title: A semi-automated method for measuring the evolution of both lumen area and blood flow in carotid from Phase Contrast MRI.
abstract: Phase-Contrast (PC) velocimetry Magnetic Resonance Imaging (MRI) is a useful modality to explore cardiovascular pathologies, but requires the automatic segmentation of vessels and the measurement of both lumen area and blood flow evolutions. In this paper, we propose a semi-automated method for extracting lumen boundaries of the carotid artery and compute both lumen area and blood flow evolutions over the cardiac cycle. This method uses narrow band region-based active contours in order to correctly capture the lumen boundary without being corrupted by surrounding structures. This approach is compared to traditional edge-based active contours, considered in related works, which significantly underestimate lumen area and blood flow. Experiments are performed using both a sequence of a homemade phantom and sequences of 20 real carotids, including a comparison with manual segmentation performed by a radiologist expert. Results obtained on the phantom sequence show that the edge-based approach leads to an underestimate of carotid lumen area and related flows of respectively 18.68% and 4.95%. This appears significantly larger than weak errors obtained using the region-based approach (respectively 2.73% and 1.23%). Benefits appear even better on the real sequences. The edge-based approach leads to underestimates of 40.88% for areas and 13.39% for blood flows, compared to limited errors of 7.41% and 4.6% with our method. Experiments also illustrate the high variability and therefore the lack of reliability of manual segmentation.
authors.affiliation: LARIS Laboratory, EA4094, University of Angers, 62 avenue Notre Dame du Lac, 49000 Angers, France. Electronic address: Jean-Baptiste.Fasquel@univ-angers.fr.
authors.forename: Jean-Baptiste
authors.initials: JB
authors.lastname: Fasquel
authors.affiliation: Radiology Department, University Hospital, 4 rue Larrey, 49933 Angers, France.
authors.forename: Aldéric
authors.initials: A
authors.lastname: Lécluse
authors.affiliation: LARIS Laboratory, EA4094, University of Angers, 62 avenue Notre Dame du Lac, 49000 Angers, France.
authors.forename: Christine
authors.initials: C
authors.lastname: Cavaro-Ménard
authors.affiliation: Radiology Department, University Hospital, 4 rue Larrey, 49933 Angers, France.
authors.forename: Serge
authors.initials: S
authors.lastname: Willoteaux
mesh_terms: D000465:Algorithms; D001331:Automation; D002339:Carotid Arteries / Q000473:pathology*; D017536:Carotid Artery, Common / Q000473:pathology; D003287:Contrast Media; D004562:Electrocardiography; D064368:Healthy Volunteers; D006439:Hemodynamics; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D008279:Magnetic Resonance Imaging / Q000379:methods*; D010363:Pattern Recognition, Automated; D019047:Phantoms, Imaging; D015203:Reproducibility of Results; D012212:Rheology
chemical_list: D003287:Contrast Media
keywords: Blood flow; Magnetic Resonance Imaging; Phantom; Region-based active contour; Semi-automated analysis