Optimal technique of three-dimensional MRI of the lumbar nerve root and its radicular vein in normal and lumbar disc herniation patients

Background Although three-dimensional MRI (3D-MRI) of short T1 inversion recovery turbo spin-echo (STIR TSE) has showed superior to two-dimensional MRI (2D-MRI) in showing the spinal cord and lumbar nerve roots, it remains difficult in demonstrating radicular vein at present. We have found that short T1 inversion recovery long time echo (STIR LONG TE) was better in showing radicular vein. To further study the methods and character of the 3D-MRI of lumbar nerve root, ganglions and radicular vein in normal and lumbar disc herniation (LDH) adults, in the present study, we evaluated two 3D-MRI techniques, STIR TSE and STIR LONG TE for demonstrating lumbar nerve roots and especial radicular vein in normal and LDH adults.Methods Twelve normal adult persons and 19 LDH patients were included in this study; special oblique coronal location was adopted. STIR TSE and STIR LONG TE were performed in all participants, and the detection rates of radicular vein and nerve root of L3, L4, L5, S1 were calculated. The grading system was used in grading compromise of the intraspinal extradural lumbar nerve root, ganglion and radicular vein in LDH patients, and all the grading injury of nerve root, ganglion and radicular vein had been evaluated.Results The definite rate of radicular vein (DRRV) of 3D-MRI of STIR LONG TE was significantly different from that of STIR TSE. DRRV of STIR LONG TE was L3, 91.7%, L4, 100%, L5, 100%, S1, 100% and that of STIR TSE was L3, 33.3%, L4, 37.5%, L5, 58.3%, S1, 45.8% in normal adults. It showed no difference between STIR LONG TE and STIR TSE in the detection rate of nerve root. The different patho-injuries of nerve root, ganglion and radicular vein could be seen in all LDH patients by the 3D-MRI of STIR LONG TE. The mean score of Japanese Orthopaedic Association (JOA) was 16.16, and 29 nerve roots were calculated in all the study. The mean grading injury of nerve root was 2.17, that of nerve root ganglion was 1.28, that of radicular vein was 1.83, and the mean co-grading injury of nerve root, ganglion and radicular vein was 5.31. The correlation coefficient was 0.478 (P=0.010) between the score of JOA and that of radicular vein.Conclusion The 3D-MRI of STIR LONG TE is superior to STIR TSE for not only detecting the lumbar nerve root, ganglion and especial radicular vein in normal adults, but also displaying their patho-injuries degree in LDH patients.