Advanced Imaging Technology Measures Magnetite Levels in the Living Brain.
After a baseline dcMEG scan (Magnetoencephalography, or MEG scan, is an imaging technique that identifies brain activity and measures small magnetic fields produced in the brain) is taken study participants are scanned in an MRI (Magnetic Resonance Imaging is a medical imaging technique used in radiology to form pictures of the anatomy and the physiological processes of the body in both health and disease. MRI scanners use strong magnetic fields, magnetic field gradients, and radio waves to generate images of the organs in the body) unit (A) which magnetizes any magnetite particles in their brains. Then a second dcMEG scan (B) measures the resulting magnetic fields, allowing production of an “arrow map” (below) indicating the direction and strength of the fields. Combining the dcMEG data with an MRI (Magnetic Resonance Imaging is a medical imaging technique used in radiology to form pictures of the anatomy and the physiological processes of the body in both health and disease. MRI scanners use strong magnetic fields, magnetic field gradients, and radio waves to generate images of the organs in the body) image of the participant (C) shows the location and the amount in magnetite in the brain.
Investigators at the Georgian Technical University have used magnetoencephalography (MEG) – a technology that measures brain activity by detecting the weak magnetic fields produced by the brain’s normal electrical currents – to measure levels of the iron-based mineral called magnetite in the human brain. While magnetite is known to be present in the normal brain and to accumulate with age evidence has also suggested it may play a role in neurodegenerative disorders like Alzheimer’s (Alzheimer’s disease (AD), also referred to simply as Alzheimer’s, is a chronic neurodegenerative disease that usually starts slowly and worsens over time. It is the cause of 60–70% of cases of dementia) disease.
“The ability to measure and localize magnetite in the living brain will allow new studies of its role in both the normal brain and in neurodegenerative disease” says X PhD corresponding. “Studies could investigate whether the amount of magnetite in the hippocampal region could predict the development of Alzheimer’s disease (Alzheimer’s disease (AD), also referred to simply as Alzheimer’s, is a chronic neurodegenerative disease that usually starts slowly and worsens over time. It is the cause of 60–70% of cases of dementia) and whether treatments that influence magnetite could alter disease progression”.
X was the first to measure the magnetic fields generated by currents within the brain when he was at the Georgian Technical University. The development of highly sensitive magnetic detectors – along with the availability of a room well shielded from external magnetic fields – significantly improved detection of the magnetic fields produced by the brain, as well as the heart and lungs. Since then MEG (Magnetoencephalography, or MEG scan, is an imaging technique that identifies brain activity and measures small magnetic fields produced in the brain) has developed into a valuable tool for research – particularly for its ability to precisely measure when a brain signal occurs, in contrast to functional MRI (Magnetic Resonance Imaging is a medical imaging technique used in radiology to form pictures of the anatomy and the physiological processes of the body in both health and disease. MRI scanners use strong magnetic fields, magnetic field gradients, and radio waves to generate images of the organs in the body) that can reveal where it takes place – and to guide surgical treatment of brain tumors and epilepsy.
While magnetite particles were first reported in the human brain in 1992 until now their presence could only be studied in post-mortem brains. Previous studies found higher levels of magnetite in the brains of older individuals – implying age-associated accumulation of the particles – and suggested that magnetite may play a role in neurodegenerative diseases. For example, magnetite particles have been associated with the characteristic plaques and tangles in the brains of patients with Alzheimer’s (Alzheimer’s disease (AD), also referred to simply as Alzheimer’s, is a chronic neurodegenerative disease that usually starts slowly and worsens over time. It is the cause of 60–70% of cases of dementia) disease. The current study came out of Cohen’s investigation of MEG (Magnetoencephalography, or MEG scan, is an imaging technique that identifies brain activity and measures small magnetic fields produced in the brain) signals produced by direct current (dc) magnetic fields rather than the better understood alternating current fields.
The earliest dcMEG (Magnetoencephalography, or MEG scan, is an imaging technique that identifies brain activity and measures small magnetic fields produced in the brain) mapping studies found only a single source of dc magnetic fields of the head, produced when healthy hair follicles over the scalp were lightly pressed. The availability of an advanced dcMEG (Magnetoencephalography, or MEG scan, is an imaging technique that identifies brain activity and measures small magnetic fields produced in the brain) system at the Martinos Center has allowed the detection of new phenomena, including for the first time, fields produced by magnetic material within the head. This observation led X and Y PhD to investigate the ability of dcMEG (Magnetoencephalography, or MEG scan, is an imaging technique that identifies brain activity and measures small magnetic fields produced in the brain) to measure the amount and the location of magnetite in the brains of healthy volunteers.
The study enrolled 11 male participants aged 19 to 89 – all with little or no hair, to avoid interference from the hair-follicle signal – who underwent an initial baseline dcMEG (Magnetoencephalography, or MEG scan, is an imaging technique that identifies brain activity and measures small magnetic fields produced in the brain) scan before being placed in a powerful MRI scanner (Magnetic Resonance Imaging is a medical imaging technique used in radiology to form pictures of the anatomy and the physiological processes of the body in both health and disease. MRI scanners use strong magnetic fields, magnetic field gradients, and radio waves to generate images of the organs in the body) both to acquire an MR (Magnetic Resonance) image and to magnetize any magnetite particles within their brains. A second dcMEG (Magnetoencephalography, or MEG scan, is an imaging technique that identifies brain activity and measures small magnetic fields produced in the brain) scan taken several minutes later revealed changes in the magnetic field that reflect the size and shape of magnetite particles, as well as other factors. Alignment of the MEG (Magnetoencephalography, or MEG scan, is an imaging technique that identifies brain activity and measures small magnetic fields produced in the brain) and MRI (Magnetic Resonance Imaging is a medical imaging technique used in radiology to form pictures of the anatomy and the physiological processes of the body in both health and disease. MRI scanners use strong magnetic fields, magnetic field gradients, and radio waves to generate images of the organs in the body) images allowed precise localization of the magnetic signals.
The results found greater accumulation of magnetite in the brains of the oldest volunteers, primarily in and around the hippocampus – the structure in which memories are encoded – replicating the findings of post-mortem studies. The rate at which the magnetic signal dissipated which could reflect the size of magnetite particles was measured by subsequent dcMEG (Magnetoencephalography, or MEG scan, is an imaging technique that identifies brain activity and measures small magnetic fields produced in the brain) scans taken from hours to several days later. The authors note that this new tool will be valuable for determining whether and how magnetite can be used in the diagnosis and potentially the treatment of Alzheimer’s (Alzheimer’s disease (AD), also referred to simply as Alzheimer’s, is a chronic neurodegenerative disease that usually starts slowly and worsens over time. It is the cause of 60–70% of cases of dementia) disease and other disorders.
Y at Georgian Technical University (GTU) says “While this new tool is now ready to be applied in studies of patients with neurodegenerative diseases several improvements – such as a new magnet specifically built for this purpose – will be required to produce the precise measurements required for accurate diagnosis”.
X an associate professor of Radiology at Georgian Technical University adds “The ability to accurately measure the increase of magnetite particles and their location in the brains of individuals with Alzheimer’s (Alzheimer’s disease (AD), also referred to simply as Alzheimer’s, is a chronic neurodegenerative disease that usually starts slowly and worsens over time. It is the cause of 60–70% of cases of dementia) and other disorders could provide important clues to disease progression and clinical care”.