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Characterizing the intravascular clot in acute stroke with multi-parametric imaging

English title Characterizing the intravascular clot in acute stroke with multi-parametric imaging
Applicant Lövblad Karl-Olof
Number 182382
Funding scheme Project funding (Div. I-III)
Research institution Département de l'Imagerie et Sciences de l'Information Médicale Hôpitaux Universitaires de Genève
Institution of higher education University of Geneva - GE
Main discipline Neurology, Psychiatry
Start/End 01.07.2019 - 30.06.2022
Approved amount 525'000.00
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Keywords (3)

stroke; thrombectomy; computed tomography

Lay Summary (French)

Amélioration de l'imagerie du thrombus avant thérapie
Lay summary
L'accident vasculaire cérébral est devenu une pathologie traitable en phase aigue. Ceci a été mis en évidence par les résultats de la thrombolyse intraveineuse dans les années 1990. Toutefois le traitement restait limité en raison de la fenêtre thérapeutique restreinte et de la tendance aux hémorragies. De plus en plus d'évidence a pu démontrer que les thérapies interventionnelles extractives permettaient d'enlever le caillot avec une plus grande sécurité Toutefois les résultats semblent parfois dépendre de la consistance du caillot (rouge vs blanc) et du matériel employé. effectivement actuellement deux techniques sont principalement utilisées: l'aspiration et l'extraction assistée par stent. Nous proposons d'étudier la consistance du caillot (caillot blanc vs caillot rouge) par scanner à double énergie (dual-energy CT) afin de regarder si il est possible de déterminer sur la base de la composition CT quel type d' outil utiliser (aspiration vs stent).
Direct link to Lay Summary Last update: 28.09.2018

Responsible applicant and co-applicants


Associated projects

Number Title Start Funding scheme
121565 Multimodality MR imaging in tissue characterization after stroke 01.10.2008 Project funding (Div. I-III)
66348 Mapping the cerebral ischemic tissue at risk with diffusion and perfusion MR imaging 01.10.2002 Project funding (Div. I-III)


Acute ischemic stroke is a disabling disease that affects a large population. Ischemic cerebral stroke has become an increasingly treatable entity due to the recent developments in intravascular clot extraction. The various treatment modalities available today besides pharmacological (i.e. thrombolysis) options are mechanical approaches with thrombus extraction using either stents or aspiration techniques. Until recently, the standard of care for stroke patients, presenting at the clinic within 4.5 hours of symptom onset, was pharmacological treatment using intra venous thrombolysis to dissolve the occluding clot. For non-responders, or patients with contraindications to thrombolysis, attempts would instead be made to mechanically remove the clot via intra-arterial thrombectomy techniques such as stent retrievers and/or aspiration. Recent multi center studies, such as ESCAPE and DAWN have, however, demonstrated the benefit of brain parenchymal imaging to guide therapeutic decisions, and the advantage of the immediate and extended use of thrombectomy devices. This has led to a paradigm shift within stroke research, changing the focus of the field towards the study of image parameters which may be used to guide therapeutic decisions, and towards evaluating and improving the efficacy of existing thrombectomy devices. While many questions have been resolved in the areas of clot extraction and in brain parenchymal imaging, little has been done to better characterize the cause of the stroke itself: the clot. There seem to be two main types of clot: stiff white clots which may need extraction by aspiration, and red soft clots which may need extraction with stent retrievers. As the arsenal of thrombectomy devices is diversifying, it is highly probable that clot composition will play an increasingly important role in the choice of treatment modality. The potential knowledge about clot composition could help to improve pre-therapeutical characterization of the clot to choose appropriate tools depending on whether the clot contains more fibrin, red blood cells (RBCs), white blood cells (WBCs) or other debris. If the most appropriate clot extraction tool is chosen the treatment time will be reduced: this has potential to significantly improve clinical outcome. Despite advantages in favor of the use of MRI for the detection of early ischemia, most studies and clinical centers have relied on CT due to its ease of access, ease of interpretation for hemorrhage, and for its rapidity. In plain CT, the clot can often be seen already as the characteristic hyperdense artery sign (HAS), and visualized even clearer via the angiographic stop on post-contrast images. However, while the HAS is a known predictor of stroke, there is a general disagreement as to whether the presence and/or density of a HAS should be used to guide treatment and predict clinical outcome.