T2/FLAIR sequences show multiple serpiginous flow-voids with nidus within the left temporal lobe of the brain giving the bag of black worms appearance (maximum diameter of the nidus is 49 mm). No evidence of local mass effect or hemorrhage is seen.
MRA shows a feeding vessel from the M1 segment of the left middle cerebral artery. Multiple large draining veins are seen taking a tortuous course from the nidus to join the superior sagittal sinus at different points. Another large tortuous draining vein coursing through the left ambient and quadrigeminal plate cisterns to join the straight sinus is seen. The other intra and extracranial vessels are normal in caliber and demonstrate normal flow patterns.
Features are those of cerebral arteriovenous malformations with nidus in the left temporal lobes, having an arterial feeder from M1 branch of left MCA and multiple dilated draining veins coursing superiorly to the superior sagittal sinus - superficial vein and posteriorly to the straight sinus - deep vein. (Spetzler-Martin grade 3)
No evidence of intracranial haemorrhage or mass effect seen.