Automated quantification of velocity and flow in blood vessels using velocity-encoded cine MRI
Rob J. van der Geest
Velocity-encoded cine MRI allows the assessment of blood flow velocity in an arbitrary imaging plane at high temporal and spatial resolution.
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.
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.
Figure 1 Screen shot of the developed FLOW software package showing an example of an aortic flow data set including the derived flow curve.
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.
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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
Tel. +31 (0)71 526 2138
Fax. +31 (0)71 526 6801