MR imaging of the lumbar spine: enhancement of the radicular veins.

Enhancement of lumbar nerve roots in the setting of degenerative disk disease has been considered by several authors as evidence of a breakdown in the blood-nerve barrier induced by nerve root compression [1-3]. Unfortunately, correlation between radicular enhancement and the clinically determined level of radiculopathy has not been consistently shown [4, 5]. We recently proposed that this phenomenon represents intravascular enhancement of radicular veins that travel adjacent to or within the endoneurium of one or more nerve roots of the cauda equina [4, 5]. Our purpose in this pictorial essay is to illustrate the appearance of radicular vein enhancement so that this phenomenon will not be misinterpreted as being clinically significant in the setting of degenerative disk disease.