Intracranial aneurysmal pulsatility as a new individual criterion for rupture risk evaluation: biomechanical and numeric approach (IRRAs Project).
OBJECTIVE
The present study follows an experimental work based on the characterization of the biomechanical behavior of the aneurysmal wall and a numerical study where a significant difference in term of volume variation between ruptured and unruptured aneurysm was observed in a specific case. Our study was designed to highlight by means of numeric simulations the correlation between aneurysm sac pulsatility and the risk of rupture through the mechanical properties of the wall.


METHODS
In accordance with previous work suggesting a correlation between the risk of rupture and the material properties of cerebral aneurysms, 12 fluid-structure interaction computations were performed on 12 "patient-specific" cases, corresponding to typical shapes and locations of cerebral aneurysms. The variations of the aneurysmal volume during the cardiac cycle (ΔV) are compared by using wall material characteristics of either degraded or nondegraded tissues.


RESULTS
Aneurysms were located on 6 different arteries: middle cerebral artery (4), anterior cerebral artery (3), internal carotid artery (1), vertebral artery (1), ophthalmic artery (1), and basilar artery (1). Aneurysms presented different shapes (uniform or multilobulated) and diastolic volumes (from 18 to 392 mm3). The pulsatility (ΔV/V) was significantly larger for a soft aneurysmal material (average of 26%) than for a stiff material (average of 4%). The difference between ΔV, for each condition, was statistically significant: P=.005.


CONCLUSIONS
The difference in aneurysmal pulsatility as highlighted in this work might be a relevant patient-specific predictor of aneurysm risk of rupture.
From Philips Healthcare, Suresnes, France (M.S.) CNRS-LMGC Montpellier, Montpellier, France (M.S., F.J., D.A.) mathieu.sanchez@univ-montp.fr.
M
M
Sanchez
CHU Montpellier Neuroradiology, Montpellier, France (O.E., P.M., A.B., V.C.).
O
O
Ecker
CNRS-LMGC Montpellier, Montpellier, France (M.S., F.J., D.A.).
D
D
Ambard
CNRS-LMGC Montpellier, Montpellier, France (M.S., F.J., D.A.).
F
F
Jourdan
CNRS-I3M Montpellier, Montpellier, France (F.N., S.M.).
F
F
Nicoud
CNRS-I3M Montpellier, Montpellier, France (F.N., S.M.).
S
S
Mendez
CHU Lille Neurosurgery, Lille, France (J.-P.L., L.T.).
J-P
JP
Lejeune
CHU Lille Neurosurgery, Lille, France (J.-P.L., L.T.).
L
L
Thines
CHU Marseille Neurosurgery, Marseille, France (H.D.).
H
H
Dufour
CHU Marseille Neuroradiology, Marseille, France (H.B.).
H
H
Brunel
CHU Montpellier Neuroradiology, Montpellier, France (O.E., P.M., A.B., V.C.).
P
P
Machi
Imperial College Healthcare NHS Trust, London, England (K.L.).
K
K
Lobotesis
CHU Montpellier Neuroradiology, Montpellier, France (O.E., P.M., A.B., V.C.).
A
A
Bonafe
CHU Montpellier Neuroradiology, Montpellier, France (O.E., P.M., A.B., V.C.).
V
V
Costalat
D017542:Aneurysm, Ruptured / Q000503:physiopathology; D001696:Biomechanical Phenomena / Q000502:physiology*; D006801:Humans; D002532:Intracranial Aneurysm / Q000503:physiopathology*; D008962:Models, Theoretical; D018570:Risk Assessment; D012307:Risk Factors