Exploring brain function with magnetic resonance imaging

A useful brain imaging technique uses functional magnetic resonance imaging to analyse metabolic changes such as blood oxygenation.


Types of brain imaging techniques

Advancements in brain imaging using non-invasive technologies such as functional magnetic resonance imaging (fMRI), magnetoencephalography (MEG), and electroencephalography (EEG) have allowed neuroscientists to obtain a greater understanding of how the brain functions with its environment.

Understanding neuro-networks will assist in the development of treatments for neurodegenerative diseases such as Alzheimer’s and Parkinson’s. To complement brain imaging, various animal models have been developed to investigate the genetic nature of disease states, especially concentrating on neurophysiological processes.

A useful brain imaging technique uses functional magnetic resonance imaging (fMRI) by analysing metabolic changes such as blood oxygenation.  The advantage of using fMRI is that it produces good spatial resolution.  The disadvantage of fMRI is its poor time resolution of approximately six seconds and is therefore too slow for tracking single or clusters of neurons in real-time.  This is because the change in blood flow takes several seconds to catch up with neural activity. However, fMRI has good spatial specificity in localised brain function compared to EEG, which uses electrical and magnetic signals derived from MEG.

Consequently, both EEG and MEG have excellent temporal resolution but very poor spatial precision.  This is even though these imaging techniques can track neuron population activity within several hundreds of milliseconds.  During these processes, neither imaging modalities can distinguish which set of neurons is being used.

To circumvent these issues, fMRI is sometimes used in conjunction with EEG to obtain paramount temporal and spatial precision.

Brain imaging can make a contribution to the patient through personalised medicine in the treatment and management of neurological diseases by creating 3-D individual images in real-time. Both MRI and computed tomography (CT) hybrid scanners can be used to generate 3-D images of the brain at a specific moment.

These 3-D images of brain volume are made up of voxels.

The spatial resolution of the MRI scanner determines how the small voxels can be measured during brain imaging of the neural networks.  Therefore, the stronger magnetic field strength will increase the spatial resolution and will enable better resolution of brain structure.

Image-guided systems controlled by advanced brain navigation software will assist neurosurgeons in precise locations to perform the operation on the patient.  These systems are based on the Talairach coordinates (x, y and z).

Comparison of neuroimaging modalities

IMAGING MODALITYRESOLUTIONAPPLICATIONADVANTAGESDISADVANTAGES
EEG
S - LOW

T- HIGH
Study various rhythms, epilepsy, preoperative mapping, degenerative disordersNon-invasive, no ionising radiation, widely used, low cost
Low spatial resolution
MEGS - MEDIUM
T - HIGH
Study epilepsy
Non-invasive, no ionising radiation can identify epileptic fociLow spatial resolution
fMRIS - LOW

T - HIGH
Preoperative mapping, functional mapping
Non-invasive, no ionising radiationHigh cost

S = Spatial Resolution; T = Temporal Resolution

Shriram R, Sundhararajan M, Daimiwal N. Brain connectivity analysis methods for better understanding of coupling. IJCSIS. 2012; 10(11).

In conclusion, brain imaging assists neurosurgeons to remove disease-causing agents and preserve the function of the surrounding tissues.  These imaging modalities include MRI and CT, which generates a 3-D brain map in real-time and is essential to understanding functional measurements using EEG, MEG, Functional MRI Brain Imaging, including deep brain recording and the ability to understand brain structure and function.

References

Williams N, Henson, RN. (2018). Recent advances in functional neuroimaging analysis for cognitive neuroscience. Brain and Neuroscience Advances. CrossRef

Racine E, Bar-Ilan O, Illes J. Brain Imaging: A decade of coverage in the print media. Sci Commun. 2006; 28(1): 122-142.CrossRef PubMed


You are here: home » medical imaging blog » brain imaging

Scroll to Top