Brain aneurysm
What is a Brain aneurysm?
An aneurysm is enlargement of an artery due to weakness in the wall, like a balloon. 2% of people have a brain aneurysm but many people don’t know that they have one.
Aneurysms in the brain can grow and sometimes burst (rupture) leading to bleeding around the brain – this is a very serious condition called subarachnoid haemorrhage (SAH). 40% of patients who have a burst brain aneurysm die within one month and half of the survivors have a permanent disability. Survivors also have a higher risk of developing another aneurysm in the future.
Ideally, finding aneurysms before they burst, calculating their risk of future rupture, and imaging them every year or treating them can help to prevent the terrible outcomes associated with a burst aneurysm.
Diagnosis
- CT Angiography
- MR Angiography
- Digital Subtraction Angiography
CT angiography (CTA) is a form of imaging where you lie down on a CT scanner table, and through a cannula in an arm vein contrast (dye - containing iodine) is injected. The CT scanner then takes very detailed pictures of the arteries in your brain using X-rays while the contrast passes through the arteries.
CTA has a small amount of radiation associated with it, but the risk from that radiation is far less than the risk of not identifying an aneurysm. A small number of people have a true severe allergic reaction to the dye, but this number is far lower using modern contrast agents. If you have kidney disease, some additional precautions are required when having a CTA.
MR angiography (MRA) involves using an MRI machine to take images of the brain arteries. Most patients can have MRA without any dye needing to be injected, where the MRI machine can detect flow in the blood vessels without the need for dye. This means even patients with severe kidney disease can undergo an MRA.
Most people are safe to have an MRI (which involves magnets and radio waves) – even the more modern pacemakers are MRI compatible. Before you have an MRI, the radiographer will go through a safety checklist with you to make sure you are safe. All implants used by interventional neuroradiologists are MRI compatible.
MRA is our preferred method of imaging aneurysms and following them up, because there is no radiation and we can avoid using dye in people with poor kidney function.
Adding a special dye called gadolinium can allow us to perform a special type of MRI called vessel wall imaging, which can show us if there is inflammation in the wall of the aneurysm. There is evidence now showing that this inflammation is associated with instability of the aneurysm. At Sydney AVM, we are pioneers in the regular use of vessel wall imaging to help assess the risk of aneurysm rupture and to follow-up patients over time. We refer all our patients undergoing vessel wall imaging to the MRI Department at St Vincent’s Public Hospital, where they have the most expertise in Sydney in performing this type of advanced scan.
Dr Bhatia also works at St Vincent’s Public Hospital in the MRI Department, so we can ensure your scan is performed to the highest standard.
Digital subtraction angiography (DSA) is the gold standard for demonstrating vascular diseases of the brain and spine. It is performed as a day procedure by an interventional neuroradiologist. In adults it is performed with local anaesthesia and mild intravenous sedation (twilight) whilst in children we perform the procedure under general anaesthesia (completely asleep). The procedure involves accessing an artery in the thigh or wrist under ultrasound guidance, and then advancing a thin flexible tube through the arteries to the neck under X-ray guidance. Once in position, detailed pictures of the blood vessels are taken whilst dye (iodine containing) is injected through the tube.
Dr Bhatia is equally comfortable performing the procedure through the wrist or the thigh. Many patients prefer the wrist artery access because it is more comfortable, the recovery is quicker, and you can sit up after the procedure with a special wristband over the access site that is deflated over 2 hours. With the thigh access you have to lie flat for 3-4 hours after the procedure. You can discuss with Dr Bhatia at the time of your consultation if you have a preference – some teenagers choose thigh access so they can text more easily afterwards!
Dr Bhatia designed and ran a world first randomized controlled trial in Toronto comparing wrist with thigh artery access for brain angiography, showing they were both equally effective in obtaining the images. There are many older studies from the heart doctors showing that wrist artery access is safer with a lower risk of bleeding complications.
Treatment Options
- Endovascular Aneurysm Repair
- Open Aneurysm Repair
- Watch and Wait
Endovascular repair involves treating brain aneurysms through minimally invasive access in the thigh or wrist artery. The procedures are performed under general anaesthesia (asleep) and for some procedures requiring stents you will need to be on 1 or 2 tablet blood-thinners (such as aspirin) for 1 week before and 3-6 months after the procedure. Dr Bhatia is an expert in endovascular aneurysm repair, including more complex techniques such as stent-assisted coiling, flow diversion, and intra-saccular device placement.
The traditional method of endovascular brain aneurysm repair involves placing platinum coils (thin flexible detachable wires that loop in a coil) within the sac of the aneurysm so that it does not fill anymore. More advanced techniques such as using a stent to help keep the coils in place or placing a special stent called a flow-diverter in the main vessel are now increasingly used for difficult cases. Modern INR practitioners have a wide range of technologies available to help cure brain aneurysms.
A large study (ISAT) demonstrated that endovascular repair resulted in better clinical outcomes and less disability than open surgery for treating ruptured brain aneurysms. In most major hospitals worldwide, most brain aneurysms are now treated by endovascular techniques.
Dr Bhatia was involved in the first ever robot-assisted endovascular treatments for brain aneurysms whilst in Toronto, working with Professor Vitor Mendes Pereira – a world leader in the field. We hope in the future to be able to provide robot-assisted brain aneurysm treatments here in Sydney.
Open aneurysm repair was the first treatment available for brain aneurysms and is performed by neurosurgeons with expertise in blood vessels (cerebrovascular surgeons). This procedure involves a craniotomy (temporary removal of a bone flap from the skull) and placement of a special clip over the neck of the aneurysm by a neurosurgeon using an operating microscope. The procedure is more invasive than endovascular treatment but is the best option for some aneurysm types and locations. If Dr Bhatia believes you would benefit from consultation with a cerebrovascular surgeon, he will refer you to a colleague with expertise in the procedure.
When you consult with Dr Bhatia you can be sure he will recommend the best and safest treatment option for you and will ensure you are referred to the best person if open surgery is indicated. In addition, Dr Bhatia will follow-up with you in the long term. This way you can rest assured that when you come to Sydney AVM, you will receive comprehensive care and you will not need to go back and forth from your GP once you have been referred to us.
Watching and waiting (conservative treatment) is the safest and best option for many patients with small brain aneurysms. Only 1 in 200 brain aneurysms rupture in any given year, so not all patients need treatment. All treatments carry a risk – so the risk of aneurysm rupture should be balanced against the risk of treatment.
At Sydney AVM, we use detailed risk assessment scores (PHASES and UIATS) to help calculate your specific risk of aneurysm rupture compared with the risk of treatment. In addition, we use vessel wall imaging MRI to help detect those aneurysms that may be more unstable. Those patients found to be at low risk of rupture have the option of a watch and wait approach, with annual MRI scans to ensure the aneurysm is stable.