Exercise stress testing with imaging is widely used to detect heart disease, but current stress imaging systems suffer from false positives that may lead to unnecessary invasive testing, and false negatives that may miss disease detection until a serious event occurs. Thus, consistently accurate stress imaging remains an important target for technology development. Cardiac magnetic resonance (CMR) provides superior imaging of the heart without ionizing radiation, but technology has not been developed to allow CMR immediately following maximal exercise stress. A revolutionary change to the current landscape of cardiac stress testing could result by adding exercise testing to CMR, thus establishing a "one-stop" imaging modality for accurately assessing heart disease in a single examination. This project focuses on the research and commercialization of an MRI-based system for enhanced exercise stress testing for patients with suspected cardiovascular disease. The key enabling technology is an innovative non-ferromagnetic treadmill that enables convenient placement immediately adjacent to the MRI machine. Standard treadmills would have to be placed far from the MRI magnet outside the MRI room, leading to critical delays between exercise and image acquisition, as well as safety concerns for compromised patients who must, in a fatigued and stressed state, traverse the distance from the treadmill to the MRI table. Our innovative design overcomes these problems and thus enables image acquisition immediately post-exercise. The resulting high resolution images are expected to be superior to nuclear single photon emission tomography (SPECT) and ultrasound, and clearly show stress wall motion, stress perfusion, and viability. The design, implementation, and feasibility testing of this new technology has been completed (Phase I), and this proposed comparative effectiveness study (Phase II) is designed to evaluate how improved test accuracy translates into downstream cost savings. The anticipated positive outcome of this study is expected to lead to a sizeable commercial opportunity for the manufacture and sale of MRI stress testing equipment. Phase II of this project will be accomplished by meeting the following specific aims:
Aim 1. Demonstrate that the technical advantages of treadmill stress CMR over treadmill stress SPECT result in a superior ability to measure the extent and severity of anatomic disease, and equivalent or superior diagnostic and prognostic accuracy.
Aim 2. Demonstrate superior cost-effectiveness of treadmill stress CMR vs. treadmill stress SPECT in a prospective, randomized trial. Successful achievement of the aims of this Phase II project is expected to lead to successful introduction of the treadmill CMR system as a commercial product. Treadmill exercise stress CMR could greatly enhance our understanding of CAD, and enable earlier diagnosis and more effective treatment strategies.
Exercise stress imaging is commonly used to detect heart disease but current methods are often inaccurate. By combining a specially-designed treadmill with a magnetic resonance imaging (MRI) scanner, we can make clearer pictures of the heart under stress conditions and thereby provide more accurate diagnosis. Careful comparison to existing methods of stress testing is essential to determine the effectiveness and cost-efficiency of this new technique. It is anticipated that by providing a more accurate diagnostic test patients will be more likely to receive proper treatment and health care costs will be reduced.