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Abstract #2334

Examining the Source of T2 Components Fit with NNLS

Pamela R. Jackson1, Roland G. Henry2, Tracy Richmond McKnight2

1Joint Graduate Group in Bioengineering, University of California, Berkeley and San Francisco, San Francisco, CA, USA; 2Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, CA, USA

From a previous study, we questioned the reproducibility and source of multiple T2 components measured from cells suspended in agarose. Using NNLS, multiexponential T2s were fit in samples of different agarose concentrations and in packed cell samples washed in different gadolinium concentrations. Based on the variability in the agar samples, we established a signal fraction threshold for T2 components. Two components were fit in packed cell samples. The longer component decreased with increasing Gd concentration suggesting interaction with the extracellular compartment. This study underscores the necessity of determining thresholds of acceptance for components identified with NNLS.