Reversed-Image Mechanical Thrombectomy for Acute Ischemic Stroke in a Situs Inversus Totalis Patient.

An 85-year-old female with situs inversus totalis presented with right hemiplegia, right facial nerve palsy, eye deviation to the left, and aphasia. Magnetic resonance imaging revealed acute ischemic lesions in the left insular cortex and the frontal lobe. Magnetic resonance angiography revealed an occlusion of the left internal carotid artery. Reversed-image mechanical thrombectomy achieved complete reperfusion in three passes within 54 minutes. Six months post-intervention, the patient could walk indoors independently. Our technique, which replicates the normal arterial anatomy by inversion and angulation, was adapted to situs inversus totalis.

Predictors of Ischemic Complication in Anterior Choroidal Artery Aneurysm Repair.

BACKGROUND: Treatment of anterior choroidal artery (AchoA) aneurysms is challenging because of the risk of artery injury. The objective of the study was to evaluate the incidence and predictors of AchoA infarction in patients who underwent surgical or endovascular procedure. METHODS: We included 123 patients with AchoA aneurysms treated by surgical clipping (n = 62; 50.4%) or endovascular coiling, including flow diverter placement (n = 61; 49.6%). The clinical and radiological data were retrospectively analyzed. AchoA infarction was defined as the presence of a hyperintense signal on diffusion-weighted imaging in the area of AchoA, including the posterior limb of the internal capsule. RESULTS: AchoA infarction was detected in 8 cases (6.5%), with similar incidence in both groups (6.5% [4/62] vs. 6.6% [4/61]). It occurred in ruptured aneurysms more frequently than in unruptured aneurysms (14.3% [6/42] vs. 2.5% [2/81], P = 0.019). In the surgical group, all 4 affected patients had a non-proximal type AchoA, whereas in the non-infarction group, 9 patients (15.5%) had a non-proximal type AchoA (P = 0.001). In the endovascular group, the incidence was higher in patients with ruptured aneurysms (17.3% [4/23] vs. 0% [0/38], P = 0.017) and lower in patients with pre-admission antiplatelet therapy (0% [0/39] vs. 18.8% [4/22], P = 0.014). CONCLUSIONS: Repair of an AchoA aneurysm is associated with the risk of incurring post-procedural AchoA infarction. Surgical clipping and endovascular coiling have similar complication rates, but risk factors specific to each intervention exist. Careful surgical planning to avoid these risk factors in each therapeutic modality may improve patient outcomes.

Stent-assisted Coil Embolization Using a Transcirculation Technique for Superior Cerebellar Artery Aneurysm: A Report of Two Cases.

Stent-assisted coil embolization (SACE) is useful for treating wide-necked aneurysms. Most superior cerebellar artery (SCA) aneurysms have a wide neck, but there are few reports of SCA aneurysms treated with SACE. One reason is that the anatomical characteristic of SCA aneurysm is not suitable for standard SACE. It is often challenging to deliver a stent to SCA via the basilar artery in an anterograde manner. In contrast, it is not difficult to deliver a stent to SCA from the anterior circulation via the posterior communicating artery. This method, in which a catheter is navigated from the anterior to the posterior circulation, is called a transcirculation technique. We report two cases of SCA aneurysm successfully treated with SACE using transcirculation technique. This approach is helpful for wide-necked SCA aneurysms.

Thrombectomy for acute large vessel occlusion in posterior and anterior circulation: a single institutional retrospective observational study.

PURPOSE: Thrombectomy has been the gold standard therapy for anterior circulation occlusion; however, studies regarding thrombectomy in posterior circulation are lacking. In this study, we compared the efficiency of thrombectomy for acute large vessel occlusion between the posterior and anterior circulation at a single institution. METHODS: We retrospectively analyzed consecutive patients who underwent thrombectomy for acute large vessel occlusion at our institution between August 2014 and April 2021. Differences in the clinical background, time course, and treatment technique and outcomes were evaluated between anterior and posterior circulation occlusions. RESULTS: Overall, 353 patients (225 men and 128 women) were included: 314 patients had anterior circulation occlusion and 39 patients had posterior circulation occlusion. Between the patients with anterior and posterior circulation occlusions, the National Institutes of Health Stroke Scale (NIHSS) score (16 [12-21] vs. 29 [19-34], respectively, p < 0.001), door-to-puncture time (65 [45-99] vs. 99 [51-121] min, respectively, p = 0.018), and mortality (22 [7%] vs. 8 [20.5%] patients, respectively, p = 0.010) were significantly different; however, favorable outcome was not significantly different. CONCLUSION: Higher NIHSS score, delayed treatment, and higher mortality were observed in posterior circulation occlusion than in anterior circulation occlusion; successful reperfusion and favorable outcomes were similar between them. Similar favorable outcomes and reperfusion ratio to the anterior circulation might be achieved also in the posterior circulation; however, delayed treatment and the optimal first-pass strategy might need further improvement.

Preprocedural Prediction of Underlying Atherosclerotic Lesions in Cerebral Large-Vessel Occlusions: Clinical Backgrounds, Radiological Findings, and Treatment Outcomes.

AIMS: Mechanical thrombectomy using a standard device has been effective for acute cerebral large-vessel occlusions, particularly those due to cardiogenic embolism. However, evidence for those with underlying atherosclerotic lesions is lacking. In this study, we evaluated the predictive factors, treatment details, and outcomes of acute cerebral large-vessel occlusions with underlying atherosclerotic lesions in patients who underwent mechanical thrombectomy. METHODS: We retrospectively analyzed consecutive patients with acute large-vessel occlusions who underwent mechanical thrombectomy at our institution between August 2014 and May 2021. Predictive factors of underlying atherosclerotic lesions were evaluated using univariate and multivariate analyses. In addition, treatment details and outcomes were evaluated and compared with those of other etiologies. RESULTS: Among 322 included patients, 202 (62.7%) were males and 65 (20.2%) had underlying atherosclerotic lesions. Multivariate analysis identified dyslipidemia, lack of arterial fibrillation documented on admission, smoking, internal carotid artery lesions, and stenosis ≥ 25% in non-occluded large vessels as predictive factors of underlying atherosclerotic lesions. Regarding treatment for underlying atherosclerotic lesions, the need for percutaneous transluminal angioplasty, stent placement, medical therapy, and longer procedure time were observed, while successful reperfusion rates, favorable outcomes, and mortality rates showed no significant differences with those of other etiologies. CONCLUSION: Coexisting diseases and radiological findings were useful for predicting underlying atherosclerotic lesions. Further understanding these characteristics may lead to the early detection of underlying atherosclerotic lesions, optimal treatment strategies, and better outcomes.

Virtual test occlusion for assessing ischemic tolerance using computational fluid dynamics.

BACKGROUND: Ischemic tolerance has been evaluated by the balloon test occlusion (BTO) for cerebral aneurysms and tumors that might require parent artery occlusion during surgery. However, because of its invasiveness, a non-invasive evaluation method is needed. In this study, we assessed the possibility of virtual test occlusion using computational fluid dynamics (CFD) as a non-invasive alternative to BTO for evaluating ischemic tolerance. METHODS: Twenty-one patients who underwent BTO were included in the study. Virtual test occlusion was performed using CFD analysis, and the flow rate (FR) and wall shear stress (WSS) of the middle cerebral artery on the occlusion side were calculated. The correlations between these parameters and examination data including the parameters of computed tomography perfusion during BTO were assessed and the cutoff value of CFD parameters for detecting the good collateral group was calculated. RESULTS: The FR was strongly correlated with mean transit time (MTT) during BTO and moderately correlated with collateral flow grade based on angiographic appearance. The WSS was moderately correlated with collateral flow grade, mean stump pressure (MSP), and MTT. Furthermore, the FR and WSS were strongly correlated with the total FR and the diameters of the inlet vessels. The cutoff value of FR for detecting the good collateral group was 126.2 mL/min, while that of the WSS was 4.54 Pa. CONCLUSION: The parameters obtained through CFD analysis were correlated with collateral flow grade and MSP in addition to MTT. CFD analysis may be useful to evaluate ischemic tolerance as a non-invasive alternative to BTO.

A rare brainstem hemorrhage due to incomplete transvenous embolization of the cavernous sinus dural arteriovenous fistula: A case report.

Endovascular embolization is generally thought to be safe and effective for the cavernous sinus dural arteriovenous fistula (CS DAVF); however, some complications have been reported. We report an extremely rare brainstem hemorrhage associated with transvenous embolization (TVE) of CS DAVF. A 66-year-old man presented with right-sided conjunctival chemosis and exophthalmos. His brain magnetic resonance image showed right CS DAVF. Thus, emergent TVE was performed. Although his symptoms improved after the first TVE, magnetic resonance image showed brainstem edema, and venous congestion was suspected because of incomplete TVE. Second TVE was performed. Thereafter, computed tomography showed brainstem hemorrhage, resulting in the occurrence of right abducent nerve palsy, right-sided facial palsy, and ataxia. The patient's condition gradually improved, and a year has passed without recurrence. Incomplete TVE of CS DAVF can result in life-threatening complications, such as cerebral hemorrhage. To avoid these complications, the anatomical structure of the cavernous sinus should be understood accurately, and important drainage veins should be determined.

Current treatment options and prognostic factors for ruptured distal anterior cerebral artery aneurysms.

BACKGROUND: Distal anterior cerebral artery (ACA) aneurysms are rare, representing 1-9% of all intracranial aneurysms. The best treatment strategy for these aneurysms continues to be debated. We clarified the clinical features and treatment outcomes of patients with ruptured distal ACA aneurysms according to the treatment options at our institute. METHODS: Thirty-seven consecutive patients (26 women; mean age, 65.2 years) with ruptured distal ACA aneurysms who underwent surgical clipping or coil embolization between 2012 and 2018 were included in the study. Clinical presentations, radiographic findings, and outcomes were retrospectively reviewed and compared between patients who underwent either surgical clipping or coil embolization. Risk factors associated with poor outcomes (modified Rankin Scale 4-6) were analyzed using multiple regression analysis. RESULTS: Nineteen patients (51.4%) had World Federation Neurological Surgeons (WFNS) Grade IV-V, 18 (48.7%) had frontal lobe hematomas, and 13 (35.1%) had multiple aneurysms. Surgical clipping and endovascular coiling were performed in 28 (75.7%) and nine (24.3%) patients, respectively. Aneurysms located at the A4-5 portions were mainly treated by surgical clipping (P = 0.04). There were no significant between-group differences in procedure-related morbidity and mortality; however, the complete occlusion rate was higher in the surgical group (P < 0.01). Overall, a favorable neurological outcome at discharge (mRS 0-3) was obtained in 23 patients (62.5%). Multiple regression analysis revealed that WFNS Grade IV-V and frontal lobe hematomas were risk factors for poor outcomes (mRS 4-6). CONCLUSION: Acceptable outcomes were obtained in 62.5% of cases, and there were no significant between-group differences in treatment results between clipping and coiling. A poor WFNS grade and intracerebral hematomas were risk factors for a poor prognosis.

One-Way Valve Method for Achieving Effective Flow Reversal on Carotid Artery Stenting.

Objective: We report a simplified method of manual transfusion with a one-way valve during carotid artery stenting (CAS) with flow reversal. Case Presentation: A 77-year-old man with cervical internal carotid artery stenosis who developed vulnerable plaques was scheduled for CAS using flow reversal. Blood flow reversal was naturally caused by the arteriovenous pressure gradient, and a method with a one-way valve, which enables simplified manual transfusion using a syringe technique, was used for the patient. CAS was completed without distal embolization. Conclusion: Manual transfusion can be simplified using a one-way valve in cases of flow reversal during CAS, which often require complicated procedures.

Anomalous origin of the posterior inferior cerebellar artery from the jugular branch of the ascending pharyngeal artery: A case report.

The posterior inferior cerebellar artery usually arises from the vertebral artery and has several variants. The posterior inferior cerebellar artery originating from the jugular branch of ascending pharyngeal artery has rarely been reported. A 63-year-old woman underwent cerebral magnetic resonance imaging and magnetic resonance angiography; the latter incidentally revealed an anomalous origin of the posterior inferior cerebellar artery. We report and discuss the neuroimaging findings in a patient with this anomaly. Determining the origin of the posterior inferior cerebellar artery is an important factor in planning surgical and endovascular treatment strategies for skull base disorders.

Ischemic Tolerance Evaluated by Computed Tomography Perfusion during Balloon Test Occlusion.

OBJECTIVES: Balloon test occlusion (BTO) is performed to evaluate ischemic tolerance for large and giant cerebral aneurysms and head and neck tumors that may require parent artery occlusion. However, ischemic tolerance for the temporary test occlusion does not always guarantee a tolerance for permanent occlusion. In this study, we evaluated the utility of computed tomography (CT) perfusion during BTO to quantify ischemic tolerance for detecting delayed ischemic stroke. MATERIALS AND METHODS: Forty-one patients who underwent BTO for the internal carotid artery were included. The correlations between the parameters of CT perfusion and collateral angiographic appearance or stump pressure during BTO were evaluated. The cerebral blood flow (CBF), cerebral blood volume, mean transit time (MTT), and time to peak (TTP) were obtained through CT perfusion, and the asymmetry ratios were determined. Collateral angiographic appearances were categorized into 5 grades (0-4). RESULTS: The collateral angiographic appearance showed moderate correlations with CBF, MTT, and TTP that was significant. Of these, the absolute value of the correlation coefficient was the highest for MTT. MTT also showed a moderate correlation with stump pressure. CBF and MTT were significantly different between the poor collateral group (grades 2 and 3) and the good collateral group (grade 4). Based on the MTT, the good collateral group was identified with high sensitivity (75.0%) and specificity (81.2%). CONCLUSIONS: In BTO, the MTT obtained through CT perfusion showed a correlation with collateral angiographic appearance and stump pressure. Thus, the MTT might be useful to quantify ischemic tolerance for detecting delayed ischemic stroke.

Clinical Features of Neurogenic Pulmonary Edema in Patients with Subarachnoid Hemorrhage.

OBJECTIVE: Neurogenic pulmonary edema (NPE) is a clinical syndrome characterized by acute onset after central nervous system injury. Here, we investigated the clinical features of NPE in patients with subarachnoid hemorrhage (SAH). METHODS: We retrospectively analyzed a total of 350 patients with SAH who were treated at our hospital from April 2014 to September 2017. Patient demographics, aneurysm size and location, clinical characteristics, and patient outcomes were reviewed and compared between an NPE and a non-NPE group. RESULTS: Sixteen patients (4.6%) presented with NPE at admission. Ten of these (62.5%) recovered from NPE immediately, and ventilatory support was withdrawn within 2 days from onset. A univariate analysis showed that patients with NPE were younger (P = 0.04), had a higher rate of vertebral artery dissection (P < 0.01), more severe World Federation of Neurosurgical Societies (WFNS) grades (P = 0.01), and lower systolic blood pressure on admission (P = 0.01). A multivariate analysis revealed significant differences in the frequency of vertebral artery dissection (odds ratio 4.83, 95% confidence interval 1.50-15.56, P < 0.01) and in WFNS grades (odds ratio 3.73, 95% confidence interval 1.02-13.66, P = 0.04) between the groups. No significant group differences were found in other factors including heart rate, radiographic sign (Fisher grade), aneurysm size and location, blood sample tests on admission, and neurologic outcomes. CONCLUSIONS: Vertebral artery dissection and severe WFNS grade on admission were confirmed as significant risk factors for NPE. However, neurologic outcomes at discharge did not differ between groups, suggesting that poor outcomes due to NPE could be reduced by appropriate diagnosis and treatment.

Prevention of neointimal hyperplasia induced by an endovascular stent via intravenous infusion of mesenchymal stem cells.

OBJECTIVE: In-stent restenosis after percutaneous transluminal angioplasty and stenting (PTAS) due to neointimal hyperplasia is a potential cause of clinical complications, including repeated revascularization and ischemic events. Neointimal hyperplasia induced by an inflammatory response to the stent strut may be a possible mechanism of in-stent restenosis. Intravenous infusion of bone marrow-derived mesenchymal stem cells (MSCs) has been reported to show therapeutic efficacy for cerebral stroke, presumably by an antiinflammatory effect. This study aimed to determine whether MSCs can reduce or prevent neointimal hyperplasia induced by an endovascular stent. METHODS: In this study, two types of bare metal stents were deployed using a porcine (mini-pig) model. One stent was implanted in the common carotid artery (CCA), which is considered quite similar to the human CCA, and the other was inserted in the superficial cervical artery (SCA), which is similar in size to the human middle cerebral artery. Angiographic images, intravascular ultrasound (IVUS) imaging, and microscopic images were used for analysis. RESULTS: Angiographic images and IVUS studies revealed that intravenous infusion of MSCs immediately after deployment of stents prevented in-stent stenosis of the CCA and SCA. Histological analysis also confirmed that inflammatory responses around the stent struts were reduced in both the stented CCA and SCA in the mini-pig. CONCLUSIONS: Intravenous infusion of MSCs inhibited the inflammatory reaction to an implanted stent strut, and prevented progressive neointimal hyperplasia in the stented CCA and SCA in a porcine model. Thus, MSC treatment could attenuate the recurrence of cerebral ischemic events after stenting.

Endovascular treatment of asymptomatic free-floating thrombus in the carotid artery bifurcation: a direct aspiration first-pass technique under double balloon protection.

Free-floating thrombus (FFT) in the carotid artery has been reported as a rare cause of acute ischaemic stroke. There are various treatment strategies, but higher risk of distal embolism may limit their applicability. A 77-year-old woman noticed right upper arm weakness. A CT angiogram revealed that a large floating thrombus had strayed across the carotid bifurcation, while another thrombus was present in the right axillary artery. As for the carotid FFT, in spite of anticoagulation therapy, the number of asymptomatic microthrombuses gradually increased on diffusion-weighted MRI. We performed endovascular therapy utilising two temporary occlusion balloon catheters and performed direct aspiration with a reperfusion catheter. The procedure was uneventful. We successfully performed a new endovascular technique for FFT in the carotid bifurcation. Our method is effective, minimally invasive and safe.

Effects of Hemosiderosis on Epilepsy Following Subarachnoid Hemorrhage.

Epilepsy after aneurysmal subarachnoid hemorrhage (post-SAH epilepsy) is a critical complication that influences clinical and social prognoses. However, the underlying mechanisms remain unclear. We investigated the relationship between hemosiderosis and the incidence of post-SAH epilepsy. About 50 patients with aneurysmal SAH who were admitted to Sapporo Medical University and Oji General Hospital between April 2010 and June 2016 were enrolled in this retrospective study. Hemosiderosis detected by T2*-weighted magnetic resonance imaging(MRI) and the incidence of post-SAH epilepsy were retrospectively analyzed. Post-SAH epilepsy was defined as an unprovoked seizures occurring more than 1 week after the onset of SAH. Six patients (12%) developed post-SAH epilepsy. In all patients, hemosiderosis in the cortex or cerebral parenchyma was detected by T2*-weighted MRI. Statistical analyses revealed that hemosiderosis and the co-existence of intracerebral hemorrhage (ICH) related with post-SAH epilepsy (Fisher's exact test, univariate exact logistic regression analysis: P < 0.05). Post-SAH epilepsy was predicted by hemosiderosis and the co-existence of ICH. The present results suggest that hemosiderin is the principal cause of post-SAH epilepsy and may be a predictor of this critical complication.

Arterial Spin Labeling Method as a Supplemental Predictor to Distinguish Between High- and Low-Grade Gliomas.

BACKGROUND: Preoperative evaluation of malignancy in gliomas is important for surgical planning, particularly to determine whether a 1,3-bis-2-chloroethyl-1-nitrosourea wafer should be placed into the tumor cavity. In some cases, the intraoperative pathologic diagnosis of World Health Organization grade differs from the final diagnosis. Supplemental methods in addition to the routine contrast tomography or magnetic resonance imaging sequences may provide a more accurate preoperative diagnosis. Because tumor vascularity has been useful in distinguishing between low- and high-grade gliomas, we evaluated the accuracy of the arterial spin labeling (ASL) method, which could measure the cerebral blood flow (CBF) without using contrast medium, to determine the malignancy of gliomas. METHODS: This study included 102 patients with glioma (grade II, n = 40; grade III, n = 18; grade IV, n = 44). All patients underwent ASL to determine the tumor blood flow (TBF) and CBF in the middle cerebral region. The relative tumor vascular index (tVI), which is calculated as TBF divided by CBF in the contralateral middle cerebral region, was used to avoid dispersion of the absolute TBF value. RESULTS: tVI was significantly greater (1.46 ± 0.751) in high-grade gliomas than in low-grade gliomas (1.05 ± 0.343) (P = 0.003). As for each grade, tVI was statistically higher in grade IV than in grade II (P = 0.03) gliomas. CONCLUSIONS: The noninvasive ASL method provides additional information to distinguish high-grade glioma from low-grade gliomas without using contrast medium.

Endovascular Therapy for a Post-irradiated Cervical Pseudoaneurysm at the Carotid Stump: A Case Report.

A nearly 80-year-old man with a history of radiotherapy (RT) and total laryngectomy for laryngeal cancer 25 years previously presented with a rapidly growing mass on the right side of his neck. A huge pseudoaneurysm (pseudoAN) was detected at the right carotid bifurcation, though angiography performed four years previously had shown total occlusion of the internal carotid artery. Stent-assisted coil embolization enabled aneurysm sac shrinkage. Clinicians must be aware that the stump of an arterial occlusion associated with RT can change into a pseudoAN over the long term and must provide follow-up in such cases.

[Pediatric Iatrogenic Vertebral Arteriovenous Fistula Successfully Treated with Endovascular Treatment:A Case Report].

OBJECT: We report a relatively rare case of pediatric iatrogenic extradural vertebral arteriovenous fistula. CASE: A five-year-old boy with a history of multiple surgeries for Total Anomalous Pulmonary Venous Return(TAPVR)exhibited vascular engorgement of his right neck from about 4 years old. We thought that this was caused by his past operations. He demonstrated swollen blood vessels in the right neck and pulmonary hypertension with increased right heart load. A right extradural vertebral arteriovenous fistula was seen on angiography. A high flow shunt was present at the V1 segment, at the level of the sixth cervical vertebra, and a 12 mm venous pouch was present anterior to the vertebral artery. We recognized the outlet passages of the cranial tract were the vertebral venous plexus, internal jugular vein, and right atrium. We performed endovascular transarterial embolization using a hydrogel coil. As a result, we treated with a high volume embolization ratio. Following treatment, the arteriovenous fistula disappeared while anterograde blood flow of the vertebral artery was preserved. The patient demonstrated no neurological deficits, improved right heart load, and his venous pouch of the neck. He has had no recurrence in the two years after treatment. CONCLUSION: Endovascular surgery is effective and safe for the treatment of iatrogenic vertebral arteriovenous fistula.

Quantitative Assessment of Flow Reduction After Feeder Embolization in Meningioma by Using Pseudocontinuous Arterial Spin Labeling.

BACKGROUND: Meningioma is a hypervascular tumor of the central nervous system. Angiographic disappearance of tumor blush after preoperative feeder embolization allows qualitative, but not quantitative, assessment of flow reduction. Pseudocontinuous arterial spin labeling (PCASL), which has evolved from magnetic resonance imaging techniques, allows noninvasive measurement of cerebral blood flow (CBF) using water protons in the arterial blood flow. OBJECTIVE: We applied PCASL for assessment of blood flow in meningioma and its reduction on preoperative embolization. METHODS: Forty-one consecutive patients (11 males, 30 females) with histologically proven meningioma were evaluated by PCASL. Quantitative assessment by an absolute value of tumor blood flow (TBF) and a relative value of tumor vascular index (tVI; calculated as TBF divided by CBF) were calculated. In 8 cases, in which preoperative embolization was achieved, flow reduction rate was evaluated. RESULTS: TBF of meningiomas, 155.8 mL/100 g·min(-1) on average, was 2.6 times higher than CBF, 59.9 mL/100 g·min(-1) (P < 0.001). Patients who underwent feeder embolization showed statistically greater flow reduction rate, which was calculated as 42.7% (P < 0.05). Mean tVI before embolization was 4.1, which was reduced to 2.1 after embolization. CONCLUSION: PCASL could yield quantitative assessment of blood flow in meningioma including flow reduction rate in cases of feeder embolization.