Magnetic Resonance Imaging of Spinal Dysraphism

Abstract

Nineteen patients with lumbosacral spina bifida were studied by magnetic resonance imaging (MRI) and were divided into two groups: those with lumbosacral lipoma and those with meningomyelocele. All of the patients with meningomyelocele underwent surgery soon after birth for closure of the skin defect. Whenever possible, examination was not confined to the lumbosacral area but also included the brain and other portions of the spinal cord. Certain similarities and differences in pathology were ascertained in the two groups. The tethered cords were the same in both groups. However, Chiari malformations were observed only in patients with meningomyelocele, and hydrocephalus occurred only in patients with Chiari malformations. Syringomyelia and scoliosis were detected in both groups, but scoliosis was more prevalent in the meningomyelocele group. There appeared to be a correlation between scoliosis and syringomyelia; in five of the seven cases of syringomyelia, the locations of the scoliosis and syringomyelia were the same. With MRI, these complex pathologies, including tethered cord, syringomyelia, scoliosis, Chiari malformations, and hydrocephalus, were easily visualized. The superiority of MRI over conventional X-ray technology has been well established. First, a direct image of the spinal cord is obtained. Second, there is no necessity for injection of contrast material into the intrathecal space. Third, any scanning field is possible. There are also some disadvantages with MRI. First, the spatial resolution is inferior to that of high-resolution computed tomography. Second, MRI cannot provide information concerning bone cortex. Therefore, bone involvement cannot be accurately diagnosed. However, in the assessment of spinal dysraphism, MRI is an excellent diagnostic tool and should be the preferred method of diagnosing spinal dysraphism.