CMR real-time, free-breathing, phase contrast flow quantification: a novel approach to assess ventricular coupling in constrictive pericarditis

Abstract

Background/objective Constrictive pericarditis (CP) is an important cause of heart failure; however, with accurate diagnosis and directed treatment it is potentially curable. Cardiac magnetic resonance imaging (CMR) has played a diagnostic role, primarily by allowing assessment of pericardial morphology but with limited depiction of physiological changes. We sought to examine the feasibility of a novel CMR approach that enables real-time phase contrast (RT-PC) assessment of discordant respirophasic changes in trans-mitral and tricuspid flow velocity the signature findings in CP due to enhanced ventricular interdependence. Method Patients referred to the CMR lab pre-pericardectomy or for assessment of suspected CP were included. Following routine CMR examination for CP, transmitral (MV) and tricuspid valve (TV) flow velocities were simultaneously obtained by through-plane RT-PC imaging during unrestricted respiration using a slice position to include both valves (Figure 1) with the following parameters: TR/TE=13.7ms/2.5ms, water excitation pulse with flip angle=25, 10mm slice thickness, 160x120 matrix, EPI factor=15, TSENSE rate=2, slice thickness=10mm, and VENC=150cm/s. Shared velocity encoding was used to achieve an effective temporal