Anatomical Flow Diversion by Hybrid Strategy for Intractable Large Cerebral Aneurysms.

BACKGROUND AND IMPORTANCE: Flow diverters (FDs) provide curative endovascular treatment for wide-necked sidewall aneurysms. The efficacy of FDs for bifurcation or branching sidewall aneurysms is probably limited. We used anatomical flow diversion (AFD) for intractable large cerebral aneurysms. We report our experiences with AFD. METHODS: The concept of AFD is the transformation from the bifurcation or branching sidewall type to the nonbranching sidewall type. Linearization of the parent artery by stenting, intentional branch occlusion, and aneurysmal coil embolization were performed. Furthermore, bypass surgery is performed for patients intolerant to branch occlusions. We evaluated the clinical outcomes of intractable aneurysms treated with AFD. RESULTS: AFD was performed in seven unruptured large aneurysms. Aneurysmal locations were the top of the basilar artery (BA), BA-superior cerebellar artery (SCA), internal carotid artery (IC)-posterior communicating artery (PcomA), and IC terminal. The mean dome diameter was 17.0 ± 4.6 mm. Six patients underwent bypass surgery. The occluded branches were the PCA + SCA, PcomA, and anterior cerebral artery (ACA) A1. An FD was used in three patients and a neck bridge stent in four patients. No intraprocedural complications occurred. Two postprocedural ischemic complications occurred in one patient. Six (86%) patients demonstrated a modified Rankin Scale (mRS) 0 at the 3-month follow-up, and one with an ischemic complication showed an mRS 5. Complete occlusion of all aneurysms was maintained with a median follow-up duration of 60 months. CONCLUSION: AFD is useful for intractable large cerebral aneurysms with high curability, although safety verification is required.

Additional outlet occlusion as an important factor in avoiding retreatment after transvenous embolization for cavernous sinus dural arteriovenous fistulas.

BACKGROUND: Transvenous embolization (TVE), such as selective shunt occlusion, is the first line treatment for cavernous sinus dural arteriovenous fistula (CSDAVF). Despite the favorable outcomes of TVE, some cases necessitating retreatment due to recurrence or incomplete occlusion persist. Given the physical, psychological, and financial burden of multiple treatments, understanding the predictive factors for recurrence, spontaneous occlusion, or retreatment is important. However, few reports have addressed these factors, complicating decision making regarding the need for retreatment. This study analyzed predictive factors for retreatment and spontaneous occlusion to offer new insights into CSDAVF management. METHODS: This retrospective, observational study was conducted in two acute care hospitals. Patients aged 18-100 years undergoing endovascular treatment for CSDAVF from January 2011 to December 2022 were included. RESULTS: Of 65 patients treated with TVE, 29 experienced immediate complete occlusion. Meanwhile, 22 of 36 patients with incomplete occlusion had spontaneous occlusion, and retreatment was performed in 20% of patients. Additional outlet occlusion was negatively associated with retreatment (P=0.046), and it tended to promote spontaneous occlusion (P=0.056). Favorable functional outcomes were observed in all patients, and approximately 94% of patients showed complete occlusion at the latest follow-up. CONCLUSION: TVE is an effective treatment for CSDAVF. Outlet occlusion, when immediate complete occlusion is unattainable, is important to reduce retreatment and promote spontaneous occlusion. Substantially reducing shunt flow, carefully assessing dangerous drainage routes, and closely monitoring the residual shunt are crucial for preventing intracranial hemorrhage when outlet occlusion is performed.

Targeted Transarterial Embolization for Treatment of a Symptomatic Venous Varix in the Draining Vein of an Arteriovenous Malformation: Case Report and Literature Review.

BACKGROUND: Venous varices in the draining vein of arteriovenous malformations (AVMs) can result in compression symptoms. This condition is extremely rare, and its treatments and long-term outcomes are unresolved. METHODS: Herein, we describe the treatment of a thrombosed venous varix in a draining vein and review the relevant literature. RESULTS: The patient presented with progressive right-sided hemiparesis and aphasia. Magnetic resonance imaging revealed flow void accumulation from the corpus callosum to the left ventricle and a 30-mm mass in the left putamen. The patient underwent targeted transarterial embolization to reduce the blood flow to the venous varix and relieve the neurologic symptoms. The patient had recovered completely from the right hemiparesis and aphasia 4 years after treatment, with a modified Rankin scale score of 0. CONCLUSION: Targeted transarterial embolization for symptomatic venous varix is a palliative treatment that may improve long-term functional outcomes.

Short- versus long-term Dual AntiPlatelet Therapy for Stent-Assisted treatment of CErebral aneurysm (DAPTS ACE): a multicenter, open-label, randomized clinical trial.

BACKGROUND: The optimal duration of dual antiplatelet therapy (DAPT) after stent-assisted coil embolization (SACE) for cerebral aneurysm remains uncertain. This randomized trial of short- versus long-term Dual AntiPlatelet Therapy for Stent-Assisted treatment of CErebral aneurysm (DAPTS ACE) aimed to clarify whether long-term DAPT can reduce the occurrence of ischemic stroke in patients with cerebral aneurysms treated by SACE compared with short-term DAPT. METHODS: Patients treated for cerebral aneurysm with SACE were enrolled from 17 hospitals in Japan. Patients were enrolled within 30 days after SACE and assigned in a 1:1 ratio to receive long-term (12 months) or short-term (3 months) DAPT with aspirin and clopidogrel. Randomization was performed centrally through a web-based system. The primary outcome was the time to ischemic stroke event during 3 to 12 months after SACE. This trial was registered with the Japan Registry of Clinical Trials (jRCTs051180141). RESULTS: A total of 142 patients were recruited from November 4, 2016 to January 7, 2019. Among them, 65 and 68 patients assigned to the long- and short-term DAPT groups, respectively, were included in the full analysis set. Ischemic stroke occurred in no patients in the long-term DAPT group and in one patient in the short-term DAPT group. The incidence rate did not differ between the groups (0.0 vs 2.1/100 person-years; log rank test, P=0.33). CONCLUSIONS: In this multicenter randomized controlled trial, there was not a statistically significant difference in the rate of ischemic strokes between long- and short-term DAPT.

Hidden Bow Hunter's Syndrome Diagnosed Using Dynamic Cerebral Angiography and Successfully Treated with Spinal Surgery: A Case Report and Review of the Literature.

Hidden bow hunter's syndrome (HBHS) is a rare disease in which the vertebral artery (VA) occludes in a neutral position but recanalizes in a particular neck position. We herein report an HBHS case and assess its characteristics through a literature review. A 69-year-old man had repeated posterior-circulation infarcts with right VA occlusion. Cerebral angiography showed that the right VA was recanalized only with neck tilt. Decompression of the VA successfully prevented stroke recurrence. HBHS should be considered in patients with posterior circulation infarction with an occluded VA at its lower vertebral level. Diagnosing this syndrome correctly is important for preventing stroke recurrence.

Cancer-Associated Stroke and Acute Endovascular Reperfusion Therapy.

Since stroke is often associated with cancer, acute stroke patients with cancer undergoing endovascular therapy (EVT) are not uncommon. Reportedly, the proportion of such cases is approximately 6%-7% of all stroke EVT cases. Ischemic stroke in patients with active cancer (cancer-associated stroke) includes not only strokes caused by cancer-related hypercoagulability but also coincident strokes due to common etiologies, strokes associated with tumor emboli, direct tumor invasion of blood vessels, and strokes associated with cancer therapy. Stroke caused by cancer-related hypercoagulability itself encompasses various entities, including paradoxical embolism, stroke due to nonbacterial thrombotic endocarditis, and in situ arterial occlusion due to disseminated intravascular coagulation or thrombotic microangiopathy. Thus, diverse mechanisms contribute to cancer-associated stroke, emphasizing the need to consider individualized treatment strategies for acute cases involving large vessel occlusion. Observational studies have shown that EVT for cancer-associated stroke results in poorer clinical outcomes, but with comparable rates of successful reperfusion and symptomatic intracranial hemorrhage when compared with stroke patients without cancer. This suggests that denying patients EVT solely on the basis of comorbid active cancer is inappropriate, and decision-making should be shared with the patients and their families, preferably through a multidisciplinary team approach. Thrombi retrieved from patients with stroke caused by cancer-related hypercoagulability have unique characteristics, being predominantly platelet rich and difficult to retrieve. Preprocedural imaging and serum biomarkers, including the hyperdense vessel sign on non-contrast CT, susceptibility vessel sign on T2* or susceptibility-weighted MRI, three-territory sign on MRI, and D-dimer levels, are valuable in evaluating the stroke subtype and thrombus features. Thrombectomy techniques, such as contact aspiration and stent retriever monotherapy, have shown varying degrees of effectiveness for stroke caused by cancer-related hypercoagulability, warranting further study. After reperfusion therapy, appropriate treatment for the prevention of stroke recurrence should be initiated, considering the specific stroke subtypes. In conclusion, cancer-associated stroke encompasses diverse subtypes, and thrombi associated with stroke caused by cancer-related hypercoagulability present various challenges for thrombectomy. Individualized treatment approaches based on underlying mechanisms are essential for improving outcomes in acute stroke patients with active cancer. Optimization of preprocedural diagnosis, EVT techniques, and secondary prevention of stroke caused by cancer-related hypercoagulability will lead to better management of these patients and enhance their quality of life.

Evaluation of Venous Structures that Are Involved in Transsylvian Approach Using 3D Rotational Venography.

In the transsylvian (TS) approach, as characterized by clipping surgery, the presurgical visualization of the superficial middle cerebral vein (SMCV) can help change the surgical approach to ensure safe microsurgery. Nevertheless, identifying preoperatively the venous structures that are involved in this approach is difficult. In this study, we investigated the venous structures that are involved in the TS approach using three-dimensional (3D) rotational venography (3D-RV) and evaluated the effectiveness of this method for presurgical simulation. Patients who underwent 3D-RV between August 2018 and June 2020 were involved in this retrospective study. The 3D-RV and partial maximum intensity projection images with a thickness of 5 mm were computationally reconstructed. The venous structures were subdivided into the following three portions according to the anatomic location: superficial, intermediate, and basal portions. In the superficial portion, predominant frontosylvian veins were observed on 31 (41%) sides, predominant temporosylvian veins on seven (9%) sides, and equivalent fronto- and temporosylvian veins on 28 (37%) sides. The veins in the intermediate (deep middle cerebral and uncal veins) and basal portions (frontobasal bridging veins) emptied into the SMCV on 57 (75%) and 34 (45%) sides, respectively. The 3D-RV images were highly representative of the venous structures observed during microsurgery. In this study, 3D-RV was utilized to capture the details of the venous structures from the superficial to the deep portions. Presurgical simulation of the venous structures that are involved in the TS approach using 3D-RV may increase the safety of microsurgical approaches.

Endovascular therapy for acute intracranial large vessel occlusion due to atherothrombosis: Multicenter historical registry.

BACKGROUND: Atherothrombotic stroke-related large vessel occlusion (AT-LVO) is caused by two etiologies, the intracranial artery occlusion due to in situ occlusion (intracranial group) or due to embolism from cervical carotid occlusion or stenosis (tandem group). The prognosis and reocclusion rate of each etiology after endovascular therapy (EVT) is unclear. METHODS: We conducted a historical multicenter registry study at 51 Japanese centers to compare the prognoses of AT-LVO between two etiologies. The primary outcome was the incidence of recurrent ischemic stroke or reocclusion of the treated vessels within 90 days after EVT. Each of the primary outcome means the incidence of recurrent ischemic stroke and reocclusion of the treated vessels within 90 days after EVT. RESULTS: We analyzed 582 patients (338 in the intracranial group and 244 in the tandem group). Patients in the intracranial group were younger (mean 71.9 vs 74.5, p=0.003), more of them were female and fewer of them were current smokers than those in the tandem group. In the tandem group, the patients' National Institutes of Health Stroke Scale score on admission was higher (13 vs 15, p=0.006), onset to puncture time was shorter (299 [145-631] vs 232 [144-459] minutes, p=0.03) and Alberta Stroke Program Early CT Score (ASPECTS) was lower (8 [7-9] vs 8 [6-9], p=0.0002). The primary outcome was higher in the intracranial group (22.5% vs 8.2%, p<0.0001). However, any ICH and death were not significantly different in the two groups. CONCLUSIONS: The incidence of recurrent ischemic stroke or reocclusion after EVT for AT-LVO was higher in the intracranial group.

Relation between duration of dual antiplatelet therapy and risk of ischemic stroke after stent-assisted treatment of cerebral aneurysm (DAPTS ACE-registry).

BACKGROUND: The optimal duration of dual antiplatelet therapy (DAPT) in patients with cerebral aneurysm who undergo stent-assisted coil embolization (SACE) has not been established. We aimed to clarify the association between duration of DAPT and incidence of ischemic stroke in patients with cerebral aneurysm. METHODS: We registered patients with cerebral aneurysm who underwent SACE in 27 hospitals in Japan. Those treated with DAPT (aspirin and clopidogrel) were eligible for inclusion in a previously reported randomized control trial (RCT). Patients who were ineligible or refused to participate to the RCT were followed-up for 15 months after SACE as the non-RCT cohort. Our study examined both the RCT and non-RCT cohorts. The primary and secondary outcomes were ischemic stroke and hemorrhagic events. RESULTS: Among the 313 patients registered, 296 were included for analysis (of these, 136 were RCT patients and 160 were non-RCT patients). Patients who were treated with DAPT for more than 6 months (n=191) were classified as the long-term DAPT group. Those treated less than 6 months (n=105) were classified as the short-term group. The incidence of ischemic stroke did not significantly differ between the long-term group (2.5 per 100 person-years) and the short-term group (3.2 per 100 person-years); nor did incidence of hemorrhagic events (0.8 and 3.2 per 100 person-years, respectively). The period of DAPT was not significantly associated with incidence rates of ischemic stroke or hemorrhagic events. CONCLUSIONS: Duration of DAPT was not associated with the incidence of ischemic stroke in the first 15 months after SACE.

[Evidence and Patient Selection for Endovascular Reperfusion Therapy for Acute Ischemic Stroke:A Narrative Review].

Three former stroke trials failed to show the efficacy of endovascular stroke reperfusion therapy using intra-arterial thrombolysis or older-generation mechanical thrombectomy devices, compared with usual medical care in 2013. However, five pivotal trials in 2015(MR CLEAN, ESCAPE, EXTEND-IA, SWIFT PRIME, and REVASCAT), using newer-generation devices(e.g., stent retrievers), have shown stroke thrombectomy to clearly improve the functional outcome of patients with occlusion of the internal carotid artery or the M1 portion of the middle cerebral artery(baseline National Institutes of Health Stroke Scale score ≥ 6; baseline Alberta Stroke Program Early Computed Tomography Score ≥ 6), and who could receive thrombectomy within 6 h of symptom onset . In 2018, the efficacy of stroke thrombectomy for late-presenting patients with up to 16-24 h of onset and those who had a mismatch between neurological severity and ischemic core volume was also established by the DAWN and DEFUSE 3 trials. In 2022, the efficacies of stroke thrombectomy for patients with a large ischemic core or basilar artery occlusion were identified. This article discusses the evidence and patient selection for endovascular reperfusion therapy for acute ischemic stroke.

Levetiracetam Versus Levetiracetam Plus Sodium Channel Blockers for Postoperative Epileptic Seizure Prevention in Brain Tumor Patients.

Background Brain tumor patients tend to develop postoperative epileptic seizures, which can lead to an unfavorable outcome. Although the incidence of postoperative epileptic seizures and adverse events are improved with the advent of levetiracetam (LEV), postoperative epilepsy occurs at a frequency of 4.6% or higher. In brain tumor patients, the addition of sodium channel blockers (SCBs) to LEV significantly reduces seizures, though confirmed in a non-postoperative study. Thus, the combination of SCBs with LEV might be promising. Objective In this prospective randomized controlled trial we investigated the safety, evaluated by adverse events during one and two weeks after surgery, and the efficacy, evaluated by the incidence of early epilepsy, including non-convulsive status epilepticus (NCSE), of using LEV alone or SCBs added to LEV in patients who underwent craniotomy or biopsy for brain tumors or brain mass lesions. Methods Patients with brain tumors or brain mass lesions undergoing surgical interventions, excluding endoscopic endonasal surgery (EES), with a diagnosis of epilepsy were eligible for this study. Patients are randomized into either Group A or B (B1 or B2) after the informed consents are taken; LEV alone in Group A patients, while LEV and SCBs in Group B patients (GroupB1, intravenous fosphenytoin plus oral lacosamide (LCM) and GroupB2, intravenous LCM plus oral LCM) were administered postoperatively. Fifty-three patients were enrolled during the first two and a half years of the study and four of them were excluded, resulting in the accumulation of 49 patients' data. Results Postoperative epileptic seizures occurred only in three out of 49 patients during the first week (6.1%) and in seven patients within two weeks after surgery (14.3%, including the three patients during the first week). In Group A, epileptic seizures occurred in two out of 26 patients during the first week (7.7%) and in five patients within two weeks (19.2%) after surgery. In Group B, epileptic seizures occurred in one out of 23 patients during the first week (4.3%) and in two patients during the first two weeks (8.7%). Low complication grade of epileptic seizures was observed in Group B rather than in Group A, however, without significant difference (p=0.256). There was no difference in the frequency of adverse effects in each group. Conclusion Although not statistically significant, the incidence of epileptic seizures within one week after surgery was lesser in LEV+SCBs groups than in LEV alone. No hepatic damage or renal function worsening occurred with the addition of LCM, suggesting the safety of LEV+SCBs therapy.

A Ruptured Aneurysm in Aplastic or Twig-like Middle Cerebral Artery: A Case Report with Histological Investigation.

Aplastic or twig-like middle cerebral artery (Ap/T-MCA) is a rare vascular anomaly that can cause a hemorrhagic or ischemic event. We report a 38-year-old man who presented with intracerebral hemorrhage from a ruptured aneurysm associated with an Ap/T-MCA. After aneurysm trapping and resection, histopathological examination revealed an internal elastic lamina (IEL) disruption and a thin aneurysmal wall. The patient recovered well after surgery and rehabilitation. No hemorrhagic or ischemic events have occurred during 2 years of follow-up. Ap/T-MCA-associated aneurysms exhibit a disrupted IEL and thin wall, which demonstrates the fragility of the "twig-like" vessels.

Treatment Outcomes of Cerebral Aneurysms Presenting with Optic Neuropathy: A Retrospective Case Series.

BACKGROUND: Optic neuropathy due to an aneurysm is relatively rare, with only a few small case series on this topic, and no randomized trials having been published until now. As such, the functional prognosis and treatment for aneurysm-induced optic neuropathy remain controversial. OBJECTIVE: We quantified optic nerve injuries using an objective index (the visual impairment score) and evaluated prognostic factors of postoperative visual function. MATERIALS AND METHODS: Of 960 patients treated for an unruptured intracranial aneurysm, 18 (1.9%) patients had optic neuropathy. Visual acuity and visual field were assessed before surgery and 6 months' postoperatively. Cases were classified on the basis of treatment modality (coil embolization or flow alteration [FA]) and prognostic factors of the two treatment groups. RESULTS: Of the 18 patients with an intracranial aneurysm and optic neuropathy, 12 (67%) were treated using coil embolization and 6 (33%) were FA. Visual function improved after surgery in 8 patients (44%), 5 (42%) in the coil embolization group, and 3 (50%) in the FA group. The visual function remained stable after surgery in 6 (33%) patients and worsened in 4 (22%). Patients with an aneurysms <15 mm in size had a favorable outcome (P = 0.05). CONCLUSIONS: Surgical treatment improved vision in 44% of cases, with no difference in the prognosis of coil embolization and FA and no effect of the duration of symptoms on outcomes. Further, the prognosis of visual function recovery was better for aneurysms <15 mm in diameter.

Vascular wall components in thrombi obtained by acute stroke thrombectomy: clinical significance and related factors.

BACKGROUND AND PURPOSE: Vascular wall components (VWCs) are sometimes identified as collagen fibers in specimens retrieved by thrombectomy from acute stroke patients. However, their clinical significance and associated factors remain unclear. The purpose of this study was to clarify the factors associated with VWCs in retrieved thrombi. METHODS: Consecutive acute stroke patients treated endovascularly using the Penumbra aspiration catheter or stent retrievers (SRs) at our institute from November 2013 to April 2016 were retrospectively reviewed, and the retrieved thrombi were evaluated histopathologically. VWCs were defined as banded collagen fibers with a distinct boundary observed at the rim or outside of the retrieved thrombi. Factors associated with the presence of VWCs were studied. RESULTS: A total of 150 specimens (76 specimens retrieved by the Penumbra, 74 by SRs) from 101 patients (47 women, age 74.9±11.1 years) were investigated. Applied thrombectomy devices were aspiration catheters in 42 patients, SRs in 21 patients, and both in 38 patients. VWCs were observed in 24 specimens (16%) from 22 patients. A low proportion of erythrocyte components (41.7±24.8% vs 55.0±26.3%, P=0.01), a high frequency of the devices reaching the M2/P2 (75% vs 50%, P=0.02), and a high number of device passages (P for trend=0.02) were associated with VWC positive thrombi. Successful recanalization (Treatment in Cerebral Ischemia ≥2b) tended to be less frequent in patients with VWC positive thrombi than in those without (73% vs 89%, P=0.06). CONCLUSIONS: The histopathology of occlusive thrombi, arterial sites where devices reached, and number of device passages, might affect the presence of VWCs in retrieved thrombi.

[A case of cardiogenic embolism, which occurred under appropriate warfarin use, treated with thoracoscopic left atrial appendectomy].

A 74-year-old man with a past medical history of bradycardiac atrial fibrillation and an old cerebral infarction presented with dysarthria. He had been treated with warfarin and PT-INR on admission was 2.0. MRI of the head revealed an acute ischemic stroke involving the cerebellum and left occipital lobe. Because transesophageal cardiac echography showed a thrombus in the left atrial appendage, anticoagulant treatment with warfarin and heparin was initiated. The thrombus was enlarging; therefore, we changed the anticoagulant therapy to apixaban with heparin on day 11. On day 17, a hemorrhagic cerebral infarction occurred. After the hemorrhage diminished, we treated him with warfarin aiming for a PT-INR between 3 and 4. The thrombus gradually shrank and disappeared on day 110. Finally, a thoracoscopic left atrial appendectomy was performed as a secondary prevention, with no recurrence till date.

[How do the interventional neurologists function in the clinical setting?].

Neuroendovascular therapy is a rapidly evolving clinical subspecialty because of its minimal invasiveness and novel device development. In Japan, neurosurgeons perform a substantial portion of neuroendovascular procedures, however, the number of neurologists who certified by the Japanese Society for Neuroendovascular Therapy (interventional neurologist) is gradually increasing. Neurologists tend to deal with medical treatment in the acute stage and prevention of ischemic stroke, in addition, neuroendovascular procedures for ischemic cerebrovascular diseases performed by neurologists themselves, such as acute revascularization therapy for acute intracranial major artery occlusion or carotid artery stenting, might provide various benefits to ischemic stroke patients because of the smooth, seamless and close management from admission, to intervention, to discharge and after discharge. Because of insufficient number of interventionists to perform emergent neurointerventional procedures in the clinical setting of acute ischemic stroke in Japan, we wish that more neurologists get interested in and receive training in the neuroendovascular therapy.

Transarterial embolization with use of lipiodol and gelatin sponge for active nasal bleeding from hepatocellular carcinoma metastasis in the pituitary gland.

A 58-year-old man presented with a very rare case of pituitary metastasis from hepatocellular carcinoma with active nasal bleeding which was treated by transarterial embolization using ethiodized oil (Lipiodol) and gelatin sponge. After treatment, nasal bleeding ceased and tumor size decreased. The prognosis for patients with pituitary metastases is very poor, so aggressive treatment is recommended to alleviate symptoms. This minimally invasive approach may be a reasonable therapeutic option for pituitary metastases.

[Endovascular treatment for carotid artery stenosis].

Carotid artery stenting (CAS) is an endovascular treatment for carotid artery stenosis, and is a less invasive method than carotid endarterectomy (CEA). Reimbursement of CAS with self-expanding stents and filter protection devices had started since 2008 in Japan for the patients with symptomatic stenosis (≥ 50%) and asymptomatic stenosis (≥ 80%) with CEA high risk due to systemic diseases, advanced age, high position, restenosis after CEA, and stenosis caused by radiation. The standard methods for filter-protected CAS is pre-dilatation with a small balloon to allow stent placement and post-dilatation with a balloon of a size smaller than the diameter of the normal internal carotid artery under 2 anti-platelets drugs and full heparinization. Distal embolism is the most important complication for the patients with vulnerable plaque, which is detected by ultrasound sonography or MRI. Bradycardia and hypotension may occur during and after CAS. Hyperperfusion may also occur in patients with impairment of the cerebrovascular reactivity, which is detected by single photon emission computed tomography (SPECT) with acetazolamide challenge. We should identify patients with high risk for CAS due to anatomy or vulnerability of the plaque to avoid periprocedural complication.

Reversible hemianopsia caused by mechanical compression of the visual pathway by the dilated draining vein of an arteriovenous malformation--case report.

A 41-year-old woman presented with progressive hemianopsia caused by compression of the lateral geniculate body by the dilated basal vein draining a contralateral frontal arteriovenous malformation (AVM). Magnetic resonance (MR) imaging revealed left frontal AVM and right lateral geniculate body compression due to the dilated basal vein. Emergent presurgical transarterial embolization and surgical removal were performed. Left hemianopsia completely recovered 3 months after surgery and MR imaging indicated improvement of the compression of the lateral geniculate body. Direct mechanical compression of the enlarged drainage vein is one of the causes of homonymous hemianopsia. Early surgical treatment is recommended to obtain a rapid recovery.