New Imaging Technique May Enhance Screening for Stroke and Cardiovascular Risk

By Josh Garcia
Monday, July 1, 2019

Volumetric multispectral optoacoustic tomography (MSOT) could foster accurate characterization of the makeup of arterial plaque in real time, according to scientists.

Researchers from the Institute for Biological and Medical Imaging at the Helmholtz Center Munich in Neuherberg, Germany, designed and built a hand-held MSOT device. A study published recently in Radiology compared images of the carotid artery taken by the MSOT device with clinical B-mode ultrasound images of the same area in 16 healthy volunteers.

“Unlike most other clinical imaging modalities mainly looking at late-stage anatomical manifestations of diseases, [MSOT] is capable of sensing specific molecules in tissues without administration of contrast agents,” study co-author Daniel Razansky, PhD, Director of the Functional and Molecular Imaging Lab at the University of Zurich and the Swiss Federal Institute of Technology in Zurich, states in a news release from the Radiological Society of North America. “In the case of carotid artery disease, assessment of the entire bifurcation area in real time and in 3D is only possible with [MSOT].”

Though standard ultrasound techniques can accurately assess how much plaque is present in the carotid artery, they cannot determine the makeup of arterial plaque, which can be important in evaluating stroke risk.

“There has been a lot of hype of molecular imaging — the idea that you could analyze tissues in vivo to find out what they’re made of. Mostly, it hasn’t done well for a variety of reasons. ... This might be a step toward that goal.”
— Reuben S. Mezrich, MD, PhD, former Chair of Radiology at the University of Maryland

“Almost everyone has plaque in their arteries,” says Reuben S. Mezrich, MD, PhD, former Chair of Radiology at the University of Maryland, who wrote an editorial related to the study in the same issue of Radiology. “For most of us, it calcifies early on and becomes stable and insignificant. However, some plaques can flake off or break open and cause a stroke — this is called vulnerable plaque.”

Though the makeup of arterial plaque can be examined in vitro from cadaver samples, no clinical method exists to determine the makeup of plaque in a living subject.

“[MSOT] imaging ... holds promise for rapid volumetric assessment of the carotid artery and plaque vulnerability in an entirely noninvasive manner,” Razansky says. “It also has the additional potential for label-free identification and assessment of clinically relevant biomarkers of carotid artery disease, which helps with early and accurate diagnosis, timely treatment planning, and monitoring.”

Clinical trials will be necessary to further ascertain MSOT’s utility in screening and diagnosis.