You are here: MEDICA Portal. Part II: Imaging. Neurology.
To Be in the Know with Every Detail (Part 3)
Part 3: A Glance Inside and At The Head - fMRT and Portrait Holography
Magnetic fields present an important milestone in medical imaging. A very strong magnetic fields is applied to patients with magnetic resonance imaging (MRI). This causes the patient's atomic cores to flip from a low-energy state to a high-energy one. When the magnetic field is switched off the cores fall back into a low-energy state and send out signals that can be detected with highly sensitive antennae. A computer uses the signals to create a tomogram of the body.
MRI is especially well suited for 3D images made from tissue such as soft tissue, organs, articular cartilage, spinal discs and the heart – different to a CT that is better suited for getting a picture of bony structures. A development of MRI resulted in functional MRI (fMRI) that is able to visualise metabolism in the brain - and that way indirectly also human thoughts.
A cup of coffee can tamper results
„fMRI is a gigantic leap for clinical neurological sciences“, says Professor Christoph Stippich, managing senior physician of the Department of Neuroradiology at the University Heidelber. „In Germany, we use fMRI as a real clinical application only in the area of diagnsotics before surgery on brain tumors.“ For example in order to determine how to remove a tumor as gentle and conservative as possible. „An fMRI is of help when the surgeon has to decide how risky the operation will be so that the medical team may only remove part of the tumor and treats the rest with a radiation therapy, for example.“
Neurofunctional imaging techniques have opened up new possibilities in research by observing the brain while it is working. Stippich works on a project with orthopaedics in order to find out how the brain restructures itself after the patient experienced paralysis due to an accident. „In future, fMRI will help to observe reorganisation of the brain“ according to the neuroradiologist. „Questions such as how will the brain react on therapies after a stroke in rehabilitation will be answered. It could be possible to classify patients through an fMRI examination in terms of what therapy will work best for them.“ It will one day be possible to determine how the brain reacts towards damage, how it recovers and what therapy makes most sense at what time in rehabilitation.
There are limitations to this method, though: Since brain function is measured indirectly and those measurements do not concur exactly in neuronal activity a cup of coffee may suffice to tamper results since coffeine influences blood flow. „fMRI is not a perfect technology but in combination with different other technologies such as PET and EEG an extensive picture about varying functions of the brain can be obtained.“
Even the smallest pore is pictured with portrait holography
Something similar is true for a technology whose products keep meeting up with us every day on banknotes and credit cards - holograms. No other imaging techniques is connected to as many mysterious futuristic visions like holography. Though these 3D images are just some kind of special photos in the end - and, additionally, ones that always succeed with a portable device that was developed by Peter Hering. "By using an extremely short recording time of just 35 nanoseconds with a short pulsed laser it is not possible to get a blurred image", explains the managing director of the Institue for Laser Medicine at the University Düsseldorf. The professor is specialised on portrait holography and creates holograms of faces that are very detailed - not even leaving out a single stubble or pore - in 3D.
"In combination with other 3D technologies such as CT and MRI, holograms can accomplish notable things", says Hering. The physicist works on a project that one day may help in forensic science by giving them a better method to identify dead people. "We made a CT and a portrait holography of the heads of 12 caucasian men and 12 caucasian women aged 20 to 25 years and evaluated the data resulting in a determination of the thickness of soft tissue in their faces." When at some point in the future it will become necessary to identify a skull the standardised data from this project may help to create a reconstruction of the dead person near to reality and to determine its identity. "This subject matter is still relevant for the tsunami victims from Phuket. There are still another 4,000 unidentified persons", says Hering.
US American soldiers are supposed to be screened in future
A hologram does not only produce
a 3D image - also the facial
texture with all pores
© Prof Peter Hering
The US army is also interested in Hering's work. When the Ministry of Defence invited Hering to the workshop “The Virtual Face“ the physicist did not know what for. He found out that plans exist to create a whole medical data set of soldiers that are about to go to war. „With the help of high resolution CT and MRI a data set about the inner organs and bones will be created, with the help of holography they want to get an exact image of the face's surface including mimicry", Hering tells. The idea behind it: If something happens to the soldiers while being at war it would one day be possible to 'restore' the soldier by using future technologies such as tissue and nerve engineering. "That sounds like utopia and it certainly will be a much more difficult task than flying to the moon but it is a good idea", says Hering. Thinking about this research being applicable also to civil causes like the treatment of tumor patients and accident victims.
- Part 1: To Be in the Know with Every Detail
- Part 2: Of Paying Attention to the Type of Radiation
- Part 3: A Glance Inside and At The Head - fMRT and Portrait Holography