Abstract #1062

Altering the Inspired Oxygen Concentration Differentiates Vascular Lesions from Parenchymal Lesions: A Study Using Susceptibility Weighted Imaging in a Mouse Model of Multiple Sclerosis

Nabeela Nathoo¹, Smriti Agrawal², V. Wee Yong³, Jeffrey F. Dunn¹,⁴

¹Radiology, University of Calgary, Calgary, Alberta, Canada; ²Cell Biology and Anatomy, University of Calgary, Calgary, Alberta, Canada; ³Clinical Neurosciences, University of Calgary, Calgary, Alberta, Canada; ⁴Experimental Imaging Centre, University of Calgary, Calgary, Alberta, Canada

Susceptibility weighted imaging (SWI) detects lesions in the experimental autoimmune encephalomyelitis (EAE) animal model of multiple sclerosis (MS). SWI lesions in EAE are due to deoxyhemoglobin (vascular) or iron deposition/demyelination (parenchymal). We hypothesized that changing the percent of inspired oxygen would differentiate vascular lesions from parenchymal lesions in vivo. Some lesions disappeared upon changing the inspired gas from 30% O₂ to 100% O₂; others became hyperintense. Parenchymal lesions remained with 100% O₂. Altering the percent of inspired oxygen can differentiate lesions that are vascular in origin from those that are not, helping us better understand MS pathophysiology detected with SWI.