Abstract #0228

Origins of the Ultrashort-T2 1H NMR Signals in Myelinated Nerve: A Direct Measure of Myelin Content?

Robert Adam Horch^1,2, John C. Gore^2,3, Mark D. Does^1,2

¹Biomedical Engineering, Vanderbilt University, Nashville, TN, USA; ²Vanderbilt University Institute of Imaging Science, Vanderbilt University, Nashville, TN, USA; ³Radiology & Radiological Sciences, Vanderbilt University, Nashville, TN, USA

Ultra-short echo time (uTE) MRI of the brain has demonstrated white matter-specific signal enhancement from short T₂ (<1 ms) signals suspected to arise from myelin. However, the T₂ characteristics of these signals, as well as their origins and possible relationship to myelin, remain uncharacterized. Herein, we perform T₂ characterizations and isotopic ¹H perturbations on myelin phantoms and myelinated central and peripheral nerves to determine the origins of short-lived T₂s relevant to uTE MRI. We find sizeable signals in the ≈ 50 s 1 ms T₂ domain and provide compelling evidence that they arise from myelin membrane methylene ¹H.