Arteriovenous malformation

An arteriovenous malformation is an abnormal connection between arteries and veins that bypasses the capillary network. It can alter blood flow and rupture, causing bleeding.

Arteriovenous shunt: A direct pathway that lets blood pass from an artery into a vein without traversing a capillary bed. An AVM is a structural form of this bypass, with abnormal vessels rather than a simple channel.
Cerebral angiography: Imaging of brain blood vessels using contrast, usually with X-rays, to show their structure and flow. It maps feeding arteries, the nidus, and draining veins for diagnosis and treatment planning.
Cerebral arteriovenous malformation: An arteriovenous malformation located in the brain or its surrounding structures. Brain AVMs are a well-studied subtype with risks that include seizure and intracranial bleeding.
Cavernous malformation: A cluster of thin-walled, blood-filled vascular spaces that usually has low-flow circulation. Unlike an AVM, it generally lacks direct high-flow artery-to-vein connections and a visible nidus.
Vasculogenesis: The formation of blood vessels from precursor cells, especially during early embryonic development. Abnormal vessel formation is one proposed context for how congenital AVMs develop.
Nidus: A tangled network of abnormal vessels forming the central core of many arteriovenous malformations. The nidus connects feeding arteries to draining veins and helps define the lesion.
Magnetic resonance imaging: An imaging method that uses magnetic fields and radio waves to produce detailed pictures of the body. MRI can show an AVM and reveal associated brain injury or prior bleeding.
Spinal arteriovenous malformation: An abnormal artery-to-vein connection in or around the spinal cord. Spinal location can cause progressive neurological problems through bleeding or venous congestion.
Capillary telangiectasia: A small cluster of dilated capillaries with intervening normal brain tissue. It preserves capillary channels rather than bypassing them as an AVM does.
Angiogenesis: The growth of new blood vessels from existing vessels. Vessel growth and remodeling may contribute to AVM development or change over time.

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Hereditary hemorrhagic telangiectasiaRelated: These vascular malformations can form in the lungs, brain, liver, and other organs.