Uterine fibroid vascularization and clinical relevance to uterine fibroid embolization

Embolization has become a first-line treatment for symptomatic uterine fibroid tumors. Selective catheterization and embolization of both uterine arteries, which are the predominant source of blood flow to fibroid tumors in most cases, is the cornerstone of treatment. Although embolization for treatment of uterine fibroid tumors is widely accepted, great familiarity with the normal and variant pelvic arterial anatomy is needed to ensure the safety and success of the procedure. The uterine artery classically arises as a first or second branch of the anterior division of the internal iliac artery and is usually dilated in the presence of a uterine fibroid tumor. Angiography is used for comprehensive pretreatment assessment of the pelvic arterial anatomy; for noninvasive evaluation, Doppler ultrasonography, contrast material-enhanced magnetic resonance (MR) imaging, and MR angiography also may be used. After the uterine artery is identified, selective catheterization should be performed distal to its cervicovaginal branch. For targeted embolization of the perifibroid arterial plexus, injection of particles with diameters larger than 500 mum is generally recommended. Excessive embolization may injure normal myometrium, ovaries, or fallopian tubes and lead to uterine necrosis or infection or to ovarian failure. Incomplete treatment or additional blood supply to the tumor (eg, via an ovarian artery) may result in clinical failure. The common postembolization angiographic end point is occlusion of the uterine arterial branches to the fibroid tumor while antegrade flow is maintained in the main uterine artery.