The collateral map: prediction of lesion growth and penumbra after acute anterior circulation ischemic stroke

OBJECTIVES

This study evaluated the collateral map's ability to predict lesion growth and penumbra after acute anterior circulation ischemic strokes.

METHODS

This was a retrospective analysis of selected data from a prospectively collected database. The lesion growth ratio was the ratio of the follow-up lesion volume to the baseline lesion volume on diffusion-weighted imaging (DWI). The time-to-maximum (Tmax)/DWI ratio was the ratio of the baseline Tmax  > 6 s volume to the baseline lesion volume. The collateral ratio was the ratio of the hypoperfused lesion volume of the phase_FU (phase with the hypoperfused lesions most approximate to the follow-up DWI lesion) to the hypoperfused lesion volume of the phase_baseline of the collateral map. Multiple logistic regression analyses were conducted to identify independent predictors of lesion growth. The concordance correlation coefficients of Tmax/DWI ratio and collateral ratio for lesion growth ratio were analyzed.

RESULTS

Fifty-two patients, including twenty-six males (mean age, 74 years), were included. Intermediate (OR, 1234.5; p < 0.001) and poor collateral perfusion grades (OR, 664.7; p = 0.006) were independently associated with lesion growth. Phase_FUs were immediately preceded phases of the phase_baselines in intermediate or poor collateral perfusion grades. The concordance correlation coefficients of the Tmax/DWI ratio and collateral ratio for the lesion growth ratio were 0.28 (95% CI, 0.17-0.38) and 0.88 (95% CI, 0.82-0.92), respectively.

CONCLUSION

Precise prediction of lesion growth and penumbra can be possible using collateral maps, allowing for personalized application of recanalization treatments. Further studies are needed to generalize the findings of this study.

CLINICAL RELEVANCE STATEMENT

Precise prediction of lesion growth and penumbra can be possible using collateral maps, allowing for personalized application of recanalization treatments.

KEY POINTS

• Cell viability in cerebral ischemia due to proximal arterial steno-occlusion mainly depends on the collateral circulation. • The collateral map shows salvageable brain extent, which can survive by recanalization treatments after acute anterior circulation ischemic stroke. • Precise estimation of salvageable brain makes it possible to make patient-specific treatment decision.

Hyaluronic acid/polyphenol sunscreens with broad-spectrum UV protection properties from tannic acid and quercetin

Currently, commercial sunscreens cause a number of biotoxicity and environmental issues, making it imperative to develop biocompatible alternatives. In this study, we aimed to develop an alternative sunscreen from two ecofriendly and biocompatible natural polyphenolic compounds, tannic acid (TA) and quercetin (Que). The sunscreen was prepared through a simple process using an oil-in-water emulsion as the medium and hyaluronic acid (HA) as the base polymer to improve biocompatibility. The HA/TA/Que. sunscreen prepared in this study exhibits 0 % transmittance in the UVB region and <15 % transmittance in the UVA region, resulting in excellent sun-protection properties (SPF 30). Remarkably, the as-prepared HA/TA/Que. sunscreen has a suitable viscosity and similar UV protection properties to those of commercial sunscreens. The HA/TA/Que. sunscreen also exhibits 90.4 % antioxidant activity against 2,2-diphenyl-1-picrylhydrazyl, demonstrating an ability to effectively capture reactive oxygen species that directly affect the skin. In addition, the cell viability was >90 % at a concentration of 50 μg/mL after 7 days, indicating excellent cytocompatibility. Owing to its various advantageous features, the HA/TA/Que. sunscreen with excellent sun protection properties and multiple functionalities is expected to resolve many environmental and biological issues caused by commercial sunscreens.

Impact of Collateral Circulation on Futile Endovascular Thrombectomy in Acute Anterior Circulation Ischemic Stroke

OBJECTIVE

Collateral circulation is associated with the differential treatment effect of endovascular thrombectomy (EVT) in acute ischemic stroke. We aimed to verify the ability of the collateral map to predict futile EVT in patients with acute anterior circulation ischemic stroke.

METHODS

This secondary analysis of a prospective observational study included data from participants underwent EVT for acute ischemic stroke due to occlusion of the internal carotid artery and/or the middle cerebral artery within 8 hours of symptom onset. Multiple logistic regression analyses were conducted to identify independent predictors of futile recanalization (modified Rankin scale score at 90 days of 4-6 despite of successful reperfusion).

RESULTS

In a total of 214 participants, older age (odds ratio [OR], 2.40; 95% confidence interval [CI], 1.56 to 3.67; p<0.001), higher baseline National Institutes of Health Stroke Scale (NIHSS) scores (OR, 1.12; 95% CI, 1.04 to 1.21; p=0.004), very poor collateral perfusion grade (OR, 35.09; 95% CI, 3.50 to 351.33; p=0.002), longer door-to-puncture time (OR, 1.08; 95% CI, 1.02 to 1.14; p=0.009), and failed reperfusion (OR, 3.73; 95% CI, 1.30 to 10.76; p=0.015) were associated with unfavorable functional outcomes. In 184 participants who achieved successful reperfusion, older age (OR, 2.30; 95% CI, 1.44 to 3.67; p<0.001), higher baseline NIHSS scores (OR, 1.12; 95% CI, 1.03 to 1.22; p=0.006), very poor collateral perfusion grade (OR, 4.96; 95% CI, 1.42 to 17.37; p=0.012), and longer door-to-reperfusion time (OR, 1.09; 95% CI, 1.03 to 1.15; p=0.003) were associated with unfavorable functional outcomes.

CONCLUSION

The assessment of collateral perfusion status using the collateral map can predict futile EVT, which may help select ineligible patients for EVT, thereby potentially reducing the rate of futile EVT.

Prognostic value of collateral perfusion estimation by arterial spin labeling for acute anterior circulation ischemic stroke

PURPOSE

This study aimed to verify the value of arterial spin labeling (ASL) collateral perfusion estimation for predicting functional outcomes in acute anterior circulation ischemic stroke.

METHODS

This secondary analysis of an ongoing prospective observational study included data from participants with acute ischemic stroke due to steno-occlusion of the internal carotid artery and/or the middle cerebral artery within 8 h of symptom onset. We compared the collateral map, which is a 5-phase collateral imaging derived from dynamic contrast-enhanced magnetic resonance angiography, and ASL to validate the ASL collateral perfusion estimation. Multiple logistic regression analyses were conducted to identify independent predictors of favorable functional outcomes.

RESULTS

One hundred forty-eight participants (68 ± 13 years, 96 men) were evaluated. The ASL collateral perfusion grade was positively correlated with the collateral perfusion grade of the collateral map (P < .001). Younger age (OR = 0.53, 95% CI = 0.36-0.78, P = .002), lower baseline NIHSS score (OR = 0.85, 95% CI = 0.78-0.92, P < .001), intermediate ASL collateral perfusion grade (OR = 4.02, 95% CI = 1.43-11.26, P = .008), good ASL collateral perfusion grade (OR = 26.37, 95% CI = 1.06-655.01, P = .046), and successful reperfusion (OR = 5.84, 95% CI = 2.08-16.42, P < .001) were independently associated with favorable functional outcomes.

CONCLUSION

ASL collateral perfusion estimation provides prognostic information, which can be helpful in guiding management decisions.

Study on Sustentaculum Tali Fragment Constancy in Intraarticular Calcaneus Fracture

OBJECTIVES

To establish reproducible measurements of the sustentaculum tali (ST) fragment regarding fracture classification and patient-related factors.

DESIGN

Retrospective.

SETTING

Trauma center, University Hospital.

PATIENTS

A retrospective analysis of the 142 fractured calcanei of 122 patients (101 men and 21 women) treated at our institution between 2012 and 2020 was performed. As control, 62 unaffected calcanei were used.

INTERVENTION

Radiographic images were evaluated twice within 2 weeks by 2 orthopaedic surgeons and 1 postgraduate student. Angulation and diastasis were used to distinguish ST fragment constancy based on computed tomography. Using these parameters, the prevalence of inconstant ST fragments was assessed. We also analyzed factors related to ST fragment inconstancy. Patient factors included age, body mass index, smoking, and diabetes. Radiographic factors included the Sanders classification, location of the outermost fracture line of the posterior facet, presence of an intraarticular fracture of the ST, and ST fragment width.

MAIN OUTCOME MEASUREMENTS

Angulation and diastasis were used to confirm the ST fragment constancy. Potential risks for inconstant ST fragment subsequently defined.

RESULTS

According to the criteria, ST fragment inconstancy was observed in 34.5%. ST fragment width was significantly smaller in the inconstant group ( P < 0.001). Severe comminution of the posterior facet ( P < 0.05), intraarticular fracture of the ST ( P < 0.001), and diabetes ( P < 0.05) were significantly higher in the inconstant group. The cut-off value of the ST fragment width was 20.5 mm.

CONCLUSIONS

In intraarticular calcaneus fractures, small ST fragment width, comminuted fracture, intraarticular fracture of the ST, and diabetes were associated with the inconstant group. The ST fragment was expected to be inconstant when the width was less than 20.5 mm.

Telemedicine Protocols for the Management of Patients with Acute Spontaneous Intracerebral Hemorrhage in Rural and Medically Underserved Areas in Gangwon State: Recommendations for Doctors with Less Expertise at Local Emergency Rooms

Previously, we reported the concept of a cloud-based telemedicine platform for patients with intracerebral hemorrhage (ICH) at local emergency rooms in rural and medically underserved areas in Gangwon state by combining artificial intelligence and remote consultation with a neurosurgeon. Developing a telemedicine ICH treatment protocol exclusively for doctors with less ICH expertise working in emergency rooms should be part of establishing this system. Difficulties arise in providing appropriate early treatment for ICH in rural and underserved areas before the patient is transferred to a nearby hub hospital with stroke specialists. This has been an unmet medical need for decade. The available reporting ICH guidelines are realistically possible in university hospitals with a well-equipped infrastructure. However, it is very difficult for doctors inexperienced with ICH treatment to appropriately select and deliver ICH treatment based on the guidelines. To address these issues, we developed an ICH telemedicine protocol. Neurosurgeons from four university hospitals in Gangwon state first wrote the guidelines, and professors with extensive ICH expertise across the country revised them. Guidelines and recommendations for ICH management were described as simply as possible to allow more doctors to use them easily. We hope that our effort in developing the telemedicine protocols will ultimately improve the quality of ICH treatment in local emergency rooms in rural and underserved areas in Gangwon state.

Updated Trans-Ethnic Meta-Analysis of Associations between Inflammation-Related Genes and Intracranial Aneurysm

OBJECTIVE

We performed an expanded multi-ethnic meta-analysis to identify associations between inflammation-related loci with intracranial aneurysm (IA) susceptibility. This meta-analysis possesses increased statistical power as it is based on the most data ever evaluated.

METHODS

We searched and reviewed relevant literature through electronic search engines up to August 2022. Overall estimates were calculated under the fixed- or random-effect models using pooled odds ratio (OR) and 95% confidence intervals (CIs). Subgroup analyses were performed according to ethnicity.

RESULTS

Our meta-analysis enrolled 15 studies and involved 3070 patients and 5528 controls including European, Asian, Hispanic, and mixed ethnic populations. Of 17 inflammation-related variants, the rs1800796 locus (interleukin [IL]-6) showed the most significant genome-wide association with IA in East-Asian populations, including 1276 IA patients and 1322 controls (OR, 0.65; 95% CI, 0.56-0.75; p=3.24×10-9) under a fixed-effect model. However, this association was not observed in the European population (OR, 1.09; 95% CI, 0.80-1.47; p=0.5929). Three other variants, rs16944 (IL-1β), rs2195940 (IL-12B), and rs1800629 (tumor necrosis factor-α) showed a statistically nominal association with IA in both the overall, as well as East-Asian populations (0.01

CONCLUSION

Our updated meta-analysis with increased statistical power highlights that rs1800796 which maps on the IL-6 gene is associated with IA, and in particular confers a protective effect against occurrence of IA in the East-Asian population.

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Key Words

• Inflammation mediators
• Interleukin-6
• Intracranial aneurysm
• Meta-analysis

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MESH Headings Collapse

Grants

• HURF-2021-35 Hallym University
• Korea Bio Data Station

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Study on the Migration Behaviors of Magnesium Oxysulfate Nano-Whiskers in Polypropylene Composites with Surface Modification

In this study, surface modification aimed to enhance the compatibility between a hydrophilic inorganic filler and polypropylene (PP) matrix using hydrophobic treatment. Lauric acid, butyl acrylate, and maleic anhydride were employed to modify the filler surface. After treatment, inorganic filler/PP composites were produced using melt-mixing and extrusion-injection molding processes. The study focused on investigating compatibility and migration behavior between the filler and matrix. The findings indicated that hydrophobic modification, specifically with butyl acrylate and maleic anhydride, improved migration issues in nano-whisker, while maintaining favorable mechanical properties even under accelerated thermal aging. However, excessive hydrophobicity induced by superhydrophobic treatment using lauric acid led to reduced compatibility with the matrix, compromising its effectiveness. Consequently, the study revealed the potential of surface modification to enhance interfacial properties and mitigate migration concerns in PP composites for automotive applications.

The Efficacy of Platelet-Rich Plasma Augmentation in Microfracture Surgery Osteochondral Lesions of the Talus: A Systematic Review and Meta-Analysis

The appropriate surgical management of osteochondral lesions of the talus (OLT) remains a challenge for foot and ankle surgeons. Currently, microfracture (MF) is the first-line operative treatment for small osteochondral lesions. However, the fibrous cartilage regenerated after MF is mechanically inferior to hyaline cartilage regeneration and is susceptible to deterioration over time. Thus, this meta-analysis aimed to elucidate the efficacy of platelet-rich plasma (PRP) augmentation compared with MF only or other adjuvant supplementations combined with the PRP + MF group (others) for the management of OLT. We searched the PubMed, Embase, Web of Science, and Cochrane Library databases for studies that compared the clinical outcomes of patients who underwent MF only and those who underwent PRP or other adjuvant materials such as hyaluronic acid or BST-CarGel. After the screening, four randomized controlled trials and one quasi-randomized controlled trial were included in this review. We used the following tools for clinical evaluation: the American Orthopedic Foot and Ankle Society (AOFAS) score, Ankle-Hindfoot Scale score, Visual Analog Scale (VAS) score for pain, and the Foot and Ankle Ability Measure (FAAM) score. The standardized mean difference (SMD) was used to analyze the differences in outcomes between groups. Patients in the PRP + MF group had superior final VAS and AOFAS scores to the MF only group. (both p < 0.01) However, no significant improvements between baseline and final follow-up were noted in either score. In addition, there was no remarkable difference in the overall FAAM pain measures between the two groups. The PRP + MF and others groups revealed no significant effect differences in the clinical scores. The results of this analysis suggest that PRP + MF would be more favorable and effective than MF only or additional adjuvant supplementation.

A phase I trial of LXS196, a protein kinase C (PKC) inhibitor, for metastatic uveal melanoma

BACKGROUND

Up to 50% of patients with uveal melanoma develop metastases (MUM) with a poor prognosis and median overall survival of approximately 1 year.

METHODS

This phase I study evaluated the safety, tolerability, pharmacokinetics, pharmacodynamics and efficacy of the oral protein kinase C inhibitor LXS196 in 68 patients with MUM (NCT02601378). Patients received LXS196 doses ranging from 100-1000 mg once daily (QD; n = 38) and 200-400 mg twice daily (BID; n = 30).

RESULTS

First cycle dose-limiting toxicities (DLTs) were observed in 7/38 (18.4%) QD and 2/17 (11.8%) BID patients. Hypotension was the most common DLT, occurring at doses ≥500 mg/day, and manageable with LXS196 interruption and dose reduction. Median duration of exposure to LXS196 was 3.71 months (range: 1.81-15.28) for QD and 4.6 months (range: 0.33-58.32) for BID dosing. Clinical activity was observed in 6/66 (9.1%) evaluable patients achieving response (CR/PR), with a median duration of response of 10.15 months (range: 2.99-41.95); 45/66 had stable disease (SD) per RECIST v1.1. At 300 mg BID, the recommended dose for expansion, 2/18 (11.1%) evaluable patients achieved PR and 12/18 (66.7%) had SD.

CONCLUSION

These results suggest manageable toxicity and encouraging clinical activity of single-agent LXS196 in patients with MUM.

Is the retroauricular region a suitable donor site for full-thickness skin grafting in the era of mask wearing?

BACKGROUND

During the coronavirus disease 2019 (COVID-19) pandemic, the everyday use of face masks massively increased to prevent the spread of infection. Many people complain of ear pain and erosion when wearing a mask for extended periods of time. If prolonged mask usage is uncomfortable for ordinary people, a question arises-how much more inconvenient must mask wearing be for patients with a full-thickness skin graft (FTSG) donor site in the retroauricular region? Herein, we evaluated complications related to face mask use in 27 patients with a retroauricular FTSG donor site, with the goal of clarifying whether the retroauricular region is still an appropriate FTSG donor site in the context of the COVID-19 pandemic.

METHODS

Complications in 27 patients treated by FTSGs harvested from the retroauricular region from 2019 to 2021 were investigated. A questionnaire comparing the normal and the operated sides was administered. Pain, itching, soreness, deformity, and symmetry were further investigated.

RESULTS

Pain and itching were the only observed complications. The operated side was slightly more painful than the normal side in four patients (14.8%), and four patients (14.8%) reported itching on the operated side. However, all patients who experienced complications stated that the pain or itching did not interfere with mask wearing. Most symptomatic patients were older than 60 years of age (23.8%, p=0.185) and wore masks for longer periods of time (28.5%, p=0.326).

CONCLUSION

Few retroauricular donor site-related complications occurred, and none of these complications caused inconvenience in daily life. Therefore, in the COVID-19 pandemic, the use of the retroauricular region as an FTSG donor site remains appropriate.

Bone-Marrow-Derived Mesenchymal Stem Cells Attenuate Behavioral and Cognitive Dysfunction after Subarachnoid Hemorrhage via HMGB1-RAGE Axis Mediation

We evaluated the therapeutic effects of bone-marrow-derived mesenchymal stem cells (BMSCs) on behavioral and cognitive function in a mouse model of mild subarachnoid hemorrhage (SAH) and explored the underlying mechanisms in conjunction with the HMGB1-RAGE axis. The SAH models were generated in a total of 126 male C57BL/6J mice via endovascular perforation and evaluated 24 h and 72 h after the intravenous administration of BMSCs (3 × 105 cells). The BMSCs were administered once, at 3 h, or twice, at 3 h and 48 h after the model induction. The therapeutic effects of the BMSCs were compared to those of the saline administration. Compared to saline-treated SAH-model mice, at 3 h, the mice with mild SAH treated with the BMSCs showed significant improvements in their neurological scores and cerebral edema. The administration of the BMSCs decreased the mRNA expression of HMGB1, RAGE, TLR4, and MyD88, as well as the protein expression of HMGB1 and phosphorylated NF-kB p65. Furthermore, the numbers of slips per walking time, impairments in short-term memory, and the recognition of novel objects were improved. There was some improvement in inflammatory-marker levels and cognitive function according to the BMSCs' administration times, but no large differences were seen. The administration of BMSCs improved behavioral and cognitive dysfunction by ameliorating HMGB1-RAGE axis-mediated neuroinflammation after SAH.

WITHDRAWN: Effect of Therapeutic Hypothermia on Cognitive Impairment in a Mouse Model of Ischemia-Reperfusion Injury

Ahead of Print article withdrawn by publisher.

Recurrence of intratendinous ganglion due to incomplete excision of satellite lesion in the extensor digitorum brevis tendon: A case report

BACKGROUND

Intratendious ganglions are rare lesions, especially on the foot and ankle. Although several studies have presented the intratendinous ganglion of the foot and ankle, there are only few reported cases, and no cases of recurrence or secondary surgery have been reported.

CASE SUMMARY

We present the case of a 32-year-old man with an intratendinous ganglion of the second extensor digitorum brevis (EDB) tendon that recurred after ganglion excision. Magnetic resonance imaging (MRI) performed before the first surgery was reviewed to analyze the causes of the recurrence. We confirmed that there was a lack of satellite detection. After recurrence, MRI revealed an extra-tendinous lesion, tenosynovitis, and intratendinous ganglion of the second EDB tendon. Since the second EDB tendon can compensate for the extrinsic muscle, en bloc resection was performed alone. In addition, meticulous excision and synovectomy were performed for extra-tendinous lesions and tenosynovitis, respectively. The patient returned to daily life without any functional problems or recurrence.

CONCLUSION

If removal of the affected tendon is not fatal, en bloc resection should first be considered to prevent incomplete excision and intraoperative leakage. When planning surgical excision, it is necessary to evaluate the presence of satellite lesions along the course of the affected tendon.

Human embryonic stem cell-derived cerebral organoids for treatment of mild traumatic brain injury in a mouse model

OBJECTIVE

There are no effective treatments for relieving neuronal dysfunction after mild traumatic brain injury (TBI). Here, we evaluated therapeutic efficacy of human embryonic stem cell-derived cerebral organoids (hCOs) in a mild TBI model, in terms of repair of damaged cortical regions, neurogenesis, and improved cognitive function.

METHODS

Male C57BL/6 J mice were randomly divided into sham-operated, mild TBI, and mild TBI with hCO groups. hCOs cultured at 8 weeks were used for transplantation. Mice were sacrificed at 7 and 14 days after transplantation followed by immunofluorescence staining, cytokine profile microarray, and novel object recognition test.

RESULTS

8W-hCOs transplantation significantly reduced neuronal cell death, recovered microvessel density, and promoted neurogenesis in the ipsilateral subventricular zone and dentate gyrus of hippocampus after mild TBI. In addition, increased angiogenesis into the engrafted hCOs was observed. Microarray results of hCOs revealed neuronal differentiation potential and higher expression of early brain development proteins associated with neurogenesis, angiogenesis and extracellular matrix remodeling. Ultimately, 8W-hCO transplantation resulted in reconstruction of damaged cortex and improvement in cognitive function after mild TBI.

CONCLUSION

hCO transplantation may be feasible for treating mild TBI-related neuronal dysfunction via reconstruction of damaged cortex and neurogenesis in the hippocampus.

Symptomatic accessory soleus muscle: A cause for exertional compartment syndrome in a young soldier: A case report

BACKGROUND

Accessory soleus muscle (ASM) is a rare congenital variation that is almost asymptomatic, but several papers have recently described symptomatic ASM. The clinical features of this condition are similar to tarsal tunnel syndrome (TTS) and include pain and numbness around the medial side of the ankle. ASM commonly originates from the fibula or soleus muscle and inserts into the Achilles tendon or calcaneus. Usually, it is identified as posteromedial swelling and definitely diagnosed by magnetic resonance imaging. In most cases, treatment is observation, but surgical excision can be considered if symptoms are severe.

CASE SUMMARY

A 23-year-old male Korean soldier presented with complaints of bilateral foot and ankle pain and a swelling medial to the Achilles tendon that was more pronounced on the right side. Symptoms first occurred after playing soccer 10 mo before this presentation, worsened after physical exertion, and were relieved by rest. He had no medical history, and no one in his family had the condition. Laboratory results were non-specific. Several tests were performed to exclude common diseases such as tumors or TTS. However, MRI revealed a bulky accessory soleus muscle in both feet, though the patient complained of more severe pain on the right side during physical activity. Accordingly, surgical resection was adopted. At surgery, a large accessory soleus muscle was noted anterior to the Achilles tendon with distinctive insertion from a normal soleus muscle. At 12 mo after surgery, there was no pain, numbness, or swelling of the right foot or ankle, no evidence of recurrence, and the patient could do all sports activities.

CONCLUSION

Accessory soleus muscle should be added to the list of differential diagnosis if a patient has pain, sole numbness or swelling of the posteromedial ankle.

Racial differences in prevalence and anatomical distribution of tarsal coalition

Previous studies have reported a prevalence of tarsal coalition of 0.03-13%. Calcaneonavicular coalition is known as main anatomical type, and the bilateral occurrence of tarsal coalition is known to be 50% or more. These are the results of studies on Caucasians, there have been few studies targeting large number of East Asians so far. We hypothesized that the prevalence and characteristics of tarsal coalition in East Asians might differ from those in Caucasians. The medical records of 839 patients who underwent bilateral computed tomography on foot and ankle in our hospital from January 2012 to April 2021 were retrospectively reviewed. The overall prevalence was 6.0%, talocalcaneal coalition was the most common anatomical type. The overall bilateral occurrence was 56.5%, talocalcaneal coalition had the highest bilateral occurrence (76.0%) among anatomical types. Isolated union of the posterior facet was the most common subtype of talocalcaneal coalition (43.2%). Talocalcaneal coalition had a significantly higher proportion of coalition-related symptomatic patients than calcaneonavicular coalition (p = 0.019). Our study showed a similar trend to other East Asian studies, confirming the existence of racial differences. The possibility of tarsal coalition in foot and ankle patients in East Asians should always be considered, and bilateral examination is essential for diagnosis.

Assessment of Fusion After Anterior Cervical Discectomy and Fusion Using Convolutional Neural Network Algorithm

BACKGROUND

A convolutional neural network (CNN) is a deep learning (DL) model specialized for image processing, analysis, and classification.

OBJECTIVE

In this study, we evaluated whether a CNN model using lateral cervical spine radiographs as input data can help assess fusion after anterior cervical discectomy and fusion (ACDF).

STUDY DESIGN

Diagnostic imaging study using DL.

PATIENT SAMPLE

We included 187 patients who underwent ACDF and fusion assessment with postoperative one-year computed tomography and neutral and dynamic lateral cervical spine radiographs.

OUTCOME MEASURES

The performance of the CNN-based DL algorithm was evaluated in terms of accuracy and area under the curve.

MATERIALS AND METHODS

Fusion or nonunion was confirmed by cervical spine computed tomography. Among the 187 patients, 69.5% (130 patients) were randomly selected as the training set, and the remaining 30.5% (57 patients) were assigned to the validation set to evaluate model performance. Radiographs of the cervical spine were used as input images to develop a CNN-based DL algorithm. The CNN algorithm used three radiographs (neutral, flexion, and extension) per patient and showed the diagnostic results as fusion (0) or nonunion (1) for each radiograph. By combining the results of the three radiographs, the final decision for a patient was determined to be fusion (fusion ≥2) or nonunion (fusion ≤1). By combining the results of the three radiographs, the final decision for a patient was determined as fusion (fusion ≥2) or nonunion (nonunion ≤1).

RESULTS

The CNN-based DL model demonstrated an accuracy of 89.5% and an area under the curve of 0.889 (95% confidence interval, 0.793-0.984).

CONCLUSION

The CNN algorithm for fusion assessment after ACDF trained using lateral cervical radiographs showed a relatively high diagnostic accuracy of 89.5% and is expected to be a useful aid in detecting pseudarthrosis.

Early and Prolonged Mild Hypothermia in Patients with Poor-Grade Subarachnoid Hemorrhage: A Pilot Study

We assessed the feasibility of therapeutic early and prolonged mild hypothermia (MH) in patients with poor-grade subarachnoid hemorrhage (SAH). A retrospective pilot study was conducted for poor-grade SAH patients at two university hospitals from March 2015 to December 2018 who had received MH immediately after coil embolization and maintained a target temperature of 34-35°C for 5 days. A matched controlled design at a 1:2 ratio was used to compare MH therapy outcomes. The primary goal was to assess the two groups' severe functional outcomes at discharge defined as a modified Rankin Scale score of 4-6. The secondary aim was to assess mortality and severe vasospasm depending upon MH. A binary logistic regression analysis was performed to identify relevant risk factors for the outcomes. A total of 54 patients (18 with MH treatment and 36 without MH treatment) were included. Severe functional outcome was significantly decreased in poor-grade SAH patients with MH (n = 7, 38.9%) than those without MH (n = 25, 69.4%; p = 0.031). In patients treated with MH, mortality and severe vasospasm tended to be less common, although the difference was not statistically significant. A binary logistic regression analysis revealed that early and prolonged MH (odds ratio [OR] = 0.156, 95% confidence intervals [CI]: 0.037-0.644) and severe vasospasm (OR = 5.593, 95% CI: 1.372-22.812) were risk factors for severe functional outcomes. This study shows potential therapeutic effect of early and prolonged MH treatment in poor-grade SAH patients. A randomized controlled study with a large number of patients is warranted in the future.

Intra-articular Calcaneal Fracture Treatment With Staged Medial External Fixation

BACKGROUND

To compare the clinical and radiographic outcomes between the conventional delayed and staged approaches for intra-articular calcaneus fractures in which early definite fixation could not be performed because of severe soft tissue injury.

METHODS

From January 2015 to May 2019, a total of 32 cases with acute intra-articular calcaneal fractures met criteria and were enrolled in the study. We compared the outcomes of intra-articular calcaneal fractures that underwent delayed internal fixation between groups treated with a conventional delayed approach (non-EF group) vs a temporary medial external fixation (EF group). Clinical outcome measures included a 10-point visual analog scale score, the AOFAS score, and the Foot Function Index. Radiographic outcome measures included Böhler angle, talar declination angle, and calcaneal width. Reduction of the posterior facet was assessed on CT scans.

RESULTS

The first 15 (46.9%) were treated with a conventional delayed approach, and the latter 17 (53.1%) were treated with a staged approach with temporary medial external fixation. Clinical outcomes were not different between the groups at the last follow-up. The time from injury to definite internal fixation was shorter by an average of 3.8 days in the EF group (P = .001). The Böhler angle, talar declination angle, and calcaneal width were not different between the groups before surgery and at the last follow-up. Reduction of the posterior facet on CT scans was significantly better in the EF group than in the non-EF group (good/excellent = 94% vs 60%, respectively, P = .033).

CONCLUSION

The staged approach using medial external fixation for displaced intra-articular calcaneus fractures could be an effective method to decrease the time to definitive internal fixation and obtain optimal reduction of the posterior facet.

LEVEL OF EVIDENCE

Level III, retrospective case-control study.

Leveraging metabolic modeling to identify functional metabolic alterations associated with COVID-19 disease severity

OBJECTIVE

Since the COVID-19 pandemic began in early 2020, SARS-CoV2 has claimed more than six million lives world-wide, with over 510 million cases to date. To reduce healthcare burden, we must investigate how to prevent non-acute disease from progressing to severe infection requiring hospitalization.

METHODS

To achieve this goal, we investigated metabolic signatures of both non-acute (out-patient) and severe (requiring hospitalization) COVID-19 samples by profiling the associated plasma metabolomes of 84 COVID-19 positive University of Virginia hospital patients. We utilized supervised and unsupervised machine learning and metabolic modeling approaches to identify key metabolic drivers that are predictive of COVID-19 disease severity. Using metabolic pathway enrichment analysis, we explored potential metabolic mechanisms that link these markers to disease progression.

RESULTS

Enriched metabolites associated with tryptophan in non-acute COVID-19 samples suggest mitigated innate immune system inflammatory response and immunopathology related lung damage prevention. Increased prevalence of histidine- and ketone-related metabolism in severe COVID-19 samples offers potential mechanistic insight to musculoskeletal degeneration-induced muscular weakness and host metabolism that has been hijacked by SARS-CoV2 infection to increase viral replication and invasion.

CONCLUSIONS

Our findings highlight the metabolic transition from an innate immune response coupled with inflammatory pathway inhibition in non-acute infection to rampant inflammation and associated metabolic systemic dysfunction in severe COVID-19.

Association of Haptoglobin Phenotypes with Outcomes in Patients with Spontaneous Intracerebral Hemorrhage

Object. We aimed to investigate the association of Haptoglobin (Hp) phenotypes with perihematomal edema (PHE) and neurological outcomes after intracerebral hemorrhage (ICH). Methods. This prospective multicenter study enrolled patients that suffered ICH from March 2017 to February 2020. Hp phenotypes were determined using Western blotting; relative α1 intensity was calculated in patients with Hp2-1. A multivariable logistic regression analysis was then conducted to identify risk factors for increased relative PHE at 96 h and 3-month poor outcomes. Results. In total, 120 patients were ultimately enrolled: Hp1-1 (n = 15, 12.5%); Hp2-1 (n = 51, 42.5%); and Hp2-2 (n = 54, 45.0%). Hp phenotype was significantly associated with PHE (p = 0.028). With Hp1-1 as a reference value, Hp2-2 significantly increased the likelihood of increased rPHE (OR = 6.294, 95% CI: 1.283–30.881), while Hp2-1 did not (OR = 2.843, 95% CI: 0.566–14.284). Poor outcomes were found to be closely associated with hematoma volume at admission (OR = 1.057, 95% CI: 1.015–1.101) and surgical treatment (OR = 5.340, 95% CI: 1.665–17.122) but not Hp phenotypes (p = 0.190). Further, a high level of relative α1 intensity was identified to be significantly associated with decreased rPHE (OR = 0.020, 95% CI: 0.001–0.358). However, the relative α1 intensity was not associated with poor outcomes (OR = 0.057, 95% CI: 0.001–11.790). Conclusions: ICH patients with Hp2-2 exhibited a higher likelihood of increased rPHE than those with Hp1-1. Higher relative α1 intensities were identified to be closely associated with rPHE in patients with Hp2-1.

Association Between Copeptin and Six-Month Neurologic Outcomes in Patients With Moderate Traumatic Brain Injury

Background

Copeptin has been reported as a predictive biomarker for the prognosis after traumatic brain injury (TBI). However, most of them were in patients with severe TBI and limited value in predicting outcomes in patients with moderate TBI defined as Glasgow Coma Scale (GCS) score from 9 to 12. We aimed to investigate the predictive value of copeptin in assessing the neurologic outcome following moderate TBI.

Methods

Patients were prospectively enrolled between May 2017 and November 2020. We consecutively measured plasma copeptin within 24 h after trauma, days 3, 5, and 7 using ELISA. The primary outcome was to correlate plasma copeptin levels with poor neurologic outcome at 6 months after moderate TBI. The secondary outcome was to compare the prognostic accuracy of copeptin and C-reactive protein (CRP) in assessing the outcome of patient.

Results

A total of 70 patients were included for the final analysis. The results showed that 29 patients (41.4%) experienced a poor neurologic outcome at 6 months. Multivariable logistic regression analysis revealed that increased copeptin (odds ration [OR] = 1.020, 95% CI: 1.005–1.036), GCS score of 9 or 10 (OR = 4.507, 95% CI: 1.266–16.047), and significant abnormal findings on CT (OR = 4.770; 95% CI: 1.133–20.076) were independent risk factors for poor outcomes. Consecutive plasma copeptin levels were significantly different according to outcomes (p < 0.001). Copeptin on day 7 exhibited better prognostic performance than CRP with an area under receiver operating characteristic curve (AUROC) difference of 0.179 (95% CI: 0.032–0.325) in predicting 6-month poor outcomes.

Conclusion

Plasma copeptin level can be a useful marker in predicting 6-month outcomes in patients with moderate TBI.

Genome-wide polygenic risk impact on intracranial aneurysms and acute ischemic stroke

Polygenic risk scores (PRSs) have an important relevance to approaches for clinical usage in intracranial aneurysm (IA) patients. Hence, we aimed to develop IA-predicting PRS models including the genetic basis shared with acute ischemic stroke (AIS) in Korean populations. We applied a weighted PRS (wPRS) model based on a previous genome-wide association study (GWAS) of 250 IA patients in a hospital-based multicenter cohort, 222 AIS patients in a validation study, and 296 shared controls. Risk predictability was analyzed by the area under the receiver operating characteristic curve (AUROC). The best-fitting risk models based on wPRSs were stratified into tertiles representing the lowest, middle, and highest risk groups. The weighted PRS, which included 29 GWASs (p < 5×10⁻⁸) and two reported genetic variants (p < 0.01), showed a high predictability in IA patients (AUROC = 0.949, 95% CI: 0.933–0.966). This wPRS was significantly validated in AIS patients (AUROC = 0.842, 95% CI: 0.808–0.876; p < 0.001). Two-stage risk models stratified into tertiles showed an increased risk for IA (OR = 691.25, 95% CI: 241.77–1976.35; p = 3.1×10⁻³⁴; sensitivity/specificity = 0.728/0.963), which was replicated in AIS development (OR = 39.76, 95% CI: 16.91–93.49; p = 3.1×10⁻¹⁷; sensitivity/specificity = 0.284/0.963). A higher wPRS for IA may be associated with an increased risk of AIS in the Korean population. These findings suggest that IA and AIS may have a shared genetic architecture and should be studied further to generate a precision medicine model for use in personalized diagnosis and treatment.

Association of Haptoglobin Phenotype With Neurological and Cognitive Outcomes in Patients With Subarachnoid Hemorrhage

Background

To assess the association of haptoglobin (Hp) phenotype with neurological and cognitive outcomes in a large cohort of patients with subarachnoid hemorrhage (SAH).

Methods

This prospective multicenter study enrolled patients with aneurysmal SAH between May 2015 and September 2020. The Hp phenotype was confirmed via Western blots. The relative intensities of α1 in individuals carrying Hp2-1 were compared with those of albumin. Multivariable logistic and Cox proportional-hazard regression analyses were used to identify the risk factors for 6-month and long-term outcomes, respectively.

Results

A total of 336 patients including the phenotypes Hp1-1 (n = 31, 9.2%), Hp2-1 (n = 126, 37.5%), and Hp2-2 (n = 179, 53.3%) were analyzed. The Hp phenotype was closely associated with 6-month outcome (p = 0.001) and cognitive function (p = 0.013), and long-term outcome (p = 0.002) and cognitive function (p &lt; 0.001). Compared with Hp1-1 as the reference value, Hp2-2 significantly increased the risk of 6-month poor outcome (OR: 7.868, 95% CI: 1.764–35.093) and cognitive impairment (OR: 8.056, 95% CI: 1.020–63.616), and long-term poor outcome (HR: 5.802, 95% CI: 1.795–18.754) and cognitive impairment (HR: 7.434, 95% CI: 2.264–24.409). Long-term cognitive impairment based on the Hp phenotype was significantly higher in patients under 65 years of age (p &lt; 0.001) and female gender (p &lt; 0.001). A lower relative α1/albumin intensity (OR: 0.010, 95% CI: 0.000–0.522) was associated with poor outcome at 6 months but not cognitive impairment in patients with SAH expressing Hp2-1.

Conclusion

Hp2-2 increased the risk of poor neurological outcomes and cognitive impairment compared with Hp1-1. For Hp2-1, higher relative α1 intensities were related to 6-month favorable outcomes.

Monitoring Radiation Doses during Diagnostic and Therapeutic Neurointerventional Procedures: Multicenter Study for Establishment of Reference Levels

PURPOSE

To assess patient radiation doses during diagnostic and therapeutic neurointerventional procedures from multiple centers and propose dose reference level (RL).

MATERIALS AND METHODS

Consecutive neurointerventional procedures, performed in 22 hospitals from December 2020 to June 2021, were retrospectively studied. We collected data from a sample of 429 diagnostic and 731 therapeutic procedures. Parameters including dose-area product (DAP), cumulative air kerma (CAK), fluoroscopic time (FT), and total number of image frames (NI) were obtained. RL were calculated as the 3rd quartiles of the distribution.

RESULTS

Analysis of 1160 procedures from 22 hospitals confirmed the large variability in patient dose for similar procedures. RLs in terms of DAP, CAK, FT, and NI were 101.6 Gy·cm2, 711.3 mGy, 13.3 minutes, and 637 frames for cerebral angiography, 199.9 Gy·cm2, 3,458.7 mGy, 57.3 minutes, and 1,000 frames for aneurysm coiling, 225.1 Gy·cm2, 1,590 mGy, 44.7 minutes, and 800 frames for stroke thrombolysis, 412.3 Gy·cm2, 4,447.8 mGy, 99.3 minutes, and 1,621.3 frames for arteriovenous malformation (AVM) embolization, respectively. For all procedures, the results were comparable to most of those already published. Statistical analysis showed male and presence of procedural complications were significant factors in aneurysmal coiling. Male, number of passages, and procedural combined technique were significant factors in stroke thrombolysis. In AVM embolization, a significantly higher radiation dose was found in the definitive endovascular cure group.

CONCLUSION

Various RLs introduced in this study promote the optimization of patient doses in diagnostic and therapeutic interventional neuroradiology procedures. Proposed 3rd quartile DAP (Gy·cm2) values were 101.6 for diagnostic cerebral angiography, 199.9 for aneurysm coiling, 225.1 for stroke thrombolysis, and 412.3 for AVM embolization. Continual evolution of practices and technologies requires regular updates of RLs.

Influence of renal impairment on neurologic outcomes following mechanical thrombectomy in acute vertebrobasilar stroke

PURPOSE

Renal impairment (RI) has been regarded as a risk factor for unfavorable neurologic outcomes after mechanical thrombectomy (MT) in acute ischemic stroke. However, most of the previous studies were conducted on patients with anterior circulation stroke. Accordingly, the influence of RI on MT outcomes has not been well elucidated in detail in acute vertebrobasilar stroke.

METHODS

Consecutive stroke patients with MT due to acute vertebrobasilar artery occlusion between March 2015 and December 2020 at four institutions were included. Multivariable logistic regression analysis was conducted to assess the associations between RI and outcomes and mortality at 3 months, and the development of intracerebral hemorrhage (ICH) after the procedure. Additionally, the multivariable Cox proportional hazards model was performed to determine the influence of RI on survival probability after patient discharge.

RESULTS

A total of 110 patients were included in the final analysis. The presence of RI (OR = 0.268, 95% CI: 0.077-0.935), National Institute of Health Stroke Scale scores (OR = 0.849, 95% CI: 0.791-0.910), and puncture-to-recanalization time (OR = 0.981, 95% CI: 0.966-0.997) were related to outcomes. There was no significant association between RI and 3-month mortality or ICH. The cumulative survival probability after adjusting for relevant risk factors demonstrated that RI remained significantly associated with poorer survival after MT compared to patients without RI (HR = 2.111, 95% CI: 0.919-4.847).

CONCLUSION

RI was an independent risk factor for poor 3-month neurologic outcomes and survival probability after MT in patients with acute vertebrobasilar stroke.

Prognostic value of red blood cell distribution width in predicting 3-month functional outcome of patients undergoing thrombolysis treatment for acute ischemic stroke

This study was performed to determine whether red blood cell distribution width (RDW) is associated with 3-month poor functional outcome in patients undergoing thrombolytic therapy for acute ischemic stroke.RDW was measured in patients with thrombolytic therapy in emergency department. Functional outcome was assessed after 3 months and poor functional outcome was defined as modified Rankin scale 3 to 6.A total of 240 patients were enrolled, and 82 (34.2%) had a poor functional outcome. The median RDW was significantly elevated in patients with a poor functional outcome compare with those with a good outcome. RDW was independently associated with a 3-month poor functional outcome (odds ratio 3.369, 95% confidence interval 2.214-5.125). The optimal RDW cutoff for predicting 3-month poor functional outcome was 12.8%, and the area under the curve for RDW was 0.818 (95% confidence interval 0.761-0.876). The area under the curve for RDW was higher in male patients than in female patients. The RDW correlated positively with the modified Rankin scale score after 3 months and the initial National Institutes of Health Stroke Scale score.Initial higher RDW level is related to a 3-month poor functional outcome in patients undergoing thrombolytic therapy for acute ischemic stroke.

Diagnosis of obstructive sleep apnea with prediction of flow characteristics according to airway morphology automatically extracted from medical images: Computational fluid dynamics and artificial intelligence approach

BACKGROUND

Obstructive sleep apnea syndrome (OSAS) is being observed in an increasing number of cases. It can be diagnosed using several methods such as polysomnography.

OBJECTIVES

To overcome the challenges of time and cost faced by conventional diagnostic methods, this paper proposes computational fluid dynamics (CFD) and machine-learning approaches that are derived from the upper-airway morphology with automatic segmentation using deep learning.

METHOD

We adopted a 3D UNet deep-learning model to perform medical image segmentation. 3D UNet prevents the feature-extraction loss that may occur by concatenating layers and extracts the anteroposterior coordination and width of the airway morphology. To create flow characteristics of the upper airway training data, we analyzed the changes in flow characteristics according to the upper-airway morphology using CFD. A multivariate Gaussian process regression (MVGPR) model was used to train the flow characteristic values. The trained MVGPR enables the prompt prediction of the aerodynamic features of the upper airway without simulation. Unlike conventional regression methods, MVGPR can be trained by considering the correlation between the flow characteristics. As a diagnostic step, a support vector machine (SVM) with predicted aerodynamic and biometric features was used in this study to classify patients as healthy or suffering from moderate OSAS. SVM is beneficial as it is easy to learn even with a small dataset, and it can diagnose various flow characteristics as factors while enhancing the feature via the kernel function. As the patient dataset is small, the Monte Carlo cross-validation was used to validate the trained model. Furthermore, to overcome the imbalanced data problem, the oversampling method was applied.

RESULT

The segmented upper-airway results of the high-resolution and low-resolution models present overall average dice coefficients of 0.76±0.041 and 0.74±0.052, respectively. Furthermore, the classification accuracy, sensitivity, specificity, and F1-score of the diagnosis algorithm were 81.5%, 89.3%, 86.2%, and 87.6%, respectively.

CONCLUSION

The convenience and accuracy of sleep apnea diagnosis are improved using deep learning and machine learning. Further, the proposed method can aid clinicians in making appropriate decisions to evaluate the possible applications of OSAS.

Multi-View Convolutional Neural Networks in Rupture Risk Assessment of Small, Unruptured Intracranial Aneurysms

Auto-detection of cerebral aneurysms via convolutional neural network (CNN) is being increasingly reported. However, few studies to date have accurately predicted the risk, but not the diagnosis itself. We developed a multi-view CNN for the prediction of rupture risk involving small unruptured intracranial aneurysms (UIAs) based on three-dimensional (3D) digital subtraction angiography (DSA). The performance of a multi-view CNN-ResNet50 in accurately predicting the rupture risk (high vs. non-high) of UIAs in the anterior circulation measuring less than 7 mm in size was compared with various CNN architectures (AlexNet and VGG16), with similar type but different layers (ResNet101 and ResNet152), and single image-based CNN (single-view ResNet50). The sensitivity, specificity, and overall accuracy of risk prediction were estimated and compared according to CNN architecture. The study included 364 UIAs in training and 93 in test datasets. A multi-view CNN-ResNet50 exhibited a sensitivity of 81.82 (66.76–91.29)%, a specificity of 81.63 (67.50–90.76)%, and an overall accuracy of 81.72 (66.98–90.92)% for risk prediction. AlexNet, VGG16, ResNet101, ResNet152, and single-view CNN-ResNet50 showed similar specificity. However, the sensitivity and overall accuracy were decreased (AlexNet, 63.64% and 76.34%; VGG16, 68.18% and 74.19%; ResNet101, 68.18% and 73.12%; ResNet152, 54.55% and 72.04%; and single-view CNN-ResNet50, 50.00% and 64.52%) compared with multi-view CNN-ResNet50. Regarding F1 score, it was the highest in multi-view CNN-ResNet50 (80.90 (67.29–91.81)%). Our study suggests that multi-view CNN-ResNet50 may be feasible to assess the rupture risk in small-sized UIAs.

Role of specific IgE on staphylococcal enterotoxin B in chronic rhinosinusitis severity

OBJECTIVE

To investigate the clinical significance of specific IgE-staphylococcal enterotoxin B (IgE-SEB) in CRS (chronic rhinosinusitis).

DESIGN

Retrospective analysis of patients who were positive for specific IgE-staphylococcal enterotoxin B.

SETTING

Tertiary rhinology clinic.

PARTICIPANTS

A total of 965 patients who were tested for specific IgE-staphylococcal enterotoxin B from December 2016 to December 2017.

MAIN OUTCOME MEASURES

We retrospectively reviewed the records of 965 patients who were tested for specific IgE-staphylococcal enterotoxin B from December 2016 to December 2017. Patient demographics, titre-specific IgE to staphylococcal enterotoxin B levels, MAST, serologic test and medical records were reviewed.

RESULTS

IgE-SEB (KU/L) was higher in CRS patients than non-CRS patients (0.13 ± 0.37 vs 0.08 ± 0.22, respectively; P-value: .044), and the IgE-SEB (+, ≥0.35) rate was also higher (10.06% vs 4.46%, respectively; P-value: .030). IgE-SEB (KU/L) was higher in the CRS group than in the fungal sinusitis group (0.13 ± 0.37 vs 0.03 ± 0.05, respectively; P-value: <.001), and the IgE-SEB (+, ≥0.35) rate was also higher (10.06% vs 0%, respectively; P-value: .015). Between the CRSsNP (chronic rhinosinusitis without nasal polyps) and CRSwNP (chronic rhinosinusitis with nasal polyps) groups, there were no differences in IgE-SEB (KU/L) or IgE-SEB (+) rates. IgE-SEB positivity was not associated with the presence of polyps, concomitant asthma or postoperative recurrence. As the values of IgE-SEB (KU/L) and the IgE-SEB (+, >0.1) rate increased, the CRS severity also increased.

CONCLUSIONS

IgE-SEB showed a positive correlation with Lund-Mackay CT severity score, but not with postoperative recurrence or nasal polyps. Further studies are needed to obtain clear evidence that IgE-SEB can be considered as an independent CRS endotype.

A Preliminary Study of the Association between SOX17 Gene Variants and Intracranial Aneurysms Using Exome Sequencing

OBJECTIVE

Conflicting results regarding SOX17 genes and the risk of intracranial aneurysms (IA) exist in the Korean population, although significant positive correlations were noted in genome-wide association studies in European and Japanese populations. Therefore, we aimed to investigate an association between SOX17 gene variants and IA using exome sequencing data.

METHODS

This study included 26 age-gender matched IA patients and 26 control subjects. The SOX17 gene variants identified from whole-exome sequencing data were examined. Genetic associations to estimate odds ratio (OR) and 95% confidence interval (CI) were performed using the software EPACTS.

RESULTS

The mean age of the IA and control groups were 51.0±9.3 years and 49.4±14.3 years, respectively (p=0.623). Seven variants of SOX17, including six single nucleotide polymorphisms and one insertion and deletion, were observed. Among these variants, rs12544958 (A>G) showed the most association with IA, but the association was not statistically significant (OR, 1.97; 95% CI, 0.81-4.74; p=0.125). Minor allele frequencies of the IA patients and controls were 0.788 and 0.653, respectively. None of the remaining variants were significantly associated with IA formation.

CONCLUSION

No significant association between SOX17 gene variants and IA were noted in the Korean population. A large-scale exome sequencing study is necessary to investigate any Korean-specific genetic susceptibility to IA.

Development of a Korean Culture-Friendly Olfactory Function Test and Optimization of a Diagnostic Cutoff Value

Objectives

Cultural familiarity and safety must be considered when assessing olfactory ability. The YSK olfactory function (YOF) test is a new olfactory function test using culturally familiar odorants to Koreans.

Methods

The YOF test comprises three subtests for threshold (T), discrimination (D), and identification (I). The identification test included eight universal and four Korean culture-friendly odorants, which were selected considering eight major functional groups. Data were obtained from 1,127 subjects over 19 years old. Subjects were classified as having normosmia (n=542), hyposmia (n=472), and anosmia (n=113) by self-reported olfactory function. The YOF test and the Korean version of the Sniffin’ stick test (KVSS-II) were performed on the same day in random order. Diagnostic cutoffs for anosmia and hyposmia were calculated using the Youden index (J).

Results

The mean values for each T/D/I subtest and the total TDI score were as follows: normosmia (T, 4.6±2.3; D, 8.6±2.1; I, 11.1±1.7; TDI score, 24.2±4.5); hyposmia (T, 3.3±2.2; D, 7.1±2.5; I, 9.2±3.1; TDI score, 19.5±6.4); and anosmia (T, 1.7±1.2; D, 5.1±2.5; I, 5.0±3.2; TDI score, 11.8±5.6). The correlation coefficients between the YOF test and KVSS-II were 0.57, 0.65, 0.80, and 0.86 for T, D, I, and the TDI score, respectively (P<0.001). The diagnostic cutoffs were a TDI score ≤14.5 (J=0.67) for anosmia and 14.5(TDI score ≤21.0 (J=0.38) for hyposmia. The diagnostic efficacy of the YOF test (area under the curve [AUC], 0.88) was equivalent to that of the KVSS-II (AUC, 0.88; P=0.843; DeLong method).

Conclusion

The YOF test is a new olfactory test using safe and Korean culture-friendly odorants. It showed equivalent validity with the conventional olfactory function test. Furthermore, the YOF test provides information on the major functional groups of odorants, potentially enabling a more comprehensive interpretation for patients with olfactory disorders.

Genome-wide blood DNA methylation analysis in patients with delayed cerebral ischemia after subarachnoid hemorrhage

Little is known about the epigenetic changes associated with delayed cerebral ischemia (DCI) pathogenesis after subarachnoid hemorrhage (SAH). Here, we investigated genome-wide DNA methylation profiles specifically associated with DCI, which is a major contributor to poor clinical outcomes. An epigenome-wide association study (EWAS) and quantitative real-time PCR (qRT-PCR) were conducted in 40 SAH patients (DCI, n = 13; non-DCI, n = 27). A replication study using bisulfite modification and methylation-specific PCR was further performed in 36 patients (DCI, n = 12; non-DCI, n = 24). The relative degree of methylation was described as the median and 25th–75th percentile. No significant differences in clinical characteristics between DCI and non-DCI groups were observed. Among the top 10 differentially methylated genes analyzed via EWAS, two aberrantly methylated CpG sites of cg00441765 (INSR gene) and cg11464053 (CDHR5 gene) were associated with decreased mRNA expression (2^−ΔCt). They include INSR [0.00020 (0.00012–0.00030) in DCI vs. 0.00050 (0.00030–0.00068) in non-DCI] and CDHR5 [0.114 (0.053–0.143) in DCI vs. 0.170 (0.110–0.212) in non-DCI]. Compared with non-DCI cases, patients with DCI exhibited an increased degree of methylation in the replication study: INSR, 0.855 (0.779–0.913) in DCI vs. 0.582 (0.565–0.689) in non-DCI; CDHR5, 0.786 (0.708–0.904) in DCI vs. 0.632 (0.610–0.679) in non-DCI. Hypermethylation of two novel genes, INSR and CDHR5 may serve as a biomarker for early detection of DCI following SAH.

Monitoring of Delayed Cerebral Ischemia in Patients with Subarachnoid Hemorrhage via Near-Infrared Spectroscopy

We investigated the role of near infrared spectroscopy (NIRS) in identifying delayed cerebral ischemia (DCI) in patients with subarachnoid hemorrhage (SAH). We measured the cerebral regional oxygen saturation (rSO2) continuously for 14 days. The differences in rSO2 according to DCI were analyzed. We also compared the diagnostic accuracy of NIRS and transcranial Doppler ultrasonography (TCD) for DCI detection using the area under receiver operator characteristic (ROC) curve. Fifty-two patients treated with coil embolization were enrolled, including 18 with DCI (34.6%) and 34 without DCI (65.4%). Significant differences in rSO2 levels were observed from days 7 to 9. The rSO2 level was 60.95 (58.10-62.30) at day 7 in the DCI vs. 63.90 (62.50-67.10) in the non-DCI patients. By day 8, it was 59.50 (56.90-64.50) in the DCI vs. 63.30 (59.70-68.70) in the non-DCI cases. By day 9, it was 61.85 (59.40-65.20) in the DCI vs. 66.00 (62.70-68.30) in the non-DCI. A decline of >12.7% in SO2 rate yielded a sensitivity of 94.44% (95% CI: 72.7-99.9%) and a specificity of 70.59% (95% CI: 52.5-84.9%) for identifying DCI. Changes in NIRS tended to yield better diagnostic accuracy than TCD, but were not statistically significant. NIRS is a feasible method for real-time detection of DCI.

Can drug-induced sleep endoscopy improve the success rates of tongue base surgery?

Background

The purpose of this study was to determine the therapeutic value of drug-induced sleep endoscopy (DISE) by comparing the outcomes of tongue base surgery based on Muller’s maneuver (MM) and those based on DISE in obstructive sleep apnea (OSA) patients.

Methods

Ninety-five patients who underwent the tongue base surgery in combination with palatal surgery for OSA at a tertiary referral hospital between March 2012 and March 2019 were enrolled in this retrospective comparative study. Forty-seven patients underwent MM for surgical decision and 48 patients underwent DISE in addition to MM for surgical decision. Surgical success was defined according to the Sher criteria (postoperative apnea-hypopnea index [AHI] < 20/h and ≥ 50% reduction in preoperative AHI), and AHI improvement (%) was defined as (preoperative AHI-postoperative AHI) × 100/preoperative AHI. For comparison between the MM and DISE groups, p-values were calculated using independent or paired t-tests for continuous variables and using chi-square test for categorical variables.

Results

By comparing the results of MM and DISE, consensus on the tongue base level showed insignificant concordance (kappa = 0.017, p = 0.865), whereas that on the oropharynx level showed fair agreement (kappa =0.241, p = 0.005). AHI, supine AHI, rapid eyeball movement (REM) AHI, non-REM AHI, and nadir oxygen saturation were all significantly improved after the tongue base surgery in both groups. The MM group showed a significant improvement in the Epworth sleepiness scale after the tongue base surgery (p = 0.014), whereas the DISE group did not (p = 0.165). However, there was no significant difference in the AHI improvement (MM group = 47.0 ± 32.0, DISE group = 48.3 ± 35.4, p = 0.852) and surgical success (MM group = 42.6%, DISE group = 45.8%, p = 0.748) between the groups. Tonsil grade (p < 0.05) and occlusion at the oropharynx lateral wall (p = 0.031) were significantly related to surgical success in the MM group.

Conclusions

In the judgment of the tongue base surgery, MM and DISE findings showed poor agreement. DISE might affect the surgical decision on the tongue base surgery in OSA patients; however, there was a lack of evidence regarding the superiority of DISE over MM with respect to the surgical outcomes.

Multiphase MR Angiography Collateral Map: Functional Outcome after Acute Anterior Circulation Ischemic Stroke

Background Collateral circulation determines tissue fate and affects treatment result in acute ischemic stroke. A precise method for collateral estimation in an optimal imaging protocol is necessary to make an appropriate treatment decision for acute ischemic stroke. Purpose To verify the value of multiphase collateral imaging data sets (MR angiography collateral map) derived from dynamic contrast material-enhanced MR angiography for predicting functional outcomes after acute ischemic stroke. Materials and Methods This secondary analysis of an ongoing prospective observational study included data from participants with acute ischemic stroke due to occlusion or stenosis of the unilateral internal carotid artery and/or M1 segment of the middle cerebral artery who were evaluated within 8 hours of symptom onset. Data were obtained from March 2016 through August 2018. The collateral grading based on the MR angiography collateral map was estimated by using six-scale MR acute ischemic stroke collateral (MAC) scores. To identify independent predictors of favorable functional outcomes, age, sex, risk factors, baseline National Institutes of Health Stroke Scale (NIHSS) score, baseline diffusion-weighted imaging (DWI) lesion volume, site of steno-occlusion, collateral grade, mode of treatment, and early reperfusion were evaluated with multiple logistic regression analyses. Results One hundred fifty-four participants (mean age ± standard deviation, 69 years ± 13; 99 men) were evaluated. Younger age (odds ratio [OR], 0.45; 95% confidence interval [CI]: 0.29, 0.70; P < .001), lower baseline NIHSS score (OR, 0.85; 95% CI: 0.78, 0.94; P < .001), MAC score of 3 (OR, 27; 95% CI: 4.0, 179; P < .001), MAC score of 4 (OR, 17; 95% CI: 2.1, 134; P = .007), MAC score of 5 (OR, 27; 95% CI: 2.5, 306; P = .007), and successful early reperfusion (OR, 7.5; 95% CI: 2.6, 22; P < .001) were independently associated with favorable functional outcomes in multivariable analysis. There was a linear negative association between collateral perfusion grades and functional outcomes (P < .001). Conclusion An MR angiography collateral map was clinically reliable for collateral estimation in patients with acute ischemic stroke. This map provided patient-specific pacing information for ischemic progression. © RSNA, 2020.

Abstract WMP13: Multiphase MRA Collateral Map: Prediction of Tissue Outcome and Penumbra in Patients With Acute Ischemic Stroke in the Anterior Circulation

Background and Purpose: We developed the MRA collateral map derived from dynamic MR angiography and grading methods with significant linear association with functional outcomes of patients with acute ischemic stroke (AIS). This study is to verify the value of the MRA collateral map for predicting tissue outcome and penumbra in patients with AIS.

Materials and Methods: From a prospectively maintained registry, patients with AIS due to occlusion or stenosis of the unilateral ICA and/or M1 MCA within 8 hours of symptom onset were included. The collateral-perfusion grading based on the MRA collateral map was estimated using 6-scale MAC. Changes of infarct area were divided into two groups with and without infarct growth (IG + and IG - ). Areas of baseline DWI lesion, Tmax > 6s, and decreased collateral-perfusion on each phases of the MRA collateral map, and infarct lesion on follow-up image were compared by visual assessment.

Results: One hundred thirty-five patients, including 85 males (mean age, 69 years old), were included. Shorter onset-to-door times (OR=1.04, 95% CI=1.01-1.08) and successful early reperfusion (OR=0.19, 95% CI=0.05-0.66) were independently associated with IG - in multivariate analysis. In subgroup analysis, good collateral-perfusion status was associated with IG - (OR=0.30, 95% CI=0.10-0.91). In IG + group, the infarction grew within hypoperfused area on the phase of the MRA collateral map immediately before the phase that matches the baseline DWI lesion. There was no infarct growth beyond hypoperfused area on the capillary phase of the MRA collateral map in both IG + and IG - groups. The area of Tmax > 6s matched with the hypoperfused area on capillary phase of the MRA collateral map in 83% of patients.

Conclusion: In this study, tissue fate in AIS was dependent on early reperfusion. In case of unsuccessful early reperfusion, it was associated with collateral-perfusion status. We suggest that the extent of penumbra can be estimated by the MRA collateral map.

P785 Left ventricular geometry and myocardial contractility modulate impact of statins on prognosis in patients with acute heart failure

Funding Acknowledgements

N/A

Background/Introduction: The benefit of statins in patients with heart failure (HF) remains controversial and the mechanism of action is largely speculative. We investigated whether survival benefit with statins differs according to left ventricular (LV) geometry and myocardial contractility in acute HF patients.

Methods

We enrolled 1792 acute HF patients receiving statins and 2296 patients not receiving statins admitted from 2009 to 2016. The LV and right ventricular (RV) global longitudinal strain (GLS) was assessed as a measure of myocardial contractility. Patients were classified into 2 groups based on ischemic etiology of HF and further divided into 4 subgroups according to the median values of LV-GLS or RV-GLS. The primary outcome was 5-year all-cause mortality. The study protocol was approved by the ethics committee at each institute and complied with the Declaration of Helsinki. The need for written informed consent was waived.

Results

During the 5-year follow-up, 1740 (40.4%) patients died and they had more unfavorable baseline characteristics. Statin therapy was significantly associated with improved survival in overall patients and in both groups with and without ischemic etiology (all p &lt;0.001). Patients with concentric remodeling/hypertrophy and eccentric hypertrophy demonstrated survival benefit with statin therapy (P = 0.033, 0.004, and 0.008, respectively), while those with normal geometry did not (p = 0.123). In the non-ischemic HF group, survival benefit with statin therapy was confined to patients with low LV-GLS (p = 0.045) or those with low RV-GLS p = 0.003). On the contrary, in ischemic HF group, survival benefit with statin therapy was observed in all patients regardless of the values of LV-GLS or RV-GLS. Significant interactions were present between statin use and diabetes mellitus and IHD (p for interaction = 0.027 and 0.003, respectively) regarding mortality.

Conclusions

LV geometry and myocardial contractility may modulate the effects of statins in patients with acute HF. These echocardiographic measures can provide prognostic information to guide tailored statin treatment in this population. Our findings may also help to develop more well-designed prospective studies, in terms of a more homogenous study population, to confirm survival benefit with statin therapy.

Abstract P785 Figure. Multivariate Cox survival curves

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.

A Novel Collateral Imaging Method Derived from Time-Resolved Dynamic Contrast-Enhanced MR Angiography in Acute Ischemic Stroke: A Pilot Study

BACKGROUND AND PURPOSE

Assessment of the collateral status has been emphasized for appropriate treatment decisions in patients with acute ischemic stroke. The purpose of this study was to introduce a multiphase MRA collateral imaging method (collateral map) derived from time-resolved dynamic contrast-enhanced MRA and to verify the value of the multiphase MRA collateral map in acute ischemic stroke by comparing it with the multiphase collateral imaging method (MRP collateral map) derived from dynamic susceptibility contrast-enhanced MR perfusion.

MATERIALS AND METHODS

From a prospectively maintained registry of acute ischemic stroke, MR imaging data of patients with acute ischemic stroke caused by steno-occlusive lesions of the unilateral ICA and/or the M1 segment of the MCA were analyzed. We generated collateral maps using dynamic signals from dynamic contrast-enhanced MRA and DSC-MRP using a Matlab-based in-house program and graded the collateral scores of the multiphase MRA collateral map and the MRP collateral map independently. Interobserver reliabilities and intermethod agreement between both collateral maps for collateral grading were tested.

RESULTS

Seventy-one paired multiphase MRA and MRP collateral maps from 67 patients were analyzed. The interobserver reliabilities for collateral grading using multiphase MRA or MRP collateral maps were excellent (weighted κ = 0.964 and 0.956, respectively). The agreement between both collateral maps was also excellent (weighted κ = 0.884; 95% confidence interval, 0.819-0.949).

CONCLUSIONS

We demonstrated that the dynamic signals of dynamic contrast-enhanced MRA could be used to generate multiphase collateral images and showed the possibility of the multiphase MRA collateral map as a useful collateral imaging method in acute ischemic stroke.

Machine Learning Application for Rupture Risk Assessment in Small-Sized Intracranial Aneurysm

The assessment of rupture probability is crucial to identifying at risk intracranial aneurysms (IA) in patients harboring multiple aneurysms. We aimed to develop a computer-assisted detection system for small-sized aneurysm ruptures using a convolutional neural network (CNN) based on images of three-dimensional digital subtraction angiography. A retrospective data set, including 368 patients, was used as a training cohort for the CNN using the TensorFlow platform. Aneurysm images in six directions were obtained from each patient and the region-of-interest in each image was extracted. The resulting CNN was prospectively tested in 272 patients and the sensitivity, specificity, overall accuracy, and receiver operating characteristics (ROC) were compared to a human evaluator. Our system showed a sensitivity of 78.76% (95% CI: 72.30%-84.30%), a specificity of 72.15% (95% CI: 60.93%-81.65%), and an overall diagnostic accuracy of 76.84% (95% CI: 71.36%-81.72%) in aneurysm rupture predictions. The area under the ROC (AUROC) in the CNN was 0.755 (95% CI: 0.699%-0.805%), better than that obtained from a human evaluator (AUROC: 0.537; p < 0.001). The CNN-based prediction system was feasible to assess rupture risk in small-sized aneurysms with diagnostic accuracy superior to human evaluators. Additional studies based on a large data set are necessary to enhance diagnostic accuracy and to facilitate clinical application.

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.

Need for rescue treatment and its implication: stent retriever versus contact aspiration thrombectomy

Backgroud

The need for rescue treatment (RT) may differ depending on first-line modality (stent retriever (SR) or contact aspiration (CA)) in endovascular thrombectomy (EVT). We aimed to investigate whether the type of first-line modality in EVT was associated with the need for RT.

Methods

We identified all patients who underwent EVT for anterior circulation large-vessel occlusion from prospectively maintained registries of 17 stroke centers. Patients were dichotomized into SR-first and CA-first. RT involved switching to the other device, balloon angioplasty, permanent stenting, thrombolytics, glycoprotein IIb/IIIa antagonist, or any combination of these. We compared clinical characteristics, procedural details, and final recanalization rate between the two groups and assessed whether first-line modality type was associated with RT requirement and if this affected clinical outcome.

Results

A total of 955 patients underwent EVT using either SR-first (n=526) or CA-first (n=429). No difference occurred in the final recanalization rate between SR-first (82.1%) and CA-first (80.2%). However, recanalization with the first-line modality alone and first-pass recanalization rates were significantly higher in SR-first than in CA-first. CA-first had more device passes and higher RT rate. The RT group had significantly longer puncture-to-recanalization time (93±48 min versus 53±28 min). After adjustment, CA-first remained associated with RT (OR, 1.367; 95% CI, 1.019 to 1.834). RT was negatively associated with good outcome (OR, 0.597; 95% CI, 0.410 to 0.870).

Conclusion

CA was associated with requiring RT, while recanalization with first-line modality alone and first-pass recanalization rates were higher with SR. RT was negatively associated with good outcome.

Medical Procedure-Related Transient Global Amnesia

BACKGROUND

Transient global amnesia (TGA) is an interesting clinical syndrome characterized by sudden memory loss for recent events and an inability to retain new memories usually lasting several hours and recovering spontaneously. We conducted a literature search of medical procedure-related TGA and its predisposing conditions.

METHODS

We performed PubMed searches using the keyword "transient global amnesia" combined with "procedure," "test," "therapy," or various other individual medical procedures. In addition, we described 2 cases of gastroscopy-related TGA.

RESULTS

Eighty-nine patients with medical procedure-related TGA in 49 articles were summarized. The most common procedure was cerebral angiography (n = 45), followed by coronary angiography (n = 10) and general anesthesia (n = 9). After categorization, neurological procedures were most common (n = 46, 51.7%), followed by cardiac (n = 17, 19.1%), anesthetic (n = 11, 12.4%), gastrointestinal (n = 4, 4.5%), and pulmonary (n = 2, 2.2%) procedures.

CONCLUSIONS

Diverse cases of medical procedure-related TGA have been reported in the literature. Valsalva-associated activities, emotional stress with anxiety, and acute pain were predisposing conditions. An understanding of medical procedure-related TGA may be important for clinicians who perform such medical procedures.

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.