1. New embolic cerebral lesions detected with diffusion-weighted imaging after carotid artery and intracranial stent placement YH Chen, CJ Chen, DC Chen, HY Hsu, YC Tseng Taipei Medical University, Shuang Ho Hospital, New Taipei City, ROC Graph.1 Pie chart of new cerebral emboli post-operation separated into negative and positive with/without contralateral lesion. Total 37 persons in each group A (Carotid) and group B (Intracranial). * The numbers in the () indicate actual number of cases. Purpose Transluminal angioplasty with stent is a method to resolve arterial stenosis. Current studies have proved carotid stenting to be safe. As for intracranial stent, there should be potential patients in whom angioplasty or stent placement might be the best approach. We had a retrospective study reviewing total 74 cases. All of these cases had routine brain MRI before and after the procedure. We intend to assess the postoperative infarcted area using diffusion weighted images, and compare the results of carotid stenting and intracranial stenting, and aim to find a better policy for intracranial stenting in the near future. Materials and Methods Study population During August 2012 to December 2014, there were total 37 patients treated with carotid stents and another 37 patients receiving intracranial or unprotected stents. Intervention All the procedures were performed by two experienced neuroradiologists. In carotid stent, a 7-8mm Precise stent (Cordis/Johnson & Johnson Co, Warren, NJ) was employed to cover the stenotic site. An Enterprise stent (4.5mmx22mm, Cordis/Johnson & Johnson Co, Warren, NJ) was used for intracranial stent. Study design In our institution, standard brain MRI including diffusion weighted images (DWI) is performed one day before the stenting; also one and three days postoperatively. There were patients received carotid (Group A) or intracranial stents (Group B). Two radiologists retrospectively review these cases on DWI, and compare the number of newly developed embolic cerebral infarcts; the number of new infarcts with size greater than 5mm; and the total area of newly developed infarcts between two groups with 2-sample t-test. Discussion In previous prospective studies, new ischemic foci were observed in 17.3% of the patients undergoing neuroprotected carotid artery stenting (CAS). (Ref.1) This result does not have big difference compared to our experience in carotid group in these 37 cases (21.6%). To our knowledge, no retrospective study had searched the new ischemic foci post intracranial stent. There is significant difference regarding the number of newly developed embolic cerebral lesions between two groups. Difference regarding the carotid and intracranial stenting is that there are cerebral protection devices used in the carotid stent. Previous study have shown the use of cerebral protection devices significantly reduces the number of new cerebral lesions detected with diffusion-weighted MRI in protected carotid angioplasty and stenting (Ref. 2). The effectiveness of cerebral protection devices appears to reduce thromboembolic complications during CAS (Ref. 3). However, other study found that using transcranial Doppler US, more microemboli are demonstrated during filter-protected CAS than during unprotected CAS (Ref.4). Conclusion Postoperative infarction is more likely to occur after intracranial stent than carotid stent. We presumed that protection device plays a big role during carotid stent. This should promote research for advance devices. Results There were at least one new lesion on the one-day brain MRI in 8 out of 37 cases in carotid group, and 21 out of 37 cases in the intracranial group (Figure.1) (Graph.1). Significant difference regarding the number of newly developed embolic cerebral lesions, number of thrombus diameter measured greater than 5mm, and total thrombus area (Table.1). Most of the DWI lesions measured no more than 3mm in diameter. One patient in the intracranial group had the largest ischemic lesion, measured 22mm at left corona radiata; clumsiness while doing fine movement is noted by neurologist when follow-up. Although lesions are ipsilateral to the procedure side in most of the cases, two cases in the carotid group and four cases in the intracranial group had contralateral lesions. (Graph. 1) (Figure.2). Figure. 2 A.VR image of right ICA revealed a stenosis in right middle cerebral artery. B/C. DWI before (B) and after procedure (C), revealed multiple new ischemic lesions in the ipsilateral and contralateral side Table. 1 Patient Characteristics and Results Group A: Carotid. Group B :Intracranial. * L: left side, R: right side, B: bilateral, P: posterior circulation. Some of the patients had multiple stenotic lesions treated. Reference 1. Piñero P, González A, Mayol A, et al. Silent Ischemia after Neuroprotected Percutaneous Carotid Stenting: A Diffusion-Weighted MRI Study. AJNR June 2006 27: 1338-1345 2. Kastrup A, Nägele T, Gröschel K, et al. Incidence of new brain lesions after carotid stenting with and without cerebral protection. Stroke. 2006 Sep;37(9):2312-6. Epub 2006 Aug 3. 3. Andreas K, Klaus G, Hilmar K, et al. Early Outcome of Carotid Angioplasty and Stenting With and Without Cerebral Protection Devices - A Systematic Review of the Literature. Stroke 2003; 34: 813-819 4. Vos JA, van den Berg JC, Ernst SM, et al. Carotid Angioplasty and Stent Placement: Comparison of Transcranial Doppler US Data and Clinical Outcome with and without Filtering Cerebral Protection Devices in 509 Patients. Radiology 2005 Feb;234(2):493-9. Epub 2004 Dec 22 Figure. 1 A. Angiography and VR image of right common carotid artery revealed a stenosis in the proximal internal carotid artery. B/C. DWI before (B) and after procedure (C), revealed a new ischemic lesion in the ipsilateral superficial territory of right MCA.