Arjen Lindenholz

159 MRI Vessel Wall Imaging after Intra-Arterial Treatment for Acute Ischemic Stroke 7 Introduction Intra-arterial treatment (IAT) has proved beneficial in selected patients with an anterior circulation acute ischemic stroke. 1 With IAT, revascularization of the occluded artery by means of mechanical thrombectomy can be achieved in most patients, restoring blood flow to the brain tissue. Although the overall effects of IAT on clinical outcome are well-known, 1,2 not much is known about the effects of thrombectomy on the local intracranial vessel wall. Recently, there has been concern that IAT might damage the arterial vessel wall. 3-6 Thrombectomy can be performed with different devices: Stent-retrievers or thrombosuction devices have been used most often. 2 Damage to the intracranial vessel wall may be caused by (repeated) mechanical sheer stress of the stent- retriever on the vessel wall, 4 or the negative pressure (up to -50 cm/Hg) when using a thrombosuction device. 5,7 This damage may consist of dissections, vessel wall edema, and rupture or damage to the endothelium, potentially leading to recurrent thrombosis and distal embolism. 3-6 Histopathological preclinical studies have shown endothelial damage to the vessel wall after thrombectomy, more evident with stent-retriever devices than with thrombosuction devices. 3-5,8-10 In recent MR imaging studies and other imaging studies performed after IAT, damage of a major vessel wall such as dissection or stenosis was only rarely reported. 5,8-12 However, the arterial vessel wall more often showed contrast enhancement or wall thickening than arteries of patients who did not undergo IAT. 11-13 In these series, patients were treated mostly with stent-retrievers and scanning was performed with 3T MR imaging scanners in the acute setting (first day to first week) after IAT. The longer-term effects after IAT performed by thrombosuction have not been reported yet. Intracranial vessel wall MRI is expected to be increasingly performed in the diagnostic work-up and follow-up of patients with stroke. The aim of this study was to assess the frequency of longer-term vessel wall changes - by assessing the presence and severity of intracranial vessel wall enhancement - in patients with stroke after IAT with thrombosuction and compare them with patients with stroke without IAT. Potential differences may support the diagnostic interpretation of intracranial vessel wall changes after acute stroke treatment.