by John R. Fischer
, Senior Reporter | March 20, 2020
Researchers at Aalto University have developed a new scanner for brain imaging that combines capabilities found in magnetoencephalography (MEG) and an unconventional type of MR imaging.
The technology was developed in two EU projects and is now being implemented in a new $1 million project funded by Business Finland, that aims to use the scanners to enhance accurate detection of cancer tissue and diagnoses for various brain diseases in humans, and is expected to help clinicians prep better for surgery.
"The purpose of the technology is to characterize brain activity as well as possible in both time and space," Cornelis Koos Zevenhoven, research group leader in the department of neuroscience and biomedical engineering at Aalto University School of Science in Finland, told HCB News. "The accuracy depends not only on the sensitivity of the instrument, but also on how precisely the electrical structure inside the head can be modeled. Here, the brain activity is measured in the same coordinate system as the structural model or image, and many modeling errors are eliminated. Accuracy is particularly critical when planning brain surgery."
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The scanner is expected to improve accuracy in cases of stroke, autism and brain injuries, as well as provider a better understanding of abnormal brain activity connected to depression and the progress of Alzheimer's disease. It also will help distinguish brain tumors and healthy tissue prior to cancer surgery.
Its use of MEG sensors outside the head to measure tiny magnetic fields produced in the brain provides information on the functioning of the nervous system, while MR produces pictures of the brain’s structure. Together, the two enable the device to produce more reliable and accurate images of brain activity.
It also uses superconducting sensors called SQUIDS, and possesses superconductive capabilities in other components. In addition, the technology is designed to have a more open device structure, in which the patient lies on a bed equipped with a helmet-shaped slot for the head, as opposed to conventional MR imaging in which a patient is placed in a long, confined tube and the scanner produces loud, unsettling noises.
A prototype requires sensitive components that are compatible with one another. Another necessary resource is liquid helium, in which the temperature is only four degrees above absolute zero. Despite the distance of the helium to the patient’s head being just a few centimetres, however, the individual experiences normal room temperatures.
The most difficult challenge is making the extremely sensitive magnetic field measurements while applying strong magnetic pulse sequences in MR imaging, with everything having to be designed in a way that is free of magnetic noise, so that the noise does not cover the measured signals. The polarizing magnet is also superconducting but can be switched on and off in some milliseconds during the measurement.
"Next steps are to improve the reliability of the different parts and to make measurements with patients and healthy subjects," said Zevenhoven. "There are many special imaging techniques for the scanner, waiting to be developed further now that there is a full-scale prototype. We are also planning the first hospital deployment."
The SQUIDs were developed by VTT Technical Research Centre of Finland.
The researchers aim to develop and commercialize the technology by the end of 2021.