MRI of Foot Drop: How We Do It

Abstract

Various pathologic conditions extending from the lumbar and pelvic regions to the lower leg may manifest as foot drop, or weakness of ankle dorsiflexion. Potential causes of foot drop include L5 radiculopathy, lumbosacral plexopathy, sciatic neuropathy, and peroneal neuropathy. Although the first-line test in lesion localization is most commonly electrodiagnostic testing, MR neurography has emerged as a useful tool to verify lesion site, to accurately characterize the cause of the neuropathy, and to guide patient treatment. MR neurography, when tailored and focused, can help overcome potential pitfalls in clinical and electrodiagnostic evaluation and is commonly performed in the authors' practice. MR neurography studies are protocoled in advance after careful review of clinical notes and electrodiagnostic findings and often after discussion with the referring clinician. Radiologists who interpret MR neurography studies should have a sound understanding not only of peripheral nerve anatomy and common pathologic conditions, but also of the clinical and electrodiagnostic evaluation performed in patients with foot drop. In this way, the radiologist can actively guide the referring clinician in ordering the most appropriate imaging examination, efficiently reaching the correct diagnosis, and deciding appropriate treatment.

MRI Study on Tibial Nerve of the Ankle Canal and Its Branches: A method of multiplanar reconstruction with 3D-FIESTA-C sequences

“…These are all necessary conditions to be able to show clear and distinguishable neural structures in multi-plane images. On the image of the transection of tibial nerve, although the tibial nerve presents low signal on the whole, multiple low-signal nerve ber bundles and slightly higher signal intervals between the ber bundles can be seen in it, and fat high signal can be seen around the tibial nerve [21]. Note the accompanying posterior tibial artery and vein on the medial side of the nerve.…”

MRI Study on Tibial Nerve of the Ankle Canal and Its Branches: A method of multiplanar reconstruction with three-dimensional dual-excitation balanced steady-state free precession sequence

“…These are all necessary conditions to be able to show clear and distinguishable neural structures in multi-plane images. On the image of the transection of tibial nerve, although the tibial nerve presents low signal on the whole, multiple low-signal nerve fiber bundles and slightly higher signal intervals between the fiber bundles can be seen in it, and fat high signal can be seen around the tibial nerve [21]. Note the accompanying posterior tibial artery and vein on the medial side of the nerve.…”

An MRI study of the tibial nerve in the ankle canal and its branches: a method of multiplanar reformation with 3D-FIESTA-C sequences

“…These are necessary conditions to show clear and distinguishable neural structures in multi-plane images. On the image of the transection of the tibial nerve, although the tibial nerve presents low signal on the whole, multiple low-signal nerve fiber bundles and slightly higher signal intervals between the fiber bundles can be seen inside, and fat high signal can be seen around the tibial nerve [21]. The accompanying posterior tibial artery and vein on the medial side of the nerve should be noted.…”