腰椎部3D MRミエログラフィにおけるmaximum intensity projection画像表示法の検討―神経根の描出

Study of the Maximum Intensity Projection (MIP) Image in Lumbar 3D MR Myelography. Visualization of Nerve Roots

　腰部神経根症状を呈する患者で，腰椎MRIを行っても責任病巣が特定できない症例では診断のため神経根造影や神経根ブロックが行われる．これらは神経に直接針を刺すため侵襲も強く，また一度で診断がつかない場合はレベルを変え繰り返して行う必要があり，患者には苦痛を強いる検査である．そこでわれわれは苦痛を伴わず，神経根の情報を得る試みとして3D MRミエログラフィに注目し，独自の画像処理を加え神経根の描出を試みた．正常例および腰椎疾患のある症例で撮影を行い，良好な神経根の描出が得られたので有用性を検討し報告する．

　We sometimes encounter patients with radicular pain and numbness of the legs whose lumbar MRI scans show no significant findings.　Other advanced examinations, such as myelography and selective nerve root block, are required to identify the cause of the symptoms and the level of the lesions in such patients, but because they are invasive, we attempt to visualize the lumbar spinal nerve roots involved by performing 3D MR myelogarphy (3D-MRM) by our original method.　The images are reconstructed by processing the 3D-MRM volume data set by our method.　Fifteen cases, including three normal subjects, were evaluated in our series.　Clearer root images in comparison with conventional 3D-MRM were obtained in every case.　Our method is very useful for visualizing nerve roots at the lumbar spine level and is helpful in identifying the cause of radicular pain when lumbar MRI scans do not show any lesions.