Brain Aneurysms

Brain aneurysms are bulges in the walls of brain arteries.  There are several different types of aneurysms.

Most occur at branching points of the arteries (so-called ‘saccular’ or ‘berry aneurysms’).

Saccular aneurysm
Saccular aneurysm

More rarely they involve the entire segment of an artery, called a ‘fusiform aneurysm’.

Fusiform aneurysm
Fusiform aneurysm


Aneurysms are often detected during tests such as MRI or CT scans.  These unruptured aneurysms present a difficult conundrum – should they be treated or not?

There are many different variables in assessing this, and the only way to meaningfully inform patients is to directly discuss the options with them whilst reviewing the imaging studies.

Many aneurysms are diagnosed when they bleed. Most aneurysms are located on arteries that surround the brain in a compartment called the subarchnoid space. When these aneurysms rupture the bleeding is around the brain, called a subarchnoid haemorrhage. The classical symptom is a sudden agonizing headache, sometimes with a transient loss of consciousness. The diagnosis of an aneurysmal subarachnoid haemorrhage is made by a CT scan.

Normal CT head:

Normal CT head

CT Head with extensive subarachnoid haemorrhage:

CT Head with extensive subarachnoid haemorrhage


Dr Adam Rennie works with the UK’s top Consultant Neurosurgeons at The National Hospital for Neurology and Neurosurgery, and not infrequently joint consultations can be arranged to fully discuss the treatment options available to the patient.

Two main treatment options exist: Endovascular coiling of aneurysms (where a catheter is inserted through arteries under x-ray guidance and tiny platinum based coils are placed inside the aneurysm), and open surgical clipping of aneurysms.

Both treatments are successful at treating aneurysms. Which is best depends on the shape, size and position of the aneurysm.

Endovascular coiling of an aneurysm
Endovascular coiling of an aneurysm

Medical devices used in Interventional Neuroradiology evolve constantly. Dr Adam Rennie uses the full range of devices available, whilst continuing to work within a careful and considered Clinical Governance structure.

These devices include stents (wire tubes which line the vessel walls an allow treatment of aneurysms which would otherwise be unfavourable for coiling alone).

Stent coiling of an aneurysm
Stent coiling of an aneurysm

He uses a significant number of flow diverting stents, which are high mesh density stent used for treatment of very large or difficult aneurysms.

Flow diverting stent
Flow diverting stent

Endovascular treatments carry risks of an ischaemic stroke or even bleeding at the time of the procedure.  The factors relevant to the patient’s particular aneurysm will be discussed fully at the time of consultation, including the need for blood thinning antiplatelet medications prior to and after the procedure to minimize these risks.

Results of Treatment

Internal audits have demonstrated that Dr Adam Rennie’s complication rate for treatment of ruptured and unruptured intracranial aneurysms is very low.

Once an aneurysm has been treated endovascularly it will require long term follow up with MRI imaging to ensure it remains adequately treated. There is a very small (<2%) chance of needing a further treatment, a figure which is dependent on the size and position of the aneurysm and also the type of initial endovascular treatment.

All of this will be discussed at the time of initial consultation.