Congestive Myelopathy Due to Cervical Perimedullary Arteriovenous Fistula Evaluated by Apparent Diffusion Coefficient Values : Case Report

A 22-year-old woman presented with a cervical perimedullary arteriovenous fistula (AVF) manifesting as right upper and lower extremity weakness. T_2-weighted magnetic resonance (MR) imaging showed intramedullary hyperintensity believed to be caused by venous congestion. Preoperative diffusion-weighted MR imaging showed increased apparent diffusion coefficient (ADC) value. Spinal angiography demonstrated an AVF fed mainly by the right C-5 radicular artery. Complete obliteration of AVF was achieved by endovascular embolization and microsurgical shunt occlusion. The ADC value was normalized and her neurological deficits improved after endovascular surgery, whereas T_2-weighted MR imaging still demonstrated the lesion. The high preoperative ADC value probably indicated reversible vasogenic edema and immediate normalization of the ADC value suggests a good clinical outcome.