Quantitative Assessment of RV Strain Using cMRI Following Catheter Intervention on PE

Acute pulmonary embolism (PE) is a condition in which the vessels carrying blood to the lungs become suddenly blocked, usually by a blood clot. There are a number of adverse consequences that result, with one of the most significant being strain on the right side of the heart (which must push blood through the blocked arteries to the lungs). Although this strain on the right heart is very important, current methods for measuring it are flawed. The standard practice is to obtain an echocardiogram (ultrasound of the heart), from which indirect measurements of the size of the heart are used to make inferences about right heart strain. This method can help guide management in some patients, but it in not a sensitive test and does not provide detailed information. Patients with PE are treated with blood thinning medications. Some patients may be referred to the Interventional Radiology (IR) team for endovascular intervention, in which catheters are placed into the patient's vessels under radiologic guidance and advanced to the lungs to remove the clot entirely. Cardiac magnetic resonance imaging (MRI) is a well-established imaging technique that produces highly detailed images of the heart's structure and function, with no risks to patients of ionizing radiation or intravenous contrast. Cardiac MRI is far superior to echocardiogram in evaluation of the right side of the heart, however it has not been widely used in the evaluation of patients with PE. We propose that by using a fast MRI protocol, we will be able to detect right heart strain with more accuracy than echocardiogram. Furthermore, we hypothesize that MRI images obtained before and after IR catheter-directed therapy will demonstrate the degree to which strain is relieved with this treatment. Finally, we believe that using MRI may help to guide management of patients with PE by detecting early or mild heart strain before it progresses. In order to test these hypotheses, we plan to image PE patients who have b