Automatic vessel wall contour detection and quantification of wall thickness in in-vivo MR images of the human aorta.
OBJECTIVE
To develop an automated technique to trace the contours of the lumen and outer boundary of the aortic wall, and measure aortic wall thickness in axial MR images.


METHODS
The algorithm uses prior knowledge of vessel wall morphology. A geometrical model (ellipse) is deformed, translated and rotated to obtain a rough approximation of the contours. Model-matching is based on image gradient measurements. To enhance edges, the images were preprocessed using gray-level stretching. Refinement is performed by means of dynamic programming. Wall thickness is computed by measuring the distance between inner and outer contour of the aortic wall.


RESULTS
The algorithm has been tested on high-resolution axial MR images from 28 human subjects of the descending thoracic aorta. The results demonstrate: High correspondence between automatic and manual area measurements: lumen (r = 0.99), outer (r = 0.96), and wall thickness (r = 0.85).


CONCLUSIONS
Though further optimization is required, our algorithm is a powerful tool to automatically draw the boundaries of the aortic wall and measure aortic wall thickness in aortic wall devoid of major lesions. J. Magn. Reson. Imaging 2006. (c) 2006 Wiley-Liss, Inc.
Adame
Isabel M
IM
Department of Radiology, Division of Image Processing, Leiden University Medical Center, Leiden, the Netherlands. I.M.Adame@lumc.nl
van der Geest
Rob J
RJ
Bluemke
David A
DA
Lima
João A C
JA
Reiber
Johan H C
JH
Lelieveldt
Boudewijn P F
BP
D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D001011:Aorta / Q000473:pathology*; D050197:Atherosclerosis / Q000473:pathology; D001331:Automation; D004730:Endothelium, Vascular / Q000473:pathology*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008875:Middle Aged; D008962:Models, Theoretical; D012044:Regression Analysis; D015203:Reproducibility of Results; D013997:Time Factors