Skip to main content
  • Oral presentation
  • Open access
  • Published:

High resolution slice-selective Fourier Velocity Encoding using spiral SENSE with velocity unwrap


In patients with congenital heart disease (CHD), it is desirable to accurately measure peak velocity (Vmax). Unfortunately, phase-contrast MR (PCMR) tends to underestimate peak velocities. Fourier Velocity Encoding (FVE) can measure peak velocities in MRI, but is not commonly used due to long acquisition times.

Therefore, we have developed a FVE sequence that combines spiral trajectories with parallel imaging (SENSE), partial-Fourier acquisition and a novel velocity-unwrap technique. The aim of this study is to validate this sequence.


FVE sequence: FVE was performed using a spiral trajectory (table 1). Spiral interleaves were undersampled (R=4) and reconstructed using an iterative SENSE algorithm. Partial Fourier (67%) was performed in kv with a homodyne reconstruction was used. The velocity-unwrap method purposefully aliases data in v (by acquiring half the number of kv-positions), and unwrapped using prior information about the flow direction. Peak velocity was determined using previously described techniques 1-3.

Table 1 Imaging Parameters

In-vitro: A pulsatile flow pump was connected to a tube phantom (13mm diameter) with a stenosis (6mm diameter). Peak velocity measurements using the following techniques were compared at 15 different flow rates; 1) US doppler, 2) low-resolution PCMR (lr-PCMR), 3) high-resolution PCMR (hr-PCMR), 4) FVE.

In-vivo: 12 CHD patients (7M:5F; 34.3±18.8 years) with stenoses were assessed. Peak velocity measurements were compared between; 1) lr-PCMR, 2) hr-PCMR, and 3) FVE.


In-vitro: There were no statistically significant differences between Vmax measured using US and FVE (table 2). However both PCMR sequences showed a statistically significant underestimation of peak flow compared to US (table 2). This is particularly true of lr-PCMR, which underestimated Vmax by >0.5m/s. In-vivo: There was a significant underestimation of Vmax measured using both PCMR sequences when compared to FVE (lr-PCMR; 229±42cm/s, hr-PCMR; 238±46cm/s, FVE; 256±67cm/s).

Table 2 In-vitro results


Fourier velocity encoding allows accurate assessment of peak velocities as it measures a velocity spectrum per pixel, rather than the average velocity. However this extra encoding takes time, which has reduced its clinical effectiveness. We have shown that it possible to achieve high resolution FVE within a short breath-hold by combining spiral trajectories, parallel imaging, partial Fourier and velocity-unwrap. This sequence was shown to be significantly more accurate than PCMR in-vitro, and also to provide higher peak velocities than PCMR in-vivo. Thus, the sequence should be able to replace Doppler echocardiography making CMR a true one-stop-shop in assessing congenital heart disease.





  1. Hansen MS: Magma. 2004, 17 (2): 86-

    Article  PubMed  Google Scholar 

  2. Baltes C: Radiology. 2007, 246 (1): 249-

    Article  PubMed  Google Scholar 

  3. Galea D: Medical Physics. 2002, 29 (8): 1719-

    Article  PubMed  Google Scholar 

Download references

Author information

Authors and Affiliations


Rights and permissions

This article is published under license to BioMed Central Ltd. This is an open access article distributed under the terms of the Creative Commons Attribution License (, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Reprints and permissions

About this article

Cite this article

Steeden, J.A., Atkinson, D., Jones, A. et al. High resolution slice-selective Fourier Velocity Encoding using spiral SENSE with velocity unwrap. J Cardiovasc Magn Reson 14 (Suppl 1), O40 (2012).

Download citation

  • Published:

  • DOI: