Usefulness of sectional images in dural AVF for the interpretation of venous anatomy.

Knowledge of the venous anatomy is essential for appropriately treating dural arteriovenous fistulas (AVFs). It is challenging to determine the overall venous structure despite performing selective angiography for dural AVFs with feeder from multiple selected arteries. This is because only a part of the veins can be observed through the shunt in the selected artery. Therefore, after performing selective angiography of all vessels to understand the approximate venous anatomy, the venous anatomy can be easily understood by closely examining the source image of computed tomographic angiography or magnetic resonance angiography. Through this, it is possible to specify the vein that is to be blocked (target embolization), thereby avoiding extensive blocking of the vein and avoiding various complications. In the case of dural AVF with feeder from single selected artery, if the multiplanar reconstruction image of the three-dimensional rotational computed tomography obtained by performing angiography is analyzed thoroughly, a shunted pouch can be identified. If embolization is performed by targeting this area, unnecessary sinus total packing can be avoided.

Endovascular Management of Iatrogenic Vertebral Artery Pseudoaneurysm: A Case Report.

Iatrogenic injury of the vertebral artery during cervical spine surgery though uncommon is critical. With advances in interventional endovascular techniques, the therapeutic approach for vertebral artery injuries has changed. Nonetheless, an established strategy for their management is lacking. We report a case of pseudoaneurysm due to vertebral artery injury, during cervical spine surgery for a tumor, that was treated successfully with endovascular coiling in a plug-and-patch fashion after triple stenting failed.

Feasibility of Prompt Lumbar Drainage in Patients with Aneurysmal Subarachnoid Hemorrhage.

BACKGROUND: Numerous studies have shown that continuous lumbar drainage (LD) reduces spontaneous subarachnoid hemorrhage (SAH)-related complications, decreasing the incidence of cerebral vasospasm, delayed cerebral ischemia , and hydrocephalus in patients treated with coiling or clipping, but performing LD before securing the aneurysm is still controversial. Our hospital has been implementing prompt LD for several years, and we present the results in this paper. METHODS: Between January 2014 and December 2020, a total of 438 patients with SAH were included in this retrospective study. The indication for prompt LD was aneurysmal SAH of modified Fisher grade III or higher without dense intraventricular hemorrhage with obstructive hydrocephalus requiring extraventricular drainage or large intracranial hemorrhage requiring immediate decompression. Prompt LD was performed for 229 patients with SAH, and the control group included 209 patients. We compared in-hospital mortality and vasospasm or hydrocephalus occurrence and procedure-related complications between the two groups. RESULTS: The in-hospital mortality rate was 7.4% for patients with prompt LD and 14.4% for patients without LD, and the difference was significant (P = 0.019). Vasospasm occurred in 10% of patients with prompt LD and 16.7% of controls (P = 0.039). Hydrocephalus requiring extraventricular drainage occurred in 10.9% of the LD group and 28.7% of the control group (P < 0.001). Rebleeding occurrence was 3.1% in the prompt LD group and 5.7% in the non-LD group (P = 0.168). Cerebrospinal fluid infection occurred in 0.4% of the prompt LD group and 1.4% of controls(P = 0.272). CONCLUSIONS: Prompt LD is a feasible option for treating patients with selective aneurysmal SAH.

Comparison of Safety and Diagnostic Efficacy of Iohexol 240 mgI/mL, Iopamidol 250 mgI/mL, and Iodixanol 270 mgI/mL in Cerebral Angiography: A Prospective, Multicenter Study.

PURPOSE: This multicenter prospective study aimed to evaluate the quality and diagnostic effectiveness of cerebral angiography images obtained using low-concentration iodinated contrast agents (iohexol 240 mgI/mL, iopamidol 250 mgI/mL, and iodixanol 270 mgI/mL) and to assess the safety thereof. The study addresses the need for safer contrast agent alternatives without compromising the diagnostic quality of identifying cerebrovascular disease. MATERIALS AND METHODS: Conducted in 5 medical centers in South Korea, we enrolled patients aged 19 years or older who were referred for diagnostic cerebral angiography under non-emergency conditions, excluding those with specific health conditions and sensitivities. The study design included a prospective, observational approach with a 1-way analysis of variance (ANOVA) for sample size calculation, aiming for a total sample of 231 participants for adequate power. Image quality was evaluated using a 4-level scale by 2 independent, blinded radiologists, and adverse reactions were monitored both immediately and up to 7 days post-procedure. Statistical analysis involved 1-way ANOVA and Kruskal-Wallis tests to assess the image quality and safety profiles of the contrast agents. RESULTS: Among 266 patients screened, 243 were included in the final analysis. The evaluation revealed no statistically significant differences in image quality among the 3 types of low-concentration contrast agents. Adverse events were observed in 28.8% of patients, with 27.2% experiencing acute reactions, primarily mild reactions, and 3.3% experiencing delayed reactions. The overall safety profile showed no significant changes in vital signs or electrocardiogram readings before and after contrast agent injection. CONCLUSION: Using low-concentration iodinated contrast agents for cerebral angiography provides image quality comparable to that of conventional high-concentration agents, with no significant increase in adverse events, suggesting a safer alternative for patients.

Effect of distal access catheter tip position on angiographic and clinical outcomes following thrombectomy using the combined stent-retriever and aspiration approach.

PURPOSE: Mechanical thrombectomy using the stent-retriever in conjunction with the distal access catheter may improve the rates of successful revascularization and clinical outcomes in patients with acute stroke. We aimed to compare two different thrombectomy techniques, according to the position of the distal access catheter tip in the combined stent-retriever and aspiration approach. METHODS: In this retrospective study, patients with middle cerebral artery occlusion treated with the combined technique were divided into two groups based on the tip position of the distal access catheter: distal group (catheter placed adjacent to the thrombus) and proximal group (catheter placed in the cavernous segment of the internal carotid artery below the ophthalmic artery). Baseline characteristics, angiographic results, and clinical outcomes were compared. RESULTS: Eighty-three patients (distal group, n = 45; proximal group, n = 38) were included. Higher complete reperfusion was observed in the distal group (unweighted analysis: 66.7% vs. 42.1%, p = 0.025; weighted analysis: 74.0% vs. 28.8%; p = 0.002). In the multivariate analysis, the distal tip position was independently associated with complete reperfusion (unweighted analysis: aOR, 4.10; 95% CI, 1.40-11.98; p = 0.01; weighted analysis: aOR, 5.20; 95% CI, 1.72-15.78; p = 0.004). The distal group also showed more favorable clinical outcomes and early neurological improvement (unweighted analysis: 62.2% vs. 55.3%; p = 0.521, 60% vs. 50%; p = 0.361, respectively; weighted analysis: 62.7% vs. 61.1%; p = 0.877, 66% vs. 45.7%; p = 0.062, respectively). However, more arterial dissections were observed in the distal group (8.9%, n = 4 vs. 2.6%, n = 1; p = 0.36). In the distal group, one patient with vascular injury died due to complications. No cases of emboli in new territory were observed. CONCLUSIONS: Distal tip position of the distal access catheter has a significant impact on reperfusion in patients with acute ischemic stroke. However, there was also a higher rate of vascular injury as the catheter was advanced further. If advancement to the target lesion is too difficult, placing it in the cavernous internal carotid artery may be a viable method without complications.

Primary Extracranial Fibrous Meningioma of the Maxillary Sinus: A Case Report and Literature Review.

Meningioma is a common neoplasm of the central nervous system; however, primary extracranial meningioma of the paranasal sinus, especially the maxillary sinus, is rare. We report a case of primary extracranial meningioma (fibrous type) of the maxillary sinus and present a literature review of the imaging features that correlate with fibrous meningioma.

Revision Superficial Temporal Artery-Middle Cerebral Artery Bypass Surgery for Recurrent Acute Ischemic Stroke Due to Delayed Occlusion of the Bypass Graft.

Intravenous thrombolysis (IVT) and endovascular treatment (EVT) are currently the main treatments for reperfusion in acute ischemic stroke. Although the EVT recanalization rate has increased, unsuccessful recanalization is still observed in 10-30% cases. Superficial temporal artery-middle cerebral artery (STA-MCA) bypass is considered a rescue therapy in such cases, but in most centers it is not usually performed for acute ischemic stroke. Graft occlusion is rare following STA-MCA bypass, but it might lead to recurrent ischemic stroke. We hereby report on a patient with right MCA infarction and in whom EVT failed due to complete proximal internal carotid artery occlusion. He underwent an emergency STA-MCA bypass, resulting in a full recovery of his motor weakness. However, six months later, the patient experienced recurrent acute ischemic stroke due to bypass graft occlusion. His EVT failed again but revision bypass surgery, using STA remnant branch, was successful with full motor weakness recovery. We recommend a revision bypass surgery as a feasible therapeutic option for recurrent cerebral infarction caused by delayed STA graft occlusion.

Thrombolysis in Large Diffusion-Weighted Imaging Lesions: Lower Chance but Still a Chance.

BACKGROUND: We sought to investigate whether early thrombolytic treatment can result in favorable functional outcome even in patients with large diffusion-weighted imaging (DWI) lesions. MATERIALS AND METHODS: We analyzed 566 patients who received intravenous alteplase within 4.5 hours from onset, initially underwent DWI and magnetic resonance angiography, and had acute infarction confined to anterior circulation. DWI lesion volumes were measured semiautomatically. The association between DWI lesion volume and 3-month outcome in patients who achieved early recanalization was assessed. The DWI lesion volume cutoff, which predicts unfavorable outcome despite recanalization, was determined. In patients with large DWI lesions, the distributions of modified Rankin Scale (mRS) score were compared according to the recanalization status. RESULTS: Four hundred thirty-six patients achieved early recanalization. Among these patients, 283 (65%) patients had a favorable functional outcome (mRS score 0-2). DWI lesion volume (odds ratio [OR], 1.38 per 10 mL; 95% confidence interval [CI], 1.22-1.56) was an independent variable associated with poor outcome, along with hypertension (OR, 1.87; 95% CI, 1.12-3.10), National Institutes of Health Stroke Scale (NIHSS) score (OR, 1.13; 95% CI, 1.08-1.19), and onset-to-needle time (OR, 1.08 per 10 minutes; 95% CI, 1.03-1.13). The DWI lesion of 60 mL or higher highly predicted an unfavorable outcome with a positive predictive value of 95.3%. In patients with a DWI lesion of 60 mL or higher, recanalization had no benefit for an mRS score of 0-2 but was significantly associated with an mRS score of 0-3 (OR, 4.64; 95% CI, 1.08-19.97). CONCLUSIONS: Despite early recanalization, the probability of favorable outcome is low in patients with a DWI lesion of 60 mL or higher. Nevertheless, the benefit of recanalization still persists in large DWI lesions.

Spontaneous Regression of an Intracranial Aneurysm Following Remote Aneurysm Clipping: Evaluation with High-Resolution Vessel Wall MRI.

Spontaneous regression of an unruptured aneurysm is very rare. We present a case of a 64-year-old woman with an unruptured cerebral aneurysm in which spontaneous regression occurred after contralateral clipping. High-resolution magnetic resonance imaging showed that the aneurysm had decreased in size and there was no evidence of thrombus. Level of Evidence Case, Level IV.

Patient Selection and Clinical Efficacy of Urgent Superficial Temporal Artery-Middle Cerebral Artery Bypass in Acute Ischemic Stroke Using Advanced Magnetic Resonance Imaging Techniques.

BACKGROUND: Selected patients with acute ischemic stroke might benefit from superficial temporal artery-middle cerebral artery (STA-MCA) bypass, but the indications for urgent STA-MCA bypass are unknown. OBJECTIVE: To report our experiences of urgent STA-MCA bypass in patients requiring urgent reperfusion who were ineligible for other reperfusion therapies, using advanced magnetic resonance imaging (MRI) techniques. METHODS: The inclusion criteria for urgent STA-MCA bypass were as follows: acute infarct volume <70 mL with a ratio of perfusion/diffusion lesion volume ≥1.2, and a regional cerebral blood volume ratio >0.85. From January 2013 to October 2015, 21 urgent STA-MCA bypass surgeries were performed. The control group included 19 patients who did not undergo bypass surgery mainly due to refusal of surgery or the decision of the neurologist. Clinical and radiological data were compared between the surgery and control group. RESULTS: The median age of the control group (70 years, interquartile range [IQR] 58-76) was higher than that of the surgery group (62 years, IQR 49-66), but the median preoperative diffusion and perfusion lesion volumes of the surgery group (13.8 mL, IQR 7.5-26.0 and 120.9 mL, IQR 84.9-176.0, respectively) were higher than those of the control group (5.6 mL, IQR 2.1-9.1 and 69.7 mL, IQR 23.9-125.3, respectively). Sixteen (76.2%) patients in the surgery group and 2 (10.5%) patients in the control group had favorable outcomes ( P < .001). Logistic regression analysis identified bypass surgery as the strongest predictive factor. CONCLUSION: STA-MCA bypass can be used as a therapeutic tool for acute ischemic stroke. Advanced MRI techniques are helpful for selecting patients and for decision making.

Impact of Prehospital Intervention on Delay Time to Thrombolytic Therapy in a Stroke Center with a Systemized Stroke Code Program.

BACKGROUND: The use of emergency medical services (EMS) and notification to hospitals by paramedics for patients with suspected stroke are crucial determinants in reducing delay time to acute stroke treatment. The aim of this study is to investigate whether EMS use and prehospital notification (PN) can shorten the time to thrombolytic therapy in a stroke center with a systemized stroke code program. METHODS: Beginning in January 2012, stroke experts in our stroke center received direct calls via mobile phone from paramedics prenotifying the transport of patients with suspected stroke. We compared baseline characteristics and prehospital/in-hospital delay time in stroke patients treated with intravenous recombinant tissue plasminogen activator for 44 months with and without EMS use and/or PN. RESULTS: Intravenous thrombolytic therapy was performed on 274 patients. Of those patients, 215 (78.5%) were transported to the hospital via EMS and 59 (21.5%) were admitted via private modes of transportation. The patients who used EMS had shorter median onset-to-arrival times (62 minutes versus 116 minutes, P < .001). There was no difference in in-hospital delay time between the 2 groups. In 28 cases (13%) of EMS transport, EMS personnel called the clinical staff to notify the incoming patient. Prenotification by EMS was associated with shorter median door-to-imaging time (9 minutes versus 12 minutes, P = .045) and door-to-needle time (20 minutes versus 29 minutes, P = .011). CONCLUSIONS: We found that EMS use reduces prehospital delay time. However, EMS use without prenotification does not shorten in-hospital processing time in a stroke center with a systemized stroke code program.

Safety of coil occlusion of the parent artery for endovascular treatment of anterior communicating artery aneurysm.

Many studies lay emphasis on the clinical importance of perforating branches of the anterior communicating artery (ACoA) and report that vascular damage of the perforators from ACoA aneurysm during surgery cause subsequent postoperative amnesia. The purpose of our study was to analyze the safety of parent artery occlusion for ACoA aneurysm coiling based on the anatomical features of the ACoA complex in 13 patients with 13 ACoA aneurysms. All patients underwent coiling of the aneurysm sac and ACoA. Aneurysm characteristics including size, dome-to-neck ratio, anterior/posterior orientation of the aneurysm dome with respect to the axis of the pericallosal artery, location of the aneurysm neck with respect to the A1-A2 segment of the anterior cerebral artery (ACA) or the ACoA, and the presence of hypoplasia/aplasia of A1 segment were assessed. The aneurysm neck was located directly on the ACoA in five aneurysms (38%), whereas eight (62%) had the neck located at the A1-A2 junction. Of the five patients whose aneurysm neck was located in the ACoA, four patients had infarcts in the basal forebrain. Three of the patients complained of amnesia. None of the aneurysms with the neck located at the A1-A2 junction were associated with infarction. There has been little evidence thus far that parent vessel occlusion of ACoA aneurysms is a safe method for the treatment of aneurysms. Patients with the aneurysm neck located at the A1-A2 junction and without A1 aplasia, who were treated with aneurysm sac and ACoA embolism, were potentially safe.

A case report of sporadic hemiplegic migraine associated cerebral hypoperfusion: comparison of arterial spin labeling and dynamic susceptibility contrast perfusion MR imaging.

The pathogenesis of sporadic hemiplegic migraine remains unclear, and perfusion-weighted magnetic resonance imaging (PWI) has been used for characterization of hemodynamic changes in migraine aura. We report a case of sporadic hemiplegic migraine in which magnetic resonance perfusion imaging showed left cerebral hypoperfusion. Dynamic susceptibility contrast (DSC) perfusion maps showed hypoperfusion with posterior predominance in the left cerebral hemisphere. Findings with arterial spin labeling (ASL) perfusion correlated well with DSC perfusion findings. CONCLUSION: With unique advantages compared with DSC PWI, ASL has significant potential in the evaluation of the patients with sporadic hemiplegic migraine. WHAT IS KNOWN: Sporadic hemiplegic migraine is a rare variety of migraine defined by migraine attacks, which include the presence of motor weakness/hemiparesis during the aura phase and where no first- or second-degree relative (parent, sibling, or child) has identical attacks. WHAT IS NEW: Reports on imaging abnormalities described in sporadic hemiplegic migraine are sparse. To our knowledge, this is the first report to describe arterial spin labeling (ASL) perfusion abnormalities in patients with sporadic hemiplegic migraine, as compared with dynamic susceptibility contrast perfusion-weighted magnetic resonance imaging (PWI).

Mismatch of delayed perfusion volume between TTP and Tmax map of perfusion MRI.

OBJECTIVE: To look for another set of parameters to predict the change in infarct size in acute stroke patients with a perfusion-weighted imaging (PWI)-diffusion-weighted imaging (DWI) mismatch. MATERIALS AND METHODS: We reviewed 54 patients who had PWI-DWI mismatch and vascular occlusion on initial MRI and no recanalization of occluded vessel. RESULTS: Time-to-peak and time-to-max (TTP-Tmax) perfusion mismatch volume was independently significant as a correlate of infarct volume change (P=.004). CONCLUSIONS: The finding of a large TTP-Tmax perfusion delay mismatch volume in patients with acute stroke who have a PWI-DWI mismatch on an initial MRI may predict that the infarct volume will not increase despite persistent vascular occlusion.

Liver Function Assessment Using Parenchyma-Specific Contrast-Enhanced Ultrasonography.

The aim of this study was to assess hepatic functional reserve by analyzing the hepatic parenchyma enhancement curve of parenchyma-specific contrast-enhanced ultrasonography (CEUS). Fifty-two patients with cirrhosis who underwent CEUS and indocyanine green tests (ICG) because of a focal liver lesion were enrolled. We evaluated the hemodynamic-related parameters of the time-intensity curve and compared these findings with the ICG retention rate at 15 min (ICG R15). The correlation between the time from peak to one half (s) and ICG R15 was statistically significant and was relatively proportional to the ICG R15. A cut-off value of 149 s was determined for the time from peak to one half for abnormal ICG R15 (>14). The sensitivity and specificity were 85.7% and 92.3%, respectively, for the detection of abnormal ICG R15. In conclusion, the time from peak to one half of the time-intensity curve of parenchyma-specific CEUS of the liver can be a useful parameter to predict the hepatic reserve in liver cirrhosis.

High residual platelet reactivity (HRPR) for adenosine diphosphate (ADP) stimuli is a determinant factor for long-term outcomes in acute ischemic stroke with anti-platelet agents: The meaning of HRPR after ADP might be more prominent in large atherosclerotic infarction than other subtypes of AIS.

High residual platelet activation (HRPA) after ADP stimuli has associated with recurrent vascular events in acute atherothrombosis with the use of antiplatelet agents (APAs). However, there has been little evidence supporting this association in acute ischemic stroke (AIS). In this study, we evaluated the influences of HRPR after ADP stimuli on the 1-year incidence of recurrent cardiovascular events and mortality in AIS with APAs. We conducted an observational, referral center cohort study on 968 AIS patients with APAs from January 2010 to December 2013 who were evaluated using optical platelet aggregometry (OPA). All patients received the dual APA combination of aspirin and clopidogrel or aspirin alone. We evaluated their platelet function 5 days after hospital admission using OPA. HRPR after ADP stimuli was defined as platelet aggregation of 70 % or greater according to OPA after 10 µM ADP stimuli. The primary endpoint was a composite of all causes of death, myocardial infarction, and stroke at the 1-year follow-up. The secondary endpoints were each component of the primary endpoint. The event rate of primary endpoint was 11.3 % (109/968). Its rate was significantly higher in the patients with HRPR (16.7 %) than in those without (9.7 %). HPRP was independently associated with the primary endpoint (OR = 1.97, CI 1.22-3.18, p < 0.01). According to the AIS subtype, the presence of HRPR was independently significant for the occurrence of the primary endpoint in the large artery atherosclerosis (LAA) subtype only (OR = 2.26, CI 1.15-4.45, p = 0.02). In this study, the presence of HRPR after ADP stimuli is associated with a poor long-term outcome after acute ischemic stroke. In particular, the influence of this factor might be more prominent in LAA compared with other types of AIS.

Thrombectomy using a stent retriever with artificially induced vertebral artery vasospasm in a patient with acute basilar artery occlusion: a case report.

An acute basilar artery occlusion is not an uncommon cause of stroke. It represents 6-10% of large vessel strokes and has been associated with poor clinical outcomes. Multimodal treatments have been introduced to recanalise a basilar artery occlusion successfully. However, all mechanical thrombectomy devices are not always usable in an emergent situation. We present a case of basilar artery occlusion treated with a stent retriever assisted by a vertebral artery vasospasm. We attempted thrombectomy with a stent retriever several times. However, the captured thrombus was not pulled out and migrated to the distal basilar artery and posterior cerebral artery due to anterograde flow of the vertebral artery. We carefully advanced the catheter into the distal vertebral artery and generated a vasospasm. The vertebral artery vasospasm reduced the forward flow significantly like a balloon-guided catheter. The thrombus was pulled out with the stent.

Pilomyxoid Astrocytoma Occurring in the Third Ventricle.

Pilomyxoid astrocytoma (PMA) is a rare central nervous system tumor that has been included in the 2007 World Health Organization Classification of Tumors of the Central Nervous System. Due to its more aggressive behavior, PMA is classified as Grade II neoplasm by the World Health Organization. PMA predominantly affects the hypothalamic/chiasmatic region and occurs in children (mean age of occurrence = 10 months). We report a case of a 24-year-old man who presented with headache, nausea, and vomiting. Brain CT and MRI revealed a mass occupying only the third ventricle. We performed partial resection. Histological findings, including monophasic growth with a myxoid background, and absence of Rosenthal fibers or eosinophilic granular bodies, as well as the strong positivity for glial fibrillary acidic protein were consistent with PMA.

Comparative Analysis of Endovascular Stroke Therapy Using Urokinase, Penumbra System and Retrievable (Solitare) Stent.

BACKGROUND: Higher reperfusion rates have been established with endovascular treatment for acute ischemic stroke patients. There are limited data on the comparative performance of mechanical thrombectomy devices. This study aimed to analyse the efficacy and safety of the stent retriever device (Solitaire stent) by comparing procedure time, angiographic outcome, complication rate and long term clinical outcome with previous chemical thrombolysis and mechanical thrombectomy using penumbra system. METHODS: A retrospective single-center analysis was undertaken of all consecutive patients who underwent chemical thrombolysis and mechanical thrombectomy using Penumbra or Solitaire stent retriever from March 2009 to March 2014. Baseline characteristics, rate of successful recanalization (modified Thrombolysis in Cerebral Infarction score 2b-3), symptomatic intracerebral hemorrhage, procedure time, mortality and independent functional outcomes (mRS ≤2) at 3 month were compared across the three method. RESULTS: Our cohort included 164 patients, mechanical thrombectomy using stent retriever device had a significant impact on recanalization rate and functional independence at 3 months. In unadjusted analysis mechanical thrombectomy using Solitaire stent retriever showed higher recanalization rate than Penumbra system and chemical thrombolysis (75% vs. 64.2% vs. 49.4%, p=0.03) and higher rate of functional independence at 3 month (53.1% vs. 37.7% vs. 35.4%, p=0.213). In view of the interrelationships between all predictors of variables associated with a good clinical outcome, when the chemical thrombolysis was used as a reference, in multiple logistic regression analysis, the use of Solitaire stent retriever showed higher odds of independent functional outcome [odds ratio (OR) 2.62, 95% confidence interval (CI) 0.96-7.17; p=0.061] in comparison with penumbra system (OR 1.57, 95% CI 0.63-3.90; p=0.331). CONCLUSION: Our initial data suggest that mechanical thrombectomy using stent retriever is superior to the mechanical thrombectomy using penumbra system and conventional chemical thrombolysis in achieving higher rates of reperfusion and better outcomes. Randomized clinical trials are needed to establish the actual benefit to specific patient populations.

A systemized stroke code significantly reduced time intervals for using intravenous tissue plasminogen activator under magnetic resonance imaging screening.

BACKGROUND: A stroke code can shorten time intervals until intravenous tissue plasminogen activator (IV t-PA) treatment in acute ischemic stroke (AIS). Recently, several reports demonstrated that magnetic resonance imaging (MRI)-based thrombolysis had reduced complications and improved outcomes in AIS despite longer processing compared with computed tomography (CT)-based thrombolysis. METHODS: In January 2009, we implemented CODE RED, a computerized stroke code, at our hospital with the aim of achieving rapid stroke assessment and treatment. We included patients with thrombolysis from January 2007 to December 2008 (prestroke code period) and from January 2009 to May 2013 (poststroke code period). The IV t-PA time intervals and 90-day modified Rankin Scale (mRS) scores were collected. RESULTS: During the observation period, 252 patients used IV t-PA under the CODE RED (MRI based: 208; CT based: 44). The remaining 71 patients (MRI based: 53; CT based: 18) received it before the implementation of our stroke code. After implementation of CODE RED, door-to-image time, door-to-needle time, and the onset-to-needle time were significantly reduced by 11, 18, and 22 minutes in MRI-based thrombolysis. Particularly, the proportion of favorable outcome (mRS score 0-2) was significantly increased (from 41.5% to 60.1%, P = .02) in poststroke than in prestroke code period in MRI-based thrombolysis. However, in ordinal regression, the presence of stroke code showed just a trend for favorable outcome (odds ratio, .99-2.87; P = .059) at 90 days of using IV t-PA after correction of age, sex, and National Institutes of Health Stroke Scale. CONCLUSIONS: In this study, we demonstrated that a systemized stroke code shortened time intervals for using IV t-PA under MRI screening. Also, our results showed a possibility that a systemized stroke code might enhance the efficacy of MRI-based thrombolysis. In the future, we need to carry out a more detailed prospective study about this notion.