Title: Diastolic function assessment with cardiac magnetic resonance imaging and echocardiography: a scan-rescan study
Funder: The Academy of Medical Sciences

Abstract: 30% of patients with clinical heart failure have preserved systolic function. However, the ability of cardiovascular magnetic resonance (CMR) to assess diastolic function is relatively poorly understood, and guidelines currently recommend further investigations with echocardiography. The limited previous studies assessing the agreement of analogous measurements made on CMR and echocardiography show only modest correlation between the modalities. This could be due to: (1) Modality differences (e.g., poorer temporal resolution of CMR) (2) Physiological differences (supine positioning (CMR) versus lateral decubitus (echocardiography)) (3) Test-retest variability (either measurement error or genuine biological variability) I have designed a study to explore the agreement between CMR and echocardiography diastolic function assessment with test-retest measurements. Patients attending for a clinical CMR scan will undergo same day focused echocardiography in both supine and left lateral positioning. Patients will then undergo CMR scanning with analogous diastolic function measurements performed twice: at scan start and end. After their CMR, patients will undergo repeat echocardiographic measurements. Finally, patients will be recalled for a brief focused re-scan by both CMR and echocardiography on a separate day. This experiment will allow me to assess the agreement and bias between CMR and echocardiographic diastolic function assessment in the context of each modality’s reproducibility. I will also be able to assess for systematic short- and medium-term biological variability, and differences in diastolic function related to patient preparation and patient relaxation during the conduct of a CMR scan.

Lay abstract: Cardiac magnetic resonance (CMR) imaging is excellent at assessing the contractility of the heart muscle. However, relatively little is known about CMR’s ability to assess the relaxation (diastolic function) of the heart between heart beats, where echocardiography remains the gold standard. This is important because in 30% of heart failure patients the overwhelming problem is diastolic dysfunction, and so they often need both tests. Studies have previously tried to compare CMR measurements of diastolic function those from echocardiography, but these have shown frequent disagreements between the two in the same patient. The reasons for this are not known. Possible explanations include differences in the way the scanners take pictures, differences in how the patient is positioned, and the reproducibility of each method. In this study we will recruit patients who are undergoing a CMR scan for clinical reasons. Before their scan we will perform an echocardiogram to assess diastolic function, with the patient lying in different positions. Then, during their CMR scan they will undergo diastolic function assessment twice, around 30 minutes apart. After the CMR scan we will repeat the echocardiogram. Finally, when patients come back to the hospital for their clinical follow-up some weeks later we will perform repeat CMR and echo scans. These assessments in each patient on the same day and different days will allow us to assess the agreement between CMR and echocardiography diastolic assessment, which is imperative if we wish to develop guidance for doctors to better assess our patients.

Research activity codes: 4.1 DISCOVERY AND PRECLINICAL TESTING OF MARKERS AND TECHNOLOGIES;4.2 EVALUATION OF MARKERS AND TECHNOLOGIES
Health categories: CARDIOVASCULAR