Carotid Plaque Assessment Using 18Fluorine (18F) -Sodium Fluoride Positron Emission Tomography (PET) /MR (CARTIS)

Carotid Plaque Assessment Using 18Fluorine (18F) -Sodium Fluoride Positron Emission Tomography (PET) /MR

Assessment of Symptomatic and Asymptomatic Carotid Plaques Using Hybrid Imaging 18F-sodium Fluoride PET/MR

Carotid plaque can lead to ischemic stroke. Treatment of asymptomatic carotid plaque, based on degree stenosis, is still controversial. Beyond the degree of stenosis, the composition of the plaque could reflect the vulnerability and the risk of ipsilateral ischemic stroke. Identification of new predictive factor of ipsilateral ischemic stroke in patients with carotid plaque could help to screen high risk patients and to guide the treatment. The aim of the study is to assess 18F-sodium fluoride uptake among carotid plaque in recently symptomatic and asymptomatic patients. Investigators conduct a pilot case-control study. Twelve patients (6 recently symptomatic and 6 asymptomatic) with carotid stenosis (≥50% NASCET) will have a 18F-sodium fluoride PET/MR. Standardized uptake value (SUV) and tissue-to-background ratio (TBR) will be measured among carotid plaques.

18F-sodium fluoride PET/MR combining 3Tesla (3T) MR and PET producing 127 slices of 2 mm on an axial field of view of 26 cm. 18F-sodium fluoride (2 à 4 megabecquerel/kilogram (MBq/kg)) will be injected 60 min before.

Number of participants with image of lipid-rich necrotic core accounting for more than 50% of the surface of the plate on a 2D section.

identification of images of intraplaque hemorrhage (defined as an hyperintense region within the plaque on a T1-weighted sequence), lipid-rich necrotic core (accounting for more than 50% of the surface of the plate on a 2D section), or thinning/rupture of the fibrous cap (identified on a T1-weighted sequence following intravenous gadolinium administration) in High Resolution MRI by two radiologists.

Number of participants with image of intraplaque hemorrhage defined as an hyperintense region within the plaque on T1-weighted sequence.

identification of images of intraplaque hemorrhage (defined as an hyperintense region within the plaque on a T1-weighted sequence), lipid-rich necrotic core (accounting for more than 50% of the surface of the plate on a 2D section), or thinning/rupture of the fibrous cap (identified on a T1-weighted sequence following intravenous gadolinium administration) in High Resolution MRI by two radiologists.

Number of participants with image of thinning/rupture of the fibrous cap on a T1-weighted sequence following intravenous gadolinium administration.

identification of images of intraplaque hemorrhage (defined as an hyperintense region within the plaque on a T1-weighted sequence), lipid-rich necrotic core (accounting for more than 50% of the surface of the plate on a 2D section), or thinning/rupture of the fibrous cap (identified on a T1-weighted sequence following intravenous gadolinium administration) in High Resolution MRI by two radiologists.

Number of participants with image of lipid-rich necrotic core accounting for more than 50% of the surface of the plate on a 2D section.

identification of images of intraplaque hemorrhage (defined as an hyperintense region within the plaque on a T1-weighted sequence), lipid-rich necrotic core (accounting for more than 50% of the surface of the plate on a 2D section), or thinning/rupture of the fibrous cap (identified on a T1-weighted sequence following intravenous gadolinium administration) in High Resolution MRI by two radiologists.

Number of participants with image of thinning/rupture of the fibrous cap on a T1-weighted sequence following intravenous gadolinium administration.

identification of images of intraplaque hemorrhage (defined as an hyperintense region within the plaque on a T1-weighted sequence), lipid-rich necrotic core (accounting for more than 50% of the surface of the plate on a 2D section), or thinning/rupture of the fibrous cap (identified on a T1-weighted sequence following intravenous gadolinium administration) in High Resolution MRI by two radiologists.

Number of participants with image of intraplaque hemorrhage defined as an hyperintense region within the plaque on T1-weighted sequence.

Quantitative assessement of the wall shear stresses (WSS, measured in Pa) and oscillatory shear indexes (OSI, unitless) along the carotid wall in 3D. An accurate analysis of the hemodynamic environment will be performed using fluid dynamics mathematical models that allow the calculation of hemodynamic stress at the plate (or "wall shear stress" measured in Pascal) and temporal oscillation of the direction of this force (arbitrary units).

Quantitative assessement of the wall shear stresses (WSS, measured in Pa) along the carotid wall in 3D.

Quantitative assessement of the wall shear stresses (WSS, measured in Pa) along the carotid wall in 3D. An accurate analysis of the hemodynamic environment will be performed using fluid dynamics mathematical models that allow the calculation of hemodynamic stress at the plate (or "wall shear stress" measured in Pascal) and temporal oscillation of the direction of this force (arbitrary units).

Quantitative assessement of oscillatory shear indexes (OSI, unitless) along the carotid wall in 3D. An accurate analysis of the hemodynamic environment will be performed using fluid dynamics mathematical models that allow the calculation of hemodynamic stress at the plate (or "wall shear stress" measured in Pascal) and temporal oscillation of the direction of this force (arbitrary units).

Number of participants with histological image of intraplaque hemorrhage, and/or lipid-rich necrotic core and /or thinning/rupture of the fibrous cap in surgical patients.

Measure of systemic markers of inflammation: Interleukine 1-Beta (IL1-beta), Tumor Necrosis Factor-alpha (TNF-alpha)

Inclusion Criteria symptomatic patients: age>18 Carotid plaque ≥ 50% symptomatic (ischemic stroke on CT or MR) during the last 15 days or asymptomatic ability to give informed consent affiliation to social security Exclusion Criteria: Modified Rankin score ˃ 3 Contraindication to MRI Renal failure (creatinine clearance by cockcroft ˂ 50 ml / min) Pregnancy / Breastfeeding Hypersensitivity to the active substance or excipients