Chronological changes in MRI findings of spinal dural arteriovenous fistula

BACKGROUND Intramedullary high-intensity changes on T2-weighted magnetic resonance ima ges (MRI) occur in patients with spinal dural arteriovenous fistulas (AVF). Reduction of the high-intensity area after treatment has been noted; howev er, there are still questions about whether the change is related to preope rative clinical grade, postoperative improvement, or efficacy of treatment. This study tried to clarify the relationship between chronological changes in the high intensity area with the treatment and clinical course. METHODS Chronological changes in an intramedullary high-intensity area after surger y were retrospectively analyzed in recent 13 patients with spinal dural AVF s who were treated and followed by MRI. RESULTS Preoperative intramedullary high-intensity areas were observed on T2-weight ed images in all cases. The extent of the high-intensity area correlated wi th preoperative neurological deficits. The intramedullary high-intensity ar ea was reduced or diminished after successful interruption of AVFs. The hig h-intensity area started to decrease within 1 to 4 months after treatment i n ail patients, and disappeared at 2 weeks to 23 months in seven patients. The reduction may suggest interruption of the fistula and improvement of ve nous circulation, but was not always correlated to clinical improvement. Th e intramedullary high-intensity areas rag idly disappeared in two patients, but did not clearly correspond to the clinical improvement. CONCLUSIONS The time course of postoperative MRI changes is helpful for evaluating the efficacy of treatment after surgery for spinal dural AVFs. (C) 2000 by Else vier Science Inc.