A new imaging technique could improve the assessment of cardiac conditions affecting microscopic heart vessels, according to a study published in Nature Biomedical Engineering.
A team of researchers from Imperial College London and University College London worked together to produce sub-millimeter high-resolution images of micro-vessels in the heart. This non-invasive technique was then tested in human patients.
Current imaging techniques can easily visualise large vessels on the surface of the heart, but cannot detect smaller vessels deep inside the heart. The authors hope this new technology will allow scientists to study heart physiology in more detail and understand the role that these small vessels play in cardiovascular diseases, such as microvascular coronary disease and cardiomyopathies, as well as undiagnosed chest pains.
“Visualising cardiac vessels is crucial for managing cardiovascular diseases, but there is a lack of understanding of how the blood flows within the small vessels of the heart. Our study images these vessels non-invasively in the highest resolution yet which, following further research, could help clinicians to manage these diseases,” said Prof Mengxing Tang, from the Department of Bioengineering at Imperial College London.
The heart needs effective blood flow to pump blood around the body, supplying oxygen and carbon dioxide. However, if blood vessels are damaged, it can cause abnormal blood flow, leading to heart failure.
To determine if the new imaging technique could assess this kind of damage, the team tested the new imaging technique on four patients with hypertrophic cardiomyopathy (HCM). This condition makes the walls of the heart chamber thicker and reduces the amount of blood pumped in and out.
The authors used ultrasounds and microbubbles (small, gas-filled bubbles used to differentiate between internal structures in medical imaging) to image small blood vessels and blood flow dynamics of the patients’ hearts in super-resolution.
Given the positive results, the authors believe this technique could potentially help evaluate different cardiac conditions. For example, doctors could use the technique to detect problems in patients with microvascular coronary disease and cardiomyopathies, making it easier to diagnose and treat. “This is the first time we demonstrated it is possible to image these vessels in such resolution, which has never been done before in humans. This has opened up a wide range of opportunities to study heart physiology and observe different diseases and conditions non-invasively and safely,” said Prof Tang.
“For the first time this technique allows direct visualisation of the very small heart muscle vessels which when diseased give rise to chest pain which can be not only debilitating but may also lead to death. Because, at present, these vessels can be assessed only by indirect means, the condition can be misdiagnosed,” added Professor Roxy Senior from the National Heart and Lung Institute at Imperial College London.
This work is still in its early stages, and more studies are needed to fully understand the clinical and research value of the technique. However, “we are optimistic about what our new technique could bring to cardiovascular patient healthcare,” said Professor Tang. The team is also exploring the use of super-resolution ultrasound technologies in a range of other diseases and they’re working with oncologists, cardiologists, radiologists, breast surgeons and other clinicians. “This far-reaching research would never happen without collaboration between interdisciplinary teams of engineering and clinical sciences researchers,” concluded the researcher.
Yan, J., Huang, B., Tonko, J. et al. Transthoracic ultrasound localization microscopy of myocardial vasculature in patients. Nat. Biomed. Eng (2024). https://doi.org/10.1038/s41551-024-01206-6