Mapping the brain

It’s not an overstatement to say that Dr Joseph Yang and his teams’ work has revolutionised epilepsy and brain tumour surgery at the RCH.

For the past eight years he has been working on developing cutting edge magnetic resonance imaging (MRI) techniques to map the brain nerve fibre tracts, a method known as “tractography”, to help assist surgeons during lifesaving brain surgery.

Planning for and performing brain surgery makes extensive use of MRI techniques to map the region for removal and to locate nearby arteries, veins and important brain nerve fibre tracts. The nerve fibres transmit information that is important for carrying out daily functioning – such as movement, language, vision and memory. Damage to the nerve fibres during surgery can be irreparable, so having the most precise and accurate picture is paramount.

What Joseph and his team do, in very simplified terms is, after a child’s brain is scanned in an MRI machine, they use sophisticated imaging modelling techniques to create what appears are colourful rainbows of images that map the different nerve fibre tracts, through the child’s brain.

By developing these highly advanced tractography images, it has enabled surgeons to meticulously plan and perform brain operations with a greater level of accuracy than ever possible.

It has allowed tumours to be removed from children’s brains that previously would have been too risky to operate on, and without the child losing any important functions such as language, movement, memory or vision.

Joseph conservatively estimates that over 100 children have been operated on at the RCH with the assistance of this technology.

Three years ago, Joseph was awarded the Di and Neville Bertalli Clinical Research Fellowship in Paediatric Neurosurgery, which he said was invaluable in allowing him to further his research and advance the technology even further.

“The fellowship enabled me to have protected research time and to update my knowledge through continued education and to further refine and develop the surgical processing pipeline and tackle the challenges of clinical translation,” Joseph said.

“The fellowship offers a unique opportunity to maximise my clinical and research skillsets – to bridge the gap between advanced imaging research and clinical practice- to enable my research work to directly impact on surgical outcomes for children suffering from epilepsy and brain tumours.”

Joseph says there have been two major developments in the past few years which have had an impact on his work.

“One major development is from a technical point of view, the modelling imaging techniques across the entire field have become more accurate, so more sophisticated imaging and processing techniques are at our disposal for implementation in clinical practice and address practical challenges and limitations that were not possible by methods and techniques previously available to us,” Joseph said.

“The other main area is that we have accumulated a lot more experience with this imaging technique; we have applied this technique assisting with clinical care of a lot more children.”

What Joseph is primarily focused on now is incorporating his research findings into clinical care through the development of an imaging processing pipeline which will enable nerve fibre tract images to be routinely imported into surgical navigational software.

“The surgical navigation platform is routinely used during brain surgery; you take an MRI picture of the child’s brain the day before surgery. During surgery, these MRI images are co-registered and overlaid on a live view of the patient’s brain, to help guiding the surgeons during removal of the brain tumour. How we make a difference here is we import and display the tractography images directly in this platform,” Joseph said.

“Currently the commercially available navigation software system doesn’t allow you to do this using advanced tractography images created from sophisticated imaging methodologies. By generating these pictures and integrating the tractography images into this platform, you can not only see the minute details of the brain you can also cut out the tumour and see where the nerve fibre tracts are.”

Joseph is also developing training modules that will enable this technology to be accessible to all neurosurgeons and their patients. And he’s not stopping there – Joseph has big plans for the future.

“Something I am actively working on is the idea of ‘real time’ tractography. The brain can ‘shift’ during surgery due to loss of brain fluid, the brain being swollen or during the course of removing the tumour – and this can affect how accurate these tractography images are at that particular time point during the operation. I’m exploring a feasible solution to recreate and update the tractography images during surgery with live MRI data acquired using the intra-operative MRI machine, during the surgery. This means we will have to improve the efficiency of data processing from hours down to 15 to 20 minutes and update these images during surgery as you go” Joseph said.

“All my work and my vision of bringing advanced tractography to routine neurosurgical practice could not be possible without the generosity of the fellowship funding. The fellowship has definitely created the opportunity for my work to directly impact on our clinical epilepsy and tumour surgical workflows, help improve surgical outcomes and quality of life in these children.”