3D Double-echo Steady-state With Water Excitation MR Imaging In Detection Of Lumbosacral Nerve

Objective:To provide the imaging basis of the pathological changes of the lumbosacral nerve,3D-DESSWE MR sequence was performed in detection of the normal anatomy lumbosacral nerve.Methods:1.3D-DESSWE sequence was performed in22healthy volunteers, male10, female12, age25to70years, mean age50.9±12.3years.2. Method of examination:using a1.5T MR scanner (Symphony, Siemens):to exclude organic disease, sagittal TSE-T2WI sequence, TSE-T1WI sequences and STIR-T2WI sequence were firstly performed; a coronal3D-DESSWE sequence was performed for scanning lumbosacral nerve. The data obtained were reconstructed in relation to the course of lumbosacral nerve by using the thin-section MIP and MPR programs.3. Evaluation method:The reconstructed images were compared with anatomical textbook diagrams. Two doctors analyzed the images in collaboration and recorded on an arbitrary scale of0-2grades.2grade, lumbosacral nerve identified with certainty;1grade, lumbosacral nerve probably identified;0grade, lumbosacral nerve not identified. After the qualitative assessments, both sides of the lengths of the main trunks of lumbosacral nerve and dimensions of dorsal root ganglions were both measured and analyzed. MIP images were adopted to measure the lengths and dimensions. The lengths of the lumbosacral nerve were straight-line measurements from the nerve entering into intervertebral foramen to it cannot be viewed. The dimensions of the DRGs, including widths and lengths, were measured as the longitudinal distance between the proximal and distal ends of DRGs. And the widths were measured vertically at the midpoint perpendicular to the longitudinal axis of DRGs. Results:1. In DESSWE imaging, adipose tissues and components were suppressed. The lumbosacral nerve, DRGs and CSF showed high signal intensity, the osseous structures showed low signal intensity. The muscular tissue surrounding the nerve showed medium high signal intensity.2. The initial parts of the lumbosacral nerve were identified bilateral in100%(44/44); the obturator nerves and branches of the lumbosacral nerve were identified in90.1%(40/44) on oblique reconstructed images.3. In all subjects,3D-DESSWE images provided reliable definition of the normal lumbosacral nerve anatomy bilaterally(score2or1).4. There were no significant difference of The lengths of the main trunks of lumbosacral nerve, dimensions of dorsal root ganglions and scores in left-right sides (P>0.05).Conclusion:1.3D DESSWE sequence is a simple technique. This sequence can demonstrate the lumbosacral trunk,the DRGs and somes branches of the lumbosacral nerve(T12-S3) by using the MIP and MPR programs.2.3D DESSWE sequence provides the imaging basis for evaluating the pathological changes of the lumbosacral nerve.