Intracardiac Flow at 4D CT: Comparison with 4D Flow MRI

Abstract

Purpose To investigate four-dimensional (4D) flow CT for the assessment of intracardiac blood flow patterns as compared with 4D flow MRI. Materials and Methods This prospective study acquired coronary CT angiography and 4D flow MRI data between February and December 2016 in a cohort of 12 participants (age range, 36-74 years; mean age, 57 years; seven men [age range, 36-74 years; mean age, 57 years] and five women [age range, 52-73 years; mean age, 64 years]). Flow simulations based solely on CT-derived cardiac anatomy were assessed together with 4D flow MRI measurements. Flow patterns, flow rates, stroke volume, kinetic energy, and flow components were quantified for both techniques and were compared by using linear regression. Results Cardiac flow patterns obtained by using 4D flow CT were qualitatively similar to 4D flow MRI measurements, as graded by three independent observers. The Cohen κ score was used to assess intraobserver variability (0.83, 0.79, and 0.70) and a paired Wilcoxon rank-sum test showed no significant change (P > .05) between gradings. Peak flow rate and stroke volumes between 4D flow MRI measurements and 4D flow CT measurements had high correlation (r = 0.98 and r = 0.81, respectively; P < .05 for both). Integrated kinetic energy quantified at peak systole correlated well (r = 0.95, P < .05), while kinetic energy levels at early and late filling showed no correlation. Flow component analysis showed high correlation for the direct and residual components, respectively (r = 0.93, P < .05 and r = 0.87, P < .05), while the retained and delayed components showed no correlation. Conclusion Four-dimensional flow CT produced qualitatively and quantitatively similar intracardiac blood flow patterns compared with the current reference standard, four-dimensional flow MRI. © RSNA, 2018 Online supplemental material is available for this article.

Impact of Pulmonary Venous Inflow on Cardiac Flow Simulations: Comparison with In Vivo 4D Flow MRI

“…The framework tracked the wall motion over the cardiac cycle, and was validated against manually segmented geometries 14. For details on the image registration framework, see earlier work 22. The extracted wall motion was then prescribed in a flow solver—see “Computational Fluid Dynamics”.…”

“…The patients included in this study are taken from an earlier study where we computed intracardiac blood flow based on CT and compared results with in vivo flow measurements. 22 In addition to 4D Flow MRI measurements of the LA and LV, the PVs were also available in the 4D flow MRI data for three of those patients, and they were included in this study. The three patients had a clinical referral for coronary CT angiography due to suspected coronary artery disease.…”

“… 14 For details on the image registration framework, see earlier work. 22 The extracted wall motion was then prescribed in a flow solver—see “ Computational Fluid Dynamics ”.…”

“…In a previous study, we computed intracardiac blood flow based on CT on twelve patients with suspected heart disease, and compared the computed results with in vivo 4D Flow MRI measurements on the same patients. 22 There, 25% of the total flow was assumed to enter the LA through each PV, and while very good agreement with in vivo measurements was found, a sensitivity analysis on inlet flow rates was not performed.…”

4D Flow MRI quantification of blood flow patterns, turbulence and pressure drop in normal and stenotic prosthetic heart valves

“…Unfortunately, numerical simulations depend heavily on the geometry and inflow and outflow conditions, which are not always possible to obtain with sufficient quality. A recent study successfully compared the intracardiac blood flow obtained from both 4D Flow MRI and CFD [73], which opens up for combining the unique advantages of 4D Flow MRI measurement and CFD.…”