Timo Krings
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1)Differentiate from look-alikes (DVA, CPA, dAVF, Moya-Moya)
2)Classify (for surgery: Spetzler-Martin. For radiosurgery: weak points (intranidal aneurysms, venous stenosis, venous ectasias), prior hemorrhage, size (12cm3: larger=lesser marginal dose you can instill into the avm), high flow fistulae (lower chance of obliteration: arterial dilatation venous ectasias very early venous filling). For Embolisation: flow related aneurysms, single/multiple, en passage/terminal, glomerular and fistulous nidus components, venous stenoses).
3)Determine pathomechanism (Seizures, Headaches, Neurological deficits vs incidental finding)
Venous congestion . Pseudophlebitic pattern, venous obstruction, calcifications (sign of decompensation of normal venous gradient of reabsorption of csf, delayed venous return, long pial course of draining vein (all of the parenchyma that would like to use this vein to drain cannot do so and this is more associated with an epileptic presentation), venous rerouting (ie predict expected drainage and see if it is anomalous. The normal brain cannot drain, will have backflow and will not be happy), perfusion abnormalities (perinidal incrased CBV and prolonged MTT).
Arterial Steal=Perilesional Hypoxemia. (However TK says that it is not sure if steal really exists in the adult). Non-sprouting angiogenesis, Transdural supply, Leptomeningeal Collaterals (shift of the watershed: these feed retrogradely the AVM and you see smaller and smaller branches, then bigger again 0:57), Perfusion anomalies.
4)Look for focal weak points
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