Trends and Progress in Neuroendovascular Treatment in Japan: Japanese Registry of Neuroendovascular Therapy (JR-NET) 4. Main Report.

We reported the main results of the Japanese Registry of Neuroendovascular Therapy (JR-NET) 4, a nationwide surveillance of therapy (NET) in Japan from January 2015 to December 2019. JR-NET 4 registered consecutive patients who underwent NETs by Japan Society of Neuroendovascular Therapy (JSNET) -certified specialists. The primary endpoint was functional independence (mRS score of 0-2) at 30 days post-NET, with secondary endpoints focusing on technical success and major adverse events within 30 days.A total of 63,230 patients and 60,354 NET procedures from 166 participating centers were analyzed. During the study period, NET cases have consistently increased, with an increase in the proportion of elderly patients. A significant trend shift was observed in the distribution of NET procedures, with endovascular treatment for acute ischemic stroke that showed a dramatic increase in 5 years. This trend aligns with key randomized clinical trials from 2015 that presented the efficacy of this treatment. Clinical outcomes at 30 days posttreatment revealed that endovascular treatment for acute ischemic stroke and other NETs maintained safety and effectiveness despite varying prevalence of functional independence between target diseases. The study also observed a steady increase in emergency treatment cases, reflecting the increase in acute ischemic stroke, a time-sensitive medical condition.This comprehensive surveillance highlights the trend of NET practices in Japan, driven by clinical evidence and advancements in treatment devices. Although these findings were specific to Japan, they offer valuable insights into the broader trends in NETs and acute stroke care.

Andexanet Alfa for the Reversal of Factor Xa Inhibitor Activity: Prespecified Subgroup Analysis of the ANNEXA-4 Study in Japan.

AIMS: Andexanet alfa, a specific antidote to factor Xa (FXa) inhibitors, has been approved for clinical use in several countries, including Japan, based on the results from the phase 3 trial ANNEXA-4. We aimed to assess the efficacy and safety of andexanet alfa treatment in FXa inhibitor-related acute major bleeding in patients enrolled for ANNEXA-4 in Japan. METHODS: This prespecified analysis included patients enrolled at Japanese sites in the prospective, open-label, single-arm ANNEXA-4 trial. Eligible patients had major bleeding within 18 hours of oral FXa inhibitor administration. The coprimary efficacy endpoints were percent change in anti-FXa activity and proportion of patients achieving excellent or good hemostatic efficacy 12 hours post-treatment. RESULTS: A total of 19 patients were enrolled, all of whom had intracranial hemorrhage; 16 patients were evaluable for efficacy. Median percent reduction in anti-FXa activity from baseline to nadir was 95.4% in patients taking apixaban, 96.1% in patients taking rivaroxaban, and 82.2% in patients taking edoxaban. Overall, 14/16 patients (88%) achieved excellent or good hemostasis (apixaban, 5/5; rivaroxaban, 6/7; edoxaban, 3/4). Within 30 days, treatment-related adverse events (AEs) and serious AEs occurred in 2 and 5 patients, respectively. One patient died during follow-up, and 2 patients experienced thrombotic events. CONCLUSION: Treatment with andexanet alfa rapidly reduced anti-FXa activity with favorable hemostatic efficacy in Japanese patients with acute major bleeding. Serious AEs of thrombotic events during rapid reversal of anti-FXa activity arose as particular safety concerns in this population as with previous studies.

Paradoxical worsening of ocular symptoms after transvenous embolization of cavernous sinus dural arteriovenous fistula due to coil-induced perifocal inflammation: A case report.

Ocular symptoms usually completely resolve after successful transvenous embolization of cavernous sinus dural arteriovenous fistulas (CS-dAVFs). Herein, we report a case of CS-dAVF in which sinus packing of the superior ophthalmic vein (SOV) caused coil-induced inflammation in orbital tissue, leading to deteriorating ocular symptoms. A 73-year-old woman presented with right-eye exophthalmos and chemosis. Cerebral angiography demonstrated right CS-dAVF, which retrogradely drained into the right SOV. We conducted sinus packing with coils via the right inferior petrosal sinus, resulting in obliteration of the shunts. One day after sinus packing, right exophthalmos and chemosis progressed, suggesting dAVF recurrence. However, no residual angiographic shunts were observed. Orbital magnetic resonance imaging (MRI) revealed edema in intraorbital tissue and gadolinium contrast enhancement of SOV wall. We presumed that the coils in SOV induced perifocal inflammation at the venous wall and surrounding orbital tissue, leading to aggravation of ocular symptoms. Following steroid therapy for 2 months, ocular symptoms and contrast enhancement on orbital MRI significantly improved without anticoagulant treatment. Posttreatment paradoxical worsening of ocular symptoms could be caused by coil-induced inflammation of the SOV wall near the orbital tissue. Steroid therapy could be effective in reducing orbital inflammatory reactions.

P2Y12 Reaction Units and Clinical Outcomes in Acute Large Artery Atherosclerotic Stroke: A Multicenter Prospective Study.

AIMS: We aimed to determine the association between acute platelet reactivity and clinical outcome in acute ischemic stroke (AIS) or transient ischemic attack (TIA) with large-artery atherosclerosis (LAA). METHODS: In this prospective, 16-multicenter study, we enrolled AIS/TIA patients with LAA receiving clopidogrel. We assessed the association of P2Y12 reaction units (PRU) 24 hours after initiation of antiplatelets with the CYP2C19 genotype and recurrent ischemic stroke within 90 days, and the difference between acute (≤ 7 days) and subacute (8-90 days) phases. RESULTS: Among the 230 AIS/TIA patients enrolled, 225 with complete outcome data and 194 with genetic results were analyzed. A higher PRU was significantly associated with recurrent ischemic stroke within 90 days (frequency, 16%), and within 7 days (10%). Twenty-nine patients (15%) belonged to a CYP2C19 poor metabolizer group (CYP2C19＊2/＊2, ＊2/＊3, or ＊3/＊3). Multivariable receiver-operating characteristic analysis showed a greater area-under-the-curve (AUC) in predicting recurrence within 7 days, compared to 8-90 days (AUC, 0.79 versus 0.64; p=0.07), with a cut-off PRU of 254. Multivariable analysis showed high PRU (≥ 254), which had a comparable predictive performance for recurrent ischemic stroke within 7 days (odds ratio, 6.82; 95% CI, 2.23-20.9; p＜0.001) to the CYP2C19 poor metabolizer genotype. The net reclassification improvement, calculated by adding high PRU (≥ 254) to a model including the CYP2C19 poor metabolizer genotype in the prediction of recurrence within 7 days, was 0.83 (p＜0.001). CONCLUSIONS: Acute PRU evaluation possesses predictive value for recurrent ischemic stroke, especially within 7 days in AIS/TIA with LAA.

Safety of Apixaban Monotherapy for Non-Valvular Atrial Fibrillation-Related Acute Stroke with Intra-/Extracranial Artery Stenosis.

INTRODUCTION: We investigated whether apixaban is safe for the prevention of further adverse events in non-valvular atrial fibrillation (NVAF) patients with intra-/extracranial artery stenosis (Stenosis group) compared with acute large vessel occlusion without intra-/extracranial artery stenosis (No stenosis group). We also examined whether combination therapy using apixaban and antiplatelet is safe. METHODS: ALVO (Apixaban on clinical outcome of patients with Large Vessel Occlusion [LVO] or stenosis) was a historical and prospective multicenter registry at 38 centers in Japan. Patients with NVAF and acute LVO or stenosis who received apixaban within 14 days after onset were included. We conducted the post hoc analysis using the ALVO dataset. We compared patients with stenosis versus those without stenosis in terms of the primary outcome, which was defined as a composite of all-cause death, major bleeding events, and ischemic events 365 days after onset. RESULTS: Of the 662 patients, 54 (8.2%) patients were classified into the Stenosis group, and 104 patients of the total (16%) reached the primary outcome. The cumulative incidence of primary outcome was not significantly different between the No stenosis and the Stenosis groups (hazard ratio [HR] 1.2, 95% confidence interval [CI]: 0.64-2.4; p = 0.52). Even after adjustment for predictive clinical variates, no significant difference in the primary endpoint between the No stenosis and the Stenosis groups was shown (adjusted HR 1.2, 95% CI: 0.59-2.5; p = 0.60). Fifty patients (7.6%) used an antiplatelet with apixaban. Among the Stenosis group patients, the cumulative incidence of the primary outcome was significantly higher among patients treated with an antiplatelet and apixaban (HR 3.5, 95% CI: 1.0-12; p = 0.048). CONCLUSION: Apixaban monotherapy appears safe for the prevention of further adverse events in the Stenosis group patients similar to the No stenosis group patients. Concomitant use of an antiplatelet might not be favorable in patients with stenosis.

Flow diverter therapy for immunosuppressant-resistant vertebral artery fusiform aneurysm due to eosinophilic granulomatosis with polyangiitis: illustrative case.

BACKGROUND: Eosinophilic granulomatosis with polyangiitis (EGPA) is a systemic small-vessel vasculitis characterized by the presence of asthma and eosinophilia. Because cerebral aneurysm formation induced by EGPA is a rare occurrence, there is no established treatment strategy for this condition. OBSERVATIONS: A 67-year-old female who was diagnosed with idiopathic eosinophilia 3 months ago developed de novo fusiform aneurysms in the left vertebral, left internal carotid, and bilateral superficial temporal arteries, as noted during a regular follow-up examination of a convexity meningioma. Pathological examination of the resected superficial temporal artery revealed eosinophilic granulomas, which led to the diagnosis of EGPA, as well as EGPA-induced aneurysm formation. As the partially thrombosed vertebral artery fusiform aneurysm enlarged, the compression of the medulla oblongata occurred despite intensive immunosuppressive therapy for 1 year. The patient underwent flow diversion therapy administered using the pipeline embolization device, resulting in complete disappearance of the aneurysm. LESSONS: Considering that the entire circumference of the aneurysmal wall is affected by necrotizing vasculitis, flow diverter therapy would be a reasonable and efficient approach for the treatment of EGPA-related aneurysms in cases in which the patient is nonresponsive to immunosuppressants.

Rupture of an adjacent cerebral aneurysm following the deployment of a Pipeline embolization device: illustrative case.

BACKGROUND: Although the Pipeline embolization device (PED) is effective for intracranial aneurysm treatment, its impact on the surrounding vascular structure is unknown. OBSERVATIONS: A 71-year-old woman was incidentally found to have a simultaneous large posterior communicating artery aneurysm and an ipsilateral small anterior choroidal artery aneurysm. She underwent flow diversion therapy for both aneurysms with a PED, but the distal shortening of the PED after deployment led to the exposure of the anterior choroidal artery aneurysm. Follow-up angiography revealed complete obliteration of the posterior communicating artery aneurysm, but the anterior choroidal artery aneurysm remained. Three years after the endovascular surgery, the patient experienced a subarachnoid hemorrhage due to the rupture of the anterior choroidal artery aneurysm. Retrospective analysis of angiographic images revealed a change in the vascular geometry surrounding the ruptured aneurysm after PED deployment; this was further accompanied by an increase in the flow velocity inside the aneurysm. LESSONS: Because PED use might induce the adverse effects on the adjacent uncovered aneurysm by changing the vascular geometry and hemodynamic stress, a cautious therapeutic strategy, such as proper placement of the stent and using a longer and appropriate-sized PED, should be chosen when deploying the PED.

Plasma tRNA derivatives concentrations for detecting early brain damage in patients with acute large vessel occlusion and predicting clinical outcomes after endovascular thrombectomy.

OBJECTIVE: Transfer RNA (tRNA) is involved in the acute stress response, which results in conformational changes and subsequent fragmentation. Using an antibody against tRNA-specific modified nucleoside 1-methyladenosine, we can selectively detect blood tRNA derivatives from damaged tissues, including neuronal tissue, which serves as a potential marker of early tissue damage. This preliminary study aimed to investigate the correlation between tRNA derivatives and clinical outcomes in patients with acute anterior large vessel occlusion, especially those who underwent endovascular thrombectomy (EVT). METHODS: Patients with acute ischemic stroke due to anterior circulation large vessel occlusion were prospectively enrolled in this study. Plasma tRNA derivatives were measured using an enzyme-linked immunosorbent assay with an anti-modified nucleoside 1-methyladenosine antibody. RESULTS: Seventeen patients were included. The plasma tRNA derivatives concentrations on admission increased significantly, corresponding to the infarction size (r = 0.492, p = 0.038), and were associated with clinical outcomes (p = 0.00309). A good clinical outcome (90-day modified Rankin scale score: 0-2) was achieved in seven patients (41.2%), and all had undergone EVT. Among these patients, tRNA derivatives concentrations were the only preoperative predictor, which was associated with good outcomes (modified Rankin scale score: 0-2) and was significantly lower than those with poor outcomes (modified Rankin scale score: 3-6) (p = 0.0333). Receiver operating characteristic analysis revealed that a tRNA derivative value of ≤ 142.0 mg/mL was associated with good clinical outcomes, with a sensitivity of 85.7% and a specificity of 100% (area under the curve, 0.952; 95% confidence interval: 0.82-1). CONCLUSION: tRNA derivatives concentration may be a sensitive marker of early brain damage in patients with acute large vessel occlusion. Patients with low levels of tRNA derivatives on arrival are likely to benefit from thrombectomy and have the potential to achieve good clinical outcomes.

Direct carotid puncture for endovascular surgery of intracranial aneurysms: Technical note for avoiding complications.

BACKGROUND: While the most intracranial aneurysms are approachable by femoral or brachial artery puncture during endovascular surgery, in some cases, the lesion is difficult to reach due to complications such as the presence of winding pathways. Direct carotid puncture (DCP) is an alternative access approach, despite the potential risk of fatal neck hematoma. Herein, we describe the DCP technique in a series of five patients with intracranial aneurysms, together with its technical considerations. METHODS: Patients with intracranial aneurysms who underwent endovascular surgery using DCP were reviewed retrospectively. We selected the 3F to 6F systems for DCP depending on the necessity of adjunctive techniques. To prevent DCP-associated complications, we (1) conducted a micropuncture before introducing the short sheaths,(2) selected the smallest possible size for the system, (3) reversed heparin postoperatively, and (4) performed perioperative intubation/sedation management. RESULTS: Five out of 535 patients underwent DCP in our hospital between 2015 and 2019; successful vascular access was achieved in all cases. Although a minor neck hematoma occurred in one case, the patient did not require additional treatment. According to a literature review, severe neck hematoma requiring rescue therapy occurs in 5 out of 95 cases (5.3%). CONCLUSION: Although the potential risk of neck hematoma is not negligible, the DCP technique appears to be a safe and effective approach in treating intracranial aneurysms with challenging access routes in cases where perioperative counter measurements are appropriately performed.

Potential hemorrhagic risk of endovascular revascularization therapy due to recanalization of the dissected perforator in intracranial internal carotid artery dissection: A case report.

BACKGROUND: Intracranial internal carotid artery (ICA) dissection manifesting as ischemic stroke is rare. Although endovascular revascularization therapy is effective in preventing the progression of stroke, little is known about the potential risk of this therapeutic approach. CASE DESCRIPTION: We report a case of a 38-year-old woman who presented with acute ischemic infarcts in the territory of the left anterior choroidal artery (AChA) due to intracranial ICA dissection. She underwent balloon angioplasty, resulting in the complete resolution of the stenosis. The AChA, which was nearly occluded preoperatively, was unexpectedly recanalized after the procedure. Four hours later, she developed a parenchymal hemorrhage in the left basal ganglia without subarachnoid hemorrhage. The AChA, suspected as the hemorrhagic source during surgical hematoma removal, was revealed to have a disrupted internal elastic lamina on pathological examination, suggesting that the dissection of the ICA extended to the AChA. CONCLUSION: To the best of our knowledge, this is the first case report demonstrating that the intracranial ICA dissection extends to the associated perforator. Considering the potential risk of subsequent hemorrhagic complications by recanalization of the dissected perforator, prudent postoperative management, including strict blood pressure control, is advisable following endovascular revascularization therapy against intracranial artery dissection involving perforators.

Reperfusion Therapy Brings Apixaban Administration Forward in Patients with Nonvalvular Arterial Fibrillation with Anterior Circulation Large Vessel Occlusion or Stenosis.

OBJECTIVE: The initiation of anticoagulant administration after large vessel occlusion (LVO) or stenosis with nonvalvular arterial fibrillation (NAVF) is controversial. We evaluate the timing of anticoagulation and its relationship with clinical factors. METHODS: We enrolled 595 anterior circulation LVO or stenosis with NAVF cases from 38 stroke centers. Laboratory data; activities of daily living; the Alberta Stroke Program Early CT Score (ASPECTS); the National Institutes of Health Stroke Scale (NIHSS) score; occluded artery; treatment methods; date of the initiation of apixaban administration and outcome were recorded. Multivariate analyses were performed after univariate analysis. RESULTS: The median start of apixaban administration after the stroke was 2 days (interquartile range, 1-5; range, 0-14). Multivariate analysis of variance showed that non-internal carotid artery occlusion (F value 4.60), reperfusion therapy (31.1), high ASPECTS (6.27) before anticoagulant intake, and absence of intracranial hemorrhage (12.9) were significantly correlated with early apixaban administration. Multiple logistic regression analysis for independent living at 90 days after the stroke showed significant factors: aging (odds, 0.94; 95% confidence interval [CI], 0.91-0.97); male (odds, 0.46; 95% CI, 0.26-0.79); prestroke independence (odds, 20.7; 95% CI, 6.48-93.9); number of white blood cells (odds, 0.99; 95% CI, 0.97-1.00); non-internal carotid artery occlusion; NIHSS score at 72 hours after the stroke (odds 0.92; 95% CI, 0.89-0.96); ASPECTS before apixaban intake (odds, 1.15; 95% CI, 1.00-1.31) and initiation of apixaban (odds, 0.91; 95% CI, 0.83-0.99). CONCLUSIONS: Early administration of apixaban is induced by nonsevere infarction, reperfusion therapy or none of intracranial hemorrhage and it correlates with an independent long-term outcome.

Rescue of distally placed stents in the setting of internal carotid artery dissection: A report of 2 cases with mechanistic insights.

Potential procedural complications of endovascular therapy for carotid artery dissection have not been clarified. Herein, we present the cases of a 46-year-old woman and a 59-year-old man who underwent carotid artery stenting for left cervical internal carotid artery dissection. During the procedure, intramural hematoma was squeezed out by stent placement, causing further extension of the pseudolumen and a prominent stenosis proximal to the stent. Additional stent deployment was subsequently performed to fully cover the newly arising stenosis, resulting in good recanalization. In cases with a long-affected lesion, we should consider the potential risk of dissection advancement following stent deployment. Using longer stents or additional rescue stenting would be efficient in counteracting this rare complication.

Stent-Assisted Embolization for Acutely Ruptured Aneurysm.

Objective: The purpose of this study was to report the results of stent-assisted embolization performed at our hospital for acutely ruptured aneurysms. Methods: This study consisted of 19 patients (4 men and 15 women) with acutely ruptured wide neck aneurysm who underwent stent-assisted coil embolization in acute stage between December 2016 and October 2020. Stent-assisted embolization in the acute stage was performed for very wide neck ruptured aneurysm only when balloon-assisted embolization was failed or was thought to be impossible. Factors related to poor clinical outcome were examined. Results: There were nine internal carotid artery (ICA) aneurysms, four anterior communicating artery (AcomA) aneurysms, three basilar artery (BA) aneurysms, two vertebral artery (VA) aneurysms and one anterior cerebral artery (ACA) aneurysm. The stents used were one Neuroform EZ and 18 Neuroform Atlas (Stryker). The contrast of the bleb disappeared in all cases with obvious bleb. Complete obliteration was achieved in two cases, neck remnant was in ten, and body filling was in seven. Both of the complete obliteration cases developed thrombotic complications. Modified Rankin score of 0-2 was observed in eight patients (good clinical outcome), whereas that of 4-6 was observed in 11 patients (poor clinical outcome). Several factors possibly affected to poor clinical outcome were examined and only age over 80 years was statically different. Complications related to procedure occurred in five patients; two cases of in-stent thrombosis, one case each of MCA perforation, stent occlusion, and coil fracture. Conclusion: Stent-assisted coil embolization using Neuroform EZ and Neuroform Atlas could be considered as an emergency treatment for acutely ruptured cerebral aneurysms with very wide neck. It is rarely indicated in patients with age over 80 years.

Giant Intraosseous Meningioma Associated with Calvarial Hyperostosis and Subcutaneous Invasion: Case Reports and Literature Review.

Most meningiomas grow intracranially, and primary intraosseous meningioma is rarely reported. We present two rare surgical cases of giant intraosseous meningothelial meningioma. The first patient was a 35-year-old male with parietal skull deformity without neurological symptoms. Total resection was successful. The origin was the parasagittal intraosseous layer, and the superior sagittal sinus was partially opened. The second patient was a 20-year-old female with a slightly upward protrusion of the frontal skull without pain or neurological deficits. The lesion was totally resected, and the origin was the parasagittal intraosseous layer invading into the dura matter and subcutaneous layer. The clinical management of these cases presented a surgical challenge because of detachment and repair from venous sinuses. The current report provides surgical tips for such rare diseases and is a good reference for the future treatment of similar diseases.

Effect of prior antiplatelet therapy on large vessel occlusion in patients with non-valvular atrial fibrillation newly initiated on apixaban.

INTRODUCTION: We evaluated the effect of prior antiplatelet therapy on large vessel occlusion (LVO) in patients with non-valvular atrial fibrillation (NVAF) newly initiated on apixaban. METHODS: Patients with acute LVO with acute stroke due to NVAF or stenosis with NVAF started on apixaban within 14 days of onset were enrolled. We compared incidence of major bleeding, cerebral hemorrhage, ischemic events, cerebral infarction, and all-cause mortality between patients with and without prior antiplatelet therapy for acute LVO. We also compared these events between patients who continued antiplatelet therapy after onset (continued group) and those who discontinued it (discontinued group). Hazard ratios were estimated after adjusting for confounders; interaction was evaluated considering intravenous thrombolysis (IVT) or endovascular treatment (EVT) according to major bleeding. RESULTS: The study comprised 686 eligible patients (excluded [n = 194]; enrolled [n = 492]). The antiplatelet group consisted of older patients (mean: 79 vs. 76 years; p = 0.006) and had a higher cumulative incidence of major bleeding (7.3% vs. 2.9%, p = 0.003). The incidence of ischemic events and all-cause mortality was similar between the groups. Among the 109 patients in the antiplatelet group, the cumulative incidence of major bleeding, ischemic events, and all-cause mortality was comparable between continued group (n = 26) and discontinued group (n = 83). There were no significant differences between groups with and without IVT/EVT. However, major bleeding occured more frequently in the antiplatelet group without IVT. CONCLUSION: Prior antiplatelet therapy for LVO in patients with NVAF newly initiated on apixaban was associated with major bleeding, which was more frequent in the antiplatelet group without IVT.

Time-outcome relationship in acute large-vessel occlusion exists across all ages: subanalysis of RESCUE-Japan Registry 2.

Early reperfusion after endovascular thrombectomy is associated with an improved outcome in ischemic stroke patients; however, the time dependency in elderly patients remains unclear. We investigated the time-outcome relationships in different age subgroups. Of 2420 patients enrolled in the RESCUE-Japan Registry 2 study, a study based on a prospective registry of stroke patients with acute cerebral large-vessel occlusion at 46 centers, we analyzed the data of 1010 patients with successful reperfusion after endovascular therapy (mTICI of 2b or 3). In 3 age subgroups (< 70, 70 to < 80, and ≥ 80 years), the mRS scores at 90 days were analyzed according to 4 categories of onset-to-reperfusion time (< 180, 180 to < 240, 240 to < 300, and ≥ 300 min). In each age subgroup, the distributions of mRS scores were better with shorter onset-to-reperfusion times. The adjusted common odds ratios for better outcomes per 1-category delay in onset-to-reperfusion time were 0.66 (95% CI 0.55-0.80) in ages < 70 years, 0.66 (95% CI 0.56-0.79) in ages 70 to < 80 years, and 0.83 (95% CI 0.70-0.98) in ages ≥ 80 years. Early reperfusion was associated with better outcomes across all age subgroups. Achieving early successful reperfusion is important even in elderly patients.

Carotid artery stenting in a patient with an incidentally found double aortic arch: A case report.

Double aortic arch is a type of congenital vascular ring, which rarely presents in adults. Herein, we report a case of carotid artery stenting (CAS) accompanied by an incidentally found double aortic arch. A 77-year-old man presented with bilateral severe carotid artery stenosis. The patient underwent truncal 3D-computed tomography angiography (CTA) to evaluate the access route before CAS, which lead to the diagnosis of an asymptomatic double aortic arch. Referring to the 3D-CTA images, a guiding catheter was successfully navigated to the targeted common carotid artery via the transfemoral approach despite the challenging, complex anatomy of the aortic arch. CAS was performed in both carotid arteries under distal balloon protection, without any neurological deficits. Considering the possible presence of anatomical variants such as double aortic arch, preoperative evaluation of the access route would be efficient for prospective CAS patients.

Relationship between Pathological Characteristics and Radiological Findings on Perfusion MR Imaging of Meningioma.

Few studies have reviewed the roles of perfusion magnetic resonance (MR) imaging in the histopathological examination of meningiomas. We analyzed the relationships between radiological findings on perfusion MR imaging and pathological characteristics such as origin of the tumor, mitotic activity, pathological subtype, and perifocal edema formation. The subjects were 21 surgical cases of meningioma preoperatively evaluated by perfusion MR imaging. A region of interest (ROI) was set inside of the tumor, and perifocal edema of the same size, cerebral blood volume (CBV), and cerebral blood flow (CBF) on perfusion MR and diffusion-weighted (DW) imaging were analyzed. These radiological data were evaluated in comparison with histopathological characteristics. On perfusion MR imaging, the average ratio of CBV against the contralateral side was 6.43 (1.13-20.0) and that of CBF was 7.73 (1.34-11.3). There was no significant relationship with perfusion MR imaging data, tumor volume, or perifocal edema volume. However, the large peritumoral edema group often had a higher CBV and CBF than the non-large peritumoral edema group. The skull base group had a significantly higher CBV and lower signal intensity on DW images than the non-skull base group. Signal intensity on DW images was higher in grade II or III than in grade I. Perfusion MR imaging data revealed that the higher ratio of peritumoral edema against tumor size was associated with higher blood flow and blood volume under intratumoral circulatory conditions, and that skull base meningioma had a higher blood volume than non-skull base meningioma.