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Abstract #1106

A Fractional-Order Model for T2 Relaxation in Normal & Degraded Cartilage

David a Reiter1, Richard L. Magin2, Weiguo Li2, Maria Pilar Velasco3, Juan Trujillo4, Richard G. Spencer1

1NIH/NIA, Baltimore, MD, United States; 2University of Illinois at Chicago; 3Universidad Complutense de Madrid; 4Universidad de La Laguna

We previously derived a fractional-order relaxation model through incorporating a memory kernel into the Bloch equations. This leads to transverse relaxation decay according to a stretched-exponential (Str-Exp) function. We apply this to cartilage degeneration by fitting Str-Exp functions to decay curves from normal and enzymatically degraded cartilage. We find that the fractional-order parameter, , is sensitive to, and increases with, proteoglycan loss. We interpret this in terms of a reduction in microstructural tissue complexity. In contrast to multiexponential analysis, Str-Exp fits describe cartilage degradation using a single parameter and may be of particular utility in the setting of limited SNR.