Objective: The risk of rebleeding and the rate of retreatment are reportedly higher in ruptured cerebral aneurysms treated with endovascular coiling than in those treated with surgical clipping. In this study, we evaluated the frequency and risk factors of recanalization on angiograms after embolization of ruptured and unruptured cerebral aneurysms.
Methods: From April 2001 to December 2003, we performed endovascular embolization on 30 ruptured and 52 unruptured aneurysms. We included 18 ruptured and 40 unruptured aneurysms, which subsequently ruptured, underwent retreatment within 5 years, or were followed up for more than 5 years. We evaluated risk factors of recanalization in terms of location, size, ratio of dome to neck, volume embolization ratio (VER), and remnant flow into aneurysms immediately after embolization.
Results: Nine (50.0%) ruptured and 11 (27.5%) unruptured aneurysms were recanalized on angiograms. We attempted retreatment for 5 recurrent aneurysms, and were unsuccessful inserting any coils in 3 aneurysms. Recanalization on subsequent angiograms was rare in cases, that were not recanalized on angiograms at 6 months (ruptured aneurysms : 0% (0/6 cases), versus unruptured aneurysms : 6.7% (2/30 cases). VER was the significant risk factor in recanalization of unruptured aneurysms. There were significant differences between VER and recanalization in unruptured aneuryms (p=0.027), but no significant risk factor related to recanalization in ruptured aneurysms.
Conclusions: Recanalization of unruptured aneurysms was more frequent in cases of low VER than in cases of high VER. It is difficult to predict recurrence and rebleeding of ruptured aneurysms treated with high VER. Long-term results of both ruptured and unruptured aneurysms are considered favorable, if there is no recanalization on angiograms at 6 months.

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Objective: We investigate the efficacy of endovascular surgery (EVS) for the residual aneurysms following surgical clipping.
Materials and Methods: Between April 1999 and May 2009, we performed endovascular treatment in 17 consecutive patients with residual aneurysms following surgical clipping. They comprised 6 men and 11 women with a mean age of 59 years. Of the 17 aneurysms, 10 were ruptured, the other 7 were unruptured, and were located at IC-PC (5), VA-PICA (4), AcomA (4), BA-tip (2), MCA (1), and BA-SCA (1). The direction of the dislocated clip was divided into 3 types: type A (n=2) the clip dislocated along with the aneurysmal neck, type B (n=6) the clip dislocated to the fundus, and type C (n=9) the clip completely dislocated from the aneurysm.
Results: The interval between clipping and EVS ranged from 6 days to 17 years (mean 4.7 years). Of 17 aneurysms, 14 were small (< 10 mm)and 3 were large (10 - 25 mm). As for type of clip dislocations; 2 were type A (11.8%), 6 were type B (35.3%), and 9 were type C (52.9%). EVS was successful in 16 of 17 cases (94.1%). Of 16 aneurysms in which EVS was successful, 12 were completely occluded and 4 were neck remnant. There were no procedural complications. Coil compaction was observed in one patient during the follow-up period.
Conclusion: EVS is a safe and effective method for residual aneurysms following surgical clipping. 3D rotational angiography is useful to clarify aneurysmal morphology and facilitates successful occlusion of the residual aneurysm.

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Objective: We report the case of a ruptured aneurysm of the distal anterior inferior cerebellar artery (AICA) treated by endosaccular embolization.
Case presentation: An 86-year-old woman presented with subarachnoid hemorrhage (SAH). Computed tomography showed Fisher group 3 SAH. Although the origin of the hemorrhage seemed to be in the posterior circulation based on the CT findings, initial digital-subtraction angiography failed to show an aneurysm in the posterior circulation. Two weeks after the onset of SAH, 3D-CT angiography revealed an aneurysm distal to the meatal loop of the left AICA, to which endosaccular embolization using detachable coils was performed. The postoperative course was uneventful.
Conclusion: To our knowledge, this is the first case report of an AICA aneurysm distal to the meatal loop that was successfully treated by endosaccular embolization.

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Objective: A case of ruptured internal carotid artery aneurysm in which local thrombosis occurred in the low flow velocity area following partial coil embolization is presented.
Case presentation: A 91-year-old woman suffered from subarachnoid hemorrhage due to rupture of a large saccular aneurysm of the right internal carotid artery. Patient was initially treated conservatively. Rebleeding occurred within a month, which lead to coil embolization of the aneurysm. Although the aneurysm was occluded incompletely because of a large sac and a wide neck, a two-week follow-up angiography disclosed progressive local thrombosis within the aneurysm. Thrombosed area corresponded to the low flow velocity area on computerized flow dynamic analysis.
Conclusion: It is suggested that local thrombosis may occur in the area of low flow velocity after partial coil embolization of the aneurysm.

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Objective: To report a case of symptomatic internal carotid artery stenosis with a persistent proatlantal artery (PPA), which was treated by carotid artery stenting (CAS) with a filter device by means of proximal occlusion of the common carotid artery (CCA) and the external carotid artery (ECA).
Case presentation: A 77-year-old man suffering from loss of consciousness was referred to our hospital. Diffusion-weighted image showed a left cerebral infarction and MR angiography revealed a PPA. PPA type 1 was confirmed by 3D-CT angiography and digital subtraction angiography revealed the carotid stenosis, located just proximal to the origin of the PPA in the left internal carotid artery (ICA). Since the stenosis was more than 50% and the patient was elderly, CAS was scheduled. To protect both the ICA and the PPA, a guiding catheter with balloon was employed to occlude the CCA and the ECA simultaneously and to induce blood flow from the PPA to the ICA. Under such conditions, a filter device was positioned in the ICA and CAS was done in an orderly manner without any complications.
Conclusion: To our knowledge, this is the first reported case of PPA treated by CAS with a filter device by proximal occlusion both of CCA and ECA which induced blood flow from ICA to PPA.

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Objective: The authors present a patient with acute ischemic stroke due to severe stenosis of the left internal carotid artery who was successfully treated with carotid artery stenting (CAS) in the acute stage.
Case: A 76-year-old man presented with aphasia and right hemiparesis. Intravenous administration of rt-PA was not indicated because the patient was outside the time-window. As perfusion CT revealed a large ischemic penumbra in the territory of the left middle cerebral artery, we attempted neuroendovascular therapy to rescue the penumbra from infarction. The regional saturation of oxygen (rSO₂) was monitored by near-infrared spectroscopy (NIRS) during the procedure. Before the procedure, rSO₂ in the left frontal area was decreased by 10% compared with that on the right side. The self-expanding stent was deployed after predilation. Just after deployment, rSO₂ on the left side increased by 10% and we intentionally did not perform postdilation to avoid hyperperfusion. The procedure was finished within 6 hours and 30 minutes after ischemic onset. The postoperative course was good and there were no hemorrhagic complications.
Conclusion: NIRS monitoring allows observation of real time changes in cerebral perfusion during the dilatative procedure, which provides useful information for intraoperative decision-making on whether stenting should be added after angioplasty and then, whether postdilation should be performed during carotid artery stenting in the acute stage.

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Objective: We report recanalization of acute embolic occlusion of internal carotid artery with loop-extraction technique using two microcatheters.
Clinical presentation: A 66-year-old female developed dysarthria and left hemiparesis due to occlusion of the right internal carotid artery at the cavernous portion. Catheter intervention started 70 hours after the onset because of deterioration of the symptom despite anticoagulation therapy. The occluded internal carotid artery was successfully recanalized by the loop-extraction technique after failure of thrombo-aspiration and thrombectomy with a microsnare. The loop-extraction technique was an endovascular thrombectomy using a loop formed by two microcatheters. The loop was made by catching one catheter with a microsnare guided through the other catheter.
Conclusion: The loop-extraction technique is useful for retrieving clots, especially for organized thrombus due to cardiogenic embolism in internal carotid artery. Further experiemce is needed in order to establish the safety and efficacy of this technique.

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