• Pial vascular malformation of brain
○ Artery → vein shunting, no intervening capillary bed
○ Supratentorial (85%), posterior fossa (15%)
○ Iso-/hyperdense serpentine vessels ± Ca++
○ Arterial feeders, nidus, draining veins enhance
○ "Bag of worms"/tangle of serpiginous "honeycomb" flow
○ No intervening normal brain in arteriovenous
○ ± high signal (gliosis) on FLAIR
○ T2* GRE "blooming" if hemorrhage present
• DSA: Best delineates internal angioarchitecture, 3
○ Nidus of tightly packed vascular channels
• Flow-related aneurysm on feeding artery (10-15%)
• Glioblastoma with arteriovenous shunting
• Annual hemorrhage risk varies widely
○ Overall annual hemorrhage risk 2-4% (cumulative)
○ However, ≤ 1% for unruptured, superficially-located nidi
with superficial venous drainage
○ ≥ 30% for ruptured, deep-seated nidi with extensive
(Left) Coronal graphic shows a
classic cerebral arteriovenous
enhancement . Wedgeshaped configuration is
classic AVM in the left parietal
lobe. The AVM nidus is seen as
at the cortical surface. There is
no normal brain visible within
than displace) brain, there is
almost no mass effect present.
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