MR Imaging of Entrapment Neuropathies of the Lower Extremity.

Entrapment neuropathies of the lower extremity are commonly encountered and present a diagnostic challenge. Historical diagnostic workhorses-the physical examination combined with electrodiagnostic studies-are now frequently supplemented by MR neurography. MR neurography is a high-resolution, noninvasive, and operator-independent imaging modality that has proven useful in diagnosis, disease severity assessment, and informing treatment decisions in the management of lower extremity entrapment neuropathies. Currently, the assessment of the peripheral nerves relies heavily on reader identification of morphologic nerve changes; however, emerging innovative MR sequences and PET/MR imaging hold the potential to provide noninvasive means of functional assessment.