CEREBRAL ARTERIOVENOUS-MALFORMATIONS - IMPROVED NIDUS DEMARCATION BY MEANS OF DYNAMIC TAGGING MR-ANGIOGRAPHY

Our purpose was to further improve the target volume definition for ra diosurgical treatment of cerebral arteriovenous malformations (AVMs) b y means of dynamic MRA (dMRA) using a blood bolus tagging sequence, We therefore compare this technique with 3D-TOF-MRA and transfemoral hig h resolution angiography in plain film technique, Twenty patients with angiographically proven cerebral AVMs were investigated by dMRA, TOF- MRA, and conventional angiography during the MB-assisted radiosurgical planning protocol, The patient's head was fixed in an MR-compatible s tereotactic device, The different angiography techniques were evaluate d by consensus of two radiologists, AVMs were characterized by the num ber and origin of feeding arteries, the maximum diameter of the AVM ni dus, and the venous drainage pattern, Dynamic MRA was able to demonstr ate the complete AVM characteristics and hemodynamics in 12 out of 20 patients, In three patients with an AVM nidus smaller than 1 cm in dia meter, the technique could not reliably depict the malformation, Techn ical problems due to steel skrews and pins in the initially used stere otactic frame occured in five patients, Due to reduced vessel overlap and the lack of disturbances caused by formations with short T-1 time, dMRA was superior to TOF-MRA in the detection and the exact localizat ion of the AVM nidus in four patients, We conclude that dMRA is able t o demonstrate reliably AVM characteristics and hemodynamics in AVMs wi th a nidus larger than 1 cm in diameter, Because of the improved demar cation of the AVM nidus, this technique may be a valuable adjunct to r adiosurgery planning of cerebral AVMs.