关键词: 椎间盘移位, 神经根病, 磁共振成像, 弥散张量成像

Abstract: Objective　To explore the clinical value of magnetic resonance（MR） principle of selective excitation technique（PROSET） and diffusion tensor imaging（DTI） technique in evaluating L4-S1 unilateral lumbosacral nerve root compression caused by lumbar disc herniation（LDH） locationally and quantitatively.Methods　We enrolled 20 cases of unilateral nerve root compression within L4-S1 innervation area due to LDH diagnosed clinically and treated in Jilin City People's Hospital in 2015.MR PROSET and DTI were performed for localizing the three regions of interest（ROI） respectively at preganglionic nerve root sheath out of dural sac，the ganglion and the anterior branch of the postganglionic nerve expenditure at the external orifice of the intervertebral foramen，and measuring fractional anisotropy（FA） and apparent diffusion coefficient（ADC） value.Meanwhile，diffusion tensor tractography（DTT） was also applied to observe the bilateral L4-S1 nerve roots.Results　There were totally 25 herniated discs among the 20 LDH patients（28 unilateral nerve root compression），including 22 lateral side types（22 unilateral nerve root compression） and 3 intraforaminal types（6 unilateral nerve root compression）．The features of PROSET of each type of LDH：the intraforaminal type showed that the nucleus pulposus pushed the ipsilateral epistatic nerve root outward and upward，and pushed the inferior nerve root inward slightly，while nucleus pulposus only pushed the ipsilateral inferior nerve root inward and backward in lateral side type of LDH.DTT of lumbosacral nerve plexus showed that tract sparsity，narrowing and abrupt break of compressed side nerve root were displayed in all the cases.On the same level of L4-S1 nerve roots，ADC value was significantly higher in the compressed side compared to the normal side nerve root（P<0.05）；the FA value was significantly lower in the compressed side compared to the normal side nerve root（P<0.05）．On the same nerve root，the difference among the three levels was statistically significant（P<0.05）．Conclusion　PROSET，DTI and FT could be used to evaluate the lumbosacral nerve root compression syndrome and locationally and quantitatively assess compressed nerve roots in patients with LDH.

Key words: Intervertebral disc displacement, Radiculopathy, Magnetic resonance imaging, Diffusion tensor imaging