Cardiovascular disease (CVD) is responsible for more than a quarter of all deaths in Australia and remains the global leading cause of death accounting for 17.9 million deaths per year. Of all CVDs, stroke and coronary artery disease account for the majority of deaths. A common underlying cause in these conditions in atherosclerosis, characterised by the build-up of abnormal deposits inside the arteries. Atherosclerotic plaques can rupture and cause thrombosis, or blood clots, resulting in stroke and myocardial infarction. Diagnostic strategies for the detection of thrombi are currently invasive and may not be sensitive to early biomarkers such as localised coagulation and inflammation.

A/Prof Ta, of Griffith University, has teamed up with researchers across Australia and internationally to develop a new form of MRI contrast agent. These ultra-small dual positive and negative contrast iron oxide nanoparticles (DCIONs) provide both T1-positive and T2-negative contrast effects, overcoming the limitations of single modality contrast agents. This duality is particularly important for imaging intravascular thromboses, as current single-contrast nanoparticles results in a black dye against a black artery. Further, the DCIONs are monodisperse, water-soluble, and biocompatible, of critical importance to biomedical applications.

In-vivo MRI of carotid artery thrombus (green arrows) detection after injection with a conjugated DCION. Image from Ta et al 2017.

Using non-invasive MRI at the NIF QLD Node, the application of a DCION conjugated to an enzyme found in activated platelets demonstrated accurate and sensitive detection of intravascular thrombosis. Work is continuing to further optimise the early detection of thrombi, expected to allow for earlier and more effective preventative treatments and improved clinical outcomes for patients at risk of stroke and myocardial infarction.

A/Prof Ta is enthusiastic about the future applications of DCIONs beyond thrombosis diagnoses, stating that “these nanoparticles have the potential to replace traditional gadolinium-based contrast agents due to their stronger T1 contrast effect. Existing alternatives cannot do what these nanoparticles can.”

If you have any concerns about heart disease or atherosclerosis, please talk to your GP and check this website.