Automated quantification of carotid artery stenosis on contrast-enhanced MRA data using a deformable vascular tube model

Division of Image Processing, Department of Radiology, Leiden University Medical Center, Albinusdreef 2, 2333 ZA, Leiden, The Netherlands.
The international journal of cardiovascular imaging (Impact Factor: 1.81). 12/2011; 28(6):1513-24. DOI: 10.1007/s10554-011-9988-x
Source: PubMed


The purpose of this study was to develop and validate a method for automated segmentation of the carotid artery lumen from volumetric MR Angiographic (MRA) images using a deformable tubular 3D Non-Uniform Rational B-Splines (NURBS) model. A flexible 3D tubular NURBS model was designed to delineate the carotid arterial lumen. User interaction was allowed to guide the model by placement of forbidden areas. Contrast-enhanced MRA (CE-MRA) from 21 patients with carotid atherosclerotic disease were included in this study. The validation was performed against expert drawn contours on multi-planar reformatted image slices perpendicular to the artery. Excellent linear correlations were found on cross-sectional area measurement (r = 0.98, P < 0.05) and on luminal diameter (r = 0.98, P < 0.05). Strong match in terms of the Dice similarity indices were achieved: 0.95 ± 0.02 (common carotid artery), 0.90 ± 0.07 (internal carotid artery), 0.87 ± 0.07 (external carotid artery), 0.88 ± 0.09 (carotid bifurcation) and 0.75 ± 0.20 (stenosed segments). Slight overestimation of stenosis grading by the automated method was observed. The mean differences was 7.20% (SD = 21.00%) and 5.2% (SD = 21.96%) when validated against two observers. Reproducibility in stenosis grade calculation by the automated method was high; the mean difference between two repeated analyses was 1.9 ± 7.3%. In conclusion, the automated method shows high potential for clinical application in the analysis of CE-MRA of carotid arteries.

Download full-text


Available from: Johan H C Reiber
  • Source
    • "These can be roughly divided into parametric model fitting and cross-section based methods. Methods based on parametric models try to fit a tube-like model into the lumen, exploiting the fact that vessels are elongated and roughly tubular [9] [8] [5]. These methods work very well on regular and uniform vessels, but a cylindrical model is not well suited to capture subtle variations in lumen calibre , as the ones consequence of mild stenotic symptoms. "
    [Show abstract] [Hide abstract]
    ABSTRACT: This papers describes GroBa, a new lumen calibre measurement technique based on growing balloons. GroBa presents the advantages of cross-sectional based methods, as it is able to cope with irregular, non-tubular vessel structures, such as stenosis or aneurysms, but at the same time it is able to obtain precise calibre measurements even when the estimated centrelines are not accurate. Experimental results using phantoms and real subtracted full-body magnetic resonance angiograms show the potential of this work. GroBa is integrated into a fully automatic system that segments the vasculature, obtains its centrelines, measures the lumen calibre at each detected artery, and presents the calibre information in false colours in the maximum intensity projection exploiting the HSV colour-space; all without any human intervention.
    Full-text · Article · Jan 2012 · Proceedings of the IEEE Symposium on Computer-Based Medical Systems
  • [Show abstract] [Hide abstract]
    ABSTRACT: In current clinical practice, examinations of the carotid artery bifurcation are commonly carried out with Computed Tomography Angiography (CTA) or contrast-enhanced Magnetic Resonance Angiography (ceMRA). Quantitative information about vessel morphology, extracted from segmentations, is promising for diagnosis of vessel pathologies. However, both above-mentioned techniques require the administration of contrast media. In contrary, non-ceMRA methods such as Time-of-Flight (TOF) provide fully non-invasive imaging without any exogenous contrast agent. The diagnostic value of TOF MRA, however, for assessment of the carotid bifurcation area can be hampered due to its susceptibility to irregular blood flow patterns. Conventional methods for lumen segmentation are very sensitive to such signal voids and produce inaccurate results. In this work, a novel, fully automatic 3D segmentation algorithm is proposed which uses prior knowledge about irregular flow patterns. The presented technique has been successfully tested on eleven volunteer datasets as well as in a patient case, offering the comparison to CTA images. The sensitivity could be increased by 29.2% to 85.6% compared to standard level set methods. The root mean squared error in diameter measurements was reduced from 4.85 mm to 1.44 mm.
    No preview · Article · Oct 2012
  • [Show abstract] [Hide abstract]
    ABSTRACT: Purpose: Currently, a multi-contrast protocol, including a combination of five MR-sequences is used as reference standard for morphologic imaging and quantitative measurements of the carotid artery vessel wall. The purpose of this study is to investigate the scan-rescan reproducibility together with intra- and inter-observer reproducibility of each of the five MR-sequences. Methods: Twenty healthy volunteers (55% male, mean age=26 years) underwent repeated MR-examinations (3T-Philips-MRI) of the left carotid artery vessel wall with five sequences; T1-TFE, T2-TSE, PD-TSE, T1-TSE and 3D TOF. A standard phased-array coil with two flexible elements of 14cm×17cm was used to obtain nine transverse imaging sections of the left carotid artery with identical in-plane resolution (0.46mm×0.46mm). Reproducibility analysis was performed in 3 slices of the common carotid artery for all sequences. Results: For, scan-rescan reproducibility, intra class correlation coefficients (ICC) were excellent for all sequences and ranged from 0.79 to 0.95. The intra-observer ICC ranged from 0.89 to 0.98 and the inter-observer ICC ranged from 0.84 to 0.96, for both lumen and vessel wall assessment. Conclusions: By high field MR imaging, vessel wall and lumen area of the carotid artery can be assessed with excellent scan-rescan, intra- and inter-observer reproducibility for all five sequences.
    No preview · Article · Dec 2012 · European journal of radiology
Show more