The Diffusion Tensor Imaging And Clinical Application Value On The Lumbosacral Nerve Root

Purpose: The objective of this study were to investigate the spatial ability ofdiffusion tensor imaging and fiber tracking in the normal lumbosacral nerveroots,and measure ractional anisotropy（FA） and apparent diffusion coeffieient（ADC）in the normal different lumbosacral nerve roots,which can provides a theoreticalbasis and technical support in clinical research about the nerve root diseases. Toinvestigate diffusion tensor imaging of lumbosacral nerve roots on lumbar discherniation,and analysis FA and ADC values of the normal and diseased nerve root.Materials and methods:30volunteer without the low back pain and29patients, who had unilateral sciatica with posterolateral or foraminal disc herniationdemonstrated on CT or MRI underwent1.5T MRI imaging.DTI with medic imagingwere performed and the lumbosacral nerve roots were visualized by setting seedpoint fiber bundles in the ROI area, and measuring ractional anisotropy（FA） andapparent diffusion coeffieient（ADC） of the lumbosacral nerve roots.Results: The lumbosacral nerve roots were clearly visualized with DTT.Thelumbosacral nerve roots were clearly visualized with DTT.Mean FA and ADC valueswere in normal fibers as follows:0.309±0.023and1.471±0.349×10^-3mm²/s.However, there is no significant different in the FA and ADC values between thedifferent sequences nerve root, meanwhile the FA and ADC values of the differentside of the nerve root have no significant differences.The mean FA value in thecompressed nerve roots （FAcompressed=0.249±0.031） was significantly lower thanmean FA value in the contralateral nerve roots （FAcontralateral=0.330±0.025） and inthe normal nerve roots （FAnormal=0.301±0.023）.The mean ADC value was higher ofcompressed nerve roots (ADCcompressed=1.772±0.499×10^-3mm²/s) than of thecontralateral nerve root(ADCcontralateral=1.467±0.449×10^-3mm²/s)and the normalnerve roots(ADCnormal=1.524±0.365×10^-3mm²/s). The single FA ROC curve showsthe High efficiency.The area under the curve was0.909.On the contrary, the singleADC ROC curve shows the low efficiency the area under the curve was0.700. Conclusion: DTI imaging can completely depict and quantitatively evaluatelumbosacral nerve roots, DTI have superiority in accurately and intuitively depictstructural change of nerve root in lumbar disc herniation. FA value and ADC valuescould mediate reflect the diffusion movement of water molecules, and providereference for to reveal pain mechanism and evaluate clinical diagnosis and treatmentof lumbosacral nerve root diseases.