IV and V in Pfirrmann scores had significantly higher VAS and ODI than IVD levels with grades I in Pfirrmann scores.

Conclusion

A good-to-excellent intra-rater and inter-rater reliability was achieved on most DH measuring methods on MRI following a standardized and structured protocol. However, small anatomical structures and different tissue borders could influence measurements. Additionally, DH can differentiate between grade IV and V Pfirrmann scores, and severe IVD degeneration (IV and V Pfirrmann) is linked to clinical outcomes.

MRI and clinical findings in 133 dogs with recurrent deficits following intervertebral disc extrusion surgery

BACKGROUND

Recurrence of neurological signs following surgery for intervertebral disc herniation (IVDH) is reported, yet many cases lack MRI-confirmed diagnosis. This study describes the MRI and clinical findings in dogs presenting with recurrence of neurological signs following surgical treatment of IVDH.

METHODS

Medical records of dogs that underwent decompressive surgery for IVDH followed by a subsequent MRI within 12 months were retrospectively reviewed.

RESULTS

One hundred and thirty-three dogs were identified, all of which initially presented with intervertebral disc extrusion (IVDE). Of these, 109 (81.9%) had a recurrent IVDE, and 24 (18.1%) had an alternative diagnosis that included haemorrhage (n = 10), infection (n = 4), soft tissue encroachment (n = 3), myelomalacia (n = 3) or other (n = 4). Same-site IVDE recurrence or alternative diagnoses were significantly more likely to present within 10 days postoperatively. Thirty-nine percent of dogs presenting with 'early recurrence' had an alternative diagnosis. Type of surgery, fenestration, neurological grade or IVDE site was not significantly associated with the subsequent MRI diagnosis.

LIMITATIONS

Limitations include the retrospective study design, the exclusion of conservatively managed recurrences, the variable length of follow-up and differences in the clinicians' surgical experience.

CONCLUSION

The most common cause for the recurrence of neurological signs following decompressive spinal surgery was IVDE. Just over one-third of dogs presenting with early recurrence had an alternative diagnosis.

Clinical, magnetic resonance imaging, surgical features and comparison of surgically treated intervertebral disc extrusion in French bulldogs

Intervertebral disc (IVD) extrusion (IVDE) is the most reported neurological condition in French bulldogs (FBD). The aim of this study was to retrospectively evaluate neurological grade, magnetic resonance imaging (MRI), surgical findings and short-term recovery in surgically treated FBD diagnosed with IVDE referred to a single institution between January 2020 and March 2022 and to compare cervical and thoracolumbar IVDE. Data was gathered from medical records and analysed via Fischer's Exact-Test and Kruskal Wallis-tests. Statistical significance was assumed when p < 0.05. Thirty-nine FBD were diagnosed with IVDE. Cervical IVDE (C-IVDE) was diagnosed in 11/39 cases; the C3-C4 IVD space was the most commonly affected site (5/11). Thoracolumbar IVDE (TL-IVDE) was diagnosed in 28 cases; the L3-L4 IVD space was the most commonly affected site (7/28). At admission, C-IVDE was significantly associated with less severe neurological grade (grade 1-2) compared to TL-IVDE (grade 2-5) (p < 0.001). The extruded IVD material (EIVDM) was hypointense in T2w images in 11/11C-IVDE vs. 2/28TL-IVDE, and hypointense in T1w images in 10/11C-IVDE vs. 1/28TL-IVDE. The EIVDM was hyperintense in T2w images in 0/11C-IVDE vs. 26/28TL-IVDE and iso-to-hypointense in T1w images in 1/11C-IVDE vs. 27/28TL-IVDE (p < 0,001). The EIVDM extended over ≥2 IVD spaces in 0/11C-IVDE vs. 19/28TL-IVDE (p < 0,001). 10/11C-IVDE underwent single ventral slot, 1/11C-IVDE underwent unilateral cervical hemilaminectomy. All TL-IVDE underwent unilateral hemilaminectomy and 19/28TL-IVDE underwent unilateral hemilaminectomy over ≥2 IVD spaces (p < 0,001). Haemorrhagic EIVDM was noticed intraoperatively in 1/11C-IVDE vs. 28/28TL-IVDE (p < 0,001). Spinal cord compression was mild in 2/11C-IVDE and 3/28TL-IVDE; moderate in 9/11C-IVDE and 16/28TL-IVDE; severe in 0/11C-IVDE and 8/28TL-IVDE. There was no spinal cord compression in 1/28TL-IVDE with foraminal IVDE. There was no statistical difference between spinal cord compression and IVDE location (p = 0.112). The mean time to improvement was 1.1 day in C-IVDE (range 1-2 days). 90.1% of C-IVDE improved within the first 24 h. The mean time to improvement was 2.1 days in TL-IVDE (range from 1 day to 4 days). All dogs that did not improve (5/39) were grade 5 TL-IVDEs at presentation. In FBD, TL-IVDE tended to cause higher grade of neurological dysfunction, tended to result in compression of neural structures over multiple IVD spaces and required more extensive surgical treatment than C-IVDE.

A case series of 37 surgically managed, paraplegic, deep pain negative French bulldogs, with thoracolumbar intervertebral disc extrusion, from two English referral centres

Background

Thoracolumbar intervertebral disc extrusions (TL-IVDEs) are a common spinal disorder in dogs, especially within chondrodystrophic breeds. Loss of deep pain perception is a well-documented negative prognostic indicator in dogs with TL-IVDE. The objectives of this study were to report the rate of return of deep pain perception and independent ambulation in surgically treated, paraplegic, deep pain perception negative French bulldogs with TL-IVDEs.

Methods

A retrospective case series of deep pain perception negative dogs with TL-IVDE presenting to two referral centres between 2015 and 2020 was conducted. Medical and MRI records were reviewed, including the following quantitative MRI changes: lesion length, extent of spinal cord swelling and severity of spinal cord compression.

Results

Thirty-seven French bulldogs met the inclusion criteria, with 14 of 37 (38%) regaining deep pain perception by the time of discharge (median hospitalisation 10.0 days [interquartile range 7.0-15.5 days]) with two dogs independently ambulatory (6%). Ten of the 37 dogs were euthanased during hospitalisation. Significantly fewer dogs (3/16, 19%) with L4-S3 lesions regained deep pain perception compared to 11 of 21 (52%) of dogs with T3-L3 lesions (p = 0.048). Quantitative MRI changes were not associated with the return of deep pain perception. After discharge, with a median 1-month follow-up period, an additional three dogs regained deep pain perception and five dogs became independently ambulatory (17/37 [46%] and 7/37 [19%], respectively).

Conclusions and clinical importance

This study adds support to the contention that the recovery of French bulldogs with TL-IVDE from surgery is poor compared with other breeds; further prospective, breed-controlled studies are indicated.

Outcomes in Dogs with Multiple Sites of Cervical Intervertebral Disc Disease Treated with Single Ventral Slot Decompression

In dogs with acute myelopathy but showing multiple sites of spinal compression from intervertebral disc disease (IVDD) on imaging, one approach is surgical decompression of the single acute disc extrusion while ignoring other previously extruded or protruded discs. However, little is known regarding the outcomes of this approach. This study described the outcomes and investigated prognostic factors in 40 dogs with multiple sites of cervical disc extrusion or protrusion on MRI who underwent ventral slot decompression for the single acute disc. The overall recovery rate was 97.5%. The median recovery time was seven days. The number of affected discs (including disc extrusion and protrusion) and the presence and number of the affected discs causing severe spinal compression did not influence the 30-day outcome. Compared with 23 dogs with single disc extrusion treated surgically, the recovery time and outcomes were similar between the two groups. The total number of affected discs was not associated with recovery time or outcomes. In conclusion, if an acute disc could be identified, ventral slot decompression targeting the single acute disc is a viable management approach for dogs with an acute presentation but diagnosed with multiple sites of spinal cord compression from IVDD.

Association between periodontitis and disc structural failure in older adults with lumbar degenerative disorders: A prospective cohort study

BACKGROUND

Bacterial microbiome as a putative trigger of inflammation might indicate the cascade of mouth-gut-disc axis for causing intervertebral disc (IVD) structural failures (such as IVD degeneration and endplate change) processed. However, direct evidence for the mouth-gut-disc axis still unclear. Therefore, it is interesting to explore periodontal inflammation related to IVD structural failures and clinical outcomes.

METHODS

This prospective cohort study enrolled older adults (aged ≥ 75 years) who scheduled to undergo elective open lumbar spine surgery. Demographic, radiological, clinical, and periodontal parameters were recorded. Independent samples t-test and Pearson's correlation analysis were calculated.

RESULTS

A total of 141 patients with lumbar degenerative disorders (56 males and 85 females; age 79.73 ± 3.34 years) were divided into edentulous group (19 patients), No/Mild group (84 patients), and Moderate/Severe group (38 patients). The incidence rates of IVD degeneration in each lumbar segmental level based on Pfirrmann grade and endplate change in the fourth and fifth lumbar vertebrae, and Visual Analogue Scale (VAS) low back pain (LBP) and leg pain of patients at preoperative in dentate group was significantly higher compared with edentulous group, especially the comparisons between Moderate/Severe and edentulous groups. There were no significant differences in the range of motion, lumbar lordosis, pelvic incidence, pelvic tilt, sacral slope, and disc height between dentate and edentulous groups. There was a positive association between plaque index (PLI) and pain scores (VAS LBP: r = 0.215, P = 0.030 and VAS leg pain: r = 0.309, P = 0.005), but no significant difference in Oswestry disability index (ODI) score.

CONCLUSION

Results show that the severity of periodontitis is associated with higher incidence rates of IVD degeneration and endplate change and clinical outcomes in older adults with lumbar degenerative disorders. Furthermore, the discovery of these relationships unveils a novel mechanism through which the alterations in oral microbiome composition potentially promote IVD degeneration and pain.

HASTE MRI sequence findings correlate with loss of deep pain perception in dogs with thoracolumbar disc extrusion

BACKGROUND

Thoracolumbar intervertebral disc extrusion (TL IVDE) is a common reason for the veterinary hospital admission. Various imaging factors including degree and length of compression have been tested for correlation with clinical severity, but no reliable correlation has been found. Half-Fourier acquisition single-shot turbo spin echo (HASTE) magnetic resonance imaging (MRI) sequences highlight the dorsal and ventral cerebrospinal fluid (CSF) columns and have been used to demonstrate spinal cord swelling in dogs with TL IVDE. This has been used as a predictor of progressive ascending-descending myelomalacia but has not been correlated with neurological grade.

OBJECTIVE

This study aims to investigate the correlation between the attenuation of CSF HASTE signal and clinical severity in dogs suffering from TL disc extrusions.

METHODS

Dogs less than 15 kg who were non-ambulatory due to suspected TL IVDE were prospectively recruited for a study into conservative management. MRI studies were undertaken under sedation including HASTE sequences. The ratio of the length of CSF attenuation to the length of the L2 vertebra was calculated and correlated with clinical severity.

RESULTS

Twenty dogs met the inclusion criteria. No statistically significant difference was demonstrated between the mean CSF attenuation and neurological grade (p = 0.17 but there was a significant difference in the mean CSF attenuation in those who retained deep pain perception and those who did not (p = 0.02). Time to loss of ambulation was also found to not be correlated with CSF attenuation (p = 0.95).

CONCLUSION

In conclusion, the length of CSF attenuation of HASTE MRI sequences in dogs less than 15 kg suffering from IVDEs may be correlated with a loss of deep pain perception.

Presentation, Diagnosis, and Management of Lower Back Pain Associated with Spinal Stenosis: A Narrative Review

Lower back pain (LBP) is an extremely common symptom experienced by people of all ages and is also one of the most frequent causes of disability worldwide. This article aims to review the presentation, diagnosis, and management of lower back pain associated with spinal stenosis. The paper we prepared was classified as a "literature narrative review." Nonetheless, when searching for manuscripts included in our work and reviewing them critically, we concentrated on the keywords: "lower back pain", "lumbar spine stenosis", "diagnostic", "rehabilitation", "neurosurgery", "spine", and "elderly". The incidence of chronic lower back pain (CLBP) increases linearly starting with the third decade of life until 60 years old, and it more often affects women. The course of non-specific LBP above all depends on factors not connected with the spine, which include psychological, behavioral, and social factors, determined by the way the condition is perceived by the patient the environment. Lumbar spine stenosis (LSS) is an age-related process of degeneration of the intervertebral discs, ligamentum flavum, and facet joints, which results in narrowing of the space around the neurovascular structures of the spine. Diagnosis of spinal pain syndromes includes radiography (RTG), computed tomography (CT), and magnetic resonance imaging (MRI). Based on the results of imaging studies, neurological examination, and the severity of the disease, treatment can consist of analgesics and rehabilitation, or, when conservative methods are insufficient, surgical treatment is indicated.

Automatic Detection, Classification, and Grading of Lumbar Intervertebral Disc Degeneration Using an Artificial Neural Network Model

BACKGROUND AND OBJECTIVES

Intervertebral disc degeneration (IDD) is a common cause of symptomatic axial low back pain. Magnetic resonance imaging (MRI) is currently the standard for the investigation and diagnosis of IDD. Deep learning artificial intelligence models represent a potential tool for rapidly and automatically detecting and visualizing IDD. This study investigated the use of deep convolutional neural networks (CNNs) for the detection, classification, and grading of IDD.

METHODS

Sagittal images of 1000 IDD T2-weighted MRI images from 515 adult patients with symptomatic low back pain were separated into 800 MRI images using annotation techniques to create a training dataset (80%) and 200 MRI images to create a test dataset (20%). The training dataset was cleaned, labeled, and annotated by a radiologist. All lumbar discs were classified for disc degeneration based on the Pfirrmann grading system. The deep learning CNN model was used for training in detecting and grading IDD. The results of the training with the CNN model were verified by testing the grading of the dataset using an automatic model.

RESULTS

The training dataset of the sagittal intervertebral disc lumbar MRI images found 220 IDDs of grade I, 530 of grade II, 170 of grade III, 160 of grade IV, and 20 of grade V. The deep CNN model was able to detect and classify lumbar IDD with an accuracy of more than 95%.

CONCLUSION

The deep CNN model can reliably automatically grade routine T2-weighted MRIs using the Pfirrmann grading system, providing a quick and efficient method for lumbar IDD classification.

Prevalence and Features of Incidental Findings in Veterinary Computed Tomography: A Single-Center Six-Years' Experience

Computed tomography (CT) is an advanced imaging technique that may lead to detect "incidentalomas", unexpected asymptomatic lesions found during unrelated examinations. Their clinical meaning and management are not clear for veterinarians, who risk unnecessary investigations that harm the patients. This study is a retrospective analysis that aims to investigate incidentalomas in CT exams and to describe their prevalence, location, types and follow-up, their correlations and associations with the species, breed, sex, and age of patients examined and with the kind and number of sites scanned. The reports of 561 CT scans performed in 512 dogs and 49 cats in a veterinary facility over six years were reviewed and compared to the clinical records of the patients. Eighty incidentalomas were found in 57 dogs and four cats. A significant positive correlation was found in dogs between age and the prevalence of incidentalomas. In dogs, the prevalence of incidentalomas was significantly higher in Boxers and in neck, thoracic, and abdominal scans. Spinal incidentalomas were the most common typologies in dogs. This study can represent a tool that allows clinicians to acquire greater awareness about incidentalomas and to carry out the evidence-based clinical management of them.

The volume of extruded materials is correlated with neurologic severity in small-breed dogs with type I thoracolumbar intervertebral disk herniation

OBJECTIVE

To assess whether the volume of extruded materials is correlated with neurologic severity in dogs with type I thoracolumbar intervertebral disk herniation (TL-IVDH).

ANIMALS

70 client-owned small-breed dogs with type I TL-IVDH diagnosed between July 1, 2016, and June 30, 2018.

PROCEDURES

For this retrospective cohort study, the medical records of 70 dogs with surgically confirmed type I TL-IVDH were reviewed. The volume and height of the intervertebral disk and the area of the maximal transverse compressed spinal cord were measured using CT myelographic images. For each dog, the volume of the disk immediately cranial to the herniated disk was an internal control. Dogs were grouped on the basis of grade of neurologic severity.

RESULTS

Preoperative grades of neurologic severity were grade 2 in 7 (10%) dogs, grade 3 in 16 (23%) dogs, grade 4 in 28 (40%) dogs, and grade 5 in 19 (27%) dogs. The total volume of the affected intervertebral disks was significantly larger than the internal control. Weak positive correlation was found between the volume of the extruded materials into the vertebral canal and the grade of neurologic severity.

CLINICAL RELEVANCE

Our findings indicated that the total volume of the affected intervertebral disks is larger in dogs with type I TL-IVDH, and the volume of the extruded materials into the vertebral canal is weakly correlated with the neurologic severity.

Association between spinal cord compression ratio in magnetic resonance imaging, initial neurological status, and recovery after ventral slot in 57 dogs with cervical disc extrusion

This retrospective, unblinded, single rater study evaluated images obtained from magnetic resonance imaging (MRI) of dogs with cervical intervertebral disc extrusion before being submitted to ventral slot decompression (VSD). Dogs were re-evaluated systematically at 10 and 30 days after VSD. The objectives of this study were to investigate the associations between the following parameters: (1) The maximal spinal cord compression ratio (SCCR) as seen on transverse MRI and pre-surgical neurological status (NS) grade; we hypothesized that dogs with greater SCCR will have worse pre-surgical NS grade at presentation; (2) Pre-surgical NS grade and postoperative recovery; we hypothesized that worse pre-surgical NS grade will be associated with longer postoperative recovery time; (3) SCCR and postoperative recovery; we hypothesized that dogs with higher SCCR will have longer recovery time; (4) Location of extrusion (cranial vs. caudal) and initial NS grade and outcomes; we hypothesized that caudal cervical extrusion will have worse NS grade and longer time to recovery; (5) Longitudinal extension of ventral CSF signal loss on HASTE pulse sequence and NS grade and time to recovery; we hypothesized that dogs with longer HASTE CSF attenuation will have higher NS grade and longer time to recovery. There was no significant association between SCCR and NS grade, suggesting that this relationship in the cervical region is similar to what is observed in the thoracolumbar region, rejecting our first hypothesis. There was a significant difference between ambulatory tetraparesis dogs versus non-ambulatory tetraparesis dogs regarding complete recovery at 10 days: dogs with NS grade 1, 2, or 3 overall recovered faster than dogs with NS grade 4. However, there was no significant difference between these groups regarding complete recovery at 30 days, thereby accepting our second hypothesis at 10 days and rejecting it at 30 days. There was no correlation between SCCR and recovery time, rejecting our third hypothesis. Caudal cervical extrusion did not show higher NS grade or longer recovery time than cranial extrusion, rejecting our fourth hypothesis. CSF attenuation length ratio on HASTE images was not significantly correlated with NS grade but weakly correlate with post-surgical recovery time, partially accepting our fifth hypothesis.

The role of nerve fibers and their neurotransmitters in regulating intervertebral disc degeneration

Intervertebral disc degeneration (IVDD) has been the major contributor to chronic lower back pain (LBP). Abnormal apoptosis, senescence, and pyroptosis of IVD cells, extracellular matrix (ECM) degradation, and infiltration of immune cells are the major molecular alternations during IVDD. Changes at tissue level frequently occur at advanced IVD tissue. Ectopic ingrowth of nerves within inner annulus fibrosus (AF) and nucleus pulposus (NP) tissue has been considered as the primary cause for LBP. Innervation at IVD tissue mainly included sensory and sympathetic nerves, and many markers for these two types of nerves have been detected since 1940. In fact, in osteoarthritis (OA), beyond pain transmission, the direct regulation of neuropeptides on functions of chondrocytes have attracted researchers' great attention recently. Many physical and pathological similarities between joint and IVD have shed us the light on the neurogenic mechanism involved in IVDD. Here, an overview of the advances in the nervous system within IVD tissue will be performed, with a discussion on in the role of nerve fibers and their neurotransmitters in regulating IVDD. We hope this review can attract more research interest to address neuromodulation and IVDD itself, which will enhance our understanding of the contribution of neuromodulation to the structural changes within IVD tissue and inflammatory responses and will help identify novel therapeutic targets and enable the effective treatment of IVDD disease.

Magnetic resonance imaging features of canine intradural/extramedullary intervertebral disc extrusion in seven cases

Intervertebral disc disease, including intervertebral disc extrusions and protrusions, is the most common spinal cord disorder in dogs. Atypical and uncommon intervertebral disc herniations include intradural/intramedullary disc extrusion, intervertebral foraminal disc extrusion and intervertebral disc herniation (Schmorl's node). Intradural/extramedullary disc extrusion is the least common type of intervertebral disc herniation in veterinary medicine, characterized by extruded disc material within the intradural space. To date, only one study has been published in veterinary medicine reporting intradural/extramedullary disc extrusions. In this study, low field MRI was used, and the authors could not find any MRI features to diagnose with confidence an intradural/extramedullary disc location of the extruded disc material. The aim of this study was to describe the high field (1.5T) MRI characteristics of surgically confirmed intradural/extramedullary disc extrusions. This is a retrospective, multicentric and descriptive study. Inclusion criteria was surgical confirmation of intradural/extramedullary disc extrusion by durotomy and complete MRI study of the spine. Seven cases were included. Images were reviewed by a radiology resident and a certified radiologist, with emphasis on the following signs: “Golf-tee sign” (widening of the subarachnoid space cranial and caudal to the lesion), “Beak sign” (pointed and sharp compressive lesion) and “Y sign” (division of the dura and arachnoid layers). MRI showed a “Y sign” in all the cases (7/7) seen from the T2-weighted sagittal views, while “Golf-tee sign” was not recognized in any of the cases (0/7). Additionally, “beak sign” was present in half of the cases (4/7). “Y sign” maybe a reliable MRI feature for identifying intradural/medullary disc extrusions from the MRI study. As the arachnoid is peeled from the dura by the disc herniation there is a splitting of the arachnoid mater and the ventral dura. The intradural disc material will be surrounded by CSF signal intensity margin, giving the appearance of a Y, which can be identified from the T2-weighted sagittal images.

Thoracolumbar retrolaminar block in seven dogs undergoing spinal surgery

Background

Thoracolumbar intervertebral disc extrusion is a common neurologic complaint in dogs and is associated with debilitating pain that requires careful analgesic management to avoid the transition to a chronic pain state. Recently, there has been an increased effort to incorporate regional anaesthetic techniques whenever possible, both for perioperative analgesia management and for prevention of chronic pain. A novel regional anaesthetic technique named retrolaminar block is a fascial plane block where the local anaesthetic is injected directly on top of the dorsal aspect of the vertebral lamina, in the fascial plane between the lamina and the epaxial muscles. The technique was recently described in humans and it is claimed to provide analgesia in patients undergoing thoracic and lumbar procedures. To the authors’ knowledge, the retrolaminar block has not been previously reported in live dogs.

Case presentation

Seven dogs presented to our hospital for suspected thoracolumbar intervertebral disc extrusion were anaesthetised using an anaesthetic premedication and induction protocol tailored for each individual animal. Once the suspected diagnosis was confirmed, all seven dogs were placed in sternal recumbency, and the target thoracolumbar vertebral spinous process was identified with palpation. A unilateral retrolaminar block was performed in all dogs with 2 mg/kg of 0.25% bupivacaine. Physiologic parameters, as well as responses to nociceptive stimuli, were monitored throughout the anaesthetic event.

Intraoperatively, one dog required a bolus of fentanyl to control nociceptive stimulation while the epaxial muscles were retracted. No further intraoperative rescue analgesia was required in any of the cases. The postoperative pain was assessed using the Short Form of Glasgow Composite Measure Pain Scale for dogs every four hours for the duration of the dogs’ hospitalization. The retrolaminar block reduced the intraoperative requirement for systemic opioids and other adjunct analgesic agents and all dogs were comfortable throughout their hospitalization and up until the time of their discharge.

Conclusions

This case report presents the performance of the retrolaminar block technique as part of multimodal analgesia management in seven dogs undergoing thoracolumbar spinal surgery.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13620-022-00224-7.

Influence of Spinal Shock on the Neurorehabilitation of ANNPE Dogs

Acute noncompressive nucleus pulposus extrusion (ANNPE) is related to contusive spinal cord injuries, and dogs usually appear to be exercising vigorously at the time of onset. ANNPE has a characteristic peracute onset of clinical signs during exercise or following trauma, with non-progressive signs during the first 24 h and possibly signs of spinal shock. The main aim was to assess if the presence of spinal shock affects the neurorehabilitation outcomes of ANNPE dogs. This prospective controlled cohort clinical study was conducted at the Arrábida Rehabilitation Center. All of the dogs had T3−L3 injuries and were paraplegic/monoplegic with/without nociception, the study group (n = 14) included dogs with ANNPE spinal shock dogs, and the control group (n = 19) included ANNPE dogs without spinal shock. The study group was also evaluated using a new scale—the Spinal Shock Scale (SSS)—and both groups were under the same intensive neurorehabilitation protocol. Spinal shock was a negative factor for a successful outcome within less time. SSS scores > 4 required additional hospitalization days. The protocol was safe, tolerable, and feasible and accomplished 32% ambulation within 7 days, 29% in 14 days, and 29% in 30 days. The results were better than those obtained in previous studies—94% at 60 days—and 75% of the dogs without nociception recovered ambulation. Long-term follows-ups carried out 4 years later revealed a positive evolution.

Prevalence and clinical features of thoracolumbar intervertebral disc-associated epidural hemorrhage in dogs

Background

Intervertebral disc‐associated epidural hemorrhage (EH) in dogs is a poorly understood neurological condition.

Objective

To compare the clinical presentation, magnetic resonance imaging (MRI) changes, and clinical outcome of dogs with acute thoracolumbar intervertebral disc herniation (TL‐IVDH) with and without EH.

Animals

One hundred sixty client‐owned dogs that underwent MRI and hemilaminectomy for acute TL‐IVDH at a private practice in Colorado, including 63 dogs with EH and 97 dogs without EH.

Methods

Retrospective review of medical record data from 160 dogs presenting sequentially to a single practice with acute TL‐IVDH that underwent MRI and hemilaminectomy surgery.

Results

Sixty‐three of 160 (39%) dogs had confirmed EH. French Bulldogs were significantly overrepresented (23/63; odds ratio [OR]: 4.1; 95% confidence interval [CI]: 1.8‐9.0; P < .001) of the EH cases. Dogs with EH were more likely to present with clinical signs less than 48 hours than were dogs without EH (24‐48 vs 48‐72 hours; OR: 2.4; 95% CI: 1.2‐4.6; P = .02) and were more likely to be nonambulatory on presentation (OR: 2.1; 95% CI: 1.0‐4.1; P = .04). Dogs with EH were more likely to have <50% cross‐sectional spinal cord compression than dogs without EH (OR: 2.3 vs. 0.4; 95% CI: 1.2‐4.4 and 0.2‐0.9, respectively), longer longitudinal spinal cord compression (3 spaces vs 1 space, P < .001), and greater intrinsic spinal cord change (grade 3/severe vs grade 1/mild; P < .001) based on MRI. The location of the intervertebral disc herniation in French Bulldogs with EH was more likely to be thoracolumbar (OR: 10.8; 95% CI: 2.1‐55.7; P = .03).

Conclusions and Clinical Importance

French Bulldogs have a high prevalence of intervertebral disc‐associated EH. Dogs with EH have a shorter clinical course and are more likely to be nonambulatory on initial presentation.

Association of hydromyelia and acute compressive myelopathy caused by intervertebral disc extrusion in dogs

BACKGROUND

Hydromyelia is a common magnetic resonance imaging (MRI) finding associated with compressive myelopathy caused by intervertebral disc extrusion (IVDE).

OBJECTIVES

To describe the MRI features of hydromyelia and explore its relationship to clinical history, neurological severity, and the duration of cord compression.

ANIMALS

Ninety-one client-owned dogs with a focal compressive myelopathy secondary to thoracolumbar IVDE.

METHODS

A retrospective observational study was conducted in which MRIs were blindly evaluated to grade and localize hydromyelia and measure the degree of spinal cord compression. Duration and severity of clinical signs were recorded. Differences between hydromyelia grades in these variables were statistically assessed using a Wilcoxon and Kruskal Wallis test. Receiver operator curve analysis was used to determine the sensitivity and specificity for duration of clinical signs to predict the presence of hydromyelia.

RESULTS

Hydromyelia was identified at sites of IVDE in 84 of 91 dogs. An absence of hydromyelia was associated a with statistically longer duration of clinical signs (mean 73.1, IQR 76 days) when compared to cases with mild (mean 17.7, IQR 7.25 days, P = .006) or severe (mean 17.9, IQR 10.25 days, P = .006) hydromyelia. Duration of clinical signs <14 days was 78.6% sensitive and 85.7% specific for predicting the presence of hydromyelia.

CONCLUSIONS AND CLINICAL IMPORTANCE

The MRI finding of hydromyelia might be a predictor of lesion chronicity in focal IVDE, helping to guide planning of hemilaminectomy surgery.

Clinical, Diagnostic, and Imaging Findings in Three Juvenile Dogs With Paraspinal Hyperesthesia or Myelopathy as a Consequence of Hemophilia A: A Case Report

Three juvenile dogs presented with an acute onset of paraspinal hyperesthesia and/or neurologic deficits. These dogs underwent anesthesia for MRI and additional diagnostics. The thoracolumbar MRI in Dog 1 revealed an accumulation of T2-weighted (T2W) hyperintense, T1-weighted (T1W) iso- to hyperintense, contrast enhancing extradural material. The differential diagnoses were meningitis with secondary hemorrhage or empyema or late subacute hemorrhage. The initial cervical MRI in Dog 2 revealed T1W meningeal contrast enhancement suspected to be secondary to meningitis. A repeat MRI following neurologic decline after CSF sampling revealed a large area of T2W and T1W hyperintensity between fascial planes of the cervical musculature as well as T2W iso- to hyperintense and T1W iso- to hypointense extradural material at the level of C1 consistent with hemorrhage. The cervical MRI in Dog 3 revealed T2W hyperintense and T1W iso- to hypointense extradural compressive material consistent with hemorrhage. Dogs 1 and 2 underwent CSF sampling and developed complications, including subcutaneous hematoma and vertebral canal hemorrhage. Dog 3 underwent surgical decompression, which revealed a compressive extradural hematoma. In each case, a hemophilia panel including factor VIII concentration confirmed the diagnosis of hemophilia A. Dog 1 had a resolution of clinical signs for ~5 months before being euthanized from gastrointestinal hemorrhage. Dog 2 was euthanized due to neurologic decompensation following CSF sampling. Dog 3 did well for 2 weeks after surgery but was then lost to follow-up. This case series provides information on clinical signs, MRI findings, and outcome in 3 juvenile dogs with hemophilia A that developed neurologic deficits or paraspinal hyperesthesia secondary to spontaneous or iatrogenic vertebral canal hemorrhage. Hemophilia A should be considered as a differential in any young dog presenting with an acute onset of hyperesthesia with or without neurologic deficits. This diagnosis should be prioritized in young male dogs that have other evidence of hemorrhage on physical exam.

Recurrence of signs consistent with cervical intervertebral disc extrusion in dogs

OBJECTIVES

Report the rate of recurrent clinical signs following successful treatment of cervical intervertebral disc extrusion, and explore the association between treatment method and recurrence.

MATERIALS AND METHODS

Medical records of dogs with MRI- or CT-confirmed cervical intervertebral disc extrusion were reviewed to verify that they recovered. Type of treatment, site of initial extrusion and whether dogs re-presented with recurrent clinical signs were recorded. Recurrence was considered presumed if based on clinical signs or confirmed if based on repeat cross-sectional imaging.

RESULTS

Complete recovery was documented following medical (36/119, 30.3%) or surgical (83/119, 69.7%) management of initial cervical disc extrusion. There was a recurrence of consistent clinical signs in 40 of 119 (34%) cases, of which 27 of 83 (33%) were initially managed surgically and 13 of 36 (36%) medically. In 24 of 40 (60%) cases, there was imaging confirmation of recurrent extrusion; in medically managed dogs, recurrence mostly occurred at the same site, whereas after surgery, recurrence most commonly involved an adjacent disc. Of the 40 recurrences, 32 (80%) occurred within 2 years of diagnosis. Rate of recurrence was similar between treatment methods in both univariable and multivariable time-to-event analyses (hazard ratio 1.03; 95% confidence interval: 0.67 to 1.53; P=0.87).

CLINICAL SIGNIFICANCE

Following successful initial medical or surgical treatment, clinical signs consistent with recurrent cervical disc extrusion occurred with similar frequency. Medically treated cases tended to have recurrence at the same site as initial presentation, whereas surgical treatment prevented this. Recurrence usually occurred within 2 years. The retrospective study design, small number of recurrences and lack of imaging confirmation of every recurrence should be considered when interpreting the results.

Utility of a flexed neck sagittal magentic resonance imaging sequence for the assessment of cerebellomedullary cistern in dogs

Cerebrospinal fluid (CSF) collection from the cerebellomedullary cistern (CM) of dogs with congenital or acquired cerebellar herniation could lead to serious complications. It is anecdotally more challenging in large brachycephalic breeds possibly due to the increased distance between the skin and CM. The first objective of this study was to assess whether flexed‐neck sagittal magnetic resonance imaging (MRI) sequences would assist in the decision‐making process of collecting CSF from the CM. The second objective was to examine the dimensions of the CM measured in extended and flexed views, and whether cranial index (CI), skull height and body weight correlated with the distance of the CM from the skin surface. Forty‐one dogs of various breeds were included in the study. Measurements were performed on T2‐weighted sagittal sequences acquired in extended and flexed‐neck positions, and transverse sequences acquired in an extended‐neck position. Mild cerebellar herniation was detected in 23/41 (56%) of the flexed‐neck views versus none in the extended views. The CM area was significantly larger in flexed‐neck views than in extended views (p < 0.05). In 29% of the cases (12/41), the trajectory of the needle intersected the cerebellar vermis. There was a positive correlation between the distance of the CM from the skin and body weight (p < 0.05) and skull height (p < 0.05), but not with the CI (p = 0.23). These findings suggest that a flexed‐neck sagittal MRI sequence helps with assessment of the size of the CM and degree of cerebellar herniation, and that skull height and body weight, but not cranial index, affect the distance of the CM from the skin surface.

Fundamentals of Intervertebral Disc Degeneration

Lumbar disc degeneration is one of the leading causes of chronic low back pain. The degenerative cascade is often initiated by an imbalance between catabolic and anabolic processes in the intervertebral discs. As a consequence of extracellular matrix degradation, neoinnervation and neovascularization take place. Ultimately, this degenerative process results in disc bulging and loss of nucleus pulposus and water content and subsequent loss of disc height. Most patients respond to conservative management and surgical interventions well initially, yet a significant number of patients continue to suffer from chronic low back pain. Because of the high prevalence of long-term discogenic pain, regenerative biological therapies, including gene therapies, growth factors, cellular-based injections, and tissue-engineered constructs, have attracted significant attention in light of their potential to directly address the degenerative process. Understanding the pathophysiology of degenerative disc disease is important in both refining existing technologies and developing innovative techniques to reverse the degenerative processes in the discs. In this review, we aimed to cover the underlying pathophysiology of degenerative disc disease as well as its associated risk factors and give a comprehensive summary about the developmental, structural, radiological, and biomechanical properties of human intervertebral discs.

Clinical Features and Risk Factors for Gastrointestinal Complications in Dogs Treated Surgically for Thoracolumbar Intervertebral Disc Extrusion

Gastrointestinal (GI) complications and their clinical implications are poorly characterized in dogs treated surgically for acute thoracolumbar intervertebral disc extrusion (TL-IVDE). The objective of this retrospective study was to characterize GI signs (including vomiting, diarrhea, melena, and hematochezia) in dogs undergoing hemilaminectomy for acute TL-IVDE. One-hundred and sixteen dogs were included. Frequency, type and severity of GI signs during hospitalization, duration of hospitalization and outcome were obtained from the medical record. Potential risk factors for the development of GI signs were explored using univariable and multivariable analyses. Gastrointestinal signs occurred in 55/116 dogs (47%); 22/55 dogs (40%) had one episode and 21/55 (38%) had ≥5 episodes. Diarrhea was the most common (40/55, 73%) while melena was rare (1/55, 2%). GI signs developed in 8/11 dogs (73%) treated perioperatively with both non-steroidal anti-inflammatories and corticosteroids with or without a washout period and in 25/52 dogs (48%) treated prophylactically with proton pump inhibitors. Median hospitalization was 7 days (4-15 days) vs. 5 days (4-11 days) in dogs with or without GI signs, respectively. Duration of hospitalization was associated with development of any GI signs, diarrhea and more severe GI signs (p = 0.001, 0.005, 0.021, respectively). Pre-operative paraplegia with absent pain perception was identified on univariable analysis (p = 0.005) and longer anesthetic duration on multivariable analysis to be associated with development of more severe GI signs (p = 0.047). In dogs undergoing surgery for acute TL-IVDE, GI signs were common and associated with duration of hospitalization and anesthesia. The influence of specific medications and neurologic severity on development of GI signs requires further investigation.

Using Deep Learning to Detect Spinal Cord Diseases on Thoracolumbar Magnetic Resonance Images of Dogs

Deep Learning based Convolutional Neural Networks (CNNs) are the state-of-the-art machine learning technique with medical image data. They have the ability to process large amounts of data and learn image features directly from the raw data. Based on their training, these networks are ultimately able to classify unknown data and make predictions. Magnetic resonance imaging (MRI) is the imaging modality of choice for many spinal cord disorders. Proper interpretation requires time and expertise from radiologists, so there is great interest in using artificial intelligence to more quickly interpret and diagnose medical imaging data. In this study, a CNN was trained and tested using thoracolumbar MR images from 500 dogs. T1- and T2-weighted MR images in sagittal and transverse planes were used. The network was trained with unremarkable images as well as with images showing the following spinal cord pathologies: intervertebral disc extrusion (IVDE), intervertebral disc protrusion (IVDP), fibrocartilaginous embolism (FCE)/acute non-compressive nucleus pulposus extrusion (ANNPE), syringomyelia and neoplasia. 2,693 MR images from 375 dogs were used for network training. The network was tested using 7,695 MR images from 125 dogs. The network performed best in detecting IVDPs on sagittal T1-weighted images, with a sensitivity of 100% and specificity of 95.1%. The network also performed very well in detecting IVDEs, especially on sagittal T2-weighted images, with a sensitivity of 90.8% and specificity of 98.98%. The network detected FCEs and ANNPEs with a sensitivity of 62.22% and a specificity of 97.90% on sagittal T2-weighted images and with a sensitivity of 91% and a specificity of 90% on transverse T2-weighted images. In detecting neoplasms and syringomyelia, the CNN did not perform well because of insufficient training data or because the network had problems differentiating different hyperintensities on T2-weighted images and thus made incorrect predictions. This study has shown that it is possible to train a CNN in terms of recognizing and differentiating various spinal cord pathologies on canine MR images. CNNs therefore have great potential to act as a “second eye” for imagers in the future, providing a faster focus on the altered image area and thus increasing workflow in radiology.

Morphometric Magnetic Resonance Imaging Evaluation of Cervical Spinal Canal and Cord in Normal Small-Breed Dogs

Cervical spinal disease is one of the most common neurological disorders in small-breed dogs. Magnetic resonance imaging (MRI) is a common test for dogs with cervical spinal diseases. However, there is no information on cervical spinal canal and cord using MRI in normal small-breed dogs. Therefore, this study aimed to perform analyses to establish morphologic MRI reference ranges of the cervical spinal canal and cord in normal small-breed dogs. Cervical MRI examinations were taken in 20 client-owned small dogs. The height, width, and cross-sectional area (CSA) of the spinal canal and cord were measured on sagittal and transverse T2-weighted images at each vertebral body level and each intervertebral disk level from C1-C2 to C7 (a total of 12 levels). The height ratio, the width ratio, and the CSA ratio were calculated. The height, width, and CSA of the spinal canal and cord increased as the dog's weight increased (p < 0.01), except for that at C1-C2. However, there was no correlation between the body weight and height ratio and the width ratio and CSA ratio at all levels, except for that at C1-C2. Also, there was a negative correlation between the body weight and CSA ratio at C1-C2. There were no statistical differences for the CSA of the spinal canal, the CSA of the spinal cord, and the CSA ratio between nearby levels, except for that at C1-C2. There was no statistical difference between measurements at each same level of the sagittal and transverse images. The results of this study may provide basic and morphometric information for diagnosing and researching cervical spinal diseases in small-breed dogs.

Glycine-Serine-Threonine Metabolic Axis Delays Intervertebral Disc Degeneration through Antioxidant Effects: An Imaging and Metabonomics Study

Although intervertebral disc degeneration (IDD) can be described as different stages of change through biological methods, this long and complex process cannot be defined in stages by single or simple combination of biological techniques. Under the background of the development of nuclear magnetic resonance (NMR) technology and the emerging metabonomics, we based on animal models and expanded to the study of clinical human degeneration models. The characteristics of different stages of IDD were analyzed by omics. Omics imaging combined with histology, cytology, and proteomics was used for screening of the intervertebral disc (IVD) of research subjects. Furthermore, mass spectrometry nontargeted metabolomics was used to explore profile of metabolites at different stages of the IDD process, to determine differential metabolic pathways and metabolites. NMR spectroscopy was used to qualitatively and quantitatively identify markers of degeneration. NMR was combined with mass spectrometry metabolomics to explore metabolic pathways. Metabolic pathways were determined through protein molecular biology and histocytology of the different groups. Distinguishing advantages of magnetic resonance spectroscopy (MRS) for analysis of metabolites and effective reflection of structural integrity and water molecule metabolism through diffusion tensor imaging (DTI) were further used to verify the macrometabolism profile during degeneration. A corresponding model of in vitro metabolomics and in vivo omics imaging was established. The findings of this study show that a series of metabolic pathways associated with the glycine-serine-threonine (Gly-Ser-Thr) metabolic axis affects carbohydrate patterns and energy utilization efficiency and ultimately delays disc degeneration through antioxidant effects.