Magnetic resonance imaging of peripheral nerves: Differences in magnetization transfer

Introduction: Magnetic resonance imaging (MRI) is an excellent imaging modality for soft tissues. Magnetization transfer (MT) imaging is an MRI technique that is sensitive to the bound protons of macromolecules and therefore can aid in the assessment of nerve damage.Methods: Measurements of the MT ratio (MTR), which provides an index of the MT effects in tissues, were performed in the wrist and foot of 5 volunteers. Results: The MTR of foot (interdigital) nerves (22.2 +/- 2.1%) was smaller than that of the median nerve (41.1 +/- 1.4%). No difference was observed between MTR in muscles adjacent to foot nerves (46.0 +/- 1.5%) and muscles adjacent to the median nerve (44.2 +/- 1.9%). Conclusions: In this study we demonstrate the feasibility of measuring the MTR of foot nerves. The difference of MTR between median and foot nerves indicates a difference in structure/composition. The MTR of peripheral nerves may serve as a biomarker of nerve damage, collagen integrity, and demyelination.