Objective: There are many cases in which computed tomography (CT) after acute thrombectomy demonstrates high-density areas, but it may be difficult to judge whether this is hemorrhage or contrast extravasation. Dual energy CT (DECT) is an imaging method that enables discrimination of substances by acquiring X-ray image data of two different energies.

Methods: We performed DECT to distinguish hemorrhage from contrast extravasation in cases with high-density areas on CT after acute thrombectomy at our hospital, and we compared with T2*-weighted image on the following day.

Results: Six patients comprising 22 areas had high-density areas on CT after acute thrombectomy. In all, 20 of the 22 high-density areas were determined to be contrast extravasation by DECT, and no cases of subsequent symptomatic cerebral hemorrhage were observed. However, 11 areas with new microbleeds were confirmed in the 20 extravasation areas on MRI-T2* images the day after thrombectomy.

Conclusion: This examination suggested that the contrast extravasation and its concentration are involved in the presence of low-intensity areas on T2*.

Objective: Stent-assisted aneurysmal embolization (SAAE) is an effective treatment for aneurysms with a low risk of recurrence. In rare cases, retreatment is necessary due to recanalization of blood flow into the aneurysm. However, only a few studies have reported on retreatment. We examined the efficacy and complications of stent-assisted aneurysm embolization for large or wide-neck aneurysms at our hospital.

Methods: Between July 2010 and June 2018, 293 patients underwent stent-assisted aneurysm embolization at our hospital. Among them, 12 (2 women, 10 men, mean age: 62 years) needed retreatment. We evaluated the initial treatment of these 12 patients, and the methods and results of their retreatment.

Results: Six of the 12 retreated patients were treated using the simple technique. It was possible to treat nine patients (75%) without placing new stents, but three needed additional stents. We were able to guide the microcatheter into the aneurysm using the trans-cell technique even with two overlapping stents. We achieved complete embolism in seven patients (58%), and remnants were observed in the neck in five (42%) patients. No complications were associated with our surgery. We were able to perform follow-up for 10 patients and there was no recurrence.

Conclusion: Embolization should be considered in recurrent cases after the initial stent-assisted coil embolization. We achieved good results and reduced the recurrence rate by selecting the appropriate treatment in each case.

Objective: Subclavian artery aneurysms are relatively rare, and have been treated by open surgery and/or endovascular treatment using a stent graft. In this article, we report a case of unruptured right subclavian artery aneurysm successfully treated using balloon-assisted coil embolization.

Case Presentation: A 77-year-old man was diagnosed with an asymptomatic unruptured right subclavian artery aneurysm of 8 mm in diameter by follow-up CTA after surgery for thoracoabdominal aortic aneurysms. He also had a history of cerebral infarction and clipping of an unruptured cerebral aneurysm. The subclavian artery aneurysm was treated by balloon-assisted coil embolization because its diameter increased to 17.6 mm in 2 years. Balloon assistance was mainly used to prevent protrusion of the framing coil into the parent artery, and satisfactory framing was achieved. Subsequently, the aneurysm was obliterated using filling and finishing coils. The postoperative course was uneventful, and the follow-up MRI at 18 months after treatment revealed no recanalization of the aneurysm.

Conclusion: Balloon-assisted coil embolization may be an effective treatment for subclavian artery aneurysms, but further long-term follow-up and case accumulation are needed.

Objective: Based on the findings of preferable outcomes from recanalization therapy in recent studies, regional partnerships for the endovascular treatment of acute ischemic stroke are being promoted. However, reports of inter-island cooperation between remote islands located far from high-volume centers on the mainland are rare.

Case Presentation: A 63-year-old man experienced an acute ischemic stroke on a small, isolated island in Okinawa, Japan. He was transferred by helicopter to the primary emergency hospital on Ishigaki Island, which was the nearest island on which he could be administered recombinant tissue plasminogen activator (rtPA). After this, he was carried again by helicopter and ambulance to the primary stroke center on Miyako Island using the drip and ship method. Mechanical thrombectomy with a stent retriever achieved recanalization of the occluded major vessels and improved the neurological disturbance. The patient became neurologically independent and could be discharged only 11 days after onset.

Conclusion: Building a local area network that includes hospitals providing mechanical thrombectomy is a meaningful approach to treating acute ischemic stroke occurring on isolated islands. It is necessary to recognize the specific restrictions imposed by helicopter transportation and to make efforts to shorten the time required for key processes to provide faster treatment.

Objective: We present a case of subarachnoid hemorrhage (SAH) due to ruptured mycotic aneurysm found in the distal superior cerebellar artery (SCA).

Case Presentation: A 64-year-old man was admitted to our hospital with sudden unconsciousness. He had a history of alcoholism but no family history of SAH. Computed tomography (CT) showed apparent SAH; however, CT angiography (CTA) showed no apparent cause of SAH except for two small aneurysms in the same branch of the left distal SCA. We suspected mycotic aneurysm and prescribed antibiotics. It was difficult to diagnose the condition as mycotic aneurysm because there were no vegetations or caries at the time of admission. Because there were two aneurysms in the same branch with partial dilatation and stenosis, we suspected dissecting aneurysm, but continued to administer antibiotics for possible mycotic aneurysm. After the first operation, we diagnosed mycotic aneurysm because a vegetation and valve degeneration was found.

Conclusion: It is difficult to distinguish mycotic aneurysms from dissecting aneurysms because of similar appearance on imaging, especially if no vegetation is found. Nevertheless, it is important to start treatment for mycotic aneurysm. If there is the possibility of mycotic aneurysm, appropriate antibiotics should be administered, and endovascular treatment could be considered for patients with deteriorating conditions.

Objective: Surgical removal of meningiomas that have partially invaded the superior sagittal sinus (SSS) is difficult because it requires reconstruction of the SSS, which can lead to SSS occlusion and venous infarction. The present report details the case of an SSS-involved meningioma treated by stereotactic radiosurgery (SRS) and stenting.

Case Presentation: A 60-year-old woman was admitted to the hospital with blurred vision and papilledema. Lumbar puncture showed markedly increased intracranial pressure (ICP; 340 mm H2O). Gadolinium-enhanced T1-weighted imaging revealed a 1-cm meningioma located mainly in the SSS. Digital subtraction angiography revealed severe stenosis, at the posterior part of the SSS, and no collateral flow. The ICP was considered a result of the stenosis caused by the meningioma. A combined therapy comprising transarterial embolization (for tumor growth suppression), endovascular stenting of the SSS (for intracranial hypertension improvement), and SRS (for tumor control) was planned. SRS was performed first to avoid interference by the metal artifacts caused by the stent. After placement of a self-expanding stent, partial recanalization was achieved. Two months after stenting, SSS stenosis improved and MRI results showed shrinkage of the meningioma. Thirty months after the treatment, no tumor recurrence was observed.

Conclusion: The treatment strategy of SRS followed by stenting was successful for a SSS-involved meningioma. ICP and a pressure gradient between the pre- and post-stenotic segments should be considered indications for stenting.

Objective: Cerebral aneurysms (ANs) in the cortical segment (CS) of the distal posterior inferior cerebellar artery (PICA) with a vertebral artery (VA) of aortic origin are markedly rare. Endovascular therapy was performed to treat subarachnoid hemorrhage caused by a ruptured cerebral AN.

Case Presentation: The patient was a 68-year-old female who was transported to emergency care for headache. Detailed examination revealed an AN in the CS of the PICA with a left VA of distal aortic origin from the left subclavian artery (LT. SA). Endovascular therapy using n-butyl-2-cyanoacrylate (NBCA) was performed to treat the cerebral AN, resulting in a favorable outcome.

Conclusion: Endovascular therapy for cerebral ANs is an effective treatment method.