To address this need, the investigative team, drawn from multiple institutions, developed a new testing method called cardiac functional MRI. It uses a breathing machine that changes the concentration of carbon dioxide in the blood. Normal blood vessels in the heart respond to these changes by efficiently adjusting blood flow to provide more or less oxygen. Diseased blood vessels do not.
By imaging the heart while changing the carbon dioxide concentrations in the blood, the investigators showed they could accurately detect inadequate oxygenation of the heart muscle and map regions of the heart affected by narrowing of the coronary arteries. They were able to do this in experimental models with and without ischemic heart disease.
"Although our findings in this study are limited to experimental models, we anticipate that our proposed cardiac functional MRI approach would translate well in humans," said Dharmakumar, professor of Biomedical Sciences. He said his team is developing imaging and gas-control strategies to translate the new technology for use in patients with ischemic heart disease, with a goal of making it available in the clinic within five years.
In addition to studying coronary artery disease, the new method potentially could be useful for evaluating other cases where heart blood flow is affected, such as a heart attack or injury to the heart from cancer treatment, according to Hsin-Jung (Randy) Yang, PhD, a project scientist in Dharmakumar's laboratory and the study's first author.
Besides Cedars-Sinai, the study authors were from UCLA; King's College London; Lawson Health Research Institute at the University of Western Ontario in Canada; University of Toronto and University Health Network in Canada; MR R&D Collaborations, Siemens Healthineers in Los Angeles; and the University of Edinburgh, Scotland. For a complete list of authors, see the Science Translational Medicine article.
Funding: Research reported in this publication was supported in part by the National Institutes of Health under award number NIH/R01 HL091989, Ontario Research Fund RS7-021, Canadian Foundation for Innovation no. 11358 and education grants from Siemens Healthineers and London X-ray Associates.
Competing interests: None declared by Cedars-Sinai authors. Two other authors are part-time employees of Thornhill Research Inc., and one is an employee of Siemens Healthineers.