Hemodynamic Changes Around a Cerebral Arteriovenous Malformation Before and After Embolization Measured with PET

Embolization is an important treatment for cerebral arteriovenous malformation (AVM). Measurement of regional cerebral blood flow around an AVM is essential for the evaluation of the embolization effect. A 12-year-old girl with an AVM was examined sequentially with angiography and PET using a O-15–labeled gas inhalation technique before and after embolization. PET depicted the increase in regional cerebral blood flow in the ipsilateral hemisphere of the AVM and the decrease of cerebral blood flow in the AVM region after embolization. PET can depict hemodynamic changes after embolization and possibly estimate the effect of embolization in patients with AVM. FIGURE 1Fig. 1: T1 weighted axial images of a 12-year-old girl with AVM (A) 7 days before the first embolization and (B) 6 months after the last embolization. Embolization was performed three times using a superselective catheterization technique with a 3-French gauge catheter (Tracker 18; Target Therapeutics, San Jose, CA). Ethylene-vinyl-alcohol co-polymer was used as an embolization material. A total of 0.5 to 2.7 ml of this polymer was injected into each feeder and one to three feeders were embolized each time. The nidus of the AVM decreased, and neither bleeding nor edema ensued after embolization on the T1 weighted image.FIGURE 2Fig. 2: Right internal carotid arteriography (A) just before the first embolization and (B) 6 months after the last embolization. The AVM was fed mainly from branches of the right middle cerebral artery before embolization. The nidus of the AVM decreased, and some feeders of the AVM were obstructed after embolization. No fresh feeders developed and no recanalization of embolized feeders were detected after embolization.FIGURE 3Fig. 3: Images of regional cerebral blood flow (rCBF) derived using a PET scanner (HEADTOME IV; Shimazu Co., Kyoto, Japan) and an O-15–labeled gas inhalation technique (A) 14 days before the first embolization and (B) 4 months after the last embolization. Before embolization, rCBF in the territory of the ipsilateral internal carotid artery was decreased compared with the contralateral territory. The rCBF in the territory of the ipsilateral internal carotid artery increased after embolization (arrowheads) on rCBF images. This increase of rCBF was interpreted as a release of the steal phenomenon caused by the AVM itself (1,2).FIGURE 4Fig. 4: Images of cerebral blood volume (CBV) created using a PET scanner (A) 14 days before the first embolization and (B) 4 months after the last embolization. The CBV of the AVM region decreased after the embolization on CBV images.