intracranial carotid curvature and brain aneurysms
DESCRIPTION
We studied the relationship between vessel curvature on sidewall aneurysm formation on the internal carotid artery (ICA) in the brain.TRANSCRIPT
CURVATURE EFFECT ON HEMODYNAMIC CONDITIONS AT THE INNER BEND OF THE CAROTID SIPHON AND ITS RELATION TO ANEURYSM FORMATION
Alexandra Lauric PhD, James Hippelheuser BS, Mina G. Safain MD, and Adel M. Malek MD PhD
Cerebrovascular and Endovascular Division
Department of Neurosurgery
Tufts Medical Center and Tufts University School of Medicine
Boston, MA 02111
Motivation:Carotid Siphon Aneurysms
Intracranial Aneurysms
• Aneurysm formation on the inner aspect of vascular bends has not been thoroughly addressed.
• We evaluated • The effect of vessel curvature on sidewall aneurysm formation
on the internal carotid artery (ICA) • The hemodynamics on aneurysm formation along the inner
carotid siphon.
Method for Curvature Analysis
• Catheter 3D-rotational angiographic volumes of 130 patients• 72 aneurysms – 10 in the inner curve of the carotid siphon• 58 controls
• The centerline of the ICA was determined and curvature along ICA was automatically computed.
• The radius of curvature and the peak curvature of the siphon bend were evaluated in 3D.
ICA Focal Curvature
ICA Focal Curvature• Intracranial ICA was measured 50 mm
caudal from the ICA bifurcation. • Distal ICA was measured from the
carotid siphon to the ICA bifurcation. • The peak curvature of the intracranial
ICA (red arrow) doesn’t always coincide with the peak curvature of the distal ICA (black arrow).
ICA Curvature Statistics
Group Feature Aneurysm Non-aneurysm p
Aneurysm (n=74) Cintra_mean 0.15±0.016 0.14±0.015 <.001
vs. Cintra_max 0.40±0.053 0.37±0.057 .002
Healthy (n=58) Cdistal_mean 0.18±0.031 0.16±0.027 <.001
Cdistal_max 0.34±0.068 0.28±0.052 <.001
• Aneurysmal ICAs have significantly higher global and focal curvature on the whole intracranial ICA, but also on the distal (dural) portion of the ICA.
ICA Curvature Statistics
• ICA curvature of aneurysmal and non-aneurysmal samples (age between 53 and 68 years old). The black arrows point to the position of the peak curvature of the distal ICA.
A. Male ICA harboring an aneurysm on the ophthalmic segment
B. Control male
C. Female ICA harboring a carotid superior hypophyseal aneurysm
D. Control female
• Local curvature features were evaluated in 10 patients with aneurysms on the inner wall of the carotid siphon. Peak focal curvature of the siphon The radius of curvature of the siphon
Inner Carotid Siphon Aneurysms
Carotid Siphon Analysis• Peak focal siphon curvature was significantly higher in
aneurysm bearing ICAs compared to controls • 0.36 ± 0.045 vs. 0.30 ± 0.048 mm-1, p=0.003
• No difference in global radius of curvature• 3.71 ± 0.64 vs. 3.93 ± 0.70 mm, p=0.36
Conclusions
• Aneurysm formation is associated with tight curvature globally, but also locally, on the hosting segments.
• In the carotid siphon, high peak focal curvature is correlated with aneurysm presence.
References
1. An Y, Shao C, Wang X, Li Z. Geometric properties estimation from discrete curves using discrete derivatives. Computers & Graphics. 2011;35(4):916-930.
2. Foutrakis GN, Yonas H, Sclabassi RJ. Saccular Aneurysm Formation in Curved and Bifurcating Arteries. American Journal of Neuroradiology. July 1, 1999 1999;20(7):1309-1317.
3. Piccinelli M, Bacigaluppi S, Boccardi E, et al. Geometry of the Internal Carotid Artery and Recurrent Patterns in Location, Orientation, and Rupture Status of Lateral Aneurysms: An Image-Based Computational Study. Neurosurgery. 2011;68(5):1270-1285
4. Lauric A, Safain MG, Hippelheuser J, Malek AM. High curvature of the internal carotid artery is associated with the presence of intracranial aneurysms. J Neurointerv Surg. 2013; Dec 11. doi: 10.1136/neurintsurg-2013-010987. [Epub ahead of print]
5. Kadasi, L.M., Dent, W.C., Malek, A.M., 2013. Colocalization of thin-walled dome regions with low hemodynamic wall shear stress in unruptured cerebral aneurysms. J Neurosurg. 2013 Jul;119(1):172-9