Ultrasound for Acute Field Triage of Stroke

Acute ischemic stroke (AIS) is responsible for considerable morbidity and mortality worldwide and has serious medico-economic and psychosocial consequences. Before the advent of mechanical thrombectomy (TM), care and telestroke networks had focused their efforts on the rapid administration of a thrombolytic agent, tissue plasminogen activator (tPA), intravenously ( IV), to all eligible patients with ischemic stroke. These care networks have been shown to improve both patient prognosis by improving early vascular recanalization, the overall quality of neurovascular care within the network, and costs at network hospitals.

In 2015, the effectiveness of another treatment, TM, for some acute ischemic stroke patients with large vessel occlusion (LVO) created new challenges for the effective triage of suspected patients stroke, especially in the prehospital setting.Indeed, non-OLV patients should receive intravenous thrombolysis without delay and thus should be transported to the nearest facility with neurological capacity. thrombolysis.In contrast, the efficacy of thrombolysis remains limited for patients with LVO stroke who likely benefit from direct transport from the field to a comprehensive stroke center capable of performing TM. In these patients, stopping at a local center to initiate thrombolysis can delay revascularization and worsen the prognosis.These sorting strategy paradigms, called "mothership" and "drip and ship"

Investigators hypothesize that the use of a compact DTC system may optimize prehospital triage of participants with suspected stroke by EMS emergency medical services with rapid applicability and limited training required. The objectives of this study will be to:

1. assess the role of cerebral pulsatility index as a marker of proximal vessel occlusion, and its added value to PSV, EDV, RI and MV,
2. optimize the engineering and ergonomics parameters of the DTC mechanical support system,
3. test its speed of application on healthy subjects, then on participants who have suffered a confirmed stroke, and
4. to use this data to derive a fully operational DTC system and a dedicated interface for a larger scale real test in a pre-hospital setting.

Eligibility Criteria:
Inclusion Criteria:

Healthy subjects (recruitment via the CIC-IC):

* Adults (Age \>18),
* free from any known cerebral pathology,
* having given their informed, dated and signed free consent
* and affiliated with a French social security scheme (CMU accepted)

Stroke topics:

* Adult patients (age \>18 years),
* admission for suspected stroke with a severity scale assessed by an NIH Stroke Scale \> 10 with or without signs of cortical damage.
* Onset of symptoms \< 24 hours.
* Proximal arterial occlusion confirmed by angio-MRI or angio-scan,
* free informed consent, dated and signed,
* affiliated to a French social security scheme (CMU accepted).

Exclusion Criteria:

(healthy subjects and patients)

* Realization of the transcranial Doppler likely to delay the treatment of the patient
* Patient eligible for thrombectomy. vs
* Major agitation (+3 on the Richmond Agitation Sedation Scale) (done only when the patient is agitated).
* Inability of the patient to consent due to the severity of the clinical symptoms, and the absence of an available relative.
* History of severe head trauma, or significant deformation of the skull.
* Recent craniofacial trauma with recent scalp or facial wounds.