Christine Fleming | Keeping an Eye on the Heart
Assistant Professor of Electrical Engineering
Cardiovascular disease is the leading cause of mortality in the United States, and researchers are exploring a wide range of approaches to understand and treat this pervasive disease. Advances in medical imaging technologies are making a difference, enabling scientists to improve early diagnosis, develop more effective therapies, and understand the underlying mechanism of cardiovascular disease.
One major advance is optical coherence tomography (OCT), a non-invasive imaging technique that provides depth-resolved, high-resolution images of tissue microstructure in real-time. An optical signal acquisition and processing method, OCT has been called “optical ultrasound” as it provides imaging reflections from within tissue to provide cross-sectional images, at a much higher resolution than other imaging techniques like MRI or ultrasound. It is used in a wide range of applications, from art conservation to medical diagnoses, especially in ophthalmology where it is used to obtain detailed images from within the retina. In addition, fiber-based OCT systems can be incorporated into catheters to image internal organs. These features have made OCT a powerful tool for cardiovascular imaging.
“OCT obtains cross sectional images of biological tissue using interferometry and near infrared light,” says Christine P. Fleming, assistant professor of electrical engineering and a leader in using OCT. “Because of the properties of light, we can obtain extremely high resolution images. Optical imaging provides a minimally invasive assessment of tissue structure, exploiting intrinsic optical contrast within the tissue. However, light is strongly absorbed and scattered by biological tissue, so we have designed flexible catheter probes to image various parts of the body. My work is focused on using OCT to aid in cardiovascular disease diagnosis and therapy monitoring.”
She explains that there is a large array of diseases and therapies of the heart that can benefit from the information provided by a high-resolution, real time imaging modality. These diseases and heart muscle abnormalities range from infections to irregularities in conduction, structure, and contraction. To examine and treat these conditions, doctors insert catheters into the heart chambers—without a direct view of the heart wall—to obtain electrical measurements, take biopsies to detect cellular changes, or to treat abnormal rhythms.
Fleming’s research is concentrated on developing tools for imaging the myocardium, to give cardiac electrophysiologists, cardiologists, and heart surgeons a view of the heart wall to help diagnose disease and guide treatment. “One of my main focuses,” she says, “is to develop optical imaging catheters to provide real time monitoring of radiofrequency ablation therapy, a procedure to treat abnormal rhythms of the heart. This will give us a better view of the areas that are producing abnormal rhythms. It will also visualize the therapy in real-time to verify efficacy and prevent complications.”
In addition to designing catheter probes, Fleming develops image analysis algorithms to extract information from OCT images and to provide automated tissue classification.
“Knowledge of the anatomical structure and composition of the patient’s heart will greatly aid in planning and monitoring procedure progress,” she explains. “Most importantly, our goal is that high-resolution real time optical imaging provided by OCT will be used to assess differences in tissue characteristics to guide and plan therapeutic strategies.
Fleming joined Columbia Engineering after completing her doctoral work at Case Western Reserve University and post-doctoral work at Harvard Medical School. As a postdoctoral fellow at Harvard, Fleming developed signal and image processing algorithms to identify cholesterol deposits within optical coherence tomography images of coronary arteries.
BS, Massachusetts Institute of Technology, 2004; MS, Case Western Reserve University, 2007; PhD, Case Western Reserve University, 2010