Vortex-ring mixing as a measure of diastolic function of the human heart: phantom validation and initial observations in healthy volunteers and patients with heart failure
Johannes Töger1,2, Mikael Kanski1, Per M Arvidsson1, Marcus Carlsson1, Sándor J Kovács3, Rasmus Borgquist4, Johan Revstedt5, Gustaf Söderlind2, Håkan Arheden1, and Einar Heiberg1,2,6

1Department of Clinical Physiology, Lund University Hospital, Lund University, Lund, Sweden, 2Department of Numerical Analysis, Centre for Mathematical Sciences, Lund University, Lund, Sweden, 3Department of Internal Medicine, Washington University School of Medicine, St Louis, MO, United States, 4Department of Arrhythmias, Lund University Hospital, Lund University, Lund, Sweden, 5Department of Energy Sciences, Lund University, Faculty of Engineering, Lund, Sweden, 6Department of Biomedical Engineering, Lund University, Faculty of Engineering, Lund, Sweden


Diastolic dysfunction of the left ventricle (LV) of the heart is a severe condition associated with poor prognosis. However, objective and reproducible assessment of diastolic function remains a challenge. We propose a new method using 4D flow MR by quantification of blood mixing within the LV diastolic vortex-ring. Phantom validation showed fair agreement between 4D flow MR and planar laser-induced fluorescence (PLIF). Quantitative vortex-ring mixing differs between healthy controls and patients with heart failure, which demonstrates its potential as a marker of diastolic dysfunction.


Diastolic dysfunction of the left ventricle (LV) of the heart is commonly seen in cardiac disease and is associated with poor prognosis.1 In clinical practice, diastolic dysfunction is diagnosed using a combination of imaging measures, and the resulting classification may be ambiguous or inconclusive.2,3 Therefore, new quantitative physiology-based indices are needed. Diastolic vortex-ring formation has been proposed as a sensitive marker of diastolic function.4 Therefore, our aim is to present and validate a new method for magnetic resonance (MR) 4D flow quantification of vortex-ring mixing during early, rapid filling (corresponding to the Doppler E-wave) of the LV as a potential index of diastolic dysfunction.


Vortex-ring mixing measurements using 4D flow MR were validated using planar laser-induced fluorescence (PLIF) in a previously described phantom setup (Figure 1).5 The phantom setup includes a custom-built pulsatile pump connected to a nozzle attached to a water tank, where vortex-rings are formed.

Controls (n=23) and patients with heart failure (n=23) were studied at 1.5T (26 subjects) or 3T (20 subjects) using a previously validated turbo-field echo (TFE) sequence.5–7 Typical scan parameters were: spatial resolution 3×3×3 mm, flip angle 8°, TR/TE 6.3/3.7 ms, VENC 100 cm/s, temporal resolution 50 ms, SENSE=2 and segmentation factor 2. Retrospective ECG triggering was used.

For phantom scans, two different methods for phase background correction were used: A) linear fit of velocities in stationary voxels, and B) subtraction of velocities from a scan performed with no flow in the tank. For in vivo scans, method A was used in all subjects.

Vortex-ring volume (VV) was determined using post-processing of 4D flow using Lagrangian Coherent Structures (LCS, Figure 2).8 The inflowing volume during diastole (VVinflow) was quantified from through-plane flow in the mitral annulus reconstructed from 4D flow. The volume mixed into the vortex-ring was then quantified as VVmix-in = VV–VVinflow. The mixing ratio was defined as MXR = VVmix-in/VV = 1 – VVinflow/VV.

To test interstudy variability, the full analysis was carried out for all subjects by two independent observers (JT and PA). Interobserver variability was defined as the mean and standard deviation of the differences in MXR between the two observers.


Figure 2 shows LV vortex-ring mixing in a control subject and a patient with heart failure, using Lagrangian Coherent Structures8 and Volume Tracking.9

As seen in Figure 3, PLIF validation of 4D flow MXR showed fair agreement (method A: R2=0.28, mean±SD: 6±7%, method B: R2=0.45, 1±6%). Interobserver variability for MXR was -4±8% in controls and -5±9% in patients.

Figure 4 shows quantitative results in controls and patients. MXR was higher in heart failure patients compared to controls (28±11% vs 16±10%, p<0.001).


The PLIF validation shows that diastolic vortex-ring mixing can be quantified using MR 4D flow. The importance of phase background corretion in computing quantitative measures from 4D flow MR is underscored by the different results for the two background correction methods.

The difference in MXR between controls and patients may be the result of impaired diastolic function in the heart failure patients. The specific mechanisms that determine MXR remain to be elucidated, but likely include LV diastolic suction and load, relaxation and stiffness,10 left atrial pressure, and mitral valve geometry.


Vortex-ring mixing can be quantified using 4D flow MR. The differences in mixing parameters observed between controls and patients motivate further investigation of fluid dynamics based indices of diastolic dysfunction and heart failure.


Tomas Hajdu at the Department of Medical Technology, Skåne University Hospital Lund, Sweden is acknowledged for design and construction of the phantom equipment.

Ann-Helen Arvidsson, Christel Carlander, Reza Farazdaghi, Johanna Koul and Lotta Åkesson at the Department of Clinical Physiology, Lund University Hospital, Lund, Sweden are acknowledged for assistance in data collection.

This abstract is based on a paper submitted to and under review in Journal of Magnetic Resonance Imaging (JMRI) at the time of abstract submission.


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Figure 1: Phantom validation setup.5 Panel (a) shows a schematic drawing of the phantom setup. A custom-built pulsatile pump is connected to a nozzle connected to a water tank, where vortex rings are formed. Panel (b) shows vortex ring formation imaged using planar laser-induced fluorescence (PLIF). Panel (c) shows vortex ring formation imaged using MR 4D flow and post-processed using Lagrangian Coherent Structures.

Figure 2: Visualization of vortex-ring mixing in a control (a, b and c) and a patient (d, e and f). Panels (a) and (d) show Lagrangian Coherent Structures indicating vortex-ring formation in the LV during diastole. Panels (b) and (e) show the manual delineation of the vortex-ring (yellow dashed line). Panels (c) and (f) show a Volume Tracking9 visualization of inflowing blood (red) mixing with the ventricular blood (blue) inside the vortex-ring. LV= left ventricle, LA = left atrium.

Figure 3: Phantom validation using planar laser-induced fluorescence (PLIF). Fair agreement was found for background correction method A (panels (a) and (b), linear fit to stationary voxels), with better performance for background correction method B (panels (c) and (d), subtraction of stationary scan).

Figure 4: Quantitative results in controls and patients. MXR was higher in heart failure patients compared to controls.

Proc. Intl. Soc. Mag. Reson. Med. 24 (2016)