T1 and T2 hypointense mass at the site of CT abnormality consistent with flow void. Note bright signal on the gradient (white blood) sequences. No spinal cord swelling or T2 brightening to indicate cord ischaemia. Large extradural venous filling early in the arterial phase of the TWIST sequence with large draining epidural veins especially to the right entering the hemiazygos vein. Note no vascular lesion within the dura. Appearnace are typical for AV fistula. It is all extradural and in this case erodes bone.