Chenyang
Wang1,2, Walter Witschey3, Ari Goldberg4,
Mark Elliott2, Joseph Calabro5, Ari Borthakur2,
Ravinder Reddy2
1Bioengineering, University of
Pennsylvania, Philadelphia, PA, United States; 2Radiology,
University of Pennsylvania, Philadelphia, PA, United States; 3Biochemistry
and Molecular Biophysics, University of Pennsylvania, Philadelphia, PA,
United States; 4Radiology, Hospital of the University of
Pennsylvania, Philadelphia, PA, United States; 5Siemens Medical
Solutions
Magnetization
transfer (MT) has previously been shown to be sensitive to collagen content
in biological tissues. In this study, we quantified MT effect by computing
the MT ratio of the intervertebral disc (IVD) on a pixel-by-pixel basis, from
in vivo MT MR images. The resulting MT ratio map of healthy IVD showed
significantly higher MT ratio in the collagen-rich annular fibrosis compared
to the proteoglycan-rich nucleus pulposus. In contrast, the MT ratio of
degenerated IVD nucleus pulposus appeared elevated, which suggests possible
increase in collagen content in the otherwise proteoglycan-rich tissue as a
result of degeneration.