SARS-CoV-2 coronavirus outbreak and end of funding

Identification of intraplaque haemorrhage using MRI is technically demanding and sometimes uncomfortable. Photoacoustic imaging is a new non-invasive technique combining multi-wavelength infrared laser light and ultrasound imaging, able to discriminate blood and other components in the tissues. The measurement by the multi-spectral photoacoustic imaging is likely to be more acceptable and therefore could replace MRI.

A total of 60 patients with stenosis grade of > 70% and considered for endarterectomy will be recruited for additional imaging. Pre-operative PA/US and 3D MR imaging will be conducted. Two patient groups are designed to allow performance assessment with respect to anatomy, i.e., penetration depth; One with favourable anatomy (i.e. superficial carotids, proximal plaques and low bifurcation), the other with no anatomical considerations. For in-vivo verification of the morphology and mechanical properties obtained with PA/US imaging, the pre-operative data will be compared to the MR data (imaging-imaging verification). Since the patient is operated on, endarterectomy specimens are available for histo-pathological examination and in-vitro testing for verification purposes: the excised tissue will be (snap freeze with liquid Nitrogen) transported to TUE in Eindhoven for in-vitro validation (imaging-histology verification). Paris patients will undergo surgery and tissues will be transferred to Eindhoven for in vitro mechanical testing. Because of the transfer (-80 °C), the rate of success for in vitro testing is expected to be smaller, around 40% (i.e. 12 subjects). Nevertheless, the power of the global analysis will be increased.

Inclusion Criteria:

• Presence of at least one carotid plaque with a degree of stenosis 70% (NASCET), indication to surgery (endarterectomy),
• Patients with favourable anatomy criteria :

x Cranio-caudal length of normal or long neck x Cervical adiposity weak or absent x Carotid bifurcation in usual situation (at the level of the mandibular angle or lower) x Normal genicity of subcutaneous tissues x Calcification of arterial moderate or absent

• Patients affiliated to the social health security system.

Exclusion Criteria:

• Refusal to participate,
• any concomitant chronic condition hampering the realization of ultrasound scanner or MRI (allergy to gel, intolerance or contraindication to gadolinium).
• Unstable patients with plaque claudication inducing procedure acceleration.
• Patients with unfavourable anatomy criteria :

x Cranio-caudal length of the neck very short x Significant cervical adiposity x Carotid bifurcation higher than the mandibular angle x High echogenic subcutaneous tissue x Calcification marked arterialH2020-ICT-29-2016 no. 731771 Ethics requirements x Patients with fat necks, Presence of extensive calcifications at the site of the stenosis.

• Patients unable to consent.
• Pregnant woman or breastfeeding woman

The project involves patients with atherosclerotic plaques (either symptomatic or not).