Magnetic Resonance Imaging

Magnetic Resonance Imaging (MRI) is a non-invasive technique which is used to study the structure and function of living organisms in vivo. In biological and medical research, MRI is paramount to enhance the understanding of tissue structures, cellular metabolism and physiological response to disease and drug therapy. It is used for research at multiple levels, from the cellular, animal model to medical diagnostic imaging of humans.

The University of Queensland has commissioned a state-of-the-art 16.4T MRI spectrometer through the Centre for Advanced Imaging (CAI), QBI and the Queensland NMR Network (QNN). This powerful system is the only one of its kind in the southern hemisphere and one of six systems in the world. QBI researchers will use this scanner to study various neurological and developmental diseases in animal models to improve the understanding of pathophysiological changes at the microscopic/cellular level.

Specifications

The Bruker Ultrashield Plus 700 WB Avance NMR spectrometer has a vertical open bore diameter of 89 mm. After the positioning of gradient, shim and transmit/receiver coils it provides a space of up to 34 mm diameter, which is optimal for mouse/small rat brain imaging.

The scanner is equipped with three types of gradient inserts: micro5, micro2.5 and mini0.5 which provide gradient strengths of 4.8, 2.5 and 0.5 mT/m/A.These systems enable atypical high-resolution imaging of brain structures in live animals (in vivo) at a sub-100 micron in-plane and in-depth (<100 µm)^3resolution. A higher (10-50 µm)^3 resolution is typically attainable for ex vivo samples, providing information at a single cell resolution.

To achieve highest sensitivity, the scanner will be equipped with new generation SAW and quadrature microimaging coils (5, 10, 15, 20, 25, 28 and 35 mm diameters). The 5-15 mm coils are suitable for imaging of excised brain, spinal cord and embryos, whereas the 20-35 mm coils are dedicated for live imaging. Especially for live mouse and rat imaging, the scanner is equipped with dual frequency proton-fluorine transmit/receiver coils, which will permit the visualisation of 19Fluorine contrast agents, analogous to those commonly used in PET imaging. The animal is maintained inside the scanner with a bed/restrain apparatus, a warm water gradient circulation and their anaesthesia is monitored using the BIOTRIG system.

Applications

The current 16.4T configuration is up to four times more sensitive than the strongest human scanner 4T system available in Australia. This provides a faster scan time at a similar sub-100 micron resolution. With this capability, the scanner will be utilised predominantly for microimaging, in particular, for in vivo / ex vivo brain imaging and spectroscopy, spinal cord and embryos; and imaging of neuronal track (fibre tracking/diffusion tensor imaging).

This scanner will play an important role in a range of QBI research projects: for example the detection of brain development abnormality, structural and metabolic changes of mutant/transgenic mice, real-time cell migration in vivo, the efficacy of treatments in spinal cord injury and stroke. It will also be used in the development of novel contrast agents.

For more information about this facility, please contact QBI facilities.


Above: The 700 MHz microimaging MR system Рa state-of-the-art imaging technology Рpurchased with the assistance of Queensland Government Smart State Funding.