The Relationship between Lesion Severity Characterized by Diffusion Tensor Imaging and Motor Function in Chronic Canine Spinal Cord Injury

Attenuated Tissue Damage With Mechanical Tissue Resuscitation in a Pig Model of Spinal Cord Injury

Our previous studies on the treatment of spinal cord injuries with Mechanical Tissue Resuscitation (MTR) in rats have demonstrated that it can significantly improve the locomotor recovery and Basso Beattie Bresnahan scores. MTR treatment also reduced fluid accumulations by T2-imaging and improved the mean neural fiber number and fiber length in injured sites by fiber tractography. Myelin volume was also significantly preserved by MTR treatment. For further clinical application, a large animal model is necessary to assess this treatment. This study examined the effects of application of MTR on traumatic spinal cord injury in a swine model. Traumatic spinal cord contusion injuries in swine were created by controlled pneumatic impact device. Negative pressure at -75 mm Hg was continuously applied to the injured site through open cell silicone manifold for 7 days. In vivo magnetic resonance imaging for T2 and gradient echo (GRE) analysis employed a 3T machine, while a 7T machine was employed for diffusion tensor imaging (DTI) and fiber tractography. Histological hematoxylin and eosin (H&E) and Luxol fast blue staining were examined. MTR significantly reduced the mean injured volumes over 46% by T2-imaging in the injured sites from 477.34 ± 146.31 mm3 in non-treated group to 255.99 ± 70.28 mm3 in MTR treated group (p < 0.01). It also reduced fluid accumulations by relative T2 signal density in the epicenter of the spinal cord injury from 1.62 ± 0.27 in non-treated group to 1.22 ± 0.10 in the MTR treated group (p < 0.05). The mean injured tissue volume measured by H&E staining was 303.71 ± 78.21 mm3 in the non-treated group and decreased significantly to 162.16 ± 33.0 mm3 in the MTR treated group (p < 0.01). The myelin fiber bundles stained by Luxol blue were preserved much more in the MTR treated group (90 ± 29.71 mm3) than in the non-treated group (33.68 ± 24.99 mm3, p < 0.01). The fractional anisotropy (FA) values processed by DTI analysis are increased from 0.203 ± 0.027 in the untreated group to 0.238 ± 0.029 in MTR treatment group (p < 0.05). Fiber tractography showings the mean fiber numbers across the impacted area were increased over 112% from 327.0 ± 99.74 in the non-treated group to 694.83 ± 297.86 in the MTR treated group (p < 0.05). These results indicate local application of MTR for 7 days to spinal cord injury in a swine model decreased tissue injury, reduced tissue edema, and preserved more myelin fibers as well as nerve fibers in the injured spinal cord.

Changes and clinical correlation of diffusion tensor imaging parameters of compressed spinal cord and nerve root in patients with cervical spondylosis

BACKGROUND

Diffusion tensor imaging (DTI) was used to quantitatively study the characteristics of the related spinal cord and nerve root compression parameters in patients with cervical spondylosis (CS), and diffusion tensor tractography (DTT) was used to visualize the spinal cord and nerve root and analyze their relevance to clinical evaluation.

METHODS

A total of 67 patients with CS and 30 healthy volunteers received 3.0 T magnetic resonance imaging. Cervical DTI and DTT were performed in all the participants, where the b value of DTI was set at 800 s/mm2. Fractional anisotropy (FA) and apparent diffusion coefficient (ADC) values of the spinal cord and cervical nerve roots were measured by using DTI. Patients with CS were scored according to the modified Japanese Orthopedic Association (mJOA) score.

RESULTS

In all the participants, the spinal cord and cervical nerve roots were clearly visible by DTT. Compared to the healthy volunteers, the FA values were significantly decreased and ADC values were significantly increased in patients with CS. mJOA score was significantly correlated with the DTI index (ADC and FA) values. Receiver operator characteristic curve analysis revealed that FA and ADC could identify mild, moderate, and severe CS.

CONCLUSIONS

DTI parameters of cervical spinal cord and nerve root compression are associated with the clinical evaluation of patients with CS and may be helpful in assessing the severity of CS.

Not all voxels are created equal: Reducing estimation bias in regional NODDI metrics using tissue-weighted means

Neurite orientation dispersion and density imaging (NODDI) estimates microstructural properties of brain tissue relating to the organisation and processing capacity of neurites, which are essential elements for neuronal communication. Descriptive statistics of NODDI tissue metrics are commonly analyzed in regions-of-interest (ROI) to identify brain-phenotype associations. Here, the conventional method to calculate the ROI mean weights all voxels equally. However, this produces biased estimates in the presence of CSF partial volume. This study introduces the tissue-weighted mean, which calculates the mean NODDI metric across the tissue within an ROI, utilising the tissue fraction estimate from NODDI to reduce estimation bias. We demonstrate the proposed mean in a study of white matter abnormalities in young onset Alzheimer's disease (YOAD). Results show the conventional mean induces significant bias that correlates with CSF partial volume, primarily affecting periventricular regions and more so in YOAD subjects than in healthy controls. Due to the differential extent of bias between healthy controls and YOAD subjects, the conventional mean under- or over-estimated the effect size for group differences in many ROIs. This demonstrates the importance of using the correct estimation procedure when inferring group differences in studies where the extent of CSF partial volume differs between groups. These findings are robust across different acquisition and processing conditions. Bias persists in ROIs at higher image resolution, as demonstrated using data obtained from the third phase of the Alzheimer's disease neuroimaging initiative (ADNI); and when performing ROI analysis in template space. This suggests that conventional ROI means of NODDI metrics are biased estimates under most contemporary experimental conditions, the correction of which requires the proposed tissue-weighted mean. The tissue-weighted mean produces accurate estimates of ROI means and group differences when ROIs contain voxels with CSF partial volume. In addition to NODDI, the technique can be applied to other multi-compartment models that account for CSF partial volume, such as the free water elimination method. We expect the technique to help generate new insights into normal and abnormal variation in tissue microstructure of regions typically confounded by CSF partial volume, such as those in individuals with larger ventricles due to atrophy associated with neurodegenerative disease.

Diffusion tensor imaging-based quantitative analysis of the spinal cord in Pembroke Welsh Corgis with degenerative myelopathy

Canine degenerative myelopathy (DM) is a progressive neurodegenerative disease of the spinal cord. The diagnosis is based on the observation of clinical signs, genetic testing, and exclusion of other spinal cord diseases, and a definitive diagnosis of DM can only be confirmed by postmortem histopathological findings. The aim of this study was to investigate the diagnostic ability of diffusion tensor imaging (DTI) for DM. Eight DM-affected Pembroke Welsh Corgis, thirteen dogs with thoracolumbar intervertebral disk herniation (IVDH), and six healthy control dogs were included. All dogs were scanned using a 3.0-T MRI system. Apparent diffusion coefficient (ADC) and fractional anisotropy (FA) values were calculated for each intervertebral disk level slice between T8–T9 and L2–L3 intervertebral disk levels, and the entire area of the thoracolumbar spinal cord between T8–T9 and L2–L3 intervertebral disk levels (T8–L3 region). The ADC and FA values of the T8–L3 region were significantly lower in the DM group than in the IVDH group. The ADC values for the T8–L3 region had a moderate negative correlation with clinical duration (r_s= −0.723, P=0.043); however, the FA values of other intervertebral disk levels and T8–L3 region had no correlation with clinical durations. The measurement of DTI indices can be used to quantitatively assess neurodegeneration and may have diagnostic value for DM. In particular, the ADC value of the T8–L3 region may aid in making a non-invasive premortem diagnosis of DM.

Nervous system modulation through electrical stimulation in companion animals

Domestic animals with severe spontaneous spinal cord injury (SCI), including dogs and cats that are deep pain perception negative (DPP-), can benefit from specific evaluations involving neurorehabilitation integrative protocols. In human medicine, patients without deep pain sensation, classified as grade A on the American Spinal Injury Association (ASIA) impairment scale, can recover after multidisciplinary approaches that include rehabilitation modalities, such as functional electrical stimulation (FES), transcutaneous electrical spinal cord stimulation (TESCS) and transcranial direct current stimulation (TDCS). This review intends to explore the history, biophysics, neurophysiology, neuroanatomy and the parameters of FES, TESCS, and TDCS, as safe and noninvasive rehabilitation modalities applied in the veterinary field. Additional studies need to be conducted in clinical settings to successfully implement these guidelines in dogs and cats.

Numbers of Axons in Spared Neural Tissue Bridges But Not Their Widths or Areas Correlate With Functional Recovery in Spinal Cord-Injured Rats

The relationships between various parameters of tissue damage and subsequent functional recovery after spinal cord injury (SCI) are not well understood. Patients may regain micturition control and walking despite large postinjury medullar cavities. The objective of this study was to establish possible correlations between morphological findings and degree of functional recovery after spinal cord compression at vertebra Th8 in rats. Recovery of motor (Basso, Beattie, Bresnahan, foot-stepping angle, rump-height index, and ladder climbing), sensory (withdrawal latency), and bladder functions was analyzed at 1, 3, 6, 9, and 12 weeks post-SCI. Following perfusion fixation, spinal cord tissue encompassing the injury site was cut in longitudinal frontal sections. Lesion lengths, lesion volumes, and areas of perilesional neural tissue bridges were determined after staining with cresyl violet. The numbers of axons in these bridges were quantified after staining for class III β-tubulin. We found that it was not the area of the spared tissue bridges, which is routinely determined by magnetic resonance imaging (MRI), but the numbers of axons in them that correlated with functional recovery after SCI (Spearman's ρ > 0.8; p < 0.001). We conclude that prognostic statements based only on MRI measurements should be considered with caution.

In vivo detection of microstructural spinal cord lesions in dogs with degenerative myelopathy using diffusion tensor imaging

Background

Degenerative myelopathy (DM) in dogs is a progressive neurodegenerative condition that causes white matter spinal cord lesions. These lesions are undetectable on standard magnetic resonance imaging (MRI), limiting diagnosis and monitoring of the disease. Spinal cord lesions cause disruption to the structural integrity of the axons causing water diffusion to become more random and less anisotropic. These changes are detectable by the technique of diffusion tensor imaging (DTI) which is highly sensitive to diffusion alterations secondary to white matter lesion development.

Objective

Perform spinal DTI on cohorts of dogs with and without DM to identify if lesions caused by DM will cause a detectable alteration in spinal cord diffusivity that correlates with neurological status.

Animals

Thirteen dogs with DM and 13 aged‐matched controls.

Methods

All animals underwent MRI with DTI of the entire spine. Diffusivity parameters fractional anisotropy (FA) and mean diffusivity (MD) were measured at each vertebral level and statistically compared between groups.

Results

Dogs with DM had significant decreases in FA within the regions of the spinal cord that had high expected lesion load. Decreases in FA were most significant in dogs with severe forms of the disease and correlated with neurological grade.

Conclusions and Clinical Importance

Findings suggest that FA has the potential to be a biomarker for spinal cord lesion development in DM and could play an important role in improving diagnosis and monitoring of this condition.

Prognostic Factors in Canine Acute Intervertebral Disc Disease

Knowledge of the prognosis of acute spinal cord injury is critical to provide appropriate information for clients and make the best treatment choices. Acute intervertebral disc extrusions (IVDE) are a common cause of pain and paralysis in dogs with several types of IVDE occurring. Important prognostic considerations are recovery of ambulation, return of urinary and fecal continence, resolution of pain and, on the negative side, development of progressive myelomalacia. Initial injury severity affects prognosis as does type of IVDE, particularly when considering recovery of continence. Overall, loss of deep pain perception signals a worse outcome. When considering Hansen type 1 IVDE, the prognosis is altered by the choice of surgical vs. medical therapy. Concentration of structural proteins in the plasma, as well as inflammatory mediators, creatine kinase, and myelin basic protein in the cerebrospinal fluid (CSF) can provide additional prognostic information. Finally, cross-sectional area and length of T2 hyperintensity and loss of HASTE signal on MRI have been associated with outcome. Future developments in plasma and imaging biomarkers will assist in accurate prognostication and optimization of patient management.

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.

Magnetization transfer and diffusion tensor imaging in dogs with intervertebral disk herniation

Background

Quantitative magnetic resonance imaging (QMRI) techniques of magnetization transfer ratio (MTR) and diffusion tensor imaging (DTI) provide microstructural information about the spinal cord.

Objective

Compare neurologic grades using the modified Frankel scale with MTR and DTI measurements in dogs with thoracolumbar intervertebral disk herniation (IVDH).

Animals

Fifty‐one dogs with thoracolumbar IVDH.

Methods

Prospective cohort study. Quantitative MRI measurements of the spinal cord were obtained at the region of compression. A linear regression generalized estimating equations model was used to compare QMRI measurements between different neurological grades after adjusting for age, weight, duration of clinical signs, and lesion location.

Results

Grade 5 (.79  ×  10⁻³ mm²/s [median], .43−.91 [range]) and axial (1.47 × 10⁻³ mm²/s, .58−1.8) diffusivity were lower compared to grades 2 (1.003, .68−1.36; P = .02 and 1.81 × 10⁻³ mm²/s, 1.36−2.12; P < .001, respectively) and 3 (1.07 × 10⁻³ mm²/s, .77−1.5; P = .04 and 1.92 × 10⁻³ mm²/s, 1.83−2.37;P < .001, respectively). Compared to dogs with acute myelopathy, chronic myelopathy was associated with higher mean (1.02 × 10⁻³ mm²/s, .77−1.36 vs. .83 × 10⁻³ mm²/s, .64−1.5; P = .03) and radial diffusivity (.75 × 10⁻³ mm²/s, .38−1.04 vs. .44 × 10⁻³ mm²/s, .22−1.01; P = .008) and lower MTR (46.76, 31.8−56.43 vs. 54.4, 45.2−62.27; P = .004) and fractional anisotropy (.58, .4−0.75 vs. .7, .46−.85; P = .02). Fractional anisotropy was lower in dogs with a T2‐weighted intramedullary hyperintensity compared to those without (.7, .45−.85 vs. .54, .4−.8; P = .01).

Conclusion and Clinical Relevance

Mean diffusivity and AD could serve as surrogates of severity of spinal cord injury and are complementary to the clinical exam in dogs with thoracolumbar IVDH.

Ambulation in Dogs With Absent Pain Perception After Acute Thoracolumbar Spinal Cord Injury

Acute thoracolumbar spinal cord injury (SCI) is common in dogs frequently secondary to intervertebral disc herniation. Following severe injury, some dogs never regain sensory function to the pelvic limbs or tail and are designated chronically "deep pain negative." Despite this, a subset of these dogs develop spontaneous motor recovery over time including some that recover sufficient function in their pelvic limbs to walk independently without assistance or weight support. This type of ambulation is commonly known as "spinal walking" and can take up to a year or more to develop. This review provides a comparative overview of locomotion and explores the physiology of locomotor recovery after severe SCI in dogs. We discuss the mechanisms by which post-injury plasticity and coordination between circuitry contained within the spinal cord, peripheral sensory feedback, and residual or recovered supraspinal connections might combine to underpin spinal walking. The clinical characteristics of spinal walking are outlined including what is known about the role of patient or injury features such as lesion location, timeframe post-injury, body size, and spasticity. The relationship between the emergence of spinal walking and electrodiagnostic and magnetic resonance imaging findings are also discussed. Finally, we review possible ways to predict or facilitate recovery of walking in chronically deep pain negative dogs. Improved understanding of the mechanisms of gait generation and plasticity of the surviving tissue after injury might pave the way for further treatment options and enhanced outcomes in severely injured dogs.

Influence of Duration of Injury on Diffusion Tensor Imaging in Acute Canine Spinal Cord Injury

Diffusion tensor imaging (DTI) quantifies microstructural lesion characteristics, but impact of the interval between spinal cord injury (SCI) and examination on imaging characteristics is unclear. Our objective was to investigate the impact of duration of injury on DTI indices in dogs with acute, spontaneous SCI from thoracolumbar intervertebral disc herniation (IVDH) and explore associations with clinical severity. Twenty-six dogs with acute thoracolumbar IVDH of variable severity who underwent DTI were included. Neurological severity was graded using the modified Frankel Score (0-V). Fractional anisotropy (FA) and mean diffusivity (MD) were calculated on regions of interest within and adjacent to the lesion epicenter. Relationships between FA or MD and duration (injury to imaging interval) or neurological severity were determined using regression analysis and Wilcoxon rank sum. Median age was 6.8 years (1-13), median duration was 1.5 days (1-9), and neurological signs ranged from ambulatory paraparesis (MFS II) to paraplegia with absent pain perception (MFS V). Mean FA was 0.61 ± 0.09 cranial to the lesion, 0.57 ± 0.12 at the epicenter and 0.55 ± 0.10 caudally. Mean MD was 1.18 × 10^-3 ± 0.0002 cranially, 1.09 × 10^-3 ± 0.0002 at the epicenter, and 1.14 × 10^-3 ± 0.0002 caudally. Accounting for neurological severity and age, FA caudal to the epicenter decreased with increasing duration of injury (p = 0.02). Lower MD within the lesion epicenter was associated with worse neurological severity (p = 0.01). Duration of injury should be considered when interpreting DTI results in dogs with acute thoracolumbar IVDH. The MD might differentiate injury severity in the acute setting and be worthy of development as an imaging biomarker.

Association between anesthesia duration and outcome in dogs with surgically treated acute severe spinal cord injury caused by thoracolumbar intervertebral disk herniation

Background

Retrospective research recently identified a possible relationship between duration of surgery and outcome in severely affected dogs treated surgically for acute thoracolumbar intervertebral disk herniation (TL‐IVDH).

Hypothesis

That increased duration of surgery is associated with poorer outcome in dogs with absent pain perception treated surgically for TL‐IVDH.

Animals

Two hundred ninety‐seven paraplegic dogs with absent pain perception surgically treated for acute TL‐IVDH.

Methods

Retrospective cohort study. Medical records of 5 institutions were reviewed. Inclusion criteria were paraplegia with absence of pain perception, surgical treatment of TL‐IVDH, and 1‐year postoperative outcome (ambulatory: yes or no). Canine data, outcome, and surgery and total anesthesia duration were retrieved.

Results

In this study, 183/297 (61.6%) dogs were ambulatory within 1 year, 114 (38.4%) dogs failed to recover, including 74 dogs (24.9%) euthanized because of progressive myelomalacia. Median anesthesia duration in dogs that regained ambulation within 1 year of surgery (4.0 hours, interquartile range [IQR] 3.2‐5.1) was significantly shorter than those that did not (4.5 hours, IQR 3.7‐5.6, P = .01). Multivariable logistic regression demonstrated a significant negative association between both duration of surgery and total anesthesia time and ambulation at 1 year when controlling for body weight and number of disk spaces operated on.

Conclusions and Clinical Importance

Findings support a negative association between increased duration of anesthesia and outcome in this group of dogs. However, the retrospective nature of the data does not imply a causal relationship.

Time course and prognostic value of serum GFAP, pNFH, and S100β concentrations in dogs with complete spinal cord injury because of intervertebral disc extrusion

BACKGROUND

A noninvasive biomarker is needed to predict recovery from severe spinal cord injury (SCI) because of thoracolumbar intervertebral disc extrusion (TL-IVDE). Proteins released from neural and glial cells can be detected in the blood and show promise as prognostic tools, but their concentration is influenced by time after injury.

HYPOTHESIS/OBJECTIVES

Serum concentrations of glial fibrillary acidic protein (GFAP), phosphorylated neurofilament heavy chain (pNFH), and S100β will follow different time courses; measurement of combinations of these proteins will predict outcome.

ANIMALS

Thirty-one dogs with TL-IVDE causing paralysis with no pain perception.

METHODS

Prospective study. Serum samples were taken at presentation and intervals over 56 days and banked at -80°C. Glial fibrillary acidic protein, pNFH, and S100β concentrations were measured using ELISA tests and plotted against time from onset of nonambulatory status. Outcome was established at 6 months. The association between biomarker concentration and outcome was examined using logistic regression, receiver operator characteristics curve analysis, and model development.

RESULTS

Thirty-one dogs participated, 3/31 (10%) developed progressive myelomalacia and 19/31 (62%) recovered ambulation. Glial fibrillary acidic protein and S100β concentrations rose for the first 1 to 3 days, and were undetectable by 14 and 28 days, respectively. Phosphorylated neurofilament heavy chain concentrations peaked at 14 days and were detectable at 56 days. Glial fibrillary acidic protein concentrations in the first 72 hours after onset of nonambulatory status predicted recovery with an accuracy of 76.7%-89% depending on sample timing.

CONCLUSIONS AND CLINICAL IMPORTANCE

Serum GFAP concentrations can be used to predict outcome in clinically complete SCI. A rapid inexpensive bedside test is needed.

Predictors of Response to 4-Aminopyridine in Chronic Canine Spinal Cord Injury

4-Aminopyridine (4AP), a potassium channel antagonist, can improve hindlimb motor function in dogs with chronic thoracolumbar spinal cord injury (SCI); however, individual response is variable. We hypothesized that injury characteristics would differ between dogs that do and do not respond to 4AP. Our objective was to compare clinical, electrodiagnostic, gait, and imaging variables between dogs that do and do not respond to 4AP, to identify predictors of response. Thirty-four dogs with permanent deficits after acute thoracolumbar SCI were enrolled. Spasticity, motor and sensory evoked potentials (MEPs, SEPs), H-reflex, F-waves, gait scores, and magnetic resonance imaging (MRI) with diffusion tensor imaging (DTI) were evaluated at baseline and after 4AP administration. Baseline variables were assessed as predictors of response; response was defined as ≥1 point change in open field gait score. Variables were compared pre- and post-4AP to evaluate 4AP effects. Fifteen of 33 (45%) dogs were responders, 18/33 (55%) were non-responders and 1 was eliminated because of an adverse event. Pre-H-reflex threshold <1.2 mA predicted non-response; pre-H-reflex threshold >1.2 mA and Canine Spasticity Scale overall score <7 were predictive of response. All responders had translesional connections on DTI. MEPs were more common post-4AP than pre-4AP (10 vs. 6 dogs) and 4AP decreased H-reflex threshold and increased spasticity in responders. 4-AP impacts central conduction and motor neuron pool excitability in dogs with chronic SCI. Severity of spasticity and H-reflex threshold might allow prediction of response. Further exploration of electrodiagnostic and imaging characteristics might elucidate additional factors contributing to response or non-response.

Diffusion Tensor Imaging in Diagnosis of Post-Traumatic Syringomyelia in Spinal Cord Injury in Rats

Background

Post-traumatic syringomyelia (PTS) is a common disease after spinal cord injury (SCI). The present study was performed to evaluate the advantages of diffusion tensor imaging (DTI) in estimating SCI and prognosing PTS in SCI rats.

Material/Methods

Forty rats were divided into 3 groups based on the extent of the individual SCI and PTS: a control group (n=10), a PTS group (n=8), and an SCI group (n=22). BBB tests were performed preoperatively and postoperatively at (1 d, 3 d, 5 d, 1 w, 2 w, 1 w, 2 w, 3 w, 4 w, 5 w, and 6 w). MRI T2 scanning was conducted postoperatively at (1 w, 2 w, 3 w, 4 w, 5 w, 6 w). DTI and diffusion tensor tractography were used for analyzing neuro-fiber changes after SCI.

Results

BBB scoring showed no differences between the PTS group and SCI group (P<0.05). PTS was found in 8 rats after SCI. MRI showed PTS formation in 3 rats at 2 w after SCI, and 5 rats showed PTS formation at postoperative 3w after SCI. Compared with the control group, ADC showed significant increase in both the PTS group (P<0.05) and the SCI group (P<0.05), FA showed significant decreases in the PTS (P<0.05) and SCI (P<0.05) groups. Compared with the SCI group, the PTS group showed an increase in ADC, but no statistical difference was found in ADC (P>0.05). The PTS group showed a significant increase in FA (P<0.05).

Conclusions

The combination of diffusion tensor imaging and diffusion tensor tractography has characteristics of high-sensitivity and quantitation for PTS prognosis. FA is predictive in the prognosis of PTS formation after SCI.