Trial of Thrombectomy for Stroke with a Large Infarct of Unrestricted Size.

BACKGROUND: The use of thrombectomy in patients with acute stroke and a large infarct of unrestricted size has not been well studied. METHODS: We assigned, in a 1:1 ratio, patients with proximal cerebral vessel occlusion in the anterior circulation and a large infarct (as defined by an Alberta Stroke Program Early Computed Tomographic Score of ≤5; values range from 0 to 10) detected on magnetic resonance imaging or computed tomography within 6.5 hours after symptom onset to undergo endovascular thrombectomy and receive medical care (thrombectomy group) or to receive medical care alone (control group). The primary outcome was the score on the modified Rankin scale at 90 days (scores range from 0 to 6, with higher scores indicating greater disability). The primary safety outcome was death from any cause at 90 days, and an ancillary safety outcome was symptomatic intracerebral hemorrhage. RESULTS: A total of 333 patients were assigned to either the thrombectomy group (166 patients) or the control group (167 patients); 9 were excluded from the analysis because of consent withdrawal or legal reasons. The trial was stopped early because results of similar trials favored thrombectomy. Approximately 35% of the patients received thrombolysis therapy. The median modified Rankin scale score at 90 days was 4 in the thrombectomy group and 6 in the control group (generalized odds ratio, 1.63; 95% confidence interval [CI], 1.29 to 2.06; P<0.001). Death from any cause at 90 days occurred in 36.1% of the patients in the thrombectomy group and in 55.5% of those in the control group (adjusted relative risk, 0.65; 95% CI, 0.50 to 0.84), and the percentage of patients with symptomatic intracerebral hemorrhage was 9.6% and 5.7%, respectively (adjusted relative risk, 1.73; 95% CI, 0.78 to 4.68). Eleven procedure-related complications occurred in the thrombectomy group. CONCLUSIONS: In patients with acute stroke and a large infarct of unrestricted size, thrombectomy plus medical care resulted in better functional outcomes and lower mortality than medical care alone but led to a higher incidence of symptomatic intracerebral hemorrhage. (Funded by Montpellier University Hospital; LASTE ClinicalTrials.gov number, NCT03811769.).

Management of covert brain infarction survey: A call to care for and trial this neglected population.

BACKGROUND: Covert brain infarction (CBI) is highly prevalent and linked with stroke risk factors, increased mortality, and morbidity. Evidence to guide management is sparse. We sought to gain information on current practice and attitudes toward CBI and to compare differences in management according to CBI phenotype. METHODS: We conducted a web-based, structured, international survey from November 2021 to February 2022 among neurologists and neuroradiologists. The survey captured respondents' baseline characteristics, general approach toward CBI and included two case scenarios designed to evaluate management decisions taken upon incidental detection of an embolic-phenotype and a small-vessel-disease phenotype. RESULTS: Of 627 respondents (38% vascular neurologists, 24% general neurologists, and 26% neuroradiologists), 362 (58%) had a partial, and 305 (49%) a complete response. Most respondents were university hospital senior faculty members experienced in stroke, mostly from Europe and Asia. Only 66 (18%) of respondents had established institutional written protocols to manage CBI. The majority indicated that they were uncertain regarding useful investigations and further management of CBI patients (median 67 on a slider 0-100, 95% CI 35-81). Almost all respondents (97%) indicated that they would assess vascular risk factors. Although most would investigate and treat similarly to ischemic stroke for both phenotypes, including initiating antithrombotic treatment, there was considerable diagnostic and therapeutic heterogeneity. Less than half of respondents (42%) would assess cognitive function or depression. CONCLUSIONS: There is a high degree of uncertainty and heterogeneity regarding management of two common types of CBI, even among experienced stroke physicians. Respondents were more proactive regarding the diagnostic and therapeutic management than the minimum recommended by current expert opinions. More data are required to guide management of CBI; meantime, more consistent approaches to identification and consistent application of current knowledge, that also consider cognition and mood, would be promising first steps to improve consistency of care.

Selective therapeutic cooling: To maximize benefits and minimize side effects related to hypothermia.

Selective therapeutic cooling is a promising technique for reducing final infarct volume and improving outcomes in ischemic stroke, especially as research regarding brain reperfusion continues to be explored. A recent study provided promising results on the safety and feasibility of selective therapeutic hypothermia via a closed-loop cooling catheter system for intra-carotid blood cooling in an ovine stroke model, but they failed to find efficacy of this method in this model. It is a major step forward from bench to bed side, but enhancing benefits of selective therapeutic cooling may need to take into account a more targeted induction of brain hypothermia and should mitigate potential side effects related to inducing hypothermia.

Cerebral Edema in Patients With Large Hemispheric Infarct Undergoing Reperfusion Treatment: A HERMES Meta-Analysis.

Background and Purpose: Whether reperfusion into infarcted tissue exacerbates cerebral edema has treatment implications in patients presenting with extensive irreversible injury. We investigated the effects of endovascular thrombectomy and reperfusion on cerebral edema in patients presenting with radiological evidence of large hemispheric infarction at baseline. Methods: In a systematic review and individual patient-level meta-analysis of 7 randomized controlled trials comparing thrombectomy versus medical therapy in anterior circulation ischemic stroke published between January 1, 2010, and May 31, 2017 (Highly Effective Reperfusion Using Multiple Endovascular Devices collaboration), we analyzed the association between thrombectomy and reperfusion with maximal midline shift (MLS) on follow-up imaging as a measure of the space-occupying effect of cerebral edema in patients with large hemispheric infarction on pretreatment imaging, defined as diffusion-magnetic resonance imaging or computed tomography (CT)-perfusion ischemic core 80 to 300 mL or noncontrast CT-Alberta Stroke Program Early CT Score ≤5. Risk of bias was assessed using the Cochrane tool. Results: Among 1764 patients, 177 presented with large hemispheric infarction. Thrombectomy and reperfusion were associated with functional improvement (thrombectomy common odds ratio =2.30 [95% CI, 1.32­4.00]; reperfusion common odds ratio =4.73 [95% CI, 1.66­13.52]) but not MLS (thrombectomy ß=−0.27 [95% CI, −1.52 to 0.98]; reperfusion ß=−0.78 [95% CI, −3.07 to 1.50]) when adjusting for age, National Institutes of Health Stroke Score, glucose, and time-to-follow-up imaging. In an exploratory analysis of patients presenting with core volume >130 mL or CT-Alberta Stroke Program Early CT Score ≤3 (n=76), thrombectomy was associated with greater MLS after adjusting for age and National Institutes of Health Stroke Score (ß=2.76 [95% CI, 0.33­5.20]) but not functional improvement (odds ratio, 1.71 [95% CI, 0.24­12.08]). Conclusions: In patients presenting with large hemispheric infarction, thrombectomy and reperfusion were not associated with MLS, except in the subgroup with very large core volume (>130 mL) in whom thrombectomy was associated with increased MLS due to space-occupying ischemic edema. Mitigating cerebral edema-mediated secondary injury in patients with very large infarcts may further improve outcomes after reperfusion therapies.

Astrocytes constitute the major TNF-α-producing cell population in the infarct cortex in dMCAO rats receiving intravenous MSC infusion.

Recent studies report that inhibiting TNF-α might be a novel therapeutic strategy for managing brain ischemia. Our previous study reported that mesenchymal stem cell (MSC) transplantation could suppress TNF-α level in both serum and brain. However, the cell type(s) that contribute to the production of TNF-α during ischemia following MSC transplantation has not been well studied. In the present study, we found by fluorescent immunohistochemistry, that 7.95 ± 6.17% of TNF-α+ cells co-expressed Iba-1 in the infarct area of dMCAO rats, a majority of which were found to be CD68+ (activated microglia), suggesting that resident microglial population were not the major source of TNF-α expression. 68.49 ± 5.12% of the TNF-α+ cells in the infarct area could be labeled by GFAP, a specific marker for astrocytes, indicating that resident GFAP+ astrocytes might be the major source of TNF-α expression in the infarct area. In addition to the infarct area, the GFAP+/TNF-α+ double-positive astrocytes accounted for 73.68 ± 7.48% of the TNF-α+ cells in striatum and corpus callosum. The infiltrating cells, including monocytes and lymphocytes, were not the main source of TNF-α either. In response to MSC transplantation, the total TNF-α+ cells as well as the percentage of TNF-α-expressing astrocytes were significantly reduced in the infarct area, suggesting that MSC transplantation could suppress the expression of TNF-α by astrocytes. Taken together, the results demonstrated that resident astrocytes, but not microglia, were the major source of TNF-α expression and could be suppressed by MSC infusion.

MRI Diffusion-Weighted Imaging to Measure Infarct Volume: Assessment of Manual Segmentation Variability.

BACKGROUND AND PURPOSE: Manual segmentation of infarct volume on follow-up MRI diffusion-weighted imaging (MRI-DWI) is considered the gold standard but is prone to rater variability. We assess the variability of manual segmentations of MRI-DWI infarct volume. METHODS: Consecutive patients (May 2018 to May 2019) with the anterior circulation stroke and endovascularly treated were enrolled. All patients underwent 24- to 32-hour follow-up MRI. Three users manually segmented DWI infarct volumes slice by slice twice. The reference standard of DWI infarct volume was generated by the STAPLE algorithm. Intra- and interrater reliability was evaluated using the intraclass correlation coefficient (ICC) by comparing manual segmentations with the reference standard. Spatial measurements were evaluated using metrics of the Dice similarity coefficient (DSC). Volumetric measurements were compared using the lesion volume. RESULTS: The dataset consisted of 44 patients, mean (SD) age was 70.1 years (±10.3), 43% were women, and median baseline NIHSS score was 16. Among three users, the mean DSC for MRI-DWI infarct volume segmentations ranged from 80.6% ± 11.7% to 88.6% ± 7.5%, and the mean absolute volume difference was 2.8 ± 6.8 to 13.0 ± 14.0 ml. Interrater ICC among the users for DSC and infarct volume was .86 (95% confidence interval [95% CI]: .78-.91) and .997 (95% CI: .995-.998). Intrarater ICC for the three users was .83 (95% CI: .69-.93), .84 (95% CI: .72-.91), and .80 (95% CI: .64-.89) for DSC, and .99 (95% CI: .987-.996), .991 (95% CI: .983-.995), and .996 (95% CI: .993-.998) for infarct volume. CONCLUSIONS: Manual segmentation of infarct volume on follow-up MRI-DWI shows excellent agreement and good spatial overlap with the reference standard, suggesting its usefulness for measuring infarct volume on 24- to 32-hour MRI-DWI.

Clinical Outcomes and Medical Costs of Hydration Therapy with Hydroxyethyl Starch (130/0.4) or Acute Single Infarction.

OBJECTIVES: To investigate the effects of hydration with or without Hydroxyethyl Starch (HES) 130/0.4 on neurological outcomes and medical costs during hospitalisation in patients with a single infarction (SI) in the posterior lenticulostriate artery (LSA) territory. MATERIALS AND METHODS: In this retrospective, single-centre, non-blinded cohort study, SI in the posterior LSA was defined as an ischaemic lesion with a high-signal intensity area ≥20 mm. All patients received basic stroke care within 48 h of symptom onset between April 2015 and January 2019. Patients were divided into the following two groups by clinician's preference: 1) those administered HES 130/0.4 and 2) those receiving other infusion fluid. The relationships between hospital costs and hydration therapy type were examined. RESULTS: Eighteen (31%) of 58 patients received HES 130/0.4. The HES group had a significantly lower total cost than the control group (3.6 vs. 6.4 million yen, p=0.006). Moreover, the HES group had a significantly shorter hospital stay duration (79.5 vs. 141.0 days) and lower National Institutes of Health Stroke Scale score on day 7. Multivariate analysis found that HES 130/0.4 administration was an independent factor associated with high costs. CONCLUSIONS: Hydration therapy with HES 130/0.4 significantly decreased the total costs and hospitalisation duration of patients with SI in the posterior LSA territory.

Predictors of brain infarction in adult patients on extracorporeal membrane oxygenation: an observational cohort study.

Non-hemorrhagic brain infarction (BI) is a recognized complication in adults treated with extracorporeal membrane oxygenation (ECMO) and associated with increased mortality. However, predictors of BI in these patients are poorly understood. The aim of this study was to identify predictors of BI in ECMO-treated adult patients. We conducted an observational cohort study of all adult patients treated with venovenous or venoarterial (VA) ECMO at our center between 2010 and 2018. The primary endpoint was a computed tomography (CT) verified BI. Logistic regression models were employed to identify BI predictors. In total, 275 patients were included, of whom 41 (15%) developed a BI. Pre-ECMO Simplified Acute Physiology Score III, pre-ECMO cardiac arrest, VA ECMO and conversion between ECMO modes were identified as predictors of BI. In the multivariable analysis, VA ECMO demonstrated independent risk association. VA ECMO also remained the independent BI predictor in a sub-group analysis excluding patients who did not undergo a head CT scan during ECMO treatment. The incidence of BI in adult ECMO patients may be higher than previously believed and is independently associated with VA ECMO mode. Larger prospective trials are warranted to validate these findings and ascertain their clinical significance.

Brain Computed Tomography Angiography Maximum Intensity Projection Images for ASPECTS Derivation and Detection of Large Infarct Volumes: Preliminary Study.

PURPOSE: Non-contrast CT ASPECTS (NCCTasp) has an established role in determining eligibility for mechanical thrombectomy in centers without ready access to perfusion or DWI. Moreover, it has been suggested that CTA source ASPECTS (CTAasp) may be superior to NCCTasp in predicting final infarct volume (FIV). In this study, we hypothesized that CTA maximum intensity projection ASPECTS (MIPSasp) would be superior compared to both NCCTasp and CTAasp in predicting FIV as measured by DWI. MATERIALS AND METHODS: In 41 consecutive patients with MCA territory infarcts, NCCTasp, CTAasp and MIPSasp were visually assessed by 2 neuroradiologists. Disagreements were adjudicated by a third neuroradiologist, and the reconciled data used for all further analysis. MR-DWI was used as the standard for FIV determination. Receiver operating characteristic curve analysis was used to compare the area under the curve for all three CT-based methods in predicting FIV ≥70 ml. RESULTS: MIPSasp (AUC: 0.98, CI: 0.88-1.00) were statistically better than NCCTasp (AUC: 0.87, 95% CI: 0.72-0.95; p=0.01) in predicting FIV ≥70 ml. MIPSasp were also superior to CTAasp (AUC: 0.9, CI: 0.79-.98; p˂0.05). Optimal test performance for predicting FIV ≥70 ml for MIPSasp was ≤6 (sensitivity=100%, specificity=91.4%; Youden's J=0.98). CONCLUSION: Our preliminary study suggests that a novel CTA-MIPS derived ASPECTS better predicts large MCA territory infarcts compared to CTA source and non-contrast ASPECTS. Thus, MIPSasp may be a promising technique for future studies aimed at improving ischemic stroke treatment in centers using ASPECTS for stroke management.

The Effect of Hyperglycemia on Infarct Growth after Reperfusion: An Analysis of the DEFUSE 3 trial.

BACKGROUND AND PURPOSE: Brain infarct growth, despite successful reperfusion, decreases the likelihood of good functional outcome after ischemic stroke. In patients undergoing reperfusion, admission glucose is associated with poor outcome but the effect of glucose level on infarct growth is not well studied. MATERIALS AND METHODS: This is a secondary analysis of the DEFUSE 3 trial. The primary predictor was baseline glucose level and the primary outcome is the change of the ischemic core volume from the baseline to 24-hour follow-up imaging (∆core), transformed as a cube root to reduce right skew. We included DEFUSE 3 patients who were randomized to endovascular therapy, had perfusion imaging data at baseline, an MRI at 24 hours, and who achieved TICI 2b or 3. Linear regression models, both unadjusted and adjusted, were fit to the primary outcome and all models included the baseline core volume as a covariate to normalize ∆core. RESULTS: We identified 62 patients who met our inclusion criteria. The mean age was 68.1±13.1 (years), 48.4% (30/62) were men, and the median (IQR) cube root of ∆core was 2.8 (2.0-3.8) mL. There was an association between baseline glucose level and normalized ∆core in unadjusted analysis (beta coefficient 0.010, p = 0.01) and after adjusting for potential confounders (beta coefficient 0.008, p = 0.03). CONCLUSION: In acute ischemic stroke patients with large vessel occlusion undergoing successful endovascular reperfusion, baseline hyperglycemia is associated with infarction growth. Further study is needed to establish potential neuroprotective benefits of aggressive glycemic control prior to and after reperfusion.

Intracranial Calcification is Predictive for Hemorrhagic Transformation and Prognosis After Intravenous Thrombolysis in Non-Cardioembolic Stroke Patients.

AIM: Hemorrhagic transformation is the major complication of intravenous thrombolysis. Calcification is used widely as an imaging indicator of atherosclerotic burden and cerebrovascular function. The relationship between intracranial calcification and hemorrhagic transformation has not been explored fully. We aimed to identify and quantify calcification in the main cerebral vessels to investigate the correlations between quantitative calcification parameters, hemorrhagic transformation, and prognosis. METHODS: Acute, non-cardiogenic, ischemic stroke patients with anterior circulation who received intravenous thrombolysis therapy in the First Hospital of Jilin University were retrospectively and consecutively included. All included patients underwent a baseline CT before intravenous thrombolysis and a follow-up CT at 24 hours. A third-party software, ITK-SNAP, was used to segment and measure the calcification volume. A vascular non-bone component with a CT value ＞130 HU was considered calcified. Hemorrhagic transformation was determined based on the ECASS II classification criteria. RESULTS: The study included 242 patients, 214 of whom were identified as having calcification. Thirty-one patients developed hemorrhagic transformation. The calcification volume on the lesion side (0.1ml) was associated with hemorrhagic transformation (p=0.004, OR=1.504, 95% CI: 1.140-1.985). Ninety-six patients had poor prognoses. The poor prognosis group had more calcified vessels than the good prognosis group (p=0.014, OR=1.477, 95% CI: 1.083-2.015). CONCLUSIONS: The arterial calcification volume on the lesion side is associated with hemorrhagic transformation after thrombolysis. The higher the number of calcified vessels, the greater the risk of poor prognosis.

Jaw Pain and Oromandibular Dysfunction After a Complex Hospital Course: A Clinical Vignette.

ABSTRACT: A 38-yr-old man presented to the emergency department with severe chest pain and was found to have a type A aortic dissection. Forty-eight hours after an emergency mechanical Bentall and ascending hemiarch replacement, the patient developed agitation prompting administration of high-dose haloperidol. He was found to have evidence of multiple acute infarcts on head computed tomography/computed tomography angiography and brain magnetic resonance imaging. Four days later, he began to complain of jaw pain and difficulty opening his mouth. After admission to inpatient rehabilitation, he was found to have strong activity in the masseters bilaterally at rest on electromyography, indicating a diagnosis of oromandibular dystonia. Starting in the intensive care unit, the patient reported jaw pain and dysfunction for 40 days before having a diagnosis of oromandibular dystonia. At this point, treatment with onabotulinumtoxinA injections and baclofen did not provide relief. Because of an extended delay in diagnosis, it is believed that the patient has developed joint contractures. Oromandibular dystonia is an important diagnosis to consider in patients who experience jaw pain or difficulty with mouth opening. Treatment of this condition can decrease pain and trauma to oral structures as well as improve ability to perform oral hygiene, eat, and communicate.

Reliability and Reproducibility of the Diameters Method in Rapid Determination of Acute Infarct Volume in Magnetic Resonance Diffusion-Weighted Imaging.

BACKGROUND: In acute ischemic stroke, diffusion-weighted imaging (DWI) volume is an independent predictive factor of poor outcome and an exclusion criterion for thrombolytic treatment. A simplified diameters method (ABC/2, orthogonal diameter [OD], and the maximum diameter [MD]) was proposed to replace the conventional measuring method and overcome the tedious and time-consuming defects, but its accuracy remains to be determined. OBJECTIVE: The objective of this study is to clarify the reliability and reproducibility of the diameter-based estimations in the infarct volume in DWI (Vol-DWI) measured by automated software. METHODS: Data of 316 patients with acute ischemic stroke who underwent MRI within 72 h at Jinling Hospital were retrospectively reviewed. Subgroup analysis by the location (cortex, white matter and deep gray nuclei, and combined) and volume (<70 and >70 mL) of cerebral infarction was evaluated. Relationship and consistency between the diameters methods and Vol-DWI were determined using Spearman rank correlation, Wilcoxon signed-rank test, and Bland-Altman plots. The OD and MD thresholds indicating infarct size >15, 70, and 100 mL were determined by generating receiver-operating characteristic (ROC) curves. Interobserver reliability was established using intraclass correlation coefficient and Bland-Altman plot. RESULTS: There was a strong positive correlation between the diameters and the Vol-DWI (ABC/2: r = 0.992, OD: r = 0.984, MD: r = 0.970, p < 0.001). Infarct volumes measured using the ABC/2 formula were significantly lower than those measured with Vol-DWI (Wilcoxon signed-rank test, z = 6.476, p < 0.001). Bland-Altman plot showed that the agreement of the volume <70 mL group, and white matter and deep gray nuclei groups was better than that of the other subgroups. For infarct volumes >15, 70, and 100 mL, the cutoff value for the MD was identified at 5, 6.9, and 8.4 cm, and the OD was identified at 12.47, 26.4, and 36.4 cm2, respectively, with a sensitivity and specificity >90%. CONCLUSIONS: The MD method was the best for achieving a rapid and excellent interobserver reliability for estimating infarct volume. Both OD and MD methods can quickly screen patients suitable for recanalization treatment and predict poor prognosis through threshold evaluation.

Mechanisms of early Recurrence in Intracranial Atherosclerotic Disease (MyRIAD): Rationale and design.

RATIONALE: Intracranial atherosclerotic disease (ICAD) is the most common cause of ischemic stroke with the highest rate of recurrence, despite aggressive medical management. Diverse mechanisms may be responsible for ICAD-related cerebral ischemia, with potential therapeutic implications. Here we present the rationale, design and methods of the Mechanisms of Early Recurrence in Intracranial Atherosclerotic Disease (MyRIAD) study. The aim of MyRIAD is to determine the mechanisms of stroke in ICAD through physiologic imaging biomarkers that evaluate impaired antegrade flow, poor distal perfusion, abnormal vasoreactivity, artery to artery embolism, and their interaction. METHODS AND DESIGN: This is a prospective observational study of patients with recently symptomatic (<21 days) ICAD with 50-99% stenosis treated medically and monitored for up to 1 year. An estimated 110 participants are recruited at 10 sites to identify the association between the presence of each mechanism of ischemia and recurrent stroke. The primary outcome is ischemic stroke in the territory of the symptomatic artery. Secondary outcomes include new cerebral infarction on MRI at 6-8 weeks and recurrent TIA in the territory of the symptomatic artery. DISCUSSION: MyRIAD is positioned to define the role of specific mechanisms of recurrent ischemia in patients with symptomatic ICAD. This knowledge will allow the development and implementation of effective and specific treatments for this condition.

Mechanical thrombectomy for a 12-year-old boy with acute ischemic stroke: A case report.

RATIONALE: Acute ischemic stroke (AIS) is one of the most severe diseases that endanger human health. It is very common among middle-aged and elderly people, but it is rare in children. The treatment varies among children and adults, since the cause for AIS in children differs from that in adults. In adults with AIS, endovascular therapy has been recommended, but guidelines for endovascular therapy in children with AIS have not been established yet. In China, few relevant evidence is present so far in clinical research of mechanical thrombectomy in the treatment for children with AIS. PATIENT CONCERNS: A 12-year-old boy without any special physical collision and trauma was admitted to emergency department of Changsha central hospital due to hemiplegia of left limbs for 3 hours. DIAGNOSES: He was diagnosed with AIS after magnetic resonance imaging (MRI) examination and magnetic resonance angiography (MRA) examination. Cerebral infarction in the right parietal, temporal, insular, and frontal lobes was revealed by the MRI test. The MRA test detected occlusions in right internal carotid artery, A1 segment of right anterior cerebral artery, right middle cerebral artery, and distal branch. INTERVENTIONS: Mechanic thrombectomy and antiplatelet aggregation therapy with clopidogrel helped the patient to recover, along with active rehabilitation training. OUTCOMES: A significant improvement in muscle strength of his left limbs was proved. He walked by himself and had 2 of Modified Rankin Scale (MRS). At 1-year follow-up visit, he recovered well except feeling a bit pain of left lower limb when walking, with finally MRS of 1. CONCLUSIONS: Mechanical thrombectomy can be performed safely for children with AIS, but needs a further research with large samples.

Cortical and Internal Watershed Infarcts Might Be Key Signs for Predicting Neurological Deterioration in Patients with Internal Carotid Artery Occlusion with Mild Symptoms.

BACKGROUND: Treatment for acute ischemic stroke due to large vessel occlusion (LVO) with mild symptoms is under discussion. Although most patients have good outcomes, some patients deteriorate and have unfavorable results. Imaging findings that predict the prognosis of LVO with mild symptoms are needed to identify patients who require treatment. In this study, we focused on watershed infarctions (WSIs), because this clinical phenomenon quite sensitively reflects changes in cerebral blood flow. The purpose of this study was to assess positive rates of WSI on MRI findings in patients with internal carotid artery (ICA) occlusion, and compare WSI-positive rates between patients divided according to their clinical course. METHODS: We retrospectively collected data of 1,531 patients who presented with acute ischemic stroke between June 2006 and July 2019. Among them, we chose symptomatic ICA occlusion patients with a past history of atrial fibrillation who were treated conservatively. We divided these patients into two groups, those with maintenance or improvement in their NIHSS score after hospitalization, and those whose NIHSS score worsened. We compared WSI-positive rates between these two groups. RESULTS: Thirty-seven of the 1,531 patients were included in this study. Of them, total NIHSS score was maintained or improved in 8 patients (group A), 3 of whom (37.5%) had internal watershed infarctions (IWIs). In group B, consisting of patients whose NIHSS score worsened by >2 at 7 days from symptom onset, 24 (82.8%) had IWIs. Group A thus had statistically lower IWI positivity rates than group B (p = 0.02). Three patients (37.5%) in group A had cortical watershed infarctions (CWIs), while 27 patients in group B (93.1%) had CWIs. Group A thus had a significantly lower CWI positivity rate than group B (p = 0.002). CONCLUSION: In patients with mildly symptomatic ICA occlusion, CWIs and IWIs might be key signs for predicting neurological deterioration after hospitalization.

Thalamic perforating artery stroke on computed tomography perfusion in a patient with coronavirus disease 2019.

Emerging evidence suggests that patients with coronavirus disease 2019 (COVID-19) are at risk of thromboembolic complications, including ischemic strokes. We present a case illustrating the value of CT perfusion to identify acute small subcortical infarcts in a patient with COVID-19 admitted to an intensive care unit for bilateral pneumonia and pulmonary embolism presenting with sudden right limb weakness.

Absence of an infarct on MRI is not uncommon after clinical diagnosis of ischemic stroke.

INTRODUCTION: An infarct on brain MRI is often seen as gold standard when diagnosing ischemic stroke. Although MRI has high sensitivity in detecting a lesion shortly after ischemic stroke, this rapidly declines when time progresses. We assessed the occurrence of a negative MRI 4-6 weeks after a discharge diagnosis of ischemic stroke, and compared the clinical characteristics of patients with a positive or negative MRI. PATIENTS AND METHODS: The first 125 patients from a prospective longitudinal study of cognitive recovery after ischemic stroke were included in this study. Clinical characteristics were collected during admission. Per protocol, 4-6 weeks after stroke a brain MRI was performed. We operationalized different levels of certainty of the clinical diagnosis of ischemic stroke of a panel of 3 expert vascular neurologists. RESULTS: Thirty patients (24%) were MRI negative. Patients that were MRI negative had lower stroke severity at admission, shorter duration of hospital-stay, and better functional status at discharge. The panel judged that 18/30 (60%) MRI negative patients and 27/30 (90%) MRI positive patients had a likely diagnosis of ischemic stroke. Compared to MRI negative patients with a less likely diagnosis, those with a likely diagnosis had higher admission stroke severity and more often received an acute intervention. DISCUSSION AND CONCLUSION: Absence of an infarct on MRI is not uncommon 4-6 weeks after a clinical diagnosis of ischemic stroke. The relatively high proportion of MRI negative strokes with a likely clinical diagnosis of ischemic stroke indicates that neurologists should be cautious ruling out the diagnosis based on MRI beyond the acute stroke stage.