[Preoperative Simulation of Neuroendovascular Therapy Using a Three-Dimensional Printer Model of a Tailor-Made Hollow Cerebral Aneurysm].

Several studies have reported the importance of preoperative simulations. This report describes the methods and utility of neuroendovascular treatment using a three-dimensional(3D)-printed hollow cerebral aneurysm model. This model was created using a stereolithography apparatus-type 3D printer with digital imaging and communications in medicine data from 3D digital subtraction angiograms. The 3D model was used to perform preoperative simulations of microcatheter placement in aneurysms, microguidewire manipulation, and stent deployment. We performed each simulated procedure during surgery. The hollow cerebral aneurysm 3D model can also be used as a training model for surgical trainees. Preoperative simulation using a high-precision hollow cerebral aneurysm model created using 3D printers enables the discussion of specific treatment strategies for each case, including new devices and device sizes, and is expected to develop into "tailor-made medicine" in the future, contributing to safe and reliable treatment implementation.

[Angioarchitecture and Associated Dural Arteriovenous Fistulas of the Superior Petrosal Sinus and Petrosal Vein].

The superior petrosal sinus and petrosal vein are important drainage routes for the posterior cranial fossa, with some variations and collateral vessels. An anterolateral-type tentorial dural arteriovenous fistula, which occurs around the petrosal vein, often develops aggressive symptoms due to venous reflux to the brainstem and cerebellum. Neuroendovascular treatment of this fistula is usually challenging because transarterial embolization has a high risk and indications for transvenous embolization are limited. In the cavernous sinus and transverse sinus/sigmoid sinus dural arteriovenous fistulas, venous reflux to the petrosal vein is dangerous, and a treatment strategy with the occlusion of the petrosal vein is indispensable. Furthermore, attention should be paid to venous approaches through the superior petrosal sinus.

A case of delayed foreshortening and disconnection of pipeline embolization device detected by chronological cone-beam computed tomography fusion image.

OBJECTIVE: The morphological changes of the pipeline embolization device (PED; Medtronic, Minneapolis, MN, USA), such as delayed migration or foreshortening, can relate to the incomplete occlusion of aneurysms. CASE PRESENTATION: A 30-year-old man with a giant cavernous carotid artery aneurysm was treated with two PEDs using the overlapping technique. Six months after treatment, follow-up angiography showed morphological changes of the PEDs and residual flow into the aneurysm. Chronological cone-beam computed tomography fusion imaging clearly revealed the dynamic foreshortening of the first PED and the disconnection of both PEDs, so we decided to implant an additional PED. CONCLUSION: This case illustrates that a three-dimensional understanding can be useful for assessing the cause of treatment failure or recurrence.

Treatment outcome of coil embolization for distal anterior cerebral artery aneurysms: A single-center experience.

OBJECTIVE: In recent years, endovascular treatment has become the treatment of choice for distal anterior cerebral artery (DACA) aneurysms. In this study, we report the outcomes of coil embolization for DACA aneurysms. METHODS: Eighteen DACA aneurysms in 16 patients treated with endovascular treatment between January 2010 and December 2020 were included in this study. We retrospectively analyzed patient characteristics, data on aneurysms, the reason for the selection of endovascular treatment, treatment technique, and treatment outcomes. RESULTS: There were 18 procedures in 16 patients. The average age was 65.7 years and 56% of patients were male. The average diameter of the dome was 5.5 mm, and the location of aneurysm was A3 in 83% and A4 in 17%. We mainly selected endovascular treatment for patients with a past history of craniotomy and head trauma, or with systemic comorbidities. The technical success rate was 94%, and adequate obliteration immediately after treatment was achieved in 72%. There were no symptomatic periprocedural complications. The retreatment rate was 11.1%. CONCLUSION: Coil embolization for DACA aneurysms yielded good treatment outcomes. Endovascular treatment for DACA aneurysms will become more common with advances in endovascular devices and the establishment of stable perioperative antiplatelet therapy.

[Neuroendovascular Therapy and Infection].

In this paper, we will discuss the relationship between neuroendovascular therapy and infection in two parts: the risk of infectious complications in neuroendovascular therapy and neuroendovascular therapy for infectious diseases. The risk of infectious complications associated with neuroendovascular therapy is rare but should not be ignored. We must comply with clean procedures and consider prophylactic antibiotic administration in selected cases. Neuroendovascular therapy for infectious diseases is a high-risk treatment, and a safer treatment strategy should be considered for each case.

Trends in Incidence of Intracranial and Spinal Arteriovenous Shunts: Hospital-Based Surveillance in Okayama, Japan.

BACKGROUND AND PURPOSE: To date, the incidence of intracranial and spinal arteriovenous shunts has not been thoroughly investigated. We aimed to clarify recent trends in the rates of intracranial and spinal arteriovenous shunts in Japan. METHODS: We conducted multicenter hospital-based surveillance at 8 core hospitals in Okayama Prefecture between April 1, 2009 and March 31, 2019. Patients who lived in Okayama and were diagnosed with cerebral arteriovenous malformations, dural arteriovenous fistulas (DAVFs), or spinal arteriovenous shunts (SAVSs) were enrolled. The incidence and temporal trends of each disease were calculated. RESULTS: Among a total of 393 cranial and spinal arteriovenous shunts, 201 (51.1%) cases of DAVF, 155 (39.4%) cases of cerebral arteriovenous malformation, and 34 (8.7%) cases of SAVS were identified. The crude incidence rates between 2009 and 2019 were 2.040 per 100 000 person-years for all arteriovenous shunts, 0.805 for cerebral arteriovenous malformation, 1.044 for DAVF, and 0.177 for SAVS. The incidence of all types tended to increase over the decade, with a notable increase in incidence starting in 2012. Even after adjusting for population aging, the incidence of nonaggressive DAVF increased 6.0-fold while that of SAVS increased 4.4-fold from 2010 to 2018. CONCLUSIONS: In contrast to previous studies, we found that the incidence of DAVF is higher than that of cerebral arteriovenous malformation. Even after adjusting for population aging, all of the disease types tended to increase in incidence over the last decade, with an especially prominent increase in SAVSs and nonaggressive DAVFs. Various factors including population aging may affect an increase in DAVF and SAVS.

Osseous arteriovenous fistulas in the dorsum sellae, clivus, and condyle.

PURPOSE: Arteriovenous fistulas (AVFs) located in the cavernous sinus (CS), clivus, and condyle can be osseous shunts in nature. Here, we reviewed the angioarchitecture, clinical characteristics, and treatment results of AVFs in these lesions. METHODS: Twenty-five patients with 27 lesions who underwent rotational angiography in our department between May 2013 and December 2019 were reviewed. We examined 20 CS AVFs, 2 clival AVFs, and 5 condylar AVFs. We divided the anatomical shunted pouches into five locations: the dorsum sellae (posteromedial of the CS), posterolateral wall of the CS, lateral wall of the CS, clivus, and condyle. We divided the AVFs into three categories: intraosseous, transitional, and nonosseous shunts. We analyzed the characteristics and treatment results. RESULTS: A total of 33 shunted pouches or points were identified in 27 lesions. The dorsum sellae (n = 16) was the most frequent location. Fourteen AVFs (88%) in the dorsum sellae were osseous (intraosseous or transitional) shunts. All AVFs in the clivus or condyle were also osseous shunts. Eleven lesions (92%) of intraosseous and all lesions of transitional shunts exhibited bilateral external carotid artery involvement as feeders. Ten lesions (83%) of intraosseous shunts were treated with selective transvenous embolization of the shunted pouch with or without additional partial embolization of the sinus. Eleven (92%) intraosseous shunts were completely occluded, and symptom resolution was achieved in all intraosseous shunts. CONCLUSION: Most of the CS AVFs with shunted pouches in the dorsum sellae and all of the AVFs in the clivus and condyle share similar characteristics.

[Intracerebral Hemorrhage].

CT angiography(CTA)plays a crucial role in the diagnosis of intracerebral hemorrhage(ICH). An 85-year-old woman presented with a disturbance of consciousness and right hemiparesis. Non-contrast CT of the brain revealed intracerebral hemorrhage in the left thalamus spreading to the internal capsule, corona radiata, and midbrain and a "swirl sign." CTA revealed no vascular anomaly. The early and delayed CTA phases revealed the"spot sign" and "leakage sign," respectively. Non-contrast CT three hours after the initial CT showed the enlargement of the hematoma. After the detection of ICH by initial non-contrast CT, CTA should be performed to differentiate between the causes of secondary ICH and detect the imaging markers of hematoma expansion or rebleeding. Previous studies have demonstrated that the "spot sign" detected by CTA is a valid imaging marker for hematoma expansion. In this article, the differential diagnosis of ICH and the detection of the imaging markers of hematoma expansion using non-contrast CT and CTA have been discussed.

Left temporal hemorrhage caused by cerebral venous reflux of a brachio-brachial hemodialysis fistula.

Central vein disease (CVD) is a well-known complication of central venous cannulations, indwelling dialysis catheters, and arteriovenous grafts. Brachiocephalic vein (BCV) stenosis or thrombotic occlusion can occur in dialysis patients, and the presence of an ipsilateral arteriovenous fistula can cause cerebral venous hypertension due to retrograde flow in the ipsilateral jugular vein. A 53-year-old man receiving hemodialysis (left brachiocephalic hemodialysis fistula) presented with impaired consciousness and seizures related to status epilepticus due to left temporal multifocal hemorrhages. Brain computed tomography and angiogram showed left cortical vein congestion without intracranial arteriovenous shunt. Complementary left brachial angiogram showed a left BCV stenosis and jugular and cerebral high-flow venous reflux with cortical venous reflux from the hemodialysis fistula. The left arm shunt resulted in severe cerebral venous hypertension due to ipsilateral stenosis of the BCV. BCV angioplasty immediately resolved the cerebral reflux. Patients with hemodialysis fistulas are at a higher risk of developing these intracerebral hemorrhage complications.

Detection of the common origin of the radiculomedullary artery with the feeder of spinal dural arteriovenous fistula using slab maximum intensity projection image.

PURPOSE: Endovascular therapy to the spinal dural arteriovenous fistula (SDAVF) with a common origin of the radiculomedullary artery and the feeder of the shunt has the risk of spinal cord infarction. This study aimed to retrospectively assess the detection rate of normal spinal arteries from the feeder of SDAVF. METHODS: We retrospectively collected the angiographic and clinical data of SDAVFs. This study included 19 patients with 20 SDAVF lesions admitted to our department between January 2007 and December 2018. We assessed the detection rate of normal radiculomedullary artery branched from the feeder of SDAVF between the period using the image intensifier (II) and flat panel detector (FPD) and evaluated the treatment results. RESULTS: The detection rates of the radiculomedullary artery branched from the feeder of SDAVF were 10% (1/10 lesions) during the II period and 30% (3/10 lesions) during the FPD period. During the FPD period, all normal radiculomedullary arteries branched from the feeder were only detected on slab maximum intensity projection (MIP) images of rotational angiography, and we could not detect them in 2D or 3D digital subtraction angiography. All lesions that had a common origin of a normal radiculomedullary artery and the feeder were completely obliterated without complications. There was no recurrence during the follow-up period. CONCLUSIONS: The flat panel detector and slab MIP images seem to show the common origin of the normal radiculomedullary arteries from the feeder more accurately. With detailed analyses, SDAVF can be safety treated.

Metal artifact reduction algorithm for image quality improvement of cone-beam CT images of medium or large cerebral aneurysms treated with stent-assisted coil embolization.

PURPOSE: The aim of the present study was to assess image quality improvement using a metal artifact reduction (MAR) algorithm in cases of medium or large cerebral aneurysms treated with stent-assisted coil embolization (SAC), and to analyze factors associated with the usefulness of the MAR algorithm. METHODS: We retrospectively evaluated the cone-beam computed tomography (CBCT) data sets of 18 patients with cerebral aneurysms treated with SAC. For subjective analysis, images of all cases with and without MAR processing were evaluated by five neurosurgeons based on four criteria using a five-point scale. For objective analysis, the CT values of all cases with and without MAR processing were calculated. In addition, we assessed factors associated with the usefulness of the MAR by analyzing the nine cases in which the median score for criterion 1 improved by more than two points. RESULTS: MAR processing improved the median scores for all four criteria in 17/18 cases (94.4%). Mean CT values of the region of interest at the site influenced by metal artifacts were significantly reduced after MAR processing. The maximum diameter of the coil mass (< 17 mm; odds ratio [OR], 4.0; 95% confidence interval [CI], 1.2-13.9; p = 0.02) and vessel length covered by metal artifacts (< 24 mm; OR, 2.3; 95% CI, 1.1-4.7; p = 0.03) was significantly associated with the usefulness of the MAR. CONCLUSIONS: This study suggests the feasibility of a MAR algorithm to improve the image quality of CBCT images in patients who have undergone SAC for medium or large aneurysms.

De novo vertebral artery dissecting aneurysm after internal trapping of the contralateral vertebral artery.

We present the case of a de novo vertebral artery dissecting aneurysm (VADA) after endovascular trapping of a ruptured VADA on the contralateral side. The first ruptured VADA involved the posterior inferior cerebellar artery, which was successfully treated by endovascular internal trapping using a stent. A follow-up study at 3 months revealed a de novo VADA on the contralateral side. The second VADA was successfully embolized using coils while normal arterial flow in the vertebral artery was preserved using a stent. Increased hemodynamic stress may cause the development of a de novo VADA on the contralateral side.

[Preoperative Embolization for Solid Cerebellar Hemangioblastoma on the Day of Surgery:Two Case Reports].

Surgical resection of solid cerebellar hemangioblastomas can be challenging because of the profuse blood supply and tight space. We report two cases of solid cerebellar hemangioblastomas treated via surgical resection with the aid of preoperative endovascular embolization on the day of surgery. Case 1: A 36-year-old woman presented with a two-month history of headache and vomiting. Magnetic resonance imaging(MRI)revealed a right cerebellar solid mass, mild hydrocephalus, and apparent peritumoral edema. Angiogram showed a highly vascularized mass, three feeding arteries from the superior cerebellar artery(SCA), and a dilated vein draining into the confluence. We performed preoperative embolization of the three feeders with 15% n-butyl-2-cyanoacrylate(NBCA). Final angiogram showed an absence of tumor staining. Tumor resection was performed on the same day, and gross total resection was achieved with no complications. Case 2: A 36-year-old man presented with a four-month history of headache and numbness in the left upper extremity. MRI revealed a right cerebellar solid mass with peritumoral edema. Angiogram showed a highly vascularized mass with two feeding arteries from the right SCA, one from the left posterior inferior cerebellar artery(PICA), and a dilated vein draining into the confluence. Preoperative embolization was performed with 15% NBCA, and complete devascularization was achieved. Tumor resection was performed on the same day, and gross total resection was achieved with no complications. In conclusion, preoperative embolization with NBCA on the day of surgery is a safe and effective adjunctive treatment for solid cerebellar hemangioblastoma.

[A Case of Traumatic Vertebral Arteriovenous Fistula Treated by Internal Trapping of the Vertebral Artery].

BACKGROUND: Traumatic vertebral arteriovenous fistula (TVAVF) is an uncommon disease that occurs after traumatic injury. Here we report a case of TVAVF presenting with cervical bruit successfully treated by internal trapping using coils. CASE PRESENTATION: A 66-year-old man was transferred to our hospital after falling into a ditch. Initial CT revealed a C2 fracture into the right transverse foramen, and the patient had been treated with conservative management. A vascular abnormality was suspected because the patient exhibited cervical bruit on admission. CT angiography revealed right TVAVF at the V2 segment of the right vertebral artery (VA) near the C2 fracture. Digital subtraction angiography also revealed right TVAVF between the V2 segment of the right VA and the vertebral venous plexus, draining into the right internal jugular vein and the deep cervical vein as well as the intracranial venous system. The fistula was also opacified by retrograde flow from the contralateral VA through the union, while the flow in the basilar artery was antegrade. The patient was diagnosed with TVAVF with large transection of the right VA, and underwent endovascular treatment with internal trapping of the right VA using coils starting distal to the transection and proceeding in a proximal direction. After treatment, the right VAVF and right VA were completely occluded. The patient achieved clinical symptom resolution with no neurological deficits. CONCLUSION: Endovascular treatment with internal trapping of the VA using coils is safe and effective against TVAVF.

[Stent-Assisted Coil Embolization of a Dissecting Aneurysm of the Posterior Cerebral Artery: A Case Report].

Dissecting aneurysms of the posterior cerebral artery (PCA) are rare, especially those at the P1 segment. Here, we describe the case of a 57-year-old woman with a subarachnoid hemorrhage (SAH). Computed tomography angiography (CTA) and digital subtraction angiography (DSA) revealed a small (3 mm) dissecting aneurysm with the typical pearl-and-string sign at the right P1 segment. Fourteen days after onset, the patient developed aphasia. DSA revealed vasospasm of the right middle cerebral artery, and we performed endovascular treatment by the intra-arterial injection of 1-(5-isoquinolinesulfonyl) homopiperazine. After this treatment, the patient's symptoms recovered immediately. Vertebral angiography revealed enlargement of the dissecting aneurysm (up to 7 mm diameter). We started a loading dose of 300 mg aspirin and 400 mg clopidogrel after observing growth of the aneurysm. Fifteen days after onset, we performed a stent-assisted coil embolization, and obtained nearly complete obliteration of the aneurysm with preserved patency of the parent artery. Six-month follow-up DSA demonstrated complete occlusion of the aneurysm with good patency of the stented PCA; the patient was at modified Rankin Scale 1. In the treatment of ruptured dissecting aneurysms, parent vessel occlusion (PVO) with aneurysm is common. However, PVO may cause both cerebral infarction of the distal area and perforator occlusion of the occluded vessel. Stent-assisted coil embolization can preserve parent vessel flow and obliterate the aneurysm. Stents offer a therapeutic alternative for PCA dissecting aneurysms, especially when PVO cannot be tolerated.

Nationwide survey of the nature and risk factors of complications in embolization of meningiomas and other intracranial tumors: Japanese Registry of NeuroEndovascular Therapy 2 (JR-NET2).

INTRODUCTION: Embolization of intracranial tumor is widely performed in Japan, mainly before neurosurgical resection. A retrospective, multicenter, observational study in Japan was conducted to clarify the nature, frequency, and risk factors of complications in intracranial tumor embolization. METHODS: Patients were derived from the Japanese Registry of NeuroEndovascular Therapy 2 (JR-NET2). A total of 20,854 patients were enrolled in JR-NET2, of which 1,018 patients (4.88 %) with intracranial tumors underwent embolization. The primary end point was the proportion of patients with a modified Rankin scale (mRS) score of 0-2 (independency) at 30 days. The secondary end point was the occurrence of complications related to the procedures. The risk factors of the occurrence of complications were studied. RESULTS: The proportion of patients with mRS scores ≤2 at 30 days after procedure was 91.3 %. Complications occurred in 15 of the 1,012 patients (1.48 %). Multivariate analysis showed that embolization for tumors other than meningioma (OR, 4.626; 95 % CI, 1.347-14.59; p = 0.0105) was significantly associated with the development of complications. CONCLUSION: The frequency of complications after intracranial tumor embolization was relatively low in this large Japanese cohort. Embolization for tumors other than meningioma was the only significant risk factor for the occurrence of complications.

Evaluation of the shrinkage process of a neck remnant after stent-coil treatment of a cerebral aneurysm using silent magnetic resonance angiography and computational fluid dynamics analysis: illustrative case.

BACKGROUND: Silent magnetic resonance angiography (MRA) mitigates metal artifacts, facilitating clear visualization of neck remnants after stent and coil embolization of cerebral aneurysms. This study aims to scrutinize hemodynamics at the neck remnant by employing silent MRA and computational fluid dynamics. OBSERVATIONS: The authors longitudinally tracked images of a partially thrombosed anterior communicating artery aneurysm's neck remnant, which had been treated with stent-assisted coil embolization, using silent MRA over a decade. Computational fluid dynamics delineated the neck remnant's reduction process, evaluating hemodynamic parameters such as flow rate, wall shear stress magnitude and vector, and streamlines. The neck remnant exhibited diminishing surface area, volume, neck size, dome depth, and aspect ratio. Its reduction correlated with a decline in the flow rate ratio of the remnant dome to the inflow parent artery. Analysis delineated regions within the contracting neck remnant characterized by consistently low average wall shear stress magnitude and variation, accompanied by notable variations in wall shear stress vector directionality. LESSONS: Evaluation of neck remnants after stent-coil embolization is possible through silent MRA and computational fluid dynamics. Predicting the neck remnant reduction may be achievable through hemodynamic parameter analysis.

Endovascular Treatment for Intracranial Artery Dissections in Posterior Circulation.

Intracranial artery dissections (IADs), although uncommon, are an important cause of cerebral infarction and subarachnoid hemorrhage (SAH). Some IADs can heal spontaneously after reconstitution of the vessel lumen with excellent prognosis. Meanwhile, others can progress to stroke that requires treatment. The incidence of IAD in the posterior circulation is higher than that in the anterior circulation. Anterior circulation dissections are more likely to develop into ischemia and posterior circulation lesions into hemorrhage. The mortality rate after IAD among patients with SAH is 19%-83%. Further, the mortality rate of IAD without SAH is 0%-3%. Patients with SAH commonly undergo surgery or receive neuroendovascular treatment (EVT) to prevent rebleeding. However, the treatment of IADs is empirical in the absence of data from randomized controlled trials. Recently, EVT has emerged and is considered for IADs because of its less invasiveness and perceived low rates of procedure-related morbidity with good efficacy. EVT strategies can be classified into deconstructive (involving sacrifice of the parent artery) and reconstructive (preserving blood flow via the parent vessel) techniques. In particular, the number of reports on reconstructive techniques is increasing. However, a reconstructive technique for ruptured IADs has not yet been established. This review aimed to provide an overview of IADs in the posterior circulation managed with EVT by performing a literature search.

Power suppression in EEG after the onset of SAH is a significant marker of early brain injury in rat models.

We analyzed the correlation between the duration of electroencephalogram (EEG) recovery and histological outcome in rats in the acute stage of subarachnoid hemorrhage (SAH) to find a new predictor of the subsequent outcome. SAH was induced in eight rats by cisternal blood injection, and the duration of cortical depolarization was measured. EEG power spectrums were given by time frequency analysis, and histology was evaluated. The appropriate frequency band and recovery percentage of EEG (defined as EEG recovery time) to predict the neuronal damage were determined from 25 patterns (5 bands × 5 recovery rates) of receiver operating characteristic (ROC) curves. Probit regression curves were depicted to evaluate the relationships between neuronal injury and duration of depolarization and EEG recovery. The optimal values of the EEG band and the EEG recovery time to predict neuronal damage were 10-15 Hz and 40%, respectively (area under the curve [AUC]: 0.97). There was a close relationship between the percentage of damaged neurons and the duration of depolarization or EEG recovery time. These results suggest that EEG recovery time, under the above frequency band and recovery rate, may be a novel marker to predict the outcome after SAH.

[Surgical and endovascular treatment for superior cerebellar artery aneurysms: report of two cases].

Aneurysms located on the superior cerebellar artery (SCA) are uncommon and their presentation, natural history, and clinical management are poorly understood. Reports related to the endovascular or surgical management of SCA aneurysms are rare. Herein, we report two cases of SCA aneurysm. The first is that of a 70-year-old woman who presented with subarachnoid hemorrhage (SAH). Surgical treatment (neck clipping) of the ruptured SCA aneurysm was performed, and the flow of the parent artery disappeared. The second is that of a 69-year-old woman with an unruptured SCA aneurysm who underwent endovascular surgery to occlude the parent artery. Neither patients exhibited any additional neurological deficits. SCA aneurysms often have either relatively wide or undefinable necks, so it is difficult to preserve the parent artery. According to several surgical reports, occlusion of the SCA appears well tolerated for a variety of reasons.