FRench Acute Cerebral Multimodal Imaging to Select Patient for MEchanical Thrombectomy

Emergent cerebral artery recanalization by thrombectomy within 6 hours after symptom onset is n the standard of care of an acute hemispheric infarction with a documented proximal internal carotid artery and/middle cerebral artery occlusion. The success of vessel revascularization is mostly related to the emergent reperfusion of the ischemic penumbra. Multimodal brain imaging can identify the amount of salvageable penumbra. The indirect comparison of the recently published randomized trials suggests that despite common baseline clinical characteristics, (vessel site occlusion, delay and type of treatment), the success of thrombectomy was higher in studies enrolling exclusively patients exhibiting a significant amount of penumbra defined by a target mismatch (TMM) on CTP or MRI by comparison with those enrolling patients based on non contrast CT scan without specific imaging criteria. As the prevalence of TMM has not been systematically evaluated in those trials, as TMM definition differs according to the studies and as there has been no prospective estimation of the impact of the prevalence of TMM on baseline imaging assessed blindly of clinical outcome, there is currently no demonstration that mechanical thrombectomy has to be limited to the subgroup of patients based on imaging criteria. With this as a background, we aim to investigate in a prospective cohort of patients treated by thrombectomy according to the current recommendations, the relationship between the prevalence of TMM on pretreatment brain imaging with the rate of clinical recovery after thrombectomy. MR DWI, perfusion and CTP maps processed by RAPID software will not be as usual pushed back to the PACS but anonymized and saved on a remote software leaving the investigator blinded at the time of treatment decision. We hope to learn whether MR or CTP can help to define an imaging profile to select the subgroup of patients that will benefit from thrombectomy.