Research that gave rise to the methods was awarded the 2017 Capes Thesis Award in the area of Medicine I
Health authorities estimate that 1% of the world's population, something like 70 million people, a contingent close to the population of France, has some type of epilepsy. However, the diagnosis of this brain disorder cannot always be made accurately, due to the complexity of some cases. Research carried out for the doctoral thesis of medical physicist Brunno Machado de Campos, defended at the Faculty of Medical Sciences (FCM) at Unicamp, developed two techniques that help identify the disease, based on assessments of the structural and functional connectivity of the brain. The result of the work, supervised by professor Fernando Cendes and co-supervised by professor Ana Carolina Coan, is considered very promising. The research was awarded the Capes Theses Award 2017 in the area of Medicine I.
Campos has been investigating the use of neuroimaging techniques for diagnosing epilepsy since his scientific initiation, when he was still an undergraduate student and completed his scientific initiation and course completion thesis at the Gleb Wataghin Institute of Physics (IFGW). During his doctorate, he decided to employ cutting-edge methods to assess the structural and functional connectivity of the brain. The first type of connection, explains the researcher, is made by neurons, which have a cell body and an extension called an axon, through which information is transmitted. “To make a simple-to-understand analogy, axons are like roads along which information travels,” he compares.
To assess structural connectivity, the researcher used a specific imaging protocol that allows us to see how information travels through the axon, mapping the movement of water. “Using this technique, we can check, for example, how the water is moving. With this, we can virtually reconstruct the axons and establish this network of roads in an anatomical way. Structural connectivity can assess the microanatomy of the brain. By observing this microanatomy, we can identify whether a problem is interfering with the flow of information. If this is occurring, it could be a clue that leads to the diagnosis of epilepsy”, explains Campos.
Functional connectivity, continues the author of the thesis, is related to the connection between different regions of the brain, without there necessarily being an anatomical connection between them. In other words, these regions may be physically separated, but they must maintain synchronicity with each other. “Our brain has several networks. Rest periods, for example, help consolidate memory and learning. There are also motor networks, language networks, auditory networks, etc. Thus, when a region has a high level of oxygen, the related region, even distant, must also present the same characteristic. It is this synchronicity that makes these regions functionally connected. If one is poorly functioning, the other needs to be as well”, defines Campos.
If the brain regions are not synchronized, the researcher notes, this is an indication that there may be a problem that needs to be further investigated. “What we did with the help of these techniques was to identify the functioning pattern of the structural and functional connectivity of the brain. Each one has a kind of signature, which allows us to check whether or not the connections are occurring as expected”, reinforces the medical physicist, who developed specific software to carry out the analyses. “In the case of functional connectivity, I developed a free code computational tool, which is available for download on the internet. In four years, around 500 downloads have been made, originating in 23 countries. As for structural connectivity, the software was designed for restricted use by the Neuroimaging Laboratory, which is coordinated by Professor Fernando Cendes, due to the peculiarities of the work we carry out”, he explains.
During the research, Campos considered different groups of patients with different cases of epilepsy and compared them with control groups. “We evaluated 12 functional resting networks. We investigated the interaction within each network and also the interaction between them. We were able to establish, for example, that right temporal lobe epilepsy is different from left temporal lobe epilepsy. Theoretically, it is the same syndrome, but there are differences depending on the side on which the problem is located. This already represents an important advance. The idea is to continue improving the techniques, in order to refine the diagnosis of the disease in a fully automated way, reducing human bias as much as possible”, he says.
In his work, the researcher also studied non-lesional epilepsies, those whose patients present the epileptic syndrome, but do not present visible changes in the images. “These patients would be candidates for surgical treatment, but it turns out that they do not have injuries that can be visible through imaging tests, which makes it difficult for the doctor to plan the intervention”, illustrates the medical physicist. And he continues: “When we analyze the connectivity patterns, we find that, structurally speaking, these patients actually present a non-lesional result. However, on a functional level it is possible to identify very subtle changes, which vary from subject to subject. The next step, as already said, is to improve the technique to make this diagnosis even more accurate”, understands Campos.
The fact that the work was awarded the Capes Thesis Prize in the area of Medicine I represents valuable recognition for the research, according to the medical physicist. “When the thesis was nominated by Unicamp to compete for the award, I was already happy. Winning the award made me even more satisfied. Without a doubt, it is an important recognition of my work, but also of the activities carried out by the Neuroimaging Laboratory”, he assesses.
Video presents the results of regions with changes in functional connectivity in patients with temporal lobe epilepsy and right hippocampal atrophy.
