This past weekend, the Department of Clinical Neurosciences at the University of Calgary hosted a two-day ‘International DTI Tractography Workshop’ (I know you’re wondering what ‘DTI tractography’ is … hold that thought … I’ll get back to that).
The host of the Workshop was Dr. Garnette Sutherland. Dr. Sutherland is well known in the international neuroscience community and, of course, at our university. He is a neurosurgeon whose lifelong aspiration has been to improve the surgical outcome of patients with neurological disease. He continually develops innovative technologies such as intra-operative magnetic resonance imaging and neuroArm, and then translates them into the operating room.
I am no brain surgeon (ha!) so my role as Chancellor of the University of Calgary at the weekend Workshop was limited to meeting with the delegates during their Saturday evening gala banquet. It was a privileged opportunity for me to network with the world’s leading neurosurgeons, biomedical engineers, physicists and corporate partners. During the dessert portion of the dinner, I also shared some of my spaceflight experiences. It turns out that the training and methodologies of astronauts share much in common with those of neurosurgeons.
The DTI (Diffusion Tensor Imaging) Tractography Workshop was attended by surgeons, fellows and residents to learn more about the anatomy of white matter tracts in the human brain and their relationship to disease. White matter tracts are bundles of myelinated nerve fibers that connect and transfer vital information between different regions of the brain. These tracts follow complicated pathways – crossing from left to right, front to back, and up to down. The information they relay is indispensable to our neurological functioning and controls everything we do – movements, memory, cognition. Therefore, when performing brain surgery, a neurosurgeon does her/his best to avoid damaging them.
Until recently, it was not possible to visualize the exact location of white matter tracts in conventional CT or MRI scans. Not knowing their precise location within a patient’s brain makes avoiding them intraoperatively very difficult. Accordingly, the other major focus of the Workshop was to introduce the delegates to a medical advancement known as DTI tractography. With the advent of DTI tractography, neurosurgeons are now able to visualize these tracts via 2D and 3D images.
When I arrived at Saturday evening’s gala banquet, my first question to the neurosurgeons was “how does DTI tractography work?” It’s complicated stuff but the technique has something to do with the way that water diffuses within the brain. Water molecules typically diffuse in all directions due to their spontaneous random motion. However, within white matter they tend to diffuse more readily along the direction of bundles of nerve fibers, rather than across them. Hence, by measuring the diffusion of water molecules in the brain and observing that it is faster in one direction than in others, we can deduce the direction of the fiber bundles at every point in the brain. Brilliant, eh?
Tractography is now being adopted by neurosurgeons to non-invasively and pre-operatively identify the location of these pathways in their patients using MR imaging. Knowing how their patient’s brain white matter is structured, the surgeon can plan an entry point into the brain and an operative strategy that avoids or minimizes damage to these vital connections. When so much is on the line in neurosurgery, it is invaluable to have such a tool that can minimize post-op sequelae.
For example, the above MRI is an intra-operative image of brain from one of Dr. Sutherland’s patients, a male athlete from Red Deer. The large tumour shown in purple needs to be surgically removed. What would be the best surgical approach for Dr. Sutherland to access this deep tumour to minimize collateral damage?
Using MRI and novel image analysis techniques, DTI tractography reveals the patient’s motor (i.e. movement) pathways as red tracts and his memory neural pathways as yellow-green. Damage during surgery to either of these tracts would result in serious neurologic deficits for this young man. However with this vital information, Dr. Sutherland was able to plan a surgical approach (the yellow arrow) to the tumour that avoided these critical pathways. The operation was a success and the young man is doing well today.
The two-day Workshop included lectures and practical sessions on microscopic dissection of white matter tracts and hands-on fibertracking. Delegates were also trained by Dr. Sutherland’s instructor team on DTI tractography platforms and software and learned how to apply them to pre-op planning and
I left the Workshop reflecting on a quote by Archimedes: “Give me a lever long enough and a fulcrum on which to place it, and I shall move the world.” Well, give neurosurgeons innovative tools like DTI Tractography, and they will greatly reduce post-op morbidity and mortality.
This was the second time that the International DTI Tractography Workshop was held in Calgary. It is conducted in collaboration with Dr. Sutherland’s colleagues from the Medical University of Vienna. I am proud that the University of Calgary is playing a leading role in neurosurgical training for international surgeons.
Before I headed to the airport on Sunday morning, Dr. Sutherland gave me a tour of his facility at our university’s Health Research Innovation Centre. I saw his intra-operative MRI suite that houses the original neuroArm as well as the world’s first ceiling-mounted movable high-field magnet. I also saw SYMBIS, his newest neurosurgical robot that is currently completing development and undergoing pre-clinical studies. Think of SYMBIS as the commercial daughter of neuroArm with even more impressive capabilities.
I flew home contemplating that in a high performance field like neurosurgery, the challenges are vast, the margin for error thin and the stakes high. Astronauts and neurosurgeons alike need all the training and insight that we can get to reduce risk.