Arjen Lindenholz

166 CHAPTER 7 Fourteen patients underwent IAT using thrombosuction; two of them had an occlusion in the distal intracranial ICA and 12 patients in the MCA ( Table 2 ). Twelve patients received intravenous alteplase prior to intra-arterial mechanical thrombectomy; the other 2 patients exceeded the 4.5-hour time window for alteplase treatment. In two patients a stent-retriever (Solitaire, Covidien, Irvine, California; or Trevo, Stryker, Kalamazoo, Michigan) was used in addition to the thrombosuction device (patients 4 and 14, Table 2 ). IAT was technically successful in 13 of 14 patients. No procedure-related hemorrhagic complications occurred during the procedures in any of the patients. In 9 patients one pass was sufficient; in the remaining 5 patients more passes were needed (range 2-5) to remove the culprit thrombus. In the non-IAT group, 5 of 35 patients had an ICA infarction (right-sided, n = 3) and 30 patients an MCA infarction (right-sided, n = 16) ( Supplemental table 1 ). Twelve patients received intravenous alteplase as standard ischemic stroke treatment. In the remaining 23 patients, the 4.5-hour time window was exceeded or only minor symptoms were still present on admission. Vessel wall assessment Major vessel wall changes in the IAT-group Besides a post-procedural moderate stenosis in the treated artery of one patient, no other major vessel wall changes were detected. This stenosis in the proximal left M2-segment was detected by MR vessel wall imaging and TOF-MRA ( > 6 week after IAT) at the same location as the removed thrombus and was not visible yet on the post-procedural angiogram performed within the same session as the thrombectomy. It is not clear whether this was caused by an atherosclerotic plaque or restenosis or was treatment-induced. In patients with a middle cerebral artery occlusion no T 1 -hyperintensity before contrast was found, nor did we find an MRI vessel wall indication suggesting an intramural hemorrhage. Vessel wall enhancement The interrater agreement for the number and location of the enhancing foci was an ICC of 0.91 (95% CI; 0.84-0.95) and a DSC of 0.87. Examples of foci of vessel wall enhancement at the thrombectomy site are shown in Figure 2 , Figure 3 and Figure 4 . An example of vessel wall enhancement of the non-IAT group is shown in Figure 5 . In the IAT-group 11 of 14 patients (79%) showed vessel wall enhancement compared with 17 of 35 patients (49%) in the non-IAT group. As an average of both readers, in total, 21.5 foci of vessel wall enhancement were detected in the 84 vessel segments (26%) of the IAT patients compared with 30 foci of vessel wall enhancement in the 210 vessel segments (14%) in the patients