1. Yon Kwon Ihn 1, Byung-Hee Lee 2, Sang Heum Kim 3 1 Department of Radiology, St.Vincent’s Hospital, The Catholic University of Korea 2 Department of Radiology, Chungmu Hospital, Chonan, Korea 3 Department of Radiology, Bundang CHA Hospital, CHA University College of medicine, Seongnam, Korea EP - 98

2.  We don’t have any significant financial interest or other relationship with manufacturer of any commercial products or services discussed in the exhibit.

3.  Isolated dissecting aneurysm of the posterior inferior cerebellar artery (PICA)  Rare but has a high risk of re-bleeding  Recently, endovascular treatment has been proposed as an alternative to surgery, but still they present a therapeutic challenge  To report results of various endovascular treatments in patients with isolated dissecting aneurysms of the PICA

4.  March 2005 and May 2012  11 patients (M:F=5:6)  Mean age: 44.4 years (range: 15-58 years)  Clinical presentations  Acute subarachnoid hemorrhage (n= 7, 64%) ▪ 6 Spontaneous, 1 Traumatic  Ischemia (n=2, 18%)  Severe headache (n=1, 9%)  Ruptured anterior choroidal aneurysm (n=1, 9%)

5.  Location  Anterior medullary segment (n=7, 64%))  Lateral medullary segment (n=2, 18%)  Tonsillomedullary segment (n=2,18%)  Shape  Saccular (n=8, 72%)  Fusiform (n=2, 18%)  Pearl and string (n=1, 10%)  Size  Mean 4.4mm (range: 2.5-8mm)

6.  Angiographic evaluation  Balloon occlusion test (n=5) ▪ Neurologic symptom / EEG abnormality ▪ Aneurysm sac or distal PICA filling from collateral vessels  Presence of collaterals of the PICA (n=6) ▪ PICA-PICA ▪ Ipsilateral SCA/AICA – PICA ▪ Ipsilateral VA – PICA ▪ Contralateral VA –PICA

7.  Endovascular treatment  Coiling of aneurysmal sac with/without assisted balloon (n=4)  Coiling of aneurysmal sac with assisted stent ( n=2)  Graft stent insertion (n=3) ▪ High risk of re-rupture during super-selection of aneurysm sac ▪ Acute angle ▪ Severe stenosis just proximal to aneurysmal sac ▪ Little difference of proximal and distal diameter of VA  Occlusion of vertebral artery by using coils (n=2)

8.  Medication  Preprocedural & during procedure ▪ Heparinized flushing system without systemic heparinization  Post-procedure ▪ Low molecular weight heparin for 3 days in all patients ▪ Clopidogrel loading (300mg) just after procedure and daily clopidogrel 75mg, aspirin 100mg for 3 months ▪ Graft stent cases (n=3)

9.  Angiographic follow up  Around 10 days after procedure  2-4 months & 12 months after procedure  Annual angiographic FU

10.  Technical success rate - 100%  Total occlusion (n=10)  Near-total occlusion (n=1)  PICA flow  well preserved (n=9)  sluggish PICA flow (n=2)  MR or DWI follow up  No infarction (n=4)  PICA territory embolic infarct (n=1)

11. C as e N o P at ie nt S e x/ a g e (y r) SideSide Site Signs & Sy mpto ms CT -M RI fin din gs Endo vasc ular Proc edur e Treat ment r elated compl icatio n Foll ow up An gio gra phy (m ont hs) 1 M /3 5 R TM Vertig o, nau sea Ce re bel lar inf arc tio n VA s acrifi ce None5 2 F/ 5 7 RAM Neck pain, LOC Head ache SA H Graft stent Inser tion None4 3 M /1 5 LAM LOC, Head ache SA H, IV H Graft stent Inser tion None45 4 F/ 5 0 LAM Neck pain, Head ache Inc ide nta l an eu rys m BAC Coil p rotrusi on Thro mbus fomtat ion 34 5 M /3 4 LLM Sever e hea dache Transi ent L OC SA H BAC Coil p rotrusi on Thro mbus fomtat ion 3 6 F/ 5 8 LAM Sever e occi pital head ache SA H Graft stent Inser tion None32 7 F/ 5 6 LAM Head ache, Heavi ness of occipit al regi on Inc ide nta l an eu rys m BACNone12 8 M /3 9 RLM Ataxia, dizzi ness, Walle nberg’ s syndr ome Lat er al m ed ull ary inf arc tio n BACNone15 9 F/ 4 5 RAM Occipi tal he adach e, transi ent L OC SA H VA s acrifi ce None12 1010 M /5 0 LTM Sever e hea dache Transi ent L OC SA H SACNone28 11 F/ 4 9 LAM LOC, Head ache SA H SACNone3 Note.- M indicates male; F, female; R, right; L, left; AM, anteromedullary segment; LM, lateral medullary segment, TM, tonsilomedullary segment; VA, vertebral artery; LOC, loss of consciousness; SAH, subarachnoid hemorrhage; IVH, intraventricular hemorrhage; BAC, balloon assisted coil embolization; SAC, stent assisted coil embolization

12.  Periprocedural complication  Acute thrombosis (n=2) ▪ Complete resolution with IA infusion of Reopro ® ▪ No neurologic complication  Subacute embolic infarction (n=1) resulting in minor stroke ▪ Delayed anticoagulation medication ▪ Full recovery (mRS 0) at 4 months

13.  Angiographic follow up (n=11)  mean: 18.0 months (range: 4-45Mo)  No recanalization or regrowth of aneurysm  Well preserved PICA flow by collaterals in all patients  Clinical follow up (n=11)  mean: 40.3 months (range: 6-60 Mo)  No newly developed neurologic event or re-bleeding  mRS 0 in all patients

14. 39/M, severeheadache Occlusion test 15 Mo10 days

15. 15/M Drowsy mentality after trauma SAH, HH3 7 daysOcclusion test 6 days 45 Mo initial

16. Occlusion test 4 Mo, mRS 0 Delayed anticoagulation 45/F Severe headache with N/V SAH, HH2

17.  Various endovascular approach tailored to the specific aneurysm in the specific patient seems even more appropriate than for aneurysms at other location aneurysm under careful angiographic evaluation.  Further studies are necessary to make a strategy for endovascular treatment of the PICA dissecting aneurysms.