COMPAMED.de asked Doctor Lukas Scheef from the Functional Neuroimaging Group, Experimental Radiology of the Department of Radiology at the University of Bonn, how the newly applied gentle procedure for schizophrenic patients works, how blood flow patterns in the brain are made visible and how schizophrenic patients can profit from this in the long run.
COMPAMED.de: You have used a new gentle procedure for the first time, which measures the changed blood flow in the brain. What is behind all this?
Lukas Scheef: It is the concept of measuring the blood flow in the brain with the help of magnetic resonance imaging (MRI) and without the use of a contrast agent. The basic principle consists of three steps: at first we map the head. Next we mark the blood with the help of high-frequency pulse at the cervical vessels level. Through this marking, the intensity of the signal decreases. We wait a brief moment, until the marked blood has flowed into the head and the brain, respectively, and then map the head a second time. The difference between the non-marked mapped brain and the mapped brain after it has been marked we can draw conclusions on the blood flow.
We are the first in the area of schizophrenia research to use and apply this procedure in this way. First and foremost we wanted to check – and there is already a lot of research in this area, primarily with nuclear medical scans, that is PET and SPECT – whether the procedure is sensitive enough to be able to replicate findings that are already known.
COMPAMED.de: This specific form of magnetic resonance imaging, the CASL (Continuous Arterial Spin Labelling), has been known for some time. What did you newly implement?
Scheef: The new aspect is the application – and the development toward a new patient clientele. We have examined untreated schizophrenic patients and checked to which extent we discover differences compared to an age-matched control group.
Until now this had not been realized yet.
This MRI technology has been known for a while, but so far it has not been widely used. Just the multitude of subcategories alone for this procedure points out, that not all technical issues are completely solved. This is basically a problem of stability, because very small signal differentials are being measured and very high scanner stability is required. That is why this method, which is very difficult to implement, never truly asserted itself. We hope that the studies we conducted with schizophrenic patients are able to show that these procedures are sufficiently sensitive enough to make the small subtle distinctions visible. It would be great if this procedure could be more widely used in clinical context in the future and also increasingly in the neuroscientific area of research and science, because it presents an additional modality that helps us –among things- to better understand pathologies.
COMPAMED.de: Which advantages does this procedure offer compared to other technologies?
Scheef: In the medical area we are of course always confronted with “cost pressure“ as a factor. Nuclear medical procedures are usually very expensive. With this procedure we also have the issue of having to use radioactive matter and thus the application is limited.
In contrast, an examination using the CASL procedure or general Arterial Spin Labeling (ASL) can be repeated as frequently as you like, because we are able to work non-invasively. That means, with this procedure I could also examine patients or test persons in a follow-up examination without having to repeatedly administer radioactive substances or contrast agents. Such examinations are interesting for drug efficiency studies for example. We hope in the long term that we can develop early markers which tell us more about the effectiveness of a drug – and how the individual organism is responding to medication.
COMPAMED.de: Can schizophrenic patients be better helped by this new method?
Scheef: An immediate personal benefit for the patient is not given yet at this stage. This actually means that thus far we only performed group examinations. In doing so, we compare a specific group with a correlative control group. Then we break down the differences we find to embed them into our neuroscientific and psychiatric theories. This leads to a better understanding and hopefully a better treatment. This is not only limited to the area of schizophrenia research.
We hope that in the long run such methods can be used to discover early markers of neurological and mental diseases – for example early markers of developing dementia disease or a predictor for the progress of an early onset.
COMPAMED.de: CASL measures the blood flow in the brains of schizophrenic patients. Can this procedure also be relevant for other diseases?
Scheef: As I have already mentioned, we can use it for instance in the area of dementia diseases. For scientific purposes, our task force applies this procedure in the area of sports science to monitor for instance to which extent the brain is altered by endurance sports.
OMPAMED.de: This progress is a further step to better visualize and understand brain activity. What does the future of image-guided procedures in this area look like?
Scheef: Through multimodal imaging that is through the combination of several procedures, in the long run we could detect diseases of the central nervous system earlier and understand them better. We could possibly also employ pharmacological therapies and interventions earlier and more directly, and as the case may be, modify them earlier and adapt them better to the individual patient. But those are long term goals.
Multimodal imaging means that we take a look at the structure. Then we combine it with diffusion-weighted images. This is how we obtain information on anatomical connectivity that is the connection between several areas. Through so-called functional imaging (at resting state), in addition we can understand the functional connectivity, that means looking how region A communicates with region B. Perfusion analysis also allows us to record abnormalities in the local and regional blood flow. Functional imaging also makes it possible to assign patients with particular disease patterns specific tasks and to monitor which brain regions are active here. Based on the activation patterns, under certain circumstances you might be able to draw conclusions on the pathologies.
This interview was conducted by Diana Posth and translated by Elena O'Meara.