The Study Of PROSET MR Sequence In Displaying Lumbosacral Nerve Roots

Due to complicated shape of lumbosacral nerve roots and weak contrast to surrounding tissues, imaging of lumbosacral nerve roots is difficult for the time being. Accordingly, the diagnosis of diseases related to nerve roots, such as disc herniation, tuberculosis, arachnoid cyst or adhesions and nerve roots inflammation is still confusing for clinical doctors. Nowadays, diseases of nerve roots are often displayed by X ray myelography, CT myelography and MR myelography, which can not fully display the nerve roots, especially in ganglion posterior segment. The relationship between nerve roots and its surrounding tissues can not be confirmed accurately; therefore, corresponding clinical diagnosis and therapy to these diseases is not satisfactory.With the rapid development of software and hardware of MR imaging, PROSET (PRinciple Of Selective Excitation Technique) is also developed for MR 3D fast imaging. PROSET is a selective excitation technique that employs a frequency and spatially selective excitation pulse. Many applications benefit from PROSET. Impressive results are seen in imaging of nerve roots, cartilage, pancreas and inflow angiography. The present study is to display lumbosacral nerve roots of volunteers and patients by PROSET imaging, and discuss the clinical value of PROSET sequence in diagnosing diseases related to lumbosacral nerve roots.Purpose:1. To observe the normal anatomy of lumbosacral nerve roots on PROSET images and discuss the value of PROSET in displaying lumbosacral nerve roots.2.To discuss the value of PROSET in diagnosing diseases of lumbosacral nerve roots.Methods:1. Using PROSET technique for coronal planar imaging of lumbosacral nerve roots in 20 normal cases. All original images were post-processed by 3D MIP technique.2. Using PROSET technique for coronal planar imaging of lumbosacral nerve roots in 54 suspected cases. All original images were post-processed by 3D MIP technique. Images of 10 cases were reconstructed by partial volume reconstruction method.Results:1. PROSET imaging of 20 normal cases clearly show the appearances of dura sac and dura sheath of spinal cord, spinal nerve root, ganglion and partial ganglion posterior segment. MIP images can observe the shape of nerve roots in multi directions.2. PROSET imaging of 54 suspected cases show 40 positive cases and 14 negative cases. Among positive cases, 14 cases with herniation disc show disc impression to dura sac, or lateral displacement of nerve root, and partial stenosis of spinal canal. 8 cases of sacral canal cyst and 1 case of thoracic-lumbar arachnoid cyst show clearly the appearance of cyst and its relationship with nerve roots. 5 cases of neurogenic tumor show the growth feature along with the nerve root, especially the appearance of tumor going through the intervertebral foramen. 4 cases of metastatic tumor show that nerve roots are wrapped or pushed by tumor. Moreover, peri-vertebral venae could be observed to become markedly thickened and circuitous. However, 2 cases of lumbar tuberculosis do not show ganglion and its posterior segment due to the same signals with peri-vertebral abscess, but only show the appearance of nerve root sheath. 1 case of subdural lipoma show half-moon hypo-intensity at the level of L3-4. L4 nerve root is slightly lifted to the left side and L5 nerve root becomes thickened. In addition, 1 case of lumbar fracture and 1 case of hydromyelia do not show any signal changes of nerve roots in PROSET images. 3 cases of spinal congenital malformation show variable appearances or even the absences of nerve roots. For 14 negative cases, the manifestation of PROSET is the same as result 1. Original PROSET images can easily display nerve roots. Reconstruction images of MIP can observe lesions of nerve roots in multi directions. partial volume reconstruction method can provide clearer images than MIP method.Conclusion:PROSET images can clearly show the anatomy of lumbosacral nerve roots and help to detect the pathogenesis and position of the lumbosacral nerve roots lesions. It can partially substitute the routine X-ray myelography and CT myelography. Together with routine MR images, PROSET images can provide additional information for clinical diagnosis of lumbosacral nerve roots diseases.