Scan–Rescan reproducibility of carotid bifurcation geometry from routine contrast-enhanced MR angiography

Authors

  • Payam B. Bijari MSc,

    1. Biomedical Simulation Laboratory and Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, ON, Canada
    Search for more papers by this author
  • Luca Antiga PhD,

    1. Biomedical Engineering Department, Mario Negri Institute for Pharmacological Research, Ranica (BG), Italy
    Search for more papers by this author
  • Bruce A. Wasserman MD,

    1. Russell H. Morgan Department of Radiology and Radiological Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
    Search for more papers by this author
  • David A. Steinman PhD

    Corresponding author
    1. Biomedical Simulation Laboratory and Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, ON, Canada
    • University of Toronto, 5 King's College Road, Toronto, ON, Canada, M5S 3G8
    Search for more papers by this author

Abstract

Purpose

To demonstrate the feasibility of rapid and reliable geometric characterization of normal carotid bifurcation geometry from routine 3D contrast-enhanced magnetic resonance (MR) angiograms.

Materials and Methods

Repeat scans of 61 participants, acquired as part of the Atherosclerosis Risk in Communities (ARIC) Carotid MRI substudy, were digitally segmented using automated 3D level set methods, relying on an operator only to select the branch endpoints and thresholds for the 3D lumen surface initialization. Geometric factors characterizing the 3D lumen geometry were then extracted automatically.

Results

Of 122 scans, 117 could be segmented within 5 minutes each, with 40% being of sufficiently high quality to require less than 2 minutes each. Irrespective of scan quality, geometric factors were found to be highly reproducible, with intraclass correlation coefficients (ICCs) typically above 0.9. The reconstructed lumen surfaces were reproducible to <0.3 mm on average, comparable to previous MRI-based reproducibility studies. Owing to the automated nature of the analysis, operator reliability was near-perfect (ICC >0.99), with lumen surface differences <0.1 mm.

Conclusion

The 3D geometry of the carotid bifurcation can be characterized rapidly and with a high degree of consistency, even for suboptimal image qualities. This bodes well for large-scale retrospective or prospective studies aimed at teasing out the influence of local vs. systemic risk factors for early atherosclerosis. J. Magn. Reson. Imaging 2011;33:482–489. © 2011 Wiley-Liss, Inc.

Ancillary