High frame rate cardiac cine MRI for the evaluation of diastolic function and its direct correlation with echocardiography

Abstract

Background Breath‐hold cine MR is the method of choice for evaluating left ventricular (LV) systolic function; however, the evaluation of diastolic function remains in the domain of high frame rate echocardiography. Thus, a cine MR technique for simultaneously evaluating LV systolic and diastolic function would be clinically valuable. Purpose To test the feasibility of extracting indices that characterize LV diastolic function from high frame rate cine MR. Study Type Single center, prospective. Population Asymptomatic volunteers (N = 24; age 45.8 ± 12.3 years). Field Strength/Sequence High frame rate (70 fps) cine MR and phase‐contrast MR during free breathing were acquired at 1.5T. Assessment The following MR‐based LV filling metrics were extracted from LV volume changes during the cardiac cycle: 1) the volume–rate ratio, REFP/RLFP (ratio of the peak LV filling rate during the early filling period [EFP] to that during the late filling period [LFP]); and 2) the volume ratio, VEFP/VLFP (the ratio of cumulative LV volume change between the EFP and LFP). These metrics were then compared with traditional transmitral blood flow‐based MR and echocardiographic indices. The effect of temporal resolution on these metrics was also evaluated. Statistical Tests Bland–Altman and linear regression analyses were used to evaluate the performance of the proposed metrics against traditional indices of diastolic function. Results The REFP/RLFP and VEFP/VLFP correlated well with E/AQ‐flow (r 2 = 0.66 and 0.54, respectively) and E/Aecho (r 2 = 0.58 and 0.49, respectively). Systolic indices remained robust (<3% error) for frame rates ≥20 fps. Although the proposed VEFP/VLFP was robust (<5% error) up to 25 fps, the proposed volume–rate diastolic function metrics were less reliable (>8% error) for frame rates below 35 fps. Data Conclusion In asymptomatic volunteers, cardiac cine MR images acquired at frame rates >35 fps can be used to extract LV diastolic function indices from the temporal changes in LV volume. Level of Evidence: 1 Technical Efficacy Stage: 1 J. Magn. Reson. Imaging 2019;50:1571–1582.

Enhancing diastolic function by strain-dependent detachment of cardiac myosin crossbridges

“…We used a computer model to estimate the effects of a length change on the number of myosin crossbridges attached or detached over the course of a prolonged stretch. Both early and late filling periods last ∼100 ms in healthy adults and stretch the circumference of the ventricle on the order of an additional 1-20% (Zhang et al, 2019). In our experience, the characteristic time points of a force response due to α-myosin kinetics in mouse myocardium at 17°C are roughly those of β-myosin kinetics in human myocardium at 37°C (unpublished data).…”

“…During early filling, the ventricular myocardium undergoes overall relengthening driven by the stored elastic energy, which produces a suction that draws blood into the enlarging LV from the LA, as well as by the level of LA pressure at the time of mitral valve opening (Bell et al, 2000). Early filling is not considered an energy-consuming process and accounts for as much as ∼80% of the end-diastolic volume of the normal human adult LV (Zhang et al, 2019). Once LV and LA pressures equilibrate, early filling ceases and a diastatic phase commences with little or no filling.…”

“…Late filling then occurs when the LA actively pumps blood into the LV immediately before ventricular systole. In a normal human adult LV, the endocardium may lengthen an additional 4-6% and the epicardium 1-3% over a span of ∼100 ms during late filling (Zhang et al, 2019). This seemingly small percentage change in myocardial length represents as much as ∼ 20% increase in chamber volume and plays an important part in normal LV filling.…”

Thoroughly Calibrated Modular Agent-Based Model of the Human Cardiovascular and Renal Systems for Blood Pressure Regulation in Health and Disease

“…The rate of the LV filling through the mitral valve in diastole is characterized by two peaks ( Boogers et al, 2011 ; Caudron et al, 2011 ; Zhang et al, 2019 ), which can be estimated from the time derivative of the LV volume by cardiovascular magnetic resonance ( Maceira et al, 2006a ). In normal subjects, the LV inflow is greatest immediately after opening of the mitral valve (early peak), while the left atrial contraction is responsible for smaller inflow (active peak) ( Caudron et al, 2011 ).…”

Hybrid MPI-MRI System for Dual-Modal In Situ Cardiovascular Assessments of Real-Time 3D Blood Flow Quantification—A Pre-Clinical In Vivo Feasibility Investigation

“…ultrasound. Recently, accelerated MR-based imaging sequences have been presented in [5], allowing for freebreathing cine MRI data acquisition. Whilst the reconstructed temporal resolution is superb, the overall scan time is in the range of minutes as these methods still necessitate physiological gating and triggering to cope with the slow encoding scheme.…”