White Matter Tract Integrity: An Indicator Of Axonal Pathology After Mild Traumatic Brain Injury
We seek to elucidate the underlying pathophysiology of injury sustained after mild traumatic brain injury (MTBI) using multi-shell diffusion MRI, deriving compartment-specific WM tract integrity (WMTI) metrics. WMTI allows a more biophysical interpretation of WM changes by describing microstructural characteristics in both intra- and extra-axonal environments. Thirty-two patients with MTBI within 30 days of injury and twenty-one age- and sex-matched controls were imaged on a 3T MR scanner. Multi-shell diffusion acquisition was performed with 5 b-values (250 - 2500 s/mm<sup>2</sup>) along 6 - 60 diffusion encoding directions. Tract-based spatial statistics (TBSS) was used with family-wise error (FWE) correction for multiple comparisons. TBSS results demonstrate focally lower intra-axonal diffusivity (D<sub>axon</sub>) in MTBI patients in the splenium of the corpus callosum (sCC) (p < 0.05, FWE-corrected). The Area Under the Curve (AUC)-value for was 0.76 with low sensitivity of 46.9%, but 100% specificity. These results indicate that D<sub>axon</sub> may be a useful imaging biomarker highly specific for MTBI-related WM injury. The observed decrease in D<sub>axon</sub> suggests restriction of the diffusion along the axons occurring shortly after injury.
Subcutaneous administration of alemtuzumab in patients with highly active multiple sclerosis
Alemtuzumab is an anti-CD52 monoclonal antibody with remarkable efficacy in relapsing multiple sclerosis (MS). In clinical trials and off-label use in MS, alemtuzumab has been administered intravenously (IV). Alemtuzumab is approved for chronic lymphoid leukemia as IV. Oncology guidelines recommend alemtuzumab subcutaneous (SC) over IV. There is no report of alemtuzumab SC in MS. We report two patients with highly active relapsing MS who were treated with SC alemtuzumab, had significant improvement and tolerated SC alemtuzumab well without the typical infusion-associated adverse events. SC alemtuzumab in MS warrants further studies as this may enhance patient convenience and minimize infusion-associated adverse events.