[Serial MRI study on a case of anterior spinal artery syndrome].

A 63-year-old woman suddenly began to suffer from left chest pain. She gradually became unable to walk and was admitted to the emergency room at another hospital. When she became paraplegic in spite of steroid therapy, she was admitted to our hospital. Her affliction was diagnosed as anterior spinal artery syndrome because of flaccid paraplegia and dissociated sensory loss below the Th4 dermatome. Hematological study indicated a compensated DIC and hepatic enzyme abnormality, while the CSF examinations showed an elevation of protein and positive myelin basic protein (MBP) elevation. The initial MRI taken in the acute stage showed no abnormal signals on T1-weighted (T1) and Gd-enhanced images. The sagittal T2-weighted image (T2) revealed central high intensity (HI) with longitudinal extension from Th2 through the Th11 vertebral level. On axial T2, HI was located on the gray matter at the Th3 and Th4 vertebral level, the ventral two-thirds at the Th8 vertebral level, the central ventral side at the Th9 and Th10 vertebral level, and the entire cross section at the Th12 and L1. A follow-up MRI examination showed that the range of HI on the sagittal T2 had been reduced to 5 segments from Th6 through Th10 vertebral level. The T2 HI lesion on the axial aspect had become reduced so as to localize on the left ventral side at the Th8 vertebral level and on the central ventral side at Th9 and Th10.