Magnetization transfer imaging of lumbar disc degeneration. Correlation of relaxation parameters with biochemistry.

Abstract

The authors attempted to find out if magnetization transfer (MT) imaging with magnetic resonance imaging (MRI) provides new information of disc degeneration. Magnetization transfer technique improves soft-tissue contrast and characterization. It measures the cross-relaxation and chemical exchange processes between free and macromolecule-bound water protons in tissues. The lumbar MRI and MT of four living subjects and six cadaveric spines were performed at 0.1 T. Disc water, protein, proteoglycan, and collagen contents of cadaveric samples were correlated to MT parameters. The rate of magnetization transfer between free-water protons and the macromolecule-bound protons was elevated in degenerated discs. A positive correlation was found between disc collagen and total protein concentration and the rate of transfer. The contrast of normal and degenerated discs on MT images was not altered much. More studies are needed to fully establish the importance of MT processes in the disc.