Ruptured distal anterior inferior cerebellar artery aneurysm years after stereotactic radiosurgery for vestibular schwannoma: A case report and literature review.

Background: Aneurysmal formation after stereotactic radiosurgery (SRS) for vestibular schwannoma (VS) is a rare complication. Its characteristics and the best treatment strategies remain controversial, and the clinical course is especially unknown because reported aneurysms are first incidentally detected, or aneurysmal rupture occurs suddenly, and they are treated immediately. Case Description: A 68-year-old man who underwent SRS for VS 20 years ago presented with subarachnoid hemorrhage (SAH) due to rupture of a radiation-induced fusiform anterior inferior cerebellar artery aneurysm. He was treated with parent artery occlusion, resulting in a modified Rankin scale grade 2. This report illustrates the first case of detected aneurysm formation before rupture with retrospective magnetic resonance imaging evaluation. Conclusion: We describe the possible risk of rapid progression and rupture of aneurysms, focusing on the interval from SRS to aneurysmal formation. The period of formation of SRS-induced aneurysms is suspected to vary from years to decades regardless of radiation doses; however, aneurysms estimated as pseudoaneurysms have an extremely high risk of rupture within a few years, even when small in size. If aneurysms are discovered unruptured, there are some advantages in not only the prevention of poor prognosis due to SAH but also in the availability of optional therapeutic strategies using revascularization. Long-term annual follow-up, including vessel examination, is warranted not only to assess tumor status but also for early detection of any vascular lesions.

[A case of recurrent stroke with carotid-web despite dabigatran treatment successfully treated by carotid endarterectomy].

We present a case of a 41-year-old female presenting with recurrence of ischemic stroke on subtherapeutic doses of dabigatran. She had a history of embolic stroke of undetermined sources at the age of 40, and underwent implantable cardiac monitor implantation and had started dabigatran. One year after the first ischemic stroke, she presented with sudden dysarthria and left hemiparesis and was admitted to our hospital. An MRI of the head revealed acute cerebral infarction in the right corona radiata, and an MR angiography revealed right M2 occlusion. Cervical 3D-CTA revealed a protruding structure on the posterior wall of the carotid artery bulb, which was diagnosed as carotid web. She underwent carotid endarterectomy, and the specimen was pathologically confirmed to be vascular malformation due to fibromuscular dysplasia.

[A Case of Radiation Necrosis in the Right Occipital Lobe Accompanied with Massive Hemorrhage:Histopathological Analysis].

Radiation necrosis with massive hemorrhage is a rare complication of radiotherapy. We report the case of a male patient who had undergone radiotherapy therapy 18 years earlier and presently underwent gamma knife radiosurgery for a metastatic brain tumor in his right occipital lobe. The patient showed aberrant behavior with left homonymous hemianopsia and a gradual deterioration of cognitive function after radiotherapy. A CT scan showed the presence of an intracerebral hematoma over the right occipital lobe with mass effect, and small spotty enhancements on the lesion when enhanced on gadolinium contrast-enhanced MRI. Intraoperative findings revealed necrosis of the occipital surface and a hematoma in the occipital lobe. Pathological findings showed damage to the walls of the sinusoidal capillaries and vitreous degeneration of the inner membrane with a spongiform hemangioma. After surgery, the cerebral edema resolved, and the patient's clinical symptoms improved. The cause of the radiation necrosis and bleeding in this patient was assumed to be due to the breakdown of the congested walls of the sinusoidal capillary vessels.

Safety and Feasibility of Carotid Artery Stenting with Dual-Echo Technique to Minimize Iodinated Contrast Dose.

BACKGROUND: The aim of this study was to evaluate the safety and feasibility of carotid artery stenting (CAS) employing dual-ultrasound technique and administering a minimal contrast agent in patients with renal insufficiency. METHODS: Between September 2009 and July 2013, 63 consecutive patients underwent CAS at our institution: dual-echo carotid artery stenting (DECAS) in 7 patients with renal insufficiency and standard carotid artery stenting (STCAS) in the remaining 56 patients. Periprocedural adverse events and outcomes were compared between the 2 groups. RESULTS: Technical success was achieved in all cases. The 3 procedure-related complications were 1 case of transient hemiparesis in the DECAS group and 1 transient and 1 permanent case of hemiparesis in the STCAS group. The rate of positive diffusion-weighted-imaging lesions did not differ significantly between the 2 groups (28.6% versus 12.5%, P = .26). A significantly smaller volume of contrast was used in DECAS (15 versus 163 mL, P < .01). The change in creatinine level remained stable after CAS and did not differ between the 2 groups (.02 versus .03 mg/dL, P = .96). CONCLUSIONS: DECAS is safe and feasible for patients with pre-existing renal insufficiency and can provide an alternative for patients with carotid stenosis and renal insufficiency.

White-collar sign as a predictor of outcome after endovascular treatment for cerebral aneurysms.

OBJECTIVE The white-collar sign (WCS) is known as a thick neointimal tissue formation at the aneurysm neck after endovascular coil embolization of cerebral aneurysms, which may prevent aneurysm recanalization. The purpose of this study was to evaluate factors involved in the appearance of WCS and to identify radiological and clinical outcomes of treated aneurysms with WCS. METHODS The study included 140 patients with 149 aneurysms in which it was possible to confirm the aneurysm neck between the aneurysm sac and parent artery by using conventional angiography. The WCS was defined as a radiolucent band at the aneurysm neck on the angiogram at 6 months after initial embolization. The radiological outcome was evaluated using MR angiography. RESULTS In 23 of 149 aneurysms (15.4%), a WCS appeared. The WCS-positive group had a significantly smaller neck size (3.3 ± 0.8 mm vs 4.2 ± 1.1 mm, p < 0.001) and smaller aneurysm size (4.3 ± 0.9 mm vs 6.0 ± 2.1 mm, p < 0.001) than the WCS-negative group. Multivariate analysis revealed that WCS appearance was associated with small neck size (OR 0.376, 95% CI 0.179-0.787; p = 0.009). In 106 of 149 aneurysms, the rate of complete occlusion was significantly higher in the WCS-positive group (18/18, 100%) than in the WCS-negative group (n = 54/88, 61.4%; p = 0.001) in the mean follow-up period of 31.0 ± 9.7 months (range 5-52 months). Neither major recanalization nor rupture of the aneurysm occurred in the WCS-positive group. CONCLUSIONS Appearance of the WCS was associated with complete occlusion and good clinical outcome after endovascular coil embolization. The WCS would help to determine the prognosis of cerebral aneurysms after endovascular treatment.

[Surgical Outcome of Acute and Subacute Subdural Hematoma with Endoscopic Surgery].

Acute subdural hematoma (ASDH) and subacute subdural hematoma(SASDH)evacuations are commonly performed through a large craniotomy or with external decompression surgery to avoid secondary brain injury. In the field of head trauma, minimally invasive surgeries performed with neuroendoscopy were recently reported. We report 12 patients with ASDH( n=9) and SASDH (n=3)w ho underwent endoscopic hematoma evacuation via a small craniotomy between November 2013 and May 2015. All patients were over 65 years of age(mean age, 78.8 years[range, 65-91 years]) and had subdural hematomas without extensive contusion. The mean preoperative Glasgow Coma Scale(GCS)score was 8.75 (range, 4-13). In three patients, we observed the bleeding point and substantially coagulated it. Decompression in all patients was adequate after surgery. Patients with a preoperative GCS score of 4-6 showed poor outcomes, whereas those with a score >9 showed relatively good outcomes. We performed the operations safely in patients who were on antithrombotic therapy or had a systemic bleeding tendency pre-injury. Endoscopic hematoma evacuation via a small craniotomy is a safe and minimally invasive procedure in patients older than 65 years with comorbidities.

[Stent-assisted embolization for ruptured vertebral artery dissection involving the origin of the posterior inferior cerebellar artery:a case report of staged strategy].

We report a ruptured vertebral artery dissection (VAD) involving the origin of the posterior inferior cerebellar artery(PICA)treated by a staged strategy with stent-assisted coil embolization. A 52-year-old woman was admitted with a ruptured right VAD involving the origin of the developed PICA. Endovascular internal trapping of the enlarged distal VAD was performed (Stage 1). After 1 month, following confirmation of platelet inhabitation (Stage 2) an Enterprise stent (Cordis Neurovascular, Miami Lakes, FL) placement from the PICA to the proximal VA with coil embolization for proximal VAD was performed under dual antiplatelet therapy. The dissected VA segment was occluded by coil embolization and the PICA was preserved. Advantages of this staged treatment are the avoidance of ischemic/hemorrhagic complications due to antithrombotic therapy when stent placement to the PICA is planned during the acute stage of SAH and confirmation of platelet inhabitation before stent placement in second treatment. VAD can be occluded, and this challenging endovascular treatment can be a therapeutic option for a ruptured VAD.

[Intraorbital schwannoma arising from the supraorbital nerve].

A 67-year-old man presented a three-month history of double vision and slight numbness at his right forehead. Neurological examination on admission demonstrated diplopia at lower gaze and mild hypesthesia at right frontal. MRI disclosed an extraconal cystic mass, centered over the superior rectus muscle, in the superior part of the right orbit. 3D-CT scan in bone window image showed an erosion of the right orbital roof. An operation was performed by a transcranial extradural anterior orbitotomy. It was noticed that the supraorbital nerve entered the cyst wall of the tumor. The mass was dissected from the surrounding intraorbital fat and was removed completely. Pathologically, diagnosis of schwannoma was made. Postoperatively, the diplopia diminished, although numbness at the right forehead remained. Orbital schwannomas constitute 1 to 4% of all orbital tumours. Identification of the nerve of origin of the tumours is difficult. Including this present case, only 11 cases of supraorbital nerve schwannoma, and only three cases of the tumour without neurofibromatosis, have been reported.

[A case of transorbital penetrating brain injury by a blunt metal rod].

This report presents a case of a transorbital penetrating brain injury caused by a metal rod. A 47-year-old male injured his left lower eyelid with no witness during working hours. The two days later, he presented with a right hand tremor and abnormal behavior, and was admitted to the hospital. A CT showed a bone fracture of the left orbital roof and a low-density lesion of the left frontal lobe. The initial diagnosis was a cerebral contusion due to a blow-out fracture. However, sagittal MR images on the tenth day in the hospital demonstrated a penetrating tract that was running linearly from the left orbital roof to the left caudate head. Therefore, the final diagnosis was a transorbital penetrating brain injury. This case had no severe complications in spite of the delayed diagnosis. Careful examinations are thus required in order to make a correct diagnosis at the first examination, because a transorbital penetrating brain injury might initially present as a slight wound with no neurological signs.

[Vertebral arteriovenous fistula presenting with subarachnoid hemorrhage: a case report].

We report a rare case of a vertebral arteriovenous fistula presenting with subarachnoid hemorrhage (SAH). A 60-year-old man was admitted to our hospital with a sudden onset of headache and neck pain. A neurological examination showed no abnormalities. Computed tomography scans revealed SAH in the pontine cistern and cistern magna. Although the first cerebral angiogram failed to depict the cause of bleeding, the second angiogram on day 15 demonstrated an arteriovenous fistula in the left vertebral artery at C4-5, which was draining into the internal vertebral venous plexus and forming a venous pouch. The fistula was successfully obliterated by transarterial embolization using detachable platinum coils. In patients with SAH with predominance in the posterior fossa, attention should also be paid to spinal vascular lesions. Three-dimensional digital angiography and digital subtraction angiography allow a reliable visualization of such lesions.

[Successful trans-arterial occlusion of a vertebral arteriovenous fistula with aid of intra vascular ultra sound (IVUS) and balloon catheter].

We report a case of spontaneous vertebral arteriovenous fistula manifesting pulsating tinnitus with left cervical bruit. A 50-year-old woman presented with pulsatile tinnitus of unknown duration. Angiography revealed a simple and direct fistula between the second segment of the left vertebral artery and the epidural venous system. The fistula was well visualized by intra vascular ultra sound (IVUS). Balloon catheters were used for regulating blood flow during coil embolization, which successfully obliterated the fistula, with subsequent control of the symptoms. Postoperative course (18 months) was uneventful.

Endovascular treatment for cervical carotid artery stenosis presenting with progressing stroke: three case reports.

BACKGROUND: Progressing stroke is said to occur when symptoms and signs worsen in cases of ischemic stroke. Although conservative methods using volume expansion with antithrombotic or anticoagulative agents are widely used for progressing stroke, in some hospitals, emergency carotid endarterectomy (CEA) has been performed for carotid stenosis, with mixed results. Here we report three cases with progressing ischemic stroke that were managed by endovascular surgical intervention. CASE DESCRIPTION: We performed endovascular surgery in three patients with cervical carotid artery stenosis presenting with progressing stroke or crescendo transient ischemic attacks. Endovascular treatment was less invasive and feasible for acute phase treatment. While local thrombolysis alone was found to be less effective, stent placement induced complete resolution of stenosis, but may result in hyperperfusion syndrome or hemorrhagic infarction. CONCLUSIONS: In an emergency, percutaneous transluminal angioplasty with proper dilatation is preferred, and then CEA or stenting should be considered after the patient's condition stabilizes.

Characterization of the supermirror hard-x-ray telescope for the InFOCmuS balloon experiment.

A hard-x-ray telescope is successfully produced for balloon observations by making use of depth-graded multilayers, or so-called supermirrors, with platinum-carbon (Pt/C) layer pairs. It consists of four quadrant units assembled in an optical configuration with a diameter of 40 cm and a focal length of 8 m. Each quadrant is made of 510 pieces of coaxially and confocally aligned supermirrors that significantly enhance the sensitivity in an energy range of 20-40 keV. The configuration of the telescope is similar to the x-ray telescope onboard Astro-E, but with a longer focal length. The reflectivity of supermirrors is of the order of 40% in the energy range concerned at a grazing angle of 0.2 deg. The effective area of a fully assembled telescope is 50 cm2 at 30 keV. The angular resolution is 2.37 arc min at half-power diameter 8.0 keV. The field of view is 12.6 arc min in the hard-x-ray region, depending somewhat on x-ray energies. We discuss these characteristics, taking into account the figure errors of reflectors and their optical alignment in the telescope assembly. This hard-x-ray telescope is unanimously afforded in the International Focusing Optics Collaboration for muCrab Sensitivity balloon experiment.

[A case of basilar artery stenosis treated by stent placement].

Symptomatic basilar artery stenosis invariably has poor prognosis owing to limited treatment options. Modernized stent system delivery technology has paved the way for treating tortuous vascular segments of intracranial system. The authors hereby report on the use of intracranial stent to treat basilar artery stenosis. A-61-year old man presented with one month history of recurrent dizziness and dysarthria. He remained symptomatic despite having oral antiplatelets. Magnetic resonance image showed pontine ischemic lesion. Stenosis of proximal portion of basilar artery was detected by magnetic resonance angiography (MRA). Although balloon angioplasty was performed, restenosis was demonstrated by MRA four months later. Stenting was then performed with excellent angiographic results, and there were no procedural complications. The availability of new flexible intravascular stents, allowing access to tortuous proximal intracranial vessels, provides a new therapeutic approach to basilar artery stenosis cases. However long term follow-up is advised to assess the durability of this approach.

Depicting cerebral veins by three-dimensional CT angiography before surgical clipping of aneurysms.

BACKGROUND AND PURPOSE: Cerebral veins show wide variation, and unexpected veins occasionally limit surgical procedures for clipping of cerebral aneurysms. This study was undertaken to assess the utility of three-dimensional CT angiography (3D-CTA) in the evaluation of venous anatomy before surgical clipping of cerebral aneurysms. METHODS: 3D-CTA was performed in 19 patients before pterional craniotomy. The venous anatomy visualized by use of 3D-CTA was compared retrospectively with intraoperative findings. RESULTS: 3D-CTA clearly depicted the superficial sylvian veins (SSVs) in 17 of 19 cases. In three of these 17 cases, 3D-CTA failed to reveal the additional connecting veins from SSVs to the midportion of the sphenoid wing. 3D-CTA also depicted bridging veins from: 1) the basal vein of Rosenthal to the sphenoparietal sinus (SPS) (three cases); 2) a junction of the anterior cerebral vein and the deep middle cerebral vein to the SPS (two cases); 3) the anterior cerebral vein into the cavernous sinus (one case); and 4) the deep middle cerebral vein to the cavernous sinus in one case. Surgical findings corresponded well with the angiographic findings. 3D-CTA depicted bridging veins from the frontal base into the SPS in two cases; retraction of the frontal lobe was severely limited in these cases. 3D-CTA also exhibited anatomic variation of deep cerebral veins, which suggests the utility of 3D-CTA in evaluating the risks carried by sacrifice of some bridging veins. In two patients, aneurysmal dissection was restricted because of adhering veins. 3D-CTA depicted these cerebral veins to be lying in contact with the aneurysm. In one case, the contiguous vein was hidden behind a large middle cerebral artery aneurysm; 3D-CTA was helpful for visualization of this vein. CONCLUSION: 3D-CTA can clearly depict the venous anatomy of the brain and is useful for surgical planning of a pterional or temporopolar approach for cerebral aneurysms.