New Insights into Brain Function with Molecular and Functional MRI of the Rodent Brain at Ultra-high Fields

Chemical exchange saturation transfer (CEST) is a molecular imaging technique used in 1H magnetic resonance imaging (MRI) which also has the potential to be used in translational research. CEST exploits the chemical exchange processes that take place between exchangeable protons and surrounding water molecules to quantify low concentration metabolites by highly sensitive detection through the water signal. Very few ultra-high field systems are currently used for CEST imaging.

In this webinar, MR physicist Professor Seong-Gi Kim and market product manager Tim Wokrina from Bruker BioSpin will discuss how CEST imaging significantly benefits from ultra-high fields. Highly resolved metabolic information from CEST experiments can be complemented with functional information from fMRI experiments. For the first time, it is shown that the blood-oxygen-level dependent (BOLD) signal exhibits a supra-linear increase at ultra-high field strengths, enabling new insights into the brain function in rodents.

This webinar took place on December 14th, 2017

Increased spectral dispersion at ultra-high fields leads to a high selectivity of magnetization transfer techniques such as Chemical Exchange Saturation Transfer (CEST) imaging. At the same time, higher saturation and a reduction of the exchange rate relative to the chemical shift can be achieved. Kim will demonstrate that the chemical exchange effect for the amine proton signal in rat brain at 15.2 Tesla is massively increased by 65% compared to 9.4 Tesla, offering higher molecular sensitivity and specificity with reduced overlap of background signals.

Previously, simulation studies have shown that the optimum field strength for fMRI studies is in the range of 9.4 Tesla. Here, Kim will present evidence explaining both the feasibility and the impact of using much higher field strength - 15.2 Tesla - for BOLD fMRI in animal research. Kim's data shows a much higher BOLD effect than 9.4T. This enables faster measurements, higher specificity, thereby allowing better correlation with other physiological parameters (e.g. electrophysiological recordings of firing neurons). Kim is currently investigating to use the improved sensitivity to look for associations between genes and brain function, as well as trying to understand cell-type specific neural activities in the whole brain.

In this webinar, MR physicist Prof. Seong-Gi Kim and market product manager Tim Wokrina from Bruker BioSpin will discuss:

• How the massive increase of the chemical exchange effect for the amine proton signal by 65% in rat brain at 15.2 Tesla compared to 9.4 Tesla offers higher molecular sensitivity and specificity with reduced overlap of background signals.
• How ultra-high field fMRI significantly increases the sensitivity of blood oxygen level dependent (BOLD) imaging of the rodent brain.
• Prof Kim’s data shows a never seen before high BOLD effect, enabling faster measurements, higher specificity, and allows perfect correlation with other physiological parameters.
• How ultra-high fields will achieve new insights into the function of the brain.

This webinar will appeal to anyone working in the field of preclinical MRI and high- or ultra-high field CEST and MRI research. It may also interest those in the field of basic neuroscience, who may be intrigued by how pre-clinical animal imaging enables a level of sensitivity and specificity that is not possible with humans.