Small unruptured aneurysms (SUAs) are generally considered to be at a low risk of rupture and subsequent subarachnoid hemorrhage. However, they are considered high risk if they have an irregular shape, an associated bleb is present, or they are located at a critical site such as the anterior communicating artery or internal carotid-posterior communicating artery. In addition, patients with SUAs often choose surgery owing to extreme anxiety regarding rupture, or severe restriction of activities of daily living. Stroke physicians have not yet reached a consensus regarding surgical indications for patients with SUAs concerned about such occurrences. The annual crude death rate in men is 3.4% at 75 to 79 years and 6.3% at 80 to 84 years, and rapidly increasing thereafter. Considering patients with unruptured aneurysms who visit our outpatient services and receive non-surgical treatment, 132 of 172 aneurysms (77%) were less than 5 mm in diameter, and the persistence rate at subsequent patient visits was 82% at 60 months and 62% at 120 months, with a low rupture rate (0.5%/year). Clinicians need to be cautious when explaining the risks of SUAs, and consider preemptive surgery for asymptomatic SUAs in the elderly, even if treated using minimally invasive procedures. We should reconsider strategies for management of asymptomatic SUAs based on the crude death rate and evidence of cause of death in long-term observational cohorts. Assuming shared decision-making between the medical staff and patients, risk control with medical care and follow-up by MRI are equally feasible options as the treatment of choice for unruptured aneurysms as surgery, especially for elderly patients with SUAs. Stroke physicians and neurosurgeons who are not involved in surgery might be eligible for patient care and long-term follow-up of SUAs. Studies focusing on medical management of such patients should be conducted.

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With the introduction of the diagnosis procedure combination (DPC) in Japan, it is now possible to analyze highly specific disease data. In this study, we have analyzed the current state of non-traumatic intracranial hemorrhage (NTICH) by using the DPC data from 2014.
From the website of the Ministry of Health, Labour and Welfare, we accessed data from the DPC evaluation subcommittee of the Central Social Insurance Medical Council and examined the current statof treatment of intracranial hemorrhage (ICH) using an aggregation of the NTICH and the Major Diagnostic Category (MDC) 01 database, for each diagnostic group classification in FY2014.
In FY2014, 55,378 cases of NTICH were registered, out of which, 36,162 (65.3%) and 19,216 (34.7%cases belonged to Japan Coma Scale (JCS) < 10 (mild group) and JCS ≥ 10 (severe group), respectively. The proportion of elderly people (≥ 80 years old) was 24.6% and 35.1% in the mild and severgroups, respectively, with the proportion being higher in the severe group. In the mild group, conservative and surgical treatments were used for 87.2% and 12.8%, respectively. The mortality rate at discharge was 3.2% in total, 2.6% in the conservative treatment group and 7.5% in the surgical treatmengroup. In the severe group, conservative and surgical treatments were used for 64.6% and 35.4%, respectively. The mortality rate at discharge was 28.9% in total, 35.2% in the conservative treatment group, and 17.4% in the surgical treatment group. In the mild group, 1,959 cases underwent surgicaremoval of the hematoma (5.4% in the mild group), and 74.1%, 12.0%, and 13.9% of these were cranioomies, stereotactic operations, and endoscopic operations, respectively. However, in the severe group, 4,140 cases underwent surgical removal of the hematoma (21.5% in the severe group), and 78.3%, 6.2%, and 15.5% of these were craniotomies, stereotactic operations, and endoscopic operations, respectively.
An analysis of the DPC data clarified the current state of cerebral hemorrhage treatment. In particular, in 2014, according to the insurance receipt of endoscopic hematoma removal surgery, the ratio of surgical procedures for hematoma removal was clarified by the DPC data. We believe that DPC data will be an important tool to monitor disease trends.

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Diagnosis and treatment of anterior wall aneurysm of the internal carotid artery (IC) is difficult. We hereby report a case of ruptured anterior wall aneurysm of the IC. A 71-year-old woman was transferred to our hospital with sudden headache and altered consciousness. Computed tomography (CT) brain and CT angiography demonstrated subarachnoid hemorrhage and only vascular stenosis in the C1 portion of the right IC. Angiography showed similar vascular findings. Elective surgery was planned as the origin of subarachnoid hemorrhage (SAH) was unclear. Repeat angiography revealed an outpouching from the anterior wall of the IC. The aneurysm was successfully treated by trapping of the C1 portion of the IC with a high-flow bypass. She recovered without any neurological deficit in 3 months. There is a possibility that initial angiography of the anterior wall aneurysm showed only vascular stenosis, which changed form in a short period. Magnetic resonance imaging (MRI) is useful for confirming intramural hematoma, and serial angiographic follow-up examinations are important.

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Ruptured blood blister-like aneurysms (BBAs) result in a high rate of acute morbidity and mortality. We report a case of ruptured BBA successfully treated with stent-assisted coil embolization. A 41-year-old man presented with subarachnoid hemorrhage caused by a ruptured internal carotid artery BBA located distal to the posterior communicating artery. The right anterior choroidal artery originated just behind the aneurysm; thus, surgical treatment for the present case carried the risk of ischemic complications. We treated the BBA with stent-assisted coil embolization using the semi-jailing technique. The patient had an uneventful postoperative course, and was discharged home 28 days after symptom onset. This case suggests that stent-assisted coil embolization using the semi-jailing technique is an effective treatment for ruptured BBAs.

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Purpose: This study examined the histological findings of plaque, the mechanism of plaque development, and the appearance of neurological symptoms.
Materials and Methods: We evaluated 30 patients who underwent carotid endarterectomy (CEA) and carotid artery stent placement (CAS) for stenosis. Specimens of carotid plaque were examined histologically. Serum neopterin and myeloperoxidase were measured before and after surgery.
Results: Histological findings clearly demonstrated a fibrous cap, hemorrhage, neovascularization, and lipoprotein in plaque. The levels of neopterin and myeloperoxidase were significantly higher in symptomatic cases, and decreased after surgery.
Conclusion: This study suggested the potential for a systemic approach in the study of atheromatous plaque using histology and serum markers (neopterin and myeloperoxidase). These findings clarified the development of carotid artery plaque and mechanisms of symptom development. The results suggested that an inflammatory cascade participated in the development of plaque.

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Extracranial infected carotid artery aneurysm (EICA) is rare, but requires rapid surgical repair due to the risk of multiple complications, including rupture. We report two cases of surgical repair of EICA.
Case 1: A 63-year-old man had a misplaced central venous catheter in the right common carotid artery two weeks ago. He presented with a subcutaneous tumor in the right cervical region. A contrast-enhanced computed tomography (CT) scan revealed a right common carotid artery mycotic pseudoaneurysm. Emergency surgery was performed because of rapid enlargement of the aneurysm. The mycotic pseudoaneurysm and the common carotid artery were repaired by suturing the defect in the arterial wall. The arterial wall around the defect was fragile. The postoperative course was uneventful.
Case 2: A 54-year-old man presented with a subcutaneous tumor in the left cervical region after symptoms of common cold. A contrast-enhanced CT scan revealed a left common carotid artery mycotic pseudoaneurysm. He developed thyrotoxicosis caused by destructive thyroiditis. Emergency surgery was performed due to enlargement of aneurysm, observed on follow-up CT. The mycotic pseudoaneurysm and the common carotid artery were repaired using a venous graft. The arterial wall around the defect was fragile. The postoperative course was uneventful.
An important finding was that the size of the defect in the arterial wall during surgery was estimated to be larger than that assessed during preoperative evaluation in cases of mycotic aneurysms.

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We report the case of a 58-year-old man with head injury, without any focal neurological deficit. Computed tomography demonstrated multiple skull fractures, an acute epidural hematoma, and bleeding in the sphenoid sinus. Two days after the injury, the patient developed motor aphasia with gradually progressing pulsatile proptosis, bruit, and external ophthalmoplegia on the left side, and bilateral conjunctival congestion. Magnetic resonance imaging showed venous congestion in the left frontal and temporal lobes. Cerebral angiography revealed a direct carotid cavernous fistula (CCF), two aneurysms of the right middle meningeal artery (MMA), dural arteriovenous fistulas (dAVFs) from bilateral MMAs and a dAVF into the superior sagittal sinus. We occluded the left internal carotid artery, and one of the MMA aneurysms was removed by open surgery. Complex head trauma or skull base injuries may occur in association with a secondary cerebrovascular disease (CVD). Evaluation of secondary CVDs is needed in case of delayed neurological deficits after such head injuries.

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We report a case of tentorial dural arteriovenous fistula (dAVF) embolized using Onyx via a newly introduced microcatheter through a middle meningeal artery with a migrated Onyx plug.
A 44-year-old male was admitted to our hospital due to a generalized seizure. A tentorial dAVF fed by branches of the middle meningeal artery and the mastoid branch of the occipital artery was demonstrated on digital subtraction angiography. Transarterial embolization through a double-lumen balloon catheter (Scepter C) was performed using Onyx via the petrosquamous branch of the middle meningeal artery. However, the tip of the balloon catheter was occluded by an Onyx cast during the waiting period prior to Onyx injection. With the first injection, Onyx migrated into all accessible middle meningeal branches; therefore, we lost accessible branches for further embolization.
We tried to introduce a new microcatheter (Marathon) through the Onyx cast that migrated into the posterior convexity branch of the middle meningeal artery, anticipating the softness of Onyx injected into an artery. The microcatheter could be introduced easily through the Onyx cast and reached the portion close to the shunt point. Onyx injected through this microcatheter penetrated well into the vein though the shunt as well as other feeding arteries without making a new plug in the accessed artery despite the migrated Onyx cast. The dAVF was completely obliterated with this injection.
Introduction of a microcatheter through a migrated Onyx cast is possible, and Onyx is easily injected via the microcatheter without making a plug.

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A 40-year-old man in a deep coma following sudden severe headache was admitted to our hospital. Computed tomography (CT) of the head showed diffuse intracerebral subarachnoid hemorrhage (SAH) in the frontal lobe. Digital subtraction angiography revealed an aneurysm of the anterior communicating artery. The neck of the aneurysm was clipped with external decompressive craniectomy. Altered consciousness was, however, prolonged, and a tracheostomy was performed. On day 30 in the hospital, his pupils showed dilation. Ophthalmologic examination revealed bilateral massive vitreous hemorrhage or Terson's syndrome. Owing to an unstable general medical condition, especially due to severe diabetes insipidus following SAH, there was little hope of recovering consciousness. Therefore, vitreous surgery was not considered. After a long period of continued medical management, his level of consciousness improved, and gait training was started. On day 150 of hospitalization, his general medical condition and consciousness level considerably improved, and he was able to walk. He underwent surgery for bilateral vitreous hemorrhage. The hematoma was organized and hard, and proliferative vitreoretinopathy was present. Fifteen months after SAH onset, his right eye regained useful visual acuity, and he resumed an independent life at home. Retrospective assessment of his head CT revealed that preretinal hemorrhage had been present since as early as admission. On day 30, when his pupils were dilated, the preretinal hemorrhage had disappeared, and diffuse vitreous hemorrhage was present. We have, thus, elucidated the detailed time-course of vitreous hemorrhage development after SAH using serial CT scans; this finding has not been reported to date. Vitreous hemorrhage is often missed in head CT scans during the acute phase of SAH. It can also be missed in patients with altered consciousness over a prolonged clinical course. Serial ultrasonography for detecting vitreous hemorrhage may allow timely and appropriate vitreous surgery.

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A 54-year-old female presented with non-traumatic anterior cerebral artery (ACA) dissection, manifesting as sudden onset of headache and nausea. Computed tomography (CT) and angiography revealed subarachnoid hemorrhage (SAH) due to a dissecting aneurysm at the left A1 segment accompanied with an azygos ACA. Right fronto-temporal craniotomy was performed for trapping the aneurysm, and the patient made a good recovery. A combination of A1 dissection and azygos ACA is very rare, and trapping is the most effective method for prevention of re-rupture.

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Filmless diagnosis has been widely used in clinical practice since 2008 due to a change in the health insurance system of Japan. However, in follow-up studies of unruptured intracranial aneurysms, which require frequent image comparisons, there is little benefit of filmless diagnosis. In the film era, it was easy to compare two sets of 100 images in five films. However, filmless diagnosis at that time was not only time consuming, but also increased the workload of the doctors. We introduced a DICOM viewer consisting of six monitors and made several improvements, so that its performance is good enough for reporting. Now, on double-clicking the imaging list, the viewer system consisting of six monitors shows 120 images at a time. Each monitor shows the first 20 images from the first to the sixth imaging series. Using a short cut key, the system shows the next 120 images. Each monitor then shows the first 20 images of the seventh to the twelfth imaging series. Double-clicking on the images allows precise observation by magnifying the images, and moving the mouse wheel allows scrolling through the images. For comparative diagnosis, previous combinations of the diagnostic images of the same patient are listed and continuously displayed and can be recalled by double-clicking. Interchanging the previous images with the most recent images requires only one action, i.e., drag and drop. The images are then automatically inserted at the same image number, in the same division manner, in the same magnifying power, and in the same position. This new sequence can be saved and added to the list with a single click, followed by pressing enter. Our new DICOM viewer system is more useful than not only the previous monitor system, but also the film viewing screen system in the old film era.

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