Heart attacks are caused by the interruption of blood supply to a part of the heart, depriving cells of oxygen. Dr. Arai focuses his research on understanding and intervening in this process of myocardial infarction and ischemia. He is actively involved in developing new imaging methods, in particular magnetic resonance imaging (MRI) technologies that can be used in the clinic. The new technologies are validated in pre-clinical and clinical studies, which generate another cycle of new imaging methods—a process that leads to improved understanding of myocardial ischemia and infarction and practical new imaging methods suitable for diagnostic imaging.
His laboratory currently focuses on six major areas of clinical activity and translational research:
- Assessment of the area at risk from myocardial infarction and myocardial salvage
- Quantification of myocardial perfusion by MRI
- Technical development of diagnostic cardiovascular MRI
- Anatomical and physiological evaluation of coronary artery disease by cardiovascular computed tomography (CT)
- Support for the NHLBI Advanced Cardiovascular Imaging Fellowship
- Clinical and research support for cardiovascular MRI and cardiovascular CT at the NIH Clinical Center and at the Johns Hopkins Suburban Hospital in Bethesda, MD
Dr. Arai’s laboratory has successfully moved new technologies into the clinical setting. For example, he developed new MRI methodologies that are more reliable than product-level pulse sequences, validated these methodologies in animal models, and translated them into patients. He has also worked on quantifying the extracellular volume fraction of myocardium, a measurement with potential to detect diffuse myocardial fibrosis; cardiac fibrosis is an early sign in many cardiomyopathies, and a method of detection could have great prognostic value. His laboratory has also been a leader in using cardiac MRI to understand the role of edema within the area at risk (AAR) of an acute myocardial infarction; comparing the AAR to actual infarct size offers an additional level of clinical information, as it shows the effectiveness of intervention strategies.
Quantitative analysis of myocardial perfusion has recently documented that first-pass stress perfusion cardiac MRI scans can be quantified at a pixel level, which is equivalent to approximately 32 microliter volumes of myocardium. This resolution is more than an order of magnitude higher than currently possible by the physiological reference standard, microsphere methodology, and higher resolution than clinically available methods, which someday may enable much more nuanced patient diagnosis of coronary artery disease. These studies have benefited from new image acquisition methods and analysis techniques developed within Dr. Arai’s laboratory.