There is a reason for the impressive size of magnetic resonance imaging scanners: the donut-shaped tube contains large magnets that generate a very strong magnetic field. Combined with short radio frequency pulses, the magnetic force elicits a signal from the water in the body of the person being examined, resulting in an image of the examined body region. The stronger the magnetic field, the clearer the signal - and the clearer and more detailed the image produced.
However, such powerful tomographs have two decisive disadvantages: Firstly, due to their size and weight, they are not mobile and cannot be taken directly to the patient's bedside, for example. Secondly, they are very expensive to operate: they require a lot of electricity and expensive liquids such as helium at minus 270 degrees Celsius to cool the magnets. Both of these factors mean that MRI machines can only be operated by financially strong institutions. The majority of the world's population does not have access to this technology.
A major technical hurdle in the construction of a mini MRI machine is that the signal generated is very weak. This is because such a small tomograph has to work with much weaker magnets than a conventional device. The researchers led by Stefan Glöggler, research group leader at the Göttingen MPI for Biophysical Chemistry and at the BIN of the University Medical Center Göttingen, have now found a way to significantly amplify the weak signal. For their experiments, they have built a mini MRI device themselves. It is about the size of a small barrel. The small tomograph is very flexible. It can be adapted to the size of the object to be examined - depending on whether it is just a small chemical solution or a human head. The magnetic field is about a hundred times lower than that of conventional MRI devices. Its strength is comparable to that of magnets that we stick to the fridge at home.
The scientists have now transferred a method that is already established in conventional tomographs, known as hyperpolarization, to their low-field MRI device. This enabled them to amplify the signal in the weak magnetic field to such an extent that it was measurable.
Original publication: Korchak S, Jagtap AP, Glöggler S: Signal-enhanced real-time magnetic resonance of enzymatic reactions at millitesla fields. Chemical Science (2020), doi: 10.1039/d0sc04884e
Source: MBI BPC
