Comparison of Four‐Dimensional Magnetic Resonance Imaging Analysis of Left Ventricular Fluid Dynamics and Energetics in Ischemic and Restrictive Cardiomyopathies

Abstract

Background Time‐resolved three‐directional velocity‐encoded (4D flow) magnetic resonance imaging (MRI) enables the quantification of left ventricular (LV) intracavitary fluid dynamics and energetics, providing mechanistic insight into LV dysfunctions. Before becoming a support to diagnosis and patient stratification, this analysis should prove capable of discriminating between clearly different LV derangements. Purpose To investigate the potential of 4D flow in identifying fluid dynamic and energetics derangements in ischemic and restrictive LV cardiomyopathies. Study Type Prospective observational study. Population Ten patients with post‐ischemic cardiomyopathy (ICM), 10 patients with cardiac light‐chain cardiac amyloidosis (AL‐CA), and 10 healthy controls were included. Field Strength/Sequence 1.5 T/balanced steady‐state free precession cine and 4D flow sequences. Assessment Flow was divided into four components: direct flow (DF), retained inflow, delayed ejection flow, and residual volume (RV). Demographics, LV morphology, flow components, global and regional energetics (volume‐normalized kinetic energy [KEV] and viscous energy loss [ELV]), and pressure‐derived hemodynamic force (HDF) were compared between the three groups. Statistical Tests Intergroup differences in flow components were tested by one‐way analysis of variance (ANOVA); differences in energetic variables and peak HDF were tested by two‐way ANOVA. A P‐value of <0.05 was considered significant. Results ICM patients exhibited the following statistically significant alterations vs. controls: reduced KEV, mostly in the basal region, in systole (−44%) and in diastole (−37%); altered flow components, with reduced DF (−33%) and increased RV (+26%); and reduced basal–apical HDF component on average by 63% at peak systole. AL‐CA patients exhibited the following alterations vs. controls: significantly reduced KEV at the E‐wave peak in the basal segment (−34%); albeit nonstatistically significant, increased peaks and altered time‐course of the HDF basal–apical component in diastole and slightly reduced HDF components in systole. Data Conclusion The analysis of multiple 4D flow‐derived parameters highlighted fluid dynamic alterations associated with systolic and diastolic dysfunctions in ICM and AL‐CA patients, respectively. Level of Evidence 2 Technical Efficacy Stage 3

Four-dimensional flow cardiac magnetic resonance assessment of left ventricular diastolic function

“…Of note, an earlier study by Garg et al (32) found that MI patients with preserved systolic function also had reduced peak E wave (early) diastolic KE -early evidence of the diastolic dysfunction that can occur post MI. A significant reduction in peak E wave KE was also observed in patients with cardiac amyloidosis (35), a condition characterized by diastolic dysfunction and heart failure with preserved ejection fraction.…”

Surrogate models provide new insights on metrics based on blood flow for the assessment of left ventricular function

“…Recent years have witnessed rapid advancements in imaging technology and methods of image analysis that provide deeper informative content regarding cardiac function. By first principles, heart function is about creating and sustaining blood motion; therefore, placing the focus on measures associated with blood flow promises further progress along this line 1 , 45 .…”

“…The study of the flow transit is an important step for the evaluation of blood transport and mixing inside the LV, this is useful for the identification of the blood residences and wash-out properties; conditions that are related to the risk of the thrombus formation. Following the established literature in cardiology 22 , 23 , 45 , this evaluation is obtained through the subdivision of EDV in four sub-volumes where (also indicated as ) is the volume of blood that entered during diastole and transits directly to the aortic outlet during systole, thus residing less than one heartbeat in the LV. is the quantity of blood already present in the LV at the beginning of diastole and ejected during the following systole.…”

Multimodality imaging in cardiac amyloidosis: State‐of‐the‐art review

“…In the CMR field, new techniques may also bring more insights on diagnosis and pathophysiology of amyloidosis in a near future. Four‐dimensional magnetic resonance imaging showed derangements in left ventricular diastolic fluid dynamics in patients with AL CA 89 . Diffusion tensor cardiovascular magnetic resonance demonstrated elevated mean diffusivity and reduced fractional anisotropy in CA, depicting the microstructural effects of amyloid infiltration and identifying the extent of the expanded disorganized myocardium.…”

“…Fourdimensional magnetic resonance imaging showed derangements in left ventricular diastolic fluid dynamics in patients with AL CA. 89 Diffusion tensor cardiovascular magnetic resonance demonstrated elevated mean diffusivity and reduced fractional anisotropy in CA, depicting the microstructural effects of amyloid infiltration and identifying the extent of the expanded disorganized myocardium. Diffusion tensor parameters were found to be linked to extracellular amyloid deposition assessed by ECV.…”