When an aneurysm is discovered in a patient's brain, the usual treatment is to rush them into surgery to try to remove the bulge in the blood vessel.

But Canadian researchers are using new imaging techniques to look at aneurysms in new ways, and they're discovering that in many cases they simply need to treat the aneurysm's cause, rather than the aneurysm itself.

A brain or cerebral aneurysm is a weakness in the wall of an artery or vein that causes a portion of the vessel to balloon. Sometimes, it causes no symptoms. But in other cases, the balloon can grow, bringing on everything from mild symptoms like blurred vision to severe symptoms like intense headaches.

If a growing aneurysm isn't treated, the vessel wall can often burst, causing blood to leak into the brain. That can lead to brain damage or death, depending on where the aneurysm is located.

Dr. Timo Krings is now finding that not all aneurysms are alike. His team at Toronto Western Hospital has developed new imaging techniques and has identified eight categories of brain aneurysms, all of which are described in a new study published in Nature Reviews Neurology.

Krings has found that while many aneurysms can appear the same, their underlying causes can be completely different.

In the case of one patient his team examined, detailed tests showed that the aneurysm was actually caused by a tumour on the patient's heart. The tumour was stressing the heart and needed removal in order to treat the aneurysm.

Another aneurysm they examined was caused by a severe sinus infection that was putting pressure on the vessel. Treating the infection with antibiotics caused the aneurysm to resolve on its own.

Neuroradiologist Daniel Mandell says it's an important shift to recognize that in some cases, the cause of the aneurysms has to be treated first.

"The optimal treatment is based on the cause of the aneurysm. If we never identify the cause and we just lump them all together and they are all treated similarly, then we are not treating patients properly," he says.

Krings' team has found it's better to look at what the vessel wall looks like before deciding whether brain surgery is needed. Some aneurysms have vessel walls that are so thick, they are not in danger of rupturing and the patient needs no treatment. Others need very delicate and less invasive treatment.

In the case of Linda Summerfeldt, she had developed two aneurysms that had formed in the vessels behind her eyes, causing her eyes to cross.

"I could not read, I could not watch TV. My life was very much put on hold," she remembers.

MRI imaging revealed that her aneurysms were very fragile, at high risk of rupturing, and needed immediate treatment.

"This aneurysm would truly be characterized as a ticking time bomb," says Dr. Krings.

Because her vessel walls were so weak, Summerfeldt's doctors decided to skip open brain surgery, and used angioplasty to thread a small catheter into the blood vessel in her brain. They then placed two small metal stents into the vessels to divert blood flow away from the aneurysm.

Within days, the dangerous growths had disappeared. Within a week, Summerfeldt's eyes were back to normal, and she was able to return to work.

"To have my life back was a miracle," she says.

With a report from CTV medical specialist Avis Favaro and producer Elizabeth St. Philip