Number of Stent Retriever Passes Associated With Futile Recanalization in Acute Stroke.

Background and Purpose- Stent retriever (SR) thrombectomy has become the mainstay of treatment of acute intracranial large artery occlusion. However, it is still not much known about the optimal limit of SR attempts for favorable outcome. We evaluated whether a specific number of SR passes for futile recanalization can be determined. Methods- Patients who were treated with a SR as the first endovascular modality for their intracranial large artery occlusion in anterior circulation were retrospectively reviewed. The recanalization rate for each SR pass was calculated. The association between the number of SR passes and a patient's functional outcome was analyzed. Results- A total of 467 patients were included. Successful recanalization by SR alone was achieved in 82.2% of patients. Recanalization rates got sequentially lower as the number of passes increased, and the recanalization rate achievable by ≥5 passes of the SR was 5.5%. In a multivariable analysis, functional outcomes were more favorable in patients with 1 to 4 passes of the SR than in patients without recanalization (odds ratio [OR] was 8.06 for 1 pass; OR 7.78 for 2 passes; OR 6.10 for 3 passes; OR 6.57 for 4 passes; all P<0.001). However, the functional outcomes of patients with ≥5 passes were not significantly more favorable than found among patients without recanalization (OR 1.70 with 95% CI, 0.42-6.90 for 5 passes, P=0.455; OR 0.33 with 0.02-5.70, P=0.445 for ≥6 passes). Conclusions- The likelihood of successful recanalization got sequentially lower as the number of SR passes increased. Five or more passes of the SR became futile in terms of the recanalization rate and functional outcomes.

Rescue Stenting for Failed Mechanical Thrombectomy in Acute Ischemic Stroke: A Multicenter Experience.

BACKGROUND AND PURPOSE: Effective rescue treatment has not yet been suggested in patients with mechanical thrombectomy (MT) failure. This study aimed to test whether rescue stenting (RS) improved clinical outcomes in MT-failed patients. METHODS: This is a retrospective analysis of the cohorts of the 16 comprehensive stroke centers between September 2010 and December 2015. We identified the patients who underwent MT but failed to recanalize intracranial internal carotid artery or middle cerebral artery M1 occlusion. Patients were dichotomized into 2 groups: patients with RS and without RS after MT failure. Clinical and laboratory findings and outcomes were compared between the 2 groups. It was tested whether RS is associated with functional outcome. RESULTS: MT failed in 148 (25.0%) of the 591 patients with internal carotid artery or middle cerebral artery M1 occlusion. Of these 148 patients, 48 received RS (RS group) and 100 were left without further treatment (no stenting group). Recanalization was successful in 64.6% (31 of 48 patients) of RS group. Compared with no stenting group, RS group showed a significantly higher rate of good outcome (modified Rankin Scale score, 0-2; 39.6% versus 22.0%; P=0.031) without increasing symptomatic intracranial hemorrhage (16.7% versus 20.0%; P=0.823) or mortality (12.5% versus 19.0%; P=0.360). Of the RS group, patients who had recanalization success had 54.8% of good outcome, which is comparable to that (55.4%) of recanalization success group with MT. RS remained independently associated with good outcome after adjustment of other factors (odds ratio, 3.393; 95% confidence interval, 1.192-9.655; P=0.022). Follow-up vascular imaging was available in the 23 (74.2%) of 31 patients with recanalization success with RS. The stent was patent in 20 (87.0%) of the 23 patients. Glycoprotein IIb/IIIa inhibitor was significantly associated with stent patency but not with symptomatic intracranial hemorrhage. CONCLUSIONS: RS was independently associated with good outcomes without increasing symptomatic intracranial hemorrhage or mortality. RS seemed considered in MT-failed internal carotid artery or middle cerebral artery M1 occlusion.

Collateral status affects the onset-to-reperfusion time window for good outcome.

OBJECTIVE: To characterise the time window in which endovascular thrombectomy (EVT) is associated with good outcome, and to test the differential relationship between functional outcome and onset-to-reperfusion time (ORT), depending on collateral status. METHODS: This was a retrospective analysis of clinical and imaging data of 554 consecutive patients, who had recanalisation success by EVT for anterior circulation large artery occlusion, from the prospectively maintained registries of 16 comprehensive stroke centres between September 2010 and December 2015. The patients were dichotomised into good and poor collateral groups, based on CT angiography. We tested whether the likelihood of good outcome (modified Rankin Scale, 0-2) by ORT was different between two groups. RESULTS: ORT was 298 min±113 min (range, 81-665 min), and 84.5% of patients had good collaterals. Age, diabetes mellitus, previous infarction, National Institutes of Health Stroke Scale, good collaterals (OR 40.766; 95% CI 10.668 to 155.78; p<0.001) and ORT (OR 0.926 every 30 min delay; 95% CI 0.862 to 0.995; p=0.037) were independently associated with good outcome. The drop in likelihood of good outcome associated with longer ORT was significantly faster in poor collateral group (OR 0.305 for every 30 min; 95% CI 0.113 to 0.822) than in good collateral group (OR 0.926 for every 30 min; 95% CI 0.875 to 0.980). CONCLUSIONS: Earlier successful recanalisation was strongly associated with good outcome in poor collateral group; however, this association was weak during the tested time window in good collateral group. This suggests that the ORT window for good outcome can be adjusted according to collateral status.

Consensus Statements by Korean Society of Interventional Neuroradiology and Korean Stroke Society: Hyperacute Endovascular Treatment Workflow to Reduce Door-to-Reperfusion Time.

Recent clinical trials demonstrated the clinical benefit of endovascular treatment (EVT) in patients with acute ischemic stroke due to large vessel occlusion. These trials confirmed that good outcome after EVT depends on the time interval from symptom onset to reperfusion and that in-hospital delay leads to poor clinical outcome. However, there has been no universally accepted in-hospital workflow and performance benchmark for rapid reperfusion. Additionally, wide variety in workflow for EVT is present between each stroke centers. In this consensus statement, Korean Society of Interventional Neuroradiology and Korean Stroke Society Joint Task Force Team propose a standard workflow to reduce door-to-reperfusion time for stroke patients eligible for EVT. This includes early stroke identification and pre-hospital notification to stroke team of receiving hospital in pre-hospital phase, the transfer of stroke patients from door of the emergency department to computed tomography (CT) room, warming call to neurointervention team for EVT candidate prior to imaging, neurointervention team preparation in parallel with thrombolysis, direct transportation from CT room to angiography suite following immediate decision of EVT and standardized procedure for rapid reperfusion. Implementation of optimized workflow will improve stroke time process metrics and clinical outcome of the patient treated with EVT.

Mechanical thrombectomy in cardiac myxoma stroke: a case report and review of the literature.

Cardiac myxoma is the most common primary tumor of the heart. It is a rare cause of acute ischemic stroke and commonly not detected until after the stroke. There is no current guideline for the treatment of cardiac myxoma stroke and only a few cases of mechanical thrombectomy have been reported. We present a case of cardiac myxoma stroke in a 4-year-old boy treated with a stent-retrieval device and review the literature describing the safety and efficacy of mechanical thrombectomy in cardiac myxoma stroke. We also describe imaging features of the myxoma clot on susceptibility weighted images.

Imaging characteristics of sinonasal organized hematoma.

BACKGROUND: Sinonasal organized hematoma is a rare benign disease that may be mistaken for malignancy. PURPOSE: To define the imaging characteristics of sinonasal organized hematoma. MATERIAL AND METHODS: We retrospectively reviewed computed tomography (CT) images of eight patients (4 male patients, 4 female patients; mean age, 40 years; range, 9-83 years) with pathologically proven sinonasal organized hematomas; magnetic resonance imaging (MRI) was performed in one patient among them. The following lesions characteristics were analyzed: size, shape, location, expansile nature, density, signal intensity, internal structure, enhancement pattern, and surrounding bony wall change. RESULTS: The lesion sizes were in the range of 2-5.2 cm (mean, 3.55 cm), and the shapes were lobular, lumpy, or nodular. They were located in the nasal cavity (n = 1), maxillary sinuses (n = 2), or both nasal cavities and maxillary sinuses (n = 5). Expansile lesions with locally aggressive margins were observed in two cases. All lesions were hyperdense on precontrast CT scans; the smaller lesions showed even hyperdensity, whereas the larger lesions showed uneven density. The signal intensity was mixed on MRI, consisting of hemorrhage, fibrosis, and neovascularization. Papillary or frond-like enhancement was noted after contrast injection. All cases showed smooth erosion of the medial walls of the maxillary sinuses, and the epicenters were the secondary maxillary ostia. Two lesions showed erosion of the lateral walls of the maxillary sinuses and were expansile in nature. Non-hemorrhagic polyps accompanied the organized hematomas in three cases. CONCLUSION: Although sinonasal organized hematoma can be mistaken for a malignant tumor, the following characteristic imaging findings facilitate the diagnosis of an organized hematoma: erosion of the bony sinus walls, markedly heterogeneous signal intensity, and papillary or frond-like enhancement.

Correlation of apparent diffusion coefficient values measured by diffusion MRI and MGMT promoter methylation semiquantitatively analyzed with MS-MLPA in patients with glioblastoma multiforme.

PURPOSE: To retrospectively determine whether the apparent diffusion coefficient (ADC) values correlate with O(6)-methylguanine DNA methyltransferase (MGMT) promoter methylation semiquantitatively analyzed by methylation-specific multiplex ligation-dependent probe amplification (MS-MLPA) in patients with glioblastoma. MATERIALS AND METHODS: The study was approved by the Institutional Review Board and was Health Insurance Portability and Accountability Act (HIPAA) compliant. Newly diagnosed patients with glioblastoma (n = 26) were analyzed with an ADC histogram approach based on enhancing solid portion. The methylation status of MGMT promoter was assessed by methylation-specific polymerase chain reaction (MSP) and by MS-MLPA. MS-MLPA is a semiquantitative method that determines the methylation ratio. The Ki-67 labeling index was also analyzed. The mean and 5th percentile ADC values were correlated with MGMT promoter methylation status and Ki-67 labeling index using a linear regression model. Progression-free survival (PFS) was also correlated with the ADC values using Kaplan-Meier survival analysis. RESULTS: The mean methylation ratio was 0.21 ± 0.20. By MSP, there were 5 methylated and 21 unmethylated tumors. The mean ADC revealed a positive relationship with MGMT promoter methylation ratio (P = 0.015) and was also significantly different according to MSP-determined methylation status (P = 0.011). Median PFS was significantly related with methylation ratio (P = 0.017) and MSP-derived methylation status (P = 0.025). A positive relationship was demonstrated between PFS and the mean ADC value (P = 0.001). The 5th percentile ADC values showed a significant negative relationship with Ki-67 labeling index (P = 0.036). CONCLUSION: We found that ADC values were significantly correlated with PFS as well as with MGMT promoter methylation status. We believe that ADC values may merit further investigation as a noninvasive biomarker for predicting treatment response.

Retrograde stenting through the posterior cerebral artery in coil embolization of the posterior communicating artery aneurysm.

INTRODUCTION: Protection techniques using stents or balloons are occasionally limited in coil embolization of wide-necked posterior communicating artery (PcomA) aneurysms in which the PcomA originated from the aneurysm neck at an acute angle. Here, we present two cases undergoing retrograde stenting through the posterior cerebral artery in coil embolization of the PcomA aneurysms. METHODS: To perform retrograde stenting, a microcatheter used for stent delivery was advanced from the vertebral artery (VA) to the terminal internal carotid artery (ICA) via the ipsilateral P1 and the PcomA. The aneurysm sac was selected with another microcatheter for coil delivery through the ipsilateral ICA. Coil embolization was performed under the protection of a stent placed from the terminal ICA to the PcomA. RESULTS: Deployment of the stent was successful in both aneurysms treated using retrograde stenting by the VA approach. Coil deployment was performed through the jailed microcatheter at first. The microcatheter was repositioned through the stent struts later in one case and another microcatheter was inserted into the sac through the stent struts in the other case. Both aneurysms were occluded properly with the coils without procedure-related complications. CONCLUSION: By providing complete neck coverage, retrograde stenting for coil embolization in wide-necked PcomA aneurysms seems to be a good alternative treatment strategy, when the aneurysms are incorporating extended parts of the PcomA, and the PcomA and P1 are big enough to allow passage of the microcatheter for delivery of the stent. However, this technique should be reserved for those cases with the specific vascular anatomy.

Stent-assisted coil embolization of wide-necked posterior inferior cerebellar artery aneurysms.

INTRODUCTION: Endovascular coil embolization of posterior circulation aneurysms has advantages over a surgical approach. However, the application of coil embolization is sometimes limited in wide-necked posterior inferior cerebellar artery (PICA) aneurysms, which are incorporating the origin of the branch. Presented here is a series of patients who were subjected to stent-supported coil embolization of PICA aneurysms. METHODS: From a prospective data repository, we retrieved records of seven consecutive patients with PICA aneurysms, all of whom were treated by stent-assisted coil embolization between January 2010 and November 2012. Outcomes were analyzed in terms of aneurysm morphology and clinical status. RESULTS: In all seven instances, the stents were placed from proximal PICA to vertebral artery (VA). A retrograde approach, via contralateral VA, was performed in five patients, where the origin of PICA from VA assumed an acute angle. In the other two patients, where the angles were obtuse, the stenting was done antegrade, via ipsilateral VA. Out of five patients with retrograde approach, single puncture and a single guiding catheter sufficed in three patients, whereas the remaining two patients required dual puncture and two guiding catheters. Endovascular treatments, as performed, resulted in excellent outcomes for all seven patients, although an asymptomatic thrombus developed in one patient with a ruptured aneurysm. CONCLUSION: For coil embolization of PICA aneurysm requiring stent protection, either ipsilateral or contralateral VA access routes may be used, depending on the angle of PICA origin and the configuration of the aneurysm.

Endovascular coil embolization of middle cerebral artery aneurysms of the proximal (M1) segment.

INTRODUCTION: Proximal middle cerebral artery (M1 segment) aneurysms have various configurations and are distinct from middle cerebral artery bifurcation aneurysms. We present the clinical and radiological results of coil embolization of the M1 segment aneurysms. METHODS: From a prospective database, we retrieved the data for 59 consecutive patients harboring 60 M1 aneurysms that were treated with endovascular coil embolization from January 2006 to May 2012. We assessed the clinical outcomes of the patients and morphological outcomes of the aneurysms using the Raymond classification. RESULTS: The aneurysms were located on the superior wall of the M1 segment in 43 and on the inferior wall in 17. Superior-wall aneurysms were related to the frontal cortical artery and the lateral lenticulostriate perforator while inferior-wall aneurysms were to the temporal cortical artery. With coil embolization, complete aneurysmal occlusion or residual neck could be achieved in 52 aneurysms (86.7 %) and residual aneurysm in 8. The microcatheter protection technique was most commonly used for coil embolization (41.7 %) followed by single microcatheter (31.7 %), double microcatheter (23.3 %), and stent protection (3.3 %). There was no procedure-related morbidity or mortality. Follow-up angiography more than 6 months after embolization (n = 46; mean 12.4 months) demonstrated stable occlusion in 40 (87.0 %), minor recanalization in 4 (8.7 %), and major recanalization in 2 (4.3 %). One patient experienced delayed cerebral infarction without permanent neurologic deficit. CONCLUSION: Coil embolization in M1 aneurysms seems to be safe and efficacious, although it may require various technical strategies due to distinct anatomic configurations.

Clinical outcomes of conservative management of spinal cord cavernous angiomas.

BACKGROUND: There have been numerous studies on the outcomes of surgery for spinal cord cavernous angiomas. However, the natural history of conservatively treated disease is not well known. The aim of this retrospective study was to investigate the outcomes of conservatively managed patients with spinal cord cavernous angioma to determine the appropriate treatment strategies. METHODS: Twenty-four patients who visited a single institution over an 11-year period and who were treated conservatively were enrolled in this study. Their medical records and radiological images were reviewed retrospectively. The neurologic status of the patients was assessed using the Japanese Orthopedic Association scoring system and the clinical presentation of the patients was classified into the following 4 categories: type A, asymptomatic; B, pain only; C, sensory deficits; and D, sensory and motor deficits. The results of types C and D patients were compared with the results of previously reported surgical series from our institution. RESULTS: The mean age of the enrolled patients was 52.0 years (21-73). The mean duration of the clinical follow-up was 60.5 months (11-119) and the follow-up using magnetic resonance imaging was 52.4 months (3-122). Cavernous angiomas presented in the cervical spinal cord in 12 patients, thoracic spinal cord in 10 patients and in multiple levels of the spinal cord in 2 patients. There were 5, 5, 7, and 7 patients, respectively, classified with types A, B, C, and D for clinical presentations. The rate of recurrent hemorrhage was 1.7 %/patient-year and all recurrent hemorrhages only developed in type C or D patients. In types C and D patients, improvement in the JOA score during the follow-up period was 0.77 ± 1.8 in the conservative group and 1.07 ± 1.8 in the surgical group (p = 0.500). However, improvement in the JOA sensory score after surgical treatment was statistically significant (P = 0.007). CONCLUSIONS: Conservative treatment may be a reasonable treatment strategy for patients with types A and B. If patients present with type C or D, surgical treatment is recommended considering the better improvements in sensory deficits and the high rate of recurrent hemorrhage in such patients.

A radiofrequency electrode catheter-guide wire system for arterial occlusion.

PURPOSE: To describe the design of a radiofrequency (RF) electrode catheter/guide wire system to allow endovascular coagulation of vessels. MATERIALS AND METHODS: A circuit was created by modifying an ordinary microcatheter. An electrically conductive ring was placed at a microcatheter tip, and an extension lead at the hub site. They were each connected to an inherent coil mesh. The rings (ie, cathodes) were 1, 3, 5, 10, and 20 mm in length. In egg white, a coagulation study was performed by changing the length of the guide wire (ie, anode; 1, 3, 5, 10, 20, and 40 mm) in each cathode at 20 W. The coagulation time and site were analyzed. In rabbits, the renal artery was ablated with the use of a 20-mm cathode and 10-mm anode. RESULTS: In the egg white study, the coagulation time was proportionally increased and was dependent on the lengths of the cathode and anode (P < .05). Coagula developed at the anode to the 3-mm protrusion for the 1-mm cathode, to the 5-mm protrusion for the 3-mm cathode, to the 5-mm protrusion for the 5-mm cathode, to the 10-mm protrusion for the 10-mm cathode, and to the 20-mm protrusion for the 20-mm cathode. In rabbits, the renal artery was successfully occluded. Pathologic examination showed occlusion of the renal artery with organization, and the presence of a necrotic arterial wall with fibrosis, inflammation, and intact internal elastic lamina. CONCLUSIONS: The RF electrode catheter/guide wire system successfully coagulated egg white and occluded the rabbit renal artery.

Neurointervention in the Era of COVID-19: Korean Nationwide Survey, Literature Review, and Recommendations.

The coronavirus disease 2019 (COVID-19) pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has had a tremendous impact on healthcare systems worldwide. Although the most common presentation of COVID-19 is respiratory illness, neurologic manifestations are increasing and the pandemic may have consequential effects on urgent conditions such as acute ischemic stroke. In this document, we describe the current status of neurointervention in Korea affected by COVID-19 based on a nationwide survey and review relevant literature from other countries and professional societies.

Carotid Artery Stenting and Intracranial Thrombectomy for Tandem Cervical and Intracranial Artery Occlusions.

BACKGROUND: It remains controversial whether carotid artery stenting (CAS) is needed in cases of tandem cervical internal carotid artery occlusion (cICAO) and intracranial large vessel occlusion (LVO). OBJECTIVE: To investigate the efficacy and safety of CAS in combination with endovascular thrombectomy (CAS-EVT) in cICAO-LVO patients and to compare its outcomes with those of EVT without CAS (EVT-alone). METHODS: We identified all patients who underwent EVT for tandem cICAO-LVO from the prospectively maintained registries of 17 stroke centers. Patients were classified into 2 groups: CAS-EVT and EVT-alone. Clinical characteristics and procedural and clinical outcomes were compared between 2 groups. We tested whether CAS-EVT strategy was independently associated with recanalization success. RESULTS: Of the 955 patients who underwent EVT, 75 patients (7.9%) had cICAO-LVO. Fifty-six patients underwent CAS-EVT (74.6%), and the remaining 19 patients underwent EVT-alone (25.4%). The recanalization (94.6% vs 63.2%, P = .002) and good outcome rates (64.3% vs 26.3%, P = .007) were significantly higher in the CAS-EVT than in the EVT-alone. Mortality was significantly lower in the CAS-EVT (7.1% vs 21.6%, P = .014). There was no significant difference in the rate of symptomatic intracranial hemorrhage between 2 groups (10.7 vs 15.8%; P = .684) and according to the use of glycoprotein IIb/IIIa inhibitor (10.0% vs 12.3%; P = .999) or antiplatelet medications (10.2% vs 18.8%; P = .392). CAS-EVT strategy remained independently associated with recanalization success (odds ratio: 24.844; 95% confidence interval: 1.445-427.187). CONCLUSION: CAS-EVT strategy seemed to be effective and safe in cases of tandem cICAO-LVO. CAS-EVT strategy was associated with recanalization success, resulting in better clinical outcome.

Incidence and mechanism of early neurological deterioration after endovascular thrombectomy.

BACKGROUND: We investigated the prevalence and mechanisms of neurological deterioration after endovascular thrombectomy. METHODS: Between January 2011 and October 2017, acute ischemic stroke patients treated by endovascular thrombectomy in a tertiary university hospital were included. Early neurological deterioration (END) was defined as an increase of 2 or more National Institute of Health Stroke Scale (NIHSS) compared to the best neurological status after stroke within 7 days. The END mechanism was categorized into ischemia progression, symptomatic hemorrhage, and brain edema. RESULTS: A total of 125 acute ischemic stroke patients received endovascular thrombectomy. Neurological deterioration was detected in 44 patients, and 38 cases (86.4% of END) occurred within 72 h. The END mechanism included 20 ischemia progression, 16 brain edema and 8 hemorrhagic transformation cases. Multivariable logistic regression analysis revealed that the patients who experienced END were more likely to have poor functional outcome defined as modified Rankin scale 3-6 at 90 days than neurologically stable patients (odds ratio (OR) = 4.06, confidence interval (CI) = 1.39-11.9). The risk factor of END due to ischemia progression was stroke subtype of large artery atherosclerosis (OR = 6.28, CI = 1.79-22.0). Successful recanalization (OR = 0.11, CI = 0.03-0.39) and NIHSS after endovascular thrombectomy (OR = 1.15 per one-point increase, CI = 1.06-1.24) were significantly associated with END due to hemorrhage or brain edema. CONCLUSION: Neurological deterioration frequently occurs after endovascular thrombectomy, and the risk factors of END differ according to the mechanism of END.

Clinical Significance of the Circle of Willis in Patients with Symptomatic Internal Carotid Artery Occlusion.

BACKGROUND: Despite improvements in medical treatment, many patients experience ischemic stroke owing to internal carotid artery occlusion. We retrospectively evaluated a novel method based on the arterial structure of the circle of Willis (CoW) to identify patients at a high risk of recurrent stroke. METHODS: The study enrolled 104 patients with symptomatic occlusion of the internal carotid artery. CoW integrity was evaluated by a quantitative scoring system based on conventional angiography. Patients were categorized into a good integrity (n = 45) or poor integrity (n = 59) group. Primary endpoint was early neurologic deterioration, recurrent ischemic stroke, or transient ischemic attack. RESULTS: History of ischemic stroke before initial presentation was more prevalent in the poor integrity group (22.2% vs. 47.5%, P = 0.01), and there were no differences between the 2 groups in terms of stroke risk factors. Overall estimated rate of the primary endpoint was 25.6% 2 years after angiography. It was 5.7% in the good integrity group and 39.8% in the poor integrity group (P < 0.001). In a Cox regression analysis, male sex (P = 0.01, hazard ratio = 6.60), use of a tissue plasminogen activator (P = 0.00, hazard ratio = 6.10), and poor integrity of CoW (P = 0.00, hazard ratio = 5.42) were risk factors for the primary endpoint. Patients in the poor integrity group with decreased vascular reserve experienced frequent primary endpoint events compared with patients in the good integrity group (P = 0.00). CONCLUSIONS: Patients with poor integrity of CoW are vulnerable to recurrent ischemic stroke and appear to require more aggressive treatment.

Consensus Statements by Korean Society of Interventional Neuroradiology and Korean Stroke Society: Hyperacute Endovascular Treatment Workflow to Reduce Door-to-Reperfusion Time.

Recent clinical trials demonstrated the clinical benefit of endovascular treatment (EVT) in patients with acute ischemic stroke due to large vessel occlusion. These trials confirmed that good outcome after EVT depends on the time interval from symptom onset to reperfusion and that in-hospital delay leads to poor clinical outcome. However, there has been no universally accepted in-hospital workflow and performance benchmark for rapid reperfusion. Additionally, wide variety in workflow for EVT is present between each stroke centers. In this consensus statement, Korean Society of Interventional Neuroradiology and Korean Stroke Society Joint Task Force Team propose a standard workflow to reduce door-to-reperfusion time for stroke patients eligible for EVT. This includes early stroke identification and pre-hospital notification to stroke team of receiving hospital in pre-hospital phase, the transfer of stroke patients from door of the emergency department to computed tomography (CT) room, warming call to neurointervention (NI) team for EVT candidate prior to imaging, NI team preparation in parallel with thrombolysis, direct transportation from CT room to angiography suite following immediate decision of EVT and standardized procedure for rapid reperfusion. Implementation of optimized workflow will improve stroke time process metrics and clinical outcome of the patient treated with EVT.

Quantitative Computed Tomographic Volumetry after Treatment of a Giant Intracranial Aneurysm with a Pipeline Embolization Device.

Recently developed flow diverters, such as the pipeline embolization device (PED), allow for safe and efficacious treatment of giant intracranial aneurysms, with high occlusion rates and a low incidence of complications. However, incomplete obliteration after PED treatment may lead to aneurysm regrowth and delayed rupture. Herein, we report a case of a partially thrombosed giant aneurysm of the cavernous internal carotid artery that showed progressive recanalization at 1-3 months after application of a PED. We monitored inflow volume in the aneurysm by computed tomographic angiography (CTA) and computed tomographic volumetric imaging (CTVI). Based on the imaging results, rather than applying additional PED, we decided to make the switch from a dual antiplatelet medication to low-dose aspirin alone at 3 months after the treatment; complete obliteration of the aneurysm was noted at 21 months. Similar to the findings in this unusual case, CTA and CTVI may be useful follow-up methods for optimal management of patients with giant intracranial aneurysms after PED treatment.

Mucocele in the Base of the Tongue Mimicking a Thyroglossal Duct Cyst: A Very Rare Location.

Mucoceles are one of the most common benign soft tissue masses of the oral cavity. When they occur in the tongue, the ventral surface is the usual location. Mucoceles at the base of the tongue are extremely rare and must be differentiated from intralingual thyroglossal duct cysts. We present a case of a mucocele on the base of the tongue, which was incidentally found on a cervical spinal magnetic resonance image. We include a review of the literature on image findings, pathologic type, differential diagnosis, clinical symptoms, and treatment of oral mucoceles.

Clinical significance of the circle of Willis in intracranial atherosclerotic stenosis.

INTRODUCTION: The effectiveness of a scoring system based on the circle of Willis for evaluations of collateral circulation was studied in patients with intracranial atherosclerotic stenosis. METHODS: Eighty-three patients who underwent medical or endovascular treatment for symptomatic and severe intracranial atherosclerotic stenosis were enrolled in the study. Clinical profiles, status of the circle of Willis (poor and good integrity group), and clinical outcomes were analyzed. Primary endpoints were: (1) symptomatic ischemic or hemorrhagic stroke within 30 days; and (2) recurrent transient ischemic attack or ischemic stroke beyond 30 days. RESULTS: The estimated rates of the primary endpoint at 1 and 2 years after treatment were 8.5% and 11.4% in the medical group and 7.0% and 9.7% in the endovascular group, respectively. A primary endpoint event after medical treatment was only identified in patients with poor integrity of the circle of Willis (p=0.059). In patients with poor integrity of the circle of Willis, previous antiplatelet medication before initial presentation (p=0.026) and hypertension (p=0.006) were more prevalent. During the follow-up period, complete arterial occlusion was identified in 9 patients. The circle of Willis score of the patients with complete arterial occlusion was 1.33±1.52 in the fatal stroke group (n=3) and 3.20±1.64 in the asymptomatic group (n=6, p=0.099). CONCLUSIONS: If patients have poor integrity of the circle of Willis, the risk of recurrent stroke may be increased. Such patients appear to be good candidates for endovascular treatment.