Scientists from the National University of Singapore (NUS) have developed a novel nanodiamond-based contrast agent that improves visualisation of liver cancer tumours. Better and more sensitive imaging contributes towards detecting liver cancer and is crucial for treatment planning.

Currently, there are two modes of MRI imaging, T1-weighted and T2-weighted imaging, and patients are often given contrast agents to improve imaging quality. However, each imaging mode requires a specific class of contrast agent, which cannot be used together. This poses a greater challenge in the diagnosis of liver cancer, where T2-weighted imaging is still not considered reliable, and both T1- and T2-weighted imaging can be confounded by tumour vascularity.

A NUS research team has developed a dual-mode contrast agent which enables clearer and more accurate images of tumours to be obtained in both T1- and T2-weighted MRI scans, and with lower dosages of contrast agent. The novel dual-mode contrast agent was developed using nanodiamonds in combination with a manganese base. The team also found that liver tumours that are unable to be visualised without contrast agents become readily visible even at low dosages of the novel compound.

Contrast agents work by altering the magnetic properties of nearby water molecules, which enhances the quality of MR images. Nanodiamonds, which are carbon-based particles of two to eight nanometres in diameter, have unique chemical properties that allow them to attract water molecules. This enables them to promote proton exchange between water molecules and paramagnetic ions (ie. contrast agents) that accumulate in tissues. As a result, T1 and T2 relaxation is enhanced, giving better quality images. This is unlike existing nanotechnology-based approaches, where nanomaterials are used to improve delivery of paramagnetic ions to specific tumour sites. 

The researchers are also looking into using their contrast agents to improve imaging for glioma and ovarian cancer.