What all these projects have in common is their quest to visualize what has long been invisible so doctors can, finally, have the information they need to give their patients the most appropriate and effective care.
“It’s the stuff of science fiction,” says Dr. Sandra Black, Brain Sciences Research Program director at Sunnybrook. “But it’s happening now, and our hope is that it’s going to make a huge difference for patients with serious conditions.”
THERAPEUTIC: PET-MRI WITH
In the future, patients with early-stage Alzheimer’s disease or dementia could come into a hospital, put on an ultrasound helmet and get stem cells or a combination of drugs injected with precision into the affected parts of their brain.
Sounds far-fetched? This cutting-edge treatment could be coming soon to Sunnybrook, thanks to the innovation of its scientists and a multimillion-dollar investment in a PET-MRI system.
The much-anticipated system will be housed in the future Slaight Centre for Image-Guided Brain Therapy and Repair, which is being funded by a $10-million donation from the Slaight Family Foundation at Sunnybrook Research Institute. The PET-MRI system will be modified for integration with a transcranial-focused ultrasound device fashioned as a helmet.
Developed by Sunnybrook scientist Dr. Kullervo Hynynen, the ultrasound device uses ultrasound beams and harmless, tiny gas bubbles to create a temporary opening in the brain’s blood barrier. This allows large molecules, such as growth factors, antibodies and even stem cells, to get into the brain through the barrier posed by tight junctions in the tiny blood vessels called capillaries which otherwise would keep them out. Real-time imaging from the PET-MRI scanner ensures the ultrasound and therapeutics are targeted precisely to a specific area of the brain.
“Right now intravenous infusions or injections of monoclonal antibodies are inefficient because you get only 1 per cent of them into the brain, and these are very expensive biological treatments,” says Dr. Sandra Black. “But if you could increase their access into the brain and in targeted areas where they are needed, that could be very beneficial.”
Focused ultrasound at high frequency (HiFU) is already being used in trials for other conditions, including treatment of severe tremors, notes Dr. Black. It is called knifeless surgery. Low frequency focused ultrasound (LoFU) is already in trials at Sunnybrook to deliver drugs into brain tumours by opening the blood-brain barrier as the chemotherapy is being infused.
Sunnybrook researchers are hoping they will also soon be able to use focused ultrasound to break up blood clots in the brain vessels of patients with stroke and to get drugs into the brains of people with Alzheimer’s disease. If the preliminary studies continue to go well, they hope to launch the first clinical trials using LoFU in Alzheimer’s disease within the next few years.
DIAGNOSTIC: HEART METABOLIC MRI
A new imaging method pioneered at Sunnybrook is giving doctors new perspective into a patient’s heart, allowing them to detect heart failure at an early stage and identify the best therapy.
Using a new, $2-million imaging system known as a metabolic MRI, Dr. Charles Cunningham, a physicist in the Schulich Heart Research Program, developed a technique for non-invasively measuring the metabolism in the heart muscle, capturing chemical reactions as they occur.
“As the human heart begins to fail, it starts to use glucose instead of fat as its preferred fuel,” explains Dr. Cunningham. “That’s one of the metabolic changes that occur, and there are drugs that reverse that.”
An MRI combined with ultrasound was used to guide
the biopsy and find the occult prostate cancer of
Kim Stewart, shown here with Dr. Laurent Milot.
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