In order to access more of the potential locked in NMR and MRI measurements, scientists have employed different strategies to increase sensitivity
One solution to the sensitivity challenge is to improve the hardware. The core component of NMR and MRI instruments is a large magnet. Sensitivity can be increased by increasing the size of this magnet.
For example, doubling the strength of and MRI scanner by replacing a standard 1.5 T scanner with a 3 T scanner will improve sensitivity. So instead of detecting 1 in 200,000 molecules, 1 in 100,000 molecules are revealed in a scan.
The following pictures show two of CHyM’s NMR systems, the first (400 MHz, 9.4 T) detects 1 in 32,000 molecules, while the extra magnetic field strength in the second (500 MHz, 11.8 T) detects 1 in 25,000.
For NMR spectrometers, larger magnets can also be employed (up to 1 GHz), and additional equipment such as cryoprpobes (which reduce noise levels) can be employed to increase sensitivity.
The challenge with this approach is cost. A 3 T scanner costs over $2m, double the price of a standard scanner, while a 1 GHz (23.5 T) NMR system costs around $16m and weighs 12 tonnes. This is an expensive approach to achieving sensitivity.
An alternative route to achieving sensitivity is pursued in CHyM, here chemical principles are applied to prepare chemical samples with high signal strengths in NMR and MRI measurements. These compounds can then be studied in biological and chemical applications. This approach is called hyperpolarisation.
Scientists in CHyM employ these techniques to enable detection of low concentration compounds, shorten scan times, to increase image resolution and to enable the use of smaller, lower-cost detectors.