Magnetic Resonance Imaging Subsystem for Evaluation of Valvular Disease

DESCRIPTION (provided by applicant): Valvular heart diseases are conventionally overshadowed by the very high prevalence of coronary disease. However, moderate to severe valvular heart disease is present in more than 12% of patients over the age of 70 andpresent in 80% or more of patients admitted with congestive heart failure [1]. The proper cardiac evaluation must therefore include an accurate evaluation of valvular structure and function. Cardiac magnetic resonance imaging has been shown to be one of the best technologies for the evaluation of valvular pathologies. The broad application of this promising technology is expected to significantly improve the treatment of patients with heart diseases. However, widespread adoption of this beneficial technology has been held back by the lack of both software infrastructure and specific software sequences that take advantage of this infrastructure to provide a complete cardiac examination that can be performed rapidly in the clinical environment. The aim of thisapplication is to develop a commercial robust cardiovascular subsystem that will enable the broad application of this technology to the clinical realm. Under previous NIH grant support through Stanford University, we have established real-time rapid imaging se- quences for the assessment of wall motion, valvular morphology, color flow mapping and quantitation of valvular steno- sis. We have also established the feasibility of rapidly quantitating each of these parameters. Our goal in this proposal is to integrate these methods into a robust valvular heart disease system to realize the clinical potential of cardiac MRI in the complete evaluation of heart disease. During Phase I of this proposal, HeartVista developed and tested the alpha version of the cardiovascular software infrastructure that provides an integrated environment for rapid valvular imaging. This package includes real-time evaluation of ventricular function, real-time quantitative flow mapping, interrogation of high-velocity jets, and detailed assessment of valvular morphology. We installed the system at selected alpha sites and collected patient data. Generally, our methods concern 7 obtaining adequate temporal resolution, spatial coverage, and contrast production for valvular imaging usingcustomized pulse sequences and hardware to reduce data acquisition time, 7 developing a underlying real-time imaging platform that allows the seamless real-time integration of receiver coil functions, pulse sequences, and post-processing and display that optimizes the workflow for studying patients with valvular disease. This proposal focuses on developing and validating this combined examination to provide the clinician a robust and intuitive complete cardiac evaluation package that can be performed comfortably in less than 1 hour. During Phase II of this proposal, we will continue the development of our product based on the feedback obtained during Phase I and we will conduct a clinical study to demonstrate the non-inferiority of our product compared withconventional cardiovascular MRI examinations in robustness and diagnostic accuracy. PUBLIC HEALTH RELEVANCE: Valvular heart disease is increasingly common in our aging population in the United States. Valvular disease com- plicates as many as 80% of patients admitted for heart failure [2], and moderate to severe valvular heart disease is present in more than 12% of patients over the age of 70 [1]. The evaluation of common cardiac complaints such as shortness of breath must always include an assessment of valvular heart disease. Conventional echocardiography provides excellent qualitative data but does not provide quantitative information on all the important parameters relating to valvular disease. Current MRI techniques are quantitative but have significant shortcomings related to usability and prolonged examination times. A comprehensive valvular examination is therefore not normally part of a cardiac MRI examination. However, ad hoc or incidental examination is important given the prevalence of valvular disease that is co-morbid in other heart conditions. Given the enormous number of these patients, even a modest improvement in diagnostic accuracy will have a large public-health impact. Cardiac magnetic resonance imaging has been shown to be oneof the best technologies for the evaluation of cardiovascular pathologies. It is the only imaging modality that could qualitatively and quantitatively measure all of the important valvular parameters including ventricular function, cardiac output, valvularregurgitation and valvular stenosis in a single examination. The broad application of this promising technology is expected to significantly improve the treatment of patients with heart disease. However, the adoption of this beneficial technology has beenheld back by the lack of both a software infrastructure and specific software sequences that take advantage of this infrastructure to provide a complete cardiovascular examination that can be performed rapidly in the clinical environment. The aim of thisapplication is to develop a robust commercial cardiovascular subsystem that will enable the broad clinical application of this technology.