Clinical intra-cardiac 4D flow CMR: acquisition, analysis, and clinical applications

Figures

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  Figure 1. 3D blood flow visualization with 4D flow CMR. 3D blood flow visualization on the whole heart is shown during mid-systole in a 28-year-old healthy male (top) and a 52-year-old female patient with tricuspid regurgitation (white arrow) after ventricular septal defect repair. Vectors, streamlines, and pathlines are illustrated from left to the right. Ao, aorta; MPA, main pulmonary artery; RA, right atrium; SVC, superior vena cava.

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  Figure 2. Overview of 4D flow CMR acquisition and analysis process. A typical workflow for 4D flow CMR data acquisition and analysis is demonstrated using images of a healthy volunteer (33-year-old male). On the left side, the acquisition of images in 3-direction (x, y, z) in a 3-dimensional volume of interest is displayed through flow velocity and magnitude images. Thereafter, acquired images are reconstructed and sequence-specific errors are corrected either manually or automatically. The segmentation is performed to determine the region of interest for visualization and quantification. In the middle-right, velocity overlay on the left ventricle and atrium during early diastole was illustrated. On the right side, conventional and novel hemodynamic parameters which can be generated through 4D flow CMR data are displayed. ROI, region of interest.

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  Figure 3. Two-dimensional streamline as overlay. Four-chamber view with 2-dimensional streamlines as overlay on the left atrium of a healthy volunteer (33-year-old male). Formation of a vortex can be observed in left atrium both during diastole (left side) and systole (right side) using streamlines.

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  Figure 4. Retrospective valve tracking in a patient with mitral valve regurgitation. The left part of the figure shows valve tracking in a diastolic timeframe and the right part shows valve tracking in a systolic timeframe during regurgitation of a patient (45-year-old female) with a mitral valve regurgitation. In the top images, the colours represent the in-plane speed measured from 4D flow CMR projected on to 2-chamber and 4-chamber cine images. The bottom images show the streamlines with insets of phase velocity images resulting from the valve tracking. The regurgitation volume was measured 28.5 ml/beat and forward flow volume was 82.3 mL/beat.

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  Figure 5. Demonstration of visual and quantitative abilities of KE, TKE, and EL. Visualization of KE, TKE, and EL rate in the LV and RV cavities in a healthy volunteer (48-year-old male), on a standard 4-chamber view during mid-systole, early diastole, and late diastole. Furthermore, entire LV KE, TKE, and EL rate are temporally plotted over the cardiac cycle on the far-right side of the figure.

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  Figure 6. Flow and pressure gradient assessment in the left ventricle. Demonstration of flow and pressure quantifications in the left ventricle at basal, mid, and apical levels in a 12-year-old healthy male. On the left side, determination of the levels on the long-axis and segmentation on the short-axis views, in the middle-right, flow curves and the relevant flow and pressure gradient results are displayed. On the far-right side, 3-dimensional appearances of the levels on a 2-dimensional multi-planar view are shown and the pressure differences between basal and apical levels are temporally plotted over the cardiac cycle.

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  Figure 7. Valvular flow quantification with 4D flow CMR and 4D colour Doppler echocardiography. On the left side, valvular flow visualization and quantification of 4D flow CMR is displayed in a 12-year-old healthy male. 3D blood flow on multi-planar views during systole for aortic valve and during diastole for mitral valve is visualized. The segmentations were done using an artificial intelligence approach. Furthermore, aortic and mitral valve flows are temporally plotted over the cardiac cycle and valvular flow measurements are provided. On the right side, measurement of 3D vena contracta area of functional mitral regurgitation with 4D colour Doppler transesophageal echocardiography in a 51-year-old male is shown. Volume rendering view (top left), two perpendicular long-axis views of mitral regurgitation jet and one short-axis view (bottom right) at the level of coaptation defect are visualized. Vena contracta area was measured as 0.6 cm2 and circumference of the jet as 3.3 cm.