Publications de Pierre Bouillot

Neurovascular stent artifacts in 3D-TOF and 3D-PCMRI: Influence of stent design on flow measurement

Mohamed Farhat, Pierre Bouillot, Hasan Yilmaz

Purpose: The morphological and hemodynamic evaluations of neurovascular diseases treated with stents would benefit from noninvasive imaging techniques such as 3D time-of-flight MRI (3D-TOF) and 3D phase contrast MRI (3D-PCMRI). For this purpose, a comprehe ...

WILEY2019

How Flow Reduction Influences the Intracranial Aneurysm Occlusion: A Prospective 4D Phase-Contrast MRI Study

Mohamed Farhat, Philippe Reymond, Pierre Bouillot

BACKGROUND AND PURPOSE: Flow-diverter stents are widely used for the treatment of wide-neck intracranial aneurysms. Various parameters may influence intracranial aneurysm thrombosis, including the flow reduction induced by flow-diverter stent implantation, ...

American Society of Neuroradiology (ASNR)2019

Hemodynamics of Focal Versus Global Growth of Small Cerebral Aneurysms

Pierre Bouillot, Hasan Yilmaz

Background and PurposeHemodynamics play adriving role in the life cycle of brain aneurysms from initiation through growth until eventual rupture. The specific factors behind aneurysm growth, especially in small aneurysms, are not well elucidated. The goal ...

2019

3D phase contrast MRI: Partial volume correction for robust blood flow quantification in small intracranial vessels

Mohamed Farhat, Pierre Bouillot

Purpose: Recent advances in 3D-PCMRI (phase contrast MRI) sequences allow for measuring the complex hemodynamics in cerebral arteries. However, the small size of these vessels vs spatial resolution can lead to non-negligible partial volume artifacts, which ...

Wiley2018

Bound States and Field-Polarized Haldane Modes in a Quantum Spin Ladder

Bruce Normand, Pierre Bouillot, Daniel Biner, Christian Rüegg

The challenge of one-dimensional systems is to understand their physics beyond the level of known elementary excitations. By high-resolution neutron spectroscopy in a quantum spin-ladder material, we probe the leading multiparticle excitation by characteri ...

Amer Physical Soc2017

Virtual-versus-Real Implantation of Flow Diverters: Clinical Potential and Influence of Vascular Geometry

Mohamed Farhat, Pierre Bouillot, Hasan Yilmaz

BACKGROUND AND PURPOSE: Intracranial stents have become extremely important in the endovascular management of complex intracranial aneurysms. Sizing and landing zone predictions are still very challenging steps in the procedure. Virtual stent deployment ma ...

American Society of Neuroradiology (ASNR)2016

Computational fluid dynamics with stents: quantitative comparison with particle image velocimetry for three commercial off the shelf intracranial stents

Mohamed Farhat, Pierre Bouillot, Hasan Yilmaz

Background and purpose Validation of computational fluid dynamics (CFD) in stented intracranial aneurysms (IAs) is still lacking, to reliably predict prone to occlusion hemodynamics, probing, in particular, velocity reduction, and flow pattern changes. Thi ...

Bmj Publishing Group2016

Geometrical deployment for braided stent

Mohamed Farhat, Pierre Bouillot, Hasan Yilmaz

The prediction of flow diverter stent (FDS) implantation for the treatment of intracranial aneurysms (IAs) is being increasingly required for hemodynamic simulations and procedural planning. In this paper, a deployment model was developed based on geometri ...

Elsevier2016

Hemodynamic transition driven by stent porosity in sidewall aneurysms

Mohamed Farhat, Pierre Bouillot

The healing process of intracranial aneurysms (IAs) treated with flow diverter stents (FDSs) depends on the IA flow modifications and on the epithelization process over the neck. In sidewall IA models with straight parent artery, two main hemodynamic regim ...

Elsevier2015

Intra-aneurysmal hemodynamics: evaluation of pCONus and pCANvas bifurcation aneurysm devices using DSA optical flow imaging

Pierre Bouillot

Background Implantation of self-expanding stents from the parent artery into the sac of a bifurcation aneurysm is regularly used to facilitate endovascular coil occlusion with the so-called waffle cone technique (WCT). Self-expanding aneurysm bridging sten ...

BMJ2015

Magnetic entropy landscape and Gruneisen parameter of a quantum spin ladder

Pierre Bouillot, Daniel Biner

We present measurements of the magnetic entropy landscape and Gruneisen parameter of the Cu2+ complex (C5H12N)(2)CuCl4 in a magnetic field. Our thermodynamic measurements are in very good agreement with a theoretical description by a S = 1/2 Heisenberg lad ...

American Physical Society2014

Particle Imaging Velocimetry Evaluation of Intracranial Stents in Sidewall Aneurysm: Hemodynamic Transition Related to the Stent Design

Mohamed Farhat, Pierre Bouillot

We investigated the flow modifications induced by a large panel of commercial-off-the-shelf (COTS) intracranial stents in an idealized sidewall intracranial aneurysm (IA). Flow velocities in IA silicone model were assessed with and without stent implantati ...

Public Library of Science2014

Symmetric and asymmetric excitations of a strong-leg quantum spin ladder

Pierre Bouillot

The zero-field excitation spectrum of the strong-leg spin ladder (C7H10N)(2)CuBr4 is studied with a neutron time-of-flight technique. The spectrum is decomposed into its symmetric and asymmetric parts with respect to the rung momentum and compared with the ...

American Physical Society2013

Spectrum of a Magnetized Strong-Leg Quantum Spin Ladder

Pierre Bouillot

Inelastic neutron scattering is used to measure the spin excitation spectrum of the Heisenberg S = 1/2 ladder material (C7H10N)(2)CuBr4 in its entirety, both in the gapped spin liquid and the magnetic field-induced Tomonaga-Luttinger spin liquid regimes. A ...

American Physical Society2013

Field-controlled magnetic order in the quantum spin-ladder system (Hpip)2CuBr4

Thierry Giamarchi, Bruce Normand, Henrik Moodysson Rønnow, Pierre Bouillot, Joël Mesot, Daniel Biner, Christian Rüegg

Neutron diffraction is used to investigate the field-induced, antiferromagnetically ordered state in the two-leg spin-ladder material (Hpip)(2)CuBr4. This "classical" phase, a consequence of weak interladder coupling, is nevertheless highly unconventional: ...

2009

Thermodynamics of the Spin Luttinger Liquid in a Model Ladder Material

Bruce Normand, Pierre Bouillot, Daniel Biner

The phase diagram in temperature and magnetic field of the metal-organic, two-leg, spin-ladder compound (C5H12N)(2)CuBr4 is studied by measurements of the specific heat and the magnetocaloric effect. We demonstrate the presence of an extended spin Luttinge ...

2008