Objective: Optimizing the contrast medium injection protocol used during cerebral blood volume (CBV) imaging by C-arm flat panel detector computed tomography (CT) is important in order to achieve good image quality and minimizing contrast medium dosage. The purpose of this study was to assess the feasibility of C-arm CBV obtained through aortic arch injection of 50% diluted contrast medium using a 4F diagnostic catheter positioned directly above the aortic valve.
Materials and Methods: There were 100 enrolled patients with 117 examinations in this study. The total amount of contrast medium used and the frequency of technical errors were measured. CBV values were evaluated in 23 cases with normal circulation.
Results: No complications occurred during the examination. C-arm CT measurement of CBV using the aortic arch injection method was technically successful and provided useful CBV information. However, technical errors occurred in six cases, resulting in significantly degraded CBV images. The mean amount of the contrast medium used was 46.0±4.0 ml. In normal circulation cases, there were significant differences between the left and right hemispheres in the anterior and middle cerebral artery territory, but no significant differences in the posterior cerebral artery territories and basal ganglia.
Conclusion: Preliminary results indicate that C-arm CBV maps are feasible using aortic-arch injection of 50% diluted contrast medium, with the advantage of lowering the contrast dosage requirement below that for injection of undiluted contrast medium. C-arm CBV imaging after injection with 50% diluted contrast medium may provide clinically useful information for patient management.

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Objective: We investigate the options and outcomes of reperfusion therapy for acute ischemic stroke patients by comparing pre- and post-mechanical thrombectomy (MT) periods in a single stroke center.
Methods: We defined the 10-month period before approval of mechanical thrombectomy in Japan as the pre-MT period, and the next 19 months after approval as the post-MT period. Between these two periods, we compared the number of acute ischemic stroke patients and the outcomes of these patients based on the reperfusion therapy utilized, which includes intravenous rt-PA (IV-tPA), local intra-arterial fibrinolysis (LIF), MT, and conservative therapy.
Results: Of the total patients with cerebral infarction in each period, 44.3% of patients with acute cerebral infarction were admitted to our hospital within 6 hours of onset (pre-MT period) and 52.2% were admitted post-MT. 12.4% (pre-MT) and 25.2% (post-MT) of patients with acute cerebral infarction received IV-tPA therapy. LIF was performed in 5.2% (pre-MT), and MT was performed in 11.6% (post-MT) of acute infarction. Among the patients treated by IV-tPA only, 50.0% achieved a modified Rankin Scale score of ≤2 at 30 days during the pre-MT period, and 48.0% achieved this score in the post-MT period. Among the patients who underwent MT, 37.9% achieved a modified Rankin Scale score of ≤2 at 90 days during the post-MT period.
Conclusion: After the approval of MT devices, the percentage of early-admission patients increased during the post-MT period in our hospital. The percentage of patients treated with IV-tPA among patients with acute infarction also increased during the post-MT period. MT was performed for 11.6% of patients, and brought a good outcome of mRS ≤2 at 90 days in 4.4% of the total number of acute ischemic stroke patients.

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Objective: Ruptured cerebral aneurysm is very rare in an infant. We present a case of ruptured posterior cerebral artery aneurysm in a 38-day-old boy.
Case presentation: The infant was brought to the emergency room suffering from lethargy, high grade fever, and subsequent dehydration due to poor oral intake. A head CT before performing lumbar puncture to rule out meningitis showed subarachnoid, intraventricular, and intracerebral hemorrhage, and a round mass in the interpeduncular and crural cisterns. Though MRI and MRA performed after transfer to our hospital could not confirm the mass as an aneurysm, a transfontannelar Doppler study did confirm it by detecting the blood flow within. An aneurysm of the right posterior cerebral artery (PCA) was visualized on conventional angiography thereafter. The aneurysm and parent vessel of the PCA were successfully occluded using a simple coil embolization technique. Postoperatively the infant recovered almost completely, even though diffusion abnormalities were visible in the right occipital lobe on postoperative MRI. The patient was discharged 30 days after the procedure.
Conclusion: Ruptured infantile cerebral aneurysms are rare, and diagnosis is occasionally difficult. In similar rare cases, the success of management depends on maintaining the vigilance of the emergency management team to such a possibility, and the availability of appropriate facilities and skilled neurovascular surgeons.

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Objective: We report a case of giant aneurysm of the petrous internal carotid artery in a young adult man with cutaneous findings of phakomatosis pigmentovascularis (PPV), treated with endovascular trapping of the internal carotid artery.
Case presentation: A 24-year-old male with PPV presented with headache and left abducens nerve palsy. The skin anomaly was on the left side of his body since birth. A brain magnetic resonance imaging (MRI) revealed a giant thrombosed aneurysm located at the petrous and extending to the cavernous portion of the left internal carotid artery (ICA). After thorough evaluation of hemodynamic tolerance, endovascular left ICA trapping was performed with detachable coils. The postoperative course was uneventful and the symptoms were resolved in 3 months from embolization. At one year after the treatment, MRI showed an obvious decrease in the size of the aneurysm.
Conclusions: PPV is a rare syndrome characterized by the association of a widespread vascular nevus with an extensive pigmentary nevus. Though the correlation of PPV with cerebral aneurysm is still unclear, PPV can accompany abnormalities in cerebral vessels similar to those seen in Klippel-Trenaunay syndrome and Sturge-Weber syndrome. Furthermore, the abrupt ICA occlusion may change the hemodynamics in the circle of Willis and these abnormal conditions may predispose patients to the formation of de novo aneurysms at these sites. Close and continuous follow up is particularly important.

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Objective: We describe the cases of two patients with ruptured aneurysms of the distal anterior choroidal artery (AChA) that were embolized using n-butyl cyanoacrylate (NBCA).
Case presentation: Patient 1. A 43-year-old female presented with intracerebral hemorrhage due to a ruptured distal AChA aneurysm located on collaterals running from the lateral posterior choroidal artery (LPChA) to the AChA. The internal carotid artery between the origin of the posterior communicating artery and the AChA was severely stenosed. A microcatheter was navigated into the LPChA via the posterior communicating artery and then 55% NBCA was injected during balloon occlusion at the origin of the LPChA. This strategy obliterated the aneurysm without complications.
Patient 2. A 6-year-old female presented with intracerebral hemorrhage due to a ruptured distal AChA aneurysm located on the plexal segment of the AChA, which was a feeding artery of an arteriovenous malformation. A microcatheter was navigated into the AChA beyond the junction of the LPChA. An injection of 25% NBCA obliterated the aneurysm and the arteriovenous malformation. Magnetic resonance imaging revealed asymptomatic infarction at the posterior thalamus.
Conclusion: Embolization of AChA beyond the plexal point is considered safe. However, NBCA migrating into the cisternal segment of the AChA and the occlusion of the perforating arteries supplying the thalamus from the plexal segment of the AChA confer a potential risk of infarction.

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Objective: We report a case of a wide-necked anterior communicating artery (Acom) aneurysm with a daughter sac (a bleb) arising from the neck, treated by the coil assist technique using double catheters.
Case presentation: A 75-year-old man developed disturbed consciousness while carrying a bottle of kerosene and chemical burns due to kerosene on the right side of his body, and he was taken by ambulance to our hospital. Head CT on admission revealed a subarachnoid hemorrhage with intracerebral hematoma (ICH) in the bilateral frontal lobes and the corpus callosum (World Federation of Neurological Societies grade III , Fischer group 4). Digital subtraction angiography revealed a wide-necked Acom aneurysm measuring 4.6 mm in the longer diameter with a 2.5 mm-sized daughter sac arising from the neck. The aneurysm sac as well as the daughter sac were embolized individually by the coil assist technique using double catheters. The postoperative course was uneventful, and a favorable clinical outcome was achieved.
Conclusion: Although coiling for the daughter sac of a ruptured aneurysm is not a recommended procedure, this technique appears to be effective for selected cases and can expand the indication of endovascular coiling for aneurysms with unfavorable morphology, such as a wide-necked aneurysm with a daughter sac originating from the neck.

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Objective: We report here successful stent-assisted coil embolization of a ruptured posterior inferior cerebellar artery (PICA) -involved type dissecting aneurysm of the vertebral artery (VA) associated with the hypoplasty of the contralateral VA using the Enterprise Vascular Reconstruction Device (Enterprise VRD).
Case presentation: A 77-year-old man presented with sudden decreased level of consciousness. Computed tomography of the head revealed a subarachnoid hemorrhage and cerebral angiography showed a dissecting aneurysm of the left VA involving the left posterior inferior cerebellar artery (PICA). The contralateral VA and bilateral posterior communicating arteries were poorly developed. We performed left occipital artery-PICA bypass surgery followed by stent-assisted coil embolization using the Enterprise VRD to preserve the parent artery.
Conclusion: Stent-assisted coil embolization with the Enterprise VRD may be an effective treatment for PICA-involved type dissecting VA aneurysms associated with the hypoplastic contralateral VA.

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Objective: We report a case of subclavian arterial stenosis manifesting as transient amaurosis for which a favorable outcome was achieved by stenting.
Case presentation: The patient was a 71-year-old female with transient amaurosis. Stenosis of the left subclavian artery was noted on three-dimensional computed tomographic angiography (3D-CTA). The left ophthalmic artery was also occluded, in addition to the left subclavian arterial stenosis, on digital subtraction angiography (DSA). Stenting was applied to the left subclavian artery, and successful dilation was obtained. In addition, the transient amaurosis was resolved after normal blood flow had resumed.
Conclusion: Subclavian arterial stenosis manifesting as transient amaurosis is rare, and angiography is useful to confirm the pathology. Stent placement in the stenosed segment of the subclavian artery is minimally invasive and can be safely performed.

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Objective: We report a useful technique for transarterial embolization with liquid material using a 4.2Fr Fubuki catheter as an intermediate catheter.
Materials and Methods: Five consecutive cases of dural arteriovenous fistula (dAVF) of the transverse/sigmoid sinus with cortical venous reflux were treated by transarterial embolization (TAE) using a 4.2Fr Fubuki catheter as an intermediate catheter inserted into the middle meningeal artery (MMA). With this support, the microcatheter could be advanced to the shunt point and the shunt was occluded successfully with N-butyl cyanoacrylate (NBCA). All cases were managed using the same strategy. In all cases, NBCA was injected into the venous portion of the shunt and complete obliteration of the shunt was achieved in one session. We report in detail the illustrative case of a 71-year-old man who presented with visual symptoms and speech disturbance and was found to have a Borden type III dural arteriovenous fistula in the left transverse sinus.
Conclusion: With its highly flexible distal tip and hydrophilic coating, the 4.2Fr Fubuki catheter was found to be useful in performing TAE of dAVFs via the MMA.

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Objective: Peri-procedural hemodynamic depression with carotid artery stenting (CAS) may cause adverse cardiac events in patients with concomitant severe heart disease. Intra-aortic balloon counterpulsation (IABP) increases diastolic pressure, coronary arterial flow and decreases systolic pressure, resulting in the reduction of the left ventricular afterload. We report our experiences in performing CAS with IABP in two patients with concomitant carotid artery severe stenosis and severe heart disease to prevent adverse cardiac events due to hemodynamic depression during and after CAS.
Case report: (Case 1) An 82-year old woman, who had symptomatic right carotid artery severe stenosis and severe aortic valve stenosis (AS), suffering from congestive heart failure and transient ischemic attack. Because hypotension and bradycardia with CAS might be fetal for severe AS, CAS combined with IABP was performed. We successfully placed stents without cardiac or cerebrovascular events occurring. Four weeks after CAS, the patient underwent aortic valve replacement with a blood pump and oxygenator. The postoperative course was uneventful and the patient was discharged. (Case 2) A 71-year old man, having symptoms of angina pectoris, was diagnosed with three-vessel coronary artery disease (CAD) with asymptomatic left carotid artery severe stenosis. CAS with IABP was performed before the coronary artery bypass grafting (CABG), which might need extracorporeal circulation. There were no cardiac or cerebrovascular procedural events observed. Six weeks after CAS, the patient underwent CABG successfully and was discharged.
Conclusion: We conclude that CAS with IABP is an effective method for the treatment of carotid artery stenosis with concomitant severe heart disease, such as severe AS or three-vessel CAD.

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Objective: We present a case in which the Angio-Seal arterial closure device (St. Jude Medical, Minnetonka, MN) and "route regaining technique" were used for emergency hemostasis after accidental intra-arterial collagen sponge deposition.
Case presentation: We treated a 66-year-old woman with a right basilar-anterior inferior cerebellar artery (BA-AICA) aneurysm through the left common femoral artery. After successful embolization, an Angio-Seal arterial closure device was inserted for hemostasis at the puncture site. However, hemostasis was incomplete and it was speculated that the collagen sponge was deployed intraarterially. We introduced another Angio-Seal device through the original puncture hole by using suture thread as a guide to locate intra-arterial objects.
Conclusion: This emergency hemostatic technique was useful for the management of unexpected bleeding stemming from intra-arterial collagen deployment. Physicians and staff should remain alert to the possibility of device-associated ischemic complications.

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