Neurointerventional Radiology Procedures
- Neurointerventional Radiology Procedures - Home
- Arteriovenous Malformation (AVM)
- Carotid Stenting - Extracranial (Brachiocephalic) Angioplasty
- Intracranial Angioplasty
- Vasospasm Treatment
- Cerebral Angiogram
Brain Aneurysms
A brain aneurysm, also called a cerebral or intracranial aneurysm, is an abnormal bulging outward of one of the arteries in the brain. It is estimated that up to one in 15 people in the United States will develop a brain aneurysm during their lifetime.
Brain aneurysms are often discovered when they rupture, causing a subarachnoid hemorrhage, or bleeding into the brain and the space closely surrounding the brain called the subarachnoid space. Subarachnoid hemorrhage from a ruptured brain aneurysm can lead to a hemorrhagic stroke, brain damage, and death.
The main goals of treatment once an aneurysm has ruptured are to stop the bleeding, to prevent potential permanent damage to the brain, and to reduce the risk of recurrence. Unruptured brain aneurysms are sometimes treated to prevent rupture.
Surgery or minimally-invasive endovascular
coiling techniques can be used in the treatment of brain aneurysms. It
is important to note, however, that not all aneurysms are treated at the
time of diagnosis or are amendable by either forms of treatment.
Patients need to consult a neurovascular specialist to determine if they
are candidates for either treatment.
Diagnosis of Brain Aneurysms
Diagnosis of a ruptured cerebral aneurysm is commonly made by finding signs of subarachnoid hemorrhage on a CT scan. The CT scan is a computerized test that rapidly X-rays the body in cross-sections as the body is moved through a large, circular machine. If the CT scan is negative but a ruptured aneurysm is still suspected, a lumbar puncture is performed to detect blood in the cerebrospinal fluid that surrounds the brain and the spinal cord.
To determine the exact size and shape of an aneurysm (ruptured or unruptured), neuroradiologists use either cerebral angiography or tomographic angiography.
Cerebral angiography, the traditional method, involves introducing a catheter (small plastic tube) into an artery, usually in the leg, and steering it through the blood vessels of the body to the artery involved with the aneurysm. A special dye, called a contrast agent, is injected into the patient's artery, and its distribution is shown on X-ray projections. This method may not detect some aneurysms due to overlapping structures or spasm.
Computed Tomographic Angiography (CTA) is an alternative to the traditional method and can be performed without the need for arterial catheterization. This test combines a regular CT scan with a contrast dye injected into a vein. Once the dye is injected into a vein, it travels to the brain arteries, and images are created using a CT scan. These images show exactly how blood flows into the brain arteries.
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Minimally-Invasive Treatment Coil Embolization or Endovascular Coiling Endovascular therapy is a minimally
invasive procedure that accesses the treatment area from within the
blood vessel. In the case of aneurysms, this treatment is called coil
embolization, or "coiling". In contrast to surgery, endovascular
coiling does not require open surgery. Instead, physicians use real-time
X-ray technology, called fluoroscopic imaging, to visualize the
patient's vascular system and treat the disease from inside the blood
vessel.
Surgical Treatment To get to the aneurysm, surgeons must first remove a section of the skull, a procedure commonly known as a craniotomy. The surgeon then spreads the brain tissue apart and places a tiny metal clip across the neck of the vessel to stop blood flow into the aneurysm. After clipping the aneurysm, the bone is secured in its original place, and the wound is closed. |
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Endovascular Coiling v. Surgical Clipping
Treatment of Ruptured Aneurysms
Until recently, most of the studies
regarding surgical clipping and endovascular treatment of brain
aneurysms were either small-scale studies or were retrospective studies
that relied on analyzing historical case records. The only multi-center
prospective randomized clinical trial - considered the gold-standard in
study design - comparing surgical clipping and endovascular coiling of
ruptured aneurysm is the International Subarachnoid Aneurysm Trial
(ISAT).
The study found that, in patients equally suited for both
treatment options, endovascular coiling treatment produces
substantially better patient outcomes than surgery in terms of survival
free of disability at one year. The relative risk of death or
significant disability at one year for patients treated with coils was
22.6 percent lower than in surgically-treated patients.
The study
results were so compelling that the trial was halted early after
enrolling 2,143 of the planned 2,500 patients because the trial steering
committee determined it was no longer ethical to randomize patients to
be treated with neurosurgical clipping. However, long-term follow-up
will be essential to assess the durability of the substantial early
advantage of endovascular coiling over conventional neurosurgical
clipping for the treatment of brain aneurysms.
It is important to
note that patients enrolled in the ISAT were evaluated by both a
neurosurgeon as well as an endovascular coiling specialist, and both
physicians had to collaborate and agree that the aneurysm was treatable
by either technique. This study provides compelling evidence that, if
medically possible, all patients with ruptured brain aneurysms should
receive an endovascular consultation as part of the protocol for the
treatment of brain aneurysms.
Treatment of Unruptured Aneurysms
Although no multi-center randomized clinical trial comparing endovascular coiling and surgical treatment of unruptured aneurysms has yet been conducted, retrospective analysis has found that endovascular coiling is associated with less risk of negative outcomes, shorter hospital stays and shorter recovery times compared with surgery.
Studies have shown that:
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