Novel technique for evaluating complex pelvic arteriovenous malformations with catheter-directed subtracted MR angiography.

Residual or recurrent arteriovenous malformation (AVM) nidal filling is not uncommon after embolization of complex peripheral AVMs. The major reason for this is incomplete embolization of the nidus owing to failure to detect all feeder vessels other than the dominant one. Herein, the authors describe a novel "intravenous minus intraarterial" subtraction magnetic resonance (MR) angiography technique that enabled the delineation of additional feeding branches not clearly identifiable at intravenous contrast-enhanced MR angiography or nonselective pelvic angiography. This technique may be particularly useful in the evaluation of complex AVMs and their subsequent management with embolization.