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. 2013 Aug 1;14(11):1029–1038. doi: 10.1093/ehjci/jet086

Table 1.

Summary of technical characteristics

Echo-PIV VFM CMR
Data source Echocardiographic tracking of groups of contrast agent particles Calculation of laminar and vortical flow components from Colour-Doppler Influence of flow motion on MR-signal phase: phase contrast
Main advantages
  • Low cost

  • Wide availability

  • Shorter examination times

  • Higher spatial resolution with full 3D coverage

Limitations
  • Inherent to conventional echocardiographic examinations (acoustic shadowing, technically difficult examinations, etc.)

  • Intracardiac devices not suitable for CMR studies

  • Longer examination times

  • Limited temporal resolution (poor flow characterization in brief phases of cardiac cycle)

  • Flow data are averaged over several cardiac cycles

  • Need for the use of contrast agents

  • Requiring frame rates of 60–150 fps for adequate detection of high velocities

  • Lacking ‘in vivo’ validation study

  • Underestimation of velocities in vortex areas perpendicular to ultrasound beam

Sources of error
  • Cross-plane migration of contrast agent particles

  • Manual contour detection

  • Manual de-aliasing

  • Manual definition of endocardial borders

  • Eddy current effects

  • Maxwell terms

  • Gradient field distortions

Accuracy
 High velocities Limited: affected by frame rate (upper limit of ∼60 cm/s) Accurate visualization. May require adjustment of Nyquist limit or manual de-aliasing Accurate visualization, although selectable velocity sensitivity (venc) requires some prior knowledge of the expected velocity values
 Low velocities Accurate visualization Underestimation. Nyquist limit adjustment and focus on smaller areas may improve the detection but introduces noise through the detection of cardiac wall motion