MAGNETIZATION-TRANSFER IMAGING OF LUMBAR DISC DEGENERATION - CORRELATION OF RELAXATION PARAMETERS WITH BIOCHEMISTRY

Objectives. The authors attempted to find out if magnetization transfe r (MT) imaging with magnetic-resonance imaging (MRI) provides new info rmation of disc degeneration. Summary of Background Data. Magnetizatio n transfer technique improves soft-tissue contrast and characterizatio n. It measures the cross-relaxation and chemical exchange processes be tween free and macromolecule-bound water protons in tissues. Methods. The lumbar MRI and MT of four living subjects and six cadaveric spines were performed at 0.1 T. Disc water, protein, proteoglycan, and colla gen contents of cadaveric samples were correlated to MT parameters. Re sults. The rate of magnetization transfer between free-water protons a nd the macromolecule-bound protons was elevated in degenerated discs. A positive correlation was found between disc collagen and total prote in concentration and the rate of transfer. The contrast of normal and degenerated discs on MT images was not altered much. Conclusions. More studies are needed to fully establish the importance of MT processes in the disc.