Blood Velocity & Flow

Automated quantification of velocity and flow in blood vessels using velocity-encoded cine MRI

Rob J. van der Geest

Background

Velocity-encoded cine MRI allows the assessment of blood flow velocity in an arbitrary imaging plane at high temporal and spatial resolution.

Goals

The purpose of this research is to develop contour detection methods for semi-automated analysis of flow in the greater arteries such as the ascending aorta and pulmonary artery.

Approach

An image segmentation strategy was developed that includes vessel boundary detection and vessel in-plane motion tracking that can be applied successfully for the greater arteries. The contour detection follows a two-step procedure. In the first step the user has to identify the artery of interest by identifying the vessel center. For this image the lumen contour will be detected based on adaptive thresholding and dynamic programming. In the second step the contours for the remaining phases are detected based on a newly developed ND-dynamic programming technique. This approach results in a time-continuous segmentation result.

Flow Screen
Figure 1
Screen shot of the developed FLOW software package showing an example of an aortic flow data set including the derived flow curve.

Flow Movie
Movie 1
Example of automatically detected contours for the ascending and descending aorta. (3.8 MB)

Status

Automated contour detection techniques have been developed to detect the vessel boundaries in all of the acquired phases. The contour detection algorithm corrects for motion and shape changes of the vessel cross-section. Manual contour tracing facilities are provided to allow analysis of flow in atrio-ventricular valve planes and imaging studies with sub-optimal image quality. The developed contour detection algorithms are integrated into the software package QFlow-MRA®, which is commercially available through Medis medical imaging system b.v.

Publications

  1. van der Geest RJ, Buller VGM, Reiber JHC. Automated quantification of flow velocity and volume in the ascending and descending aorta using MR flow velocity mapping. IEEE, Comput Cardiol 1995:29-32.
  2. van der Geest RJ, Niezen RA, van der Wall EE, de Roos A, Reiber JHC. Automated measurement of volume flow in the ascending aorta using MR velocity maps: evaluation of inter- and interobserver variability in healthy volunteers. J Comp Assist Tomogr 1998;22(6):904-911.
  3. Hoogendoorn LI, Pattynama PMT, Buis B, van der Geest RJ, van der Wall EE, de Roos A. Noninvasive evaluation evaluation of aortocoronary bypass grafts with magnetic resonance flow mapping. Am J Cardiol 1995;75:845-848.
  4. Niezen RA, Helbing WA , van der Geest RJ, Rebergen SA, de Roos A. Biventricular systolic function and mass studied with MR imaging in children with pulmonary regurgitation after repair for Tetralogy of Fallot. Radiology 1996;201:135-140.
  5. Helbing WA, Niezen RA, le Cessie S, van der Geest RJ, Ottenkamp J, de Roos A. Right ventricular diastolic function in children with pulmonary regurgitation after repair of Tetralogy of Fallot: Volumetric evaluation by magnetic resonance velocity mapping. J Am Coll Cardiol 1996;28:1827-1835.
  6. Kayser HWM, Stoel BC, van der Wall EE, van der Geest RJ, de Roos A. MR velocity mapping of tricuspid flow: Correction for through-plane motion. J Magn Reson Im 1997;7(4):669-673.
  7. Marcus JT, Smeenk HG, Kuijer JP, van der Geest RJ, Heethaar RM, van Rossum AC. Flow profiles in the left anterior descending and the right coronary artery assessed by MR velocity quantification: effects of through-plane and in-plane motion of the heart. J Comput Assist Tomogr 1999;23(4):567-576.

Contact

Rob J. van der Geest, PhD
Division of Image Processing
Department of Radiology, 1-C2S
Leiden University Medical Center
P.O. Box 9600
2300 RC Leiden
The Netherlands
Tel. +31 (0)71 526 2138
Fax. +31 (0)71 526 6801
e-mail: R.J.van_der_Geest@lumc.nl