An arteriovenous malformation, or AVM, is a congenital vascular abnormality consisting of a cluster of arteries and veins connected by abnormal channels without intervening capillaries. This results in high-pressure arterial blood flowing directly into the venous system, which can cause the involved veins to enlarge and potentially rupture. On Doppler ultrasound, AVMs show high-velocity, low-resistance arterial flow feeding into dilated venous channels with arterialized waveforms. AVMs can occur in the brain, liver, uterus, and other organs, and ultrasound is useful for initial detection, monitoring, and guiding treatment decisions in many locations throughout the body.
Sonography Term