Non-Regularized Multivoxel NNLS Is a Robust Analysis Approach to Quantitative T2

Thorarin A. Bjarnason¹, Cheryl R. McCreary¹, Jeff F. Dunn¹, J Ross Mitchell¹

Quantitative T₂ (qT₂) enables scientists to discern tissue microcompartments by measuring multiple T₂ decays using a multiecho acquisition. qT₂ is sensitive to myelin content. We show that traditional qT₂ analysis underestimates the myelin water fraction (MWF) with decreasing SNR. We present a robust approach to qT₂ analysis that does not underestimate the MWF with decreasing SNR, provides variance estimates for a single ROI, and has confidence intervals on the T₂ distribution.