Midsagittal tissue bridges are associated with walking ability in incomplete spinal cord injury: A magnetic resonance imaging case series.

Context: Following spinal cord injury (SCI), early prediction of future walking ability is difficult, due to factors such as spinal shock, sedation, impending surgery, and secondary long bone fracture. Accurate, objective biomarkers used in the acute stage of SCI would inform individualized patient management and enhance both patient/family expectations and treatment outcomes. Using magnetic resonance imaging (MRI) and specifically a midsagittal T2-weighted image, the amount of tissue bridging (measured as spared spinal cord tissue) shows potential to serve as such a biomarker. Ten participants with incomplete SCI received MRI of the spinal cord. Using the midsagittal T2-weighted image, anterior and posterior tissue bridges were calculated as the distance from cerebrospinal fluid to the damage. Then, the midsagittal tissue bridge ratio was calculated as the sum of anterior and posterior tissue bridges divided by the spinal cord diameter. Each participant also performed a 6-minute walk test, where the total distance walked was measured within six minutes.Findings: The midsagittal tissue bridge ratio measure demonstrated a high level of inter-rater reliability (ICC = 0.90). Midsagittal tissue bridge ratios were significantly related to distance walked in six minutes (R = 0.68, P = 0.03).Conclusion/clinical relevance: We uniquely demonstrated that midsagittal tissue bridge ratios were correlated walking ability. These preliminary findings suggest potential for this measure to be considered a prognostic biomarker of residual walking ability following SCI.

Establishing the inter-rater reliability of spinal cord damage manual measurement using magnetic resonance imaging.

Study design: Retrospective study. Objectives: To establish the inter-rater reliability in the quantitative evaluation of spinal cord damage following cervical incomplete spinal cord injury (SCI) utilizing magnetic resonance imaging (MRI). MRI was used to perform manual measurements of the cranial and caudal boundaries of edema, edema length, midsagittal tissue bridge ratio, axial damage ratio, and edema volume in 10 participants with cervical incomplete SCI. Setting: Academic university setting. Methods: Structural MRIs of 10 participants with SCI were collected from Northwestern University's Neuromuscular Imaging and Research Lab. All manual measures were performed using OsiriX (Pixmeo Sarl, Geneva, Switzerland). Intraclass correlation coefficients (ICC) were used to determine inter-rater reliability across seven raters of varying experience. Results: High-to-excellent inter-rater reliability was found for all measures. ICC values for cranial/caudal levels of involvement, edema length, midsagittal tissue bridge ratio, axial damage ratio, and edema volume were 0.99, 0.98, 0.90, 0.84, and 0.93, respectively. Conclusions: Manual MRI measures of spinal cord damage are reliable between raters. Researchers and clinicians may confidently utilize manual MRI measures to quantify cord damage. Future research to predict functional recovery following SCI and better inform clinical management is warranted.

Effects of dietary soy isoflavones and soy protein source on response of weanling pigs to porcine reproductive and respiratory syndrome viral infection.

Porcine reproductive and respiratory syndrome virus (PRRSV) is the most prevalent disease of swine globally. Infection of weanling pigs with PRRSV leads to a complex immune response resulting in significant disease and decreased growth performance. Previous experimental evidence suggests that increasing concentrations of soybean meal in the diet of young pigs confer benefits in terms of growth performance and immune parameters. The objective of this experiment was to identify potential modes of action for this benefit, specifically the ability for soy-derived isoflavones (ISF) to confer immunological benefits to young pigs infected with PRRSV. Four dietary treatments differing in soy protein source (soy protein concentrate vs. enzyme-treated soybean meal) and ISF supplementation (none vs. 1,500 mg total ISF/kg) were fed; the control diet (CON) contained soy protein concentrate and no supplemental ISF. Weanling pigs (60 barrows, 21 d of age, 5.71 ± 0.44 kg) from a naturally Mycoplasma hyopneumoniae (Mh)-infected source herd were individually housed in disease containment chambers and provided ad libitum access to experimental diets for 7 d before receiving either a sham inoculation or a 9.28 × 103 50% tissue culture infective dose of PRRSV at 28 d of age (0 d postinoculation). A total of 5 experimental treatments included an uninfected group receiving the CON diet, plus four infected groups each receiving a different dietary treatment. Growth performance and rectal temperatures were recorded throughout the study, and blood was collected for quantification of serum PRRSV load, presence of anti-PRRSV antibodies, differential complete blood counts, cytokine concentrations, and T-cell immunophenotyping. Data were analyzed as a 2-way or 3-way ANOVA for all treatments including PRRSV-infected pigs, in addition to a single degree of freedom contrast to compare uninfected and infected pigs receiving the CON diet. PRRSV-infection reduced growth rate and efficiency compared with noninfected controls with minimal influences by ISF. Supplemental ISF reduced PRRSV-induced band neutrophilia and improved cytotoxic-to-helper T-cell ratios. These results suggest that ISF contribute to activation of adaptive immune system pathways and could benefit recovery from and clearance of PRRSV infections.