Normal values for mitral and tricuspid early inflow blood flow velocity variation using real time phase contrast cardiovascular magnetic resonance

Abstract

AbstractBackgroundDiastolic ventricular interdependence influences the breathing-induced variation in early diastolic blood flow velocities across the mitral and tricuspid valve. The aim of this study was to develop a method to measure the respiratory variation in mitral and tricuspid early inflow velocities using semi-automatic analysis of real time phase contrast (RT-PC) cardiovascular magnetic resonance (CMR) images, and describe normal reference values.MethodsClinically referred patients (n=24, median [interquartile range] age 55 [46– 65] years, 48% female) with no pericardial effusion or pericardial thickening underwent through-plane RT-PC CMR imaging using a research sequence at 3T in a basal short-axis view over a 30 s acquisition during free breathing. One patient with constrictive pericarditis and one patient with a hemodynamically significant pericardial effusion were imaged to illustrate clinical feasibility. Image analysis was performed using an in-house developed plugin. A region of interest was prescribed over encompassing the mitral and tricuspid orifices, respectively. The highest (Vmax) and lowest (Vmin) early inflow velocities were then automatically recorded. Respiratory variation was defined as (Vmax-Vmin)/Vmax.ResultsThe respiratory variation in mitral and tricuspid early inflow velocity in patients without constrictive pericarditis or pericardial effusion was (mean±SD) 22±7% (upper limit 35%) and 38±7% (upper limit 51%). The patient with constrictive pericarditis had a respiratory variation in mitral and tricuspid early inflow velocities of 60% and 44%, respectively. The patient with 35 mm pericardial effusion had a respiratory variation in mitral and tricuspid early inflow velocities of 62% and 64%, respectively.