MEDICINE

18 UBC MEDICINE
research
Alex MacKay, Founding Director of the UBC MRI Research Centre (and frequent occupant of the machine). Photo credit: Don Erhardt
Thousands of shades of grey
The Canadian Olympic swim team has been inside it. Compulsive
gamblers have been inside it. Mostly, however, patients have
been inside it – people with a range of afflictions, including
Parkinson’s disease, schizophrenia, and multiple sclerosis.
The “it” is a hulking, humming, clanking machine in the basement
of UBC Hospital – a 3-Tesla magnetic resonance imaging scanner,
or MRI, that is the centrepiece of the UBC MRI Research Centre.
This year, the centre marks its 10th year, and it’s busier than ever,
with the scanner booked for a wide range of research projects
– especially those focused on the brain, because it captures
images of that organ’s soft tissue in far finer detail than X-rays or
computed tomography, and does so with greater ease and safety
than positron emitted tomography (PET).
The machine is so sought-after because it’s not your ordinary MRI.
A 3-Tesla scanner is twice as strong as clinical MRIs, producing
a magnetic field 60,000 times stronger than Earth’s magnetic field.
When used with contrast agents, the images can contain over
100,000 shades of grey. It is one of only two in B.C.; the other was
installed last year at BC Children’s Hospital.
Playing with physics and mathematics
But even as researchers exploit the machine for their own projects,
the MRI Research Centre also has found ways to tease even more
revealing data from the technology.
“MRI scanners are relatively open hardware platforms, similar to
smartphones,” says Alex Rauscher, a physicist at the centre and
an Assistant Professor in the Department of Radiology. “Just as
a smartphone comes alive due to its apps, so does the MRI
scanner. We are able to play with the physics and mathematics
behind these things and understand what tissue changes do to
the MRI signal.”
If such a technique is proven to be successful, it becomes part
of the portfolio of scans included by the manufacturer in their
newer machines.
Dr. Rauscher, for example, has developed a sensitive method of
improving image resolution by increasing the ratio of “signal”
(useful information) to “noise” (background or irrelevant
information). The signal-to-noise ratio is so high that it yields
more than just stunningly clear images; it also provides precise
numbers that delineate the structure of tissue, such as lesions too
small to be visually discerned, and the concentrations of various
biochemicals.
“You can be a chemist, measuring the outcomes of reactions,”
says Alex MacKay, the founding Director of the MRI Research
Centre, and a Professor in the Department of Radiology and
the Department of Physics and Astronomy. “But to do that, you
have to understand the physical properties of the molecules
you’re measuring. And you have to understand the signal when
the hydrogen atoms in your body are ‘flipped’ by the scanner’s
magnetic field. So you also have to be a physicist – or at least
have one at your side.” (Three of the centre’s faculty members
are physicists, including Dr. MacKay and Dr. Rauscher.)