Cerebral angiography is a form of angiography which provides images of blood vessels in and around the brain, thereby allowing detection of abnormalities such as arteriovenous malformations and aneurysms.

It was pioneered in 1927 by the Portuguese neurologist Egas Moniz at the University of Lisbon, who also helped develop thorotrast for use in the procedure.

Typically a catheter is inserted into a large artery (such as the femoral artery) and threaded through the circulatory system to the carotid artery, where a contrast agent is injected. A series of radiographs are taken as the contrast agent spreads through the brain's arterial system, then a second series as it reaches the venous system.

For some applications, cerebral angiography may yield better images than less invasive methods such as computed tomography angiography and magnetic resonance angiography.

In addition, cerebral angiography allows certain treatments to be performed immediately, based on its findings. In recent decades, cerebral angiography has so assumed a therapeutic connotation thanks to the elaboration of endovascular therapeutic techniques. Embolization (a minimally invasive surgical technique) over time has played an increasingly significant role in the multimodal treatment of cerebral MAVs, facilitating subsequent microsurgical or radiosurgical treatment. Another type of treatment possible by angiography (if the images reveal an aneurysm) is the introduction of metal coils through the catheter already in place and maneuvered to the site of aneurysm; over time these coils encourage formation of connective tissue at the site, strengthening the vessel walls.

Prior to the advent of modern neuroimaging techniques such as MRI and CT in the mid-1970s, cerebral angiographies were frequently employed as a tool to infer the existence and location of certain kinds of lesions and hematomas by looking for secondary vascular displacement caused by the mass effect related to these medical conditions. This use of angiography as an indirect assessment tool is nowadays obsolete as modern non-invasive diagnostic methods are available to image many kinds of primary intracranial abnormalities directly. It is still widely used however for evaluating various types of vascular pathologies within the skull.

Uses

Cerebral angiography is used for diagnosis but may be followed by treatment procedures in the same setting.

Intracranial diseases are: non-traumatic subarachnoid haemorrhage, non-traumatic intracerebral haemorrhage, intracranial aneurysm, stroke, cerebral vasospasm, cerebral arteriovenous malformation (for Spetzler-Martin grading and plan for intervention), dural arteriovenous fistula, embolisation of brain tumours such as meningioma, cavernous sinus haemangioma, for Wada test, and to obtain haemodynamics of cerebral blood flow such as cross flow, circulation time, and collateral flow. Cerebral angiography is also the standard of detecting intracranial aneurysm and evaluating the feasibility of endovascular coiling. Performing a cerebral angiogram by gaining access through the femoral artery or radial artery is feasible in order to treat cerebral aneurysms with a number of devices

Certain conditions such as contrast allergy, renal insufficiency, and coagulation disorders are contraindicated in this procedure. "Wet connect" is the technique that connects syringe to a sheath without air bubbles within. The frame rate of fluoroscopy is 2 to 4 frames/sec.

At the level of carotid bifurcation, AP and oblique images are taken. At the cavernous (C4) and ophthalmic segments (C6) of the internal carotid artery, Caldwell and lateral views are taken.

Any activation of primary collateral system (ACOM and PCOM arteries) or secondary collateral system (pial-pial and leptomeningeal-dural) in case of occlusion of internal carotid artery should also be documented. Leptomeningeal collaterals or pial collaterals are the small arterial connections that join the terminal branches of ACAs, MCAs, and PCAs on the surface of the brain.

Post-procedural care

Manual compression or percutaneous closure device can be used to stop the bleeding from common femoral artery. Groin haematoma should be monitored during intensive care unit (ICU) monitoring. The puncture should be immobilised (to prevent movement) for 24 hours post puncture.

Some risk factors of complications are if the subject is having subarachnoid haemorrhage, atherosclerotic cerebrovascular disease, frequent transient ischemic attacks, age more than 55 years, and poorly controlled diabetes. Besides, longer procedures, increased in number of catheter exchanges, and the use of larger size of catheters also increases the risk of complications.

Prior to the 1970s the typical technique involved a needle puncture directly into the carotid artery, as depicted in the 1973 horror film The Exorcist, which was replaced by the current method of threading a catheter from a distant artery due to common complications caused by trauma to the artery at the puncture site in the neck (particularly hematomas of the neck, with possible compromission of the airway).

References

  • Cerebral Angiography