Diffusion-weighted magnetic resonance imaging of symptomatic nerve root of patients with lumbar disk herniation
- 726 Downloads
Diffusion-weighted imaging (DWI) can provide valuable structural information that may be useful for evaluating pathological changes of the lumbar nerve root. Diffusion-weighted magnetic resonance (MR) neurography has recently been introduced as an alternative way to visualize nerves, but to date, quantitative DWI and MR neurography have not been applied to evaluate the pathology of lumbar nerve roots.
Our purpose was to visualize lumbar nerve roots and to analyze their morphology by MR neurography, and to measure the apparent diffusion coefficient (ADC) of lumbar nerve roots compressed by herniated disks using 1.5-T MR imaging. Ten consecutive patients (median age, 48.0 and range, 20–72 years) with monoradicular symptoms caused by a lumbar herniated disk and 14 healthy volunteers were studied. Regions of interests were placed on the lumbar roots at dorsal root ganglia (DRG) and distal spinal nerves on DWI to quantify mean ADC values. The spinal nerve roots were also visualized by MR neurography.
In the patients, mean ADC values were significantly greater in the compressed DRG and distal spinal nerves than in intact nerves. MR neurography also showed abnormalities such as nerve swelling at and below the compression in the symptomatic nerve root. Increased ADC values were considered to be because of edema and Wallerian degeneration of compressed nerve roots.
DWI is a potential tool for analysis of the pathophysiology of lumbar nerve roots compressed by herniated disks.
KeywordsDiffusion-weighted imaging Apparent diffusion coefficient Nerve roots Herniated lumbar disk Magnetic resonance imaging
Conflict of Interest
We declare that we have no conflict of interest.
- 19.Eguchi Y, Ohtori S, Yamashita M, Yamauchi K, Suzuki M, Orita S, Kamoda H, Arai G, Ishikawa T, Miyagi M, Ochiai N, Kishida S, Masuda Y, Ochi S, Kikawa T, Takaso M, Aoki Y, Toyone T, Suzuki T, Takahashi K (2010) Clinical applications of diffusion magnetic resonance imaging of the lumbar foraminal nerve root entrapment. Eur Spine J 19:1874–1882Google Scholar
- 23.Olmarker K, Rydevik B, Holm S (1989) Edema formation in spinal nerve roots induced by experimental, graded compression: an experimental study on the pig cauda equina with special reference to differences in effects between rapid and slow onset of compression. Spine 14:569–573PubMedCrossRefGoogle Scholar