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Seraphine Zubel

Aarhus University Hospital

Publishes on Acute Ischemic Stroke Management, Cerebrovascular and Carotid Artery Diseases, Stroke Rehabilitation and Recovery. 17 papers and 581 citations.

17Publications
581Total Citations

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Bridging Thrombolysis versus Direct Mechanical Thrombectomy in Stroke Due to Basilar Artery Occlusion
Isabel Siow, Benjamin Yong‐Qiang Tan, Keng Siang Lee et al.|Journal of Stroke|2022
Cited by 42Open Access

Background and Purpose Mechanical thrombectomy (MT) is an effective treatment for patients with basilar artery occlusion (BAO) acute ischemic stroke. It remains unclear whether bridging intravenous thrombolysis (IVT) prior to MT confers any benefit. This study compared the outcomes of acute BAO patients who were treated with direct MT versus combined IVT plus MT.Methods This multicenter retrospective cohort study included patients who were treated for acute BAO from eight comprehensive stroke centers between January 2015 and December 2019. Patients received direct MT or combined bridging IVT plus MT. Primary outcome was favorable functional outcome defined as modified Rankin Scale 0–3 measured at 90 days. Secondary outcome measures included mortality and symptomatic intracranial hemorrhage (sICH).Results Among 322 patients, 127 (39.4%) patients underwent bridging IVT followed by MT and 195 (60.6%) underwent direct MT. The mean±standard deviation age was 67.5±14.1 years, 64.0% were male and median National Institutes of Health Stroke Scale was 16 (interquartile range, 8 to 25). At 90-day, the rate of favorable functional outcome was similar between the bridging IVT and direct MT groups (39.4% vs. 34.4%, P=0.361). On multivariable analyses, bridging IVT was not as Comorbidisociated with favorable functional outcome, mortality or sICH. In subgroup analyses, patients with underlying atherosclerosis treated with bridging IVT compared to direct MT had a higher rate of favorable functional outcome at 90 days (37.2% vs. 15.5%, P=0.013).Conclusions Functional outcomes were similar in BAO patients treated with bridging IVT versus direct MT. In the subgroup of patients with underlying large-artery atherosclerosis stroke mechanism, bridging IVT may potentially confer benefit and this warrants further investigation.

Effect of Sex on Outcomes of Mechanical Thrombectomy in Basilar Artery Occlusion: A Multicentre Cohort Study
Benjamin Yong‐Qiang Tan, Isabel Siow, Keng Siang Lee et al.|Cerebrovascular Diseases|2022
Cited by 12Open Access

INTRODUCTION: Identifying differences in outcome of basilar artery occlusion (BAO) between males and females may be useful in aiding clinical management. Recent studies have demonstrated widespread underrepresentation of women in acute stroke clinical trials. This international multicentre study aimed to determine sex differences in outcome after mechanical thrombectomy (MT) for patients with acute BAO. METHODS: We performed a retrospective analysis of consecutive patients with BAO who had undergone MT in seven stroke centres across five countries (Singapore, Taiwan, United Kingdom, Sweden, and Germany), between 2015 and 2020. Primary outcome was a favourable functional outcome measured by a modified Ranking Scale (mRS) of 0-3 at 90 days. Secondary outcomes were mRS 0-3 upon discharge, mortality, symptomatic intracranial haemorrhage (sICH) and subarachnoid haemorrhage (SAH). RESULTS: Among the 322 patients who underwent MT, 206 (64.0%) patients were male and 116 (36.0%) were female. Females were older than males (mean ± SD 70.9 ± 14.3 years vs. 65.6 ± 133.6 years; p = 0.001) and had higher rates of atrial fibrillation (38.9% vs. 24.2%; p = 0.012). Time from groin puncture to reperfusion was shorter in females than males (mean ± SD 57.2 ± 37.2 min vs. 71.1 ± 50.9 min; p = 0.021). Despite these differences, primary and secondary outcome measures were similar in females and males, with comparable rates of favourable 90-day mRS scores (mean ± SD 46 ± 39.7 vs. 71 ± 34.5; OR = 1.20; 95% confidence interval [CI] = 0.59-2.43; p = 0.611), favourable discharge mRS scores (mean ± SD 39 ± 31.6 vs. 43 ± 25.9; OR = 1.38; 95% CI = 0.69-2.78; p = 0.368) and in-hospital mortality (mean ± SD 30 ± 25.9 vs. 47 ± 22.8; OR = 1.15; 95% CI = 0.55-2.43; p = 0.710. Rates of complications such as sICH (mean ± SD 5 ± 4.3 vs. 9 ± 4.4; OR = 0.46; 95% CI = 0.08-2.66; p = 0.385) and SAH (mean ± SD 4 ± 3.4 vs. 5 ± 2.4; OR = 0.29; 95% CI = 0.03-3.09; p = 0.303) comparably low in both groups. CONCLUSION: Females achieved comparable functional outcomes compared with males after undergoing MT for BAO acute ischemic stroke.

Calculation of virtual 3D subtraction angiographies using conditional generative adversarial networks (cGANs)
Cited by 2Open Access

OBJECTIVE: Subtraction angiographies are calculated using a native and a contrast-enhanced 3D angiography images. This minimizes both bone and metal artifacts and results in a pure image of the vessels. However, carrying out the examination twice means double the radiation dose for the patient. With the help of generative AI, it could be possible to simulate subtraction angiographies from contrast-enhanced 3D angiographies and thus reduce the need for another dose of radiation without a cutback in quality. We implemented this concept by using conditional generative adversarial networks. METHODS: We selected all 3D subtraction angiographies from our PACS system, which had performed between 01/01/2018 and 12/31/2022 and randomly divided them into training, validation, and test sets (66%:17%:17%). We adapted the pix2pix framework to work on 3D data and trained a conditional generative adversarial network with 621 data sets. Additionally, we used 158 data sets for validation and 164 for testing. We evaluated two test sets with (n = 72) and without artifacts (n = 92). Five (blinded) neuroradiologists compared these datasets with the original subtraction dataset. They assessed similarity, subjective image quality, and severity of artifacts. RESULTS: Image quality and subjective diagnostic accuracy of the virtual subtraction angiographies revealed no significant differences compared to the original 3D angiographies. While bone and movement artifact level were reduced, artifact level caused by metal implants differed from case to case between both angiographies without one group being significant superior to the other. CONCLUSION: Conditional generative adversarial networks can be used to simulate subtraction angiographies in clinical practice, however, new artifacts can also appear as a result of this technology.

Enlarged tumefactive perivascular, or Virchow-Robin, spaces and hydrocephalus: do we need to treat? Illustrative cases
Belal Neyazi, Vanessa M. Swiatek, Klaus‐Peter Stein et al.|Journal of Neurosurgery Case Lessons|2024
Cited by 2Open Access

BACKGROUND: Perivascular spaces (PVSs) are spaces in brain parenchyma filled with interstitial fluid surrounding small cerebral vessels. Massive enlargements of PVSs are referred to as "giant tumefactive perivascular spaces" (GTPVSs), which can be classified into three types depending on their localization. These lesions are rare, predominantly asymptomatic, and often initially misinterpreted as cystic tumor formations. However, there are several reported cases in which GTPVSs have induced neurological symptoms because of their size, mass effect, and location, ultimately leading to obstructive hydrocephalus necessitating neurosurgical intervention. Presented here are three diverse clinical presentations of GTPVS. OBSERVATIONS: Here, the authors observed an asymptomatic case of type 1 GTPVS and two symptomatic cases of type 3 GTPVS, one causing local mass effect and the other hydrocephalus. LESSONS: GTPVSs are mostly asymptomatic lesions. Patients without symptoms should be closely monitored, and biopsy is discouraged. Hydrocephalus resulting from GTPVS necessitates surgical intervention. In these cases, third ventriculostomy, shunt implantation, or direct cyst fenestration are surgical options. For patients presenting with symptoms from localized mass effect, a thorough evaluation for potential neurosurgical intervention is imperative. Follow-up in type 3 GTPVS is recommended, particularly in untreated cases. Given the infrequency of GTPVS, definitive guidelines for neurosurgical treatment and subsequent follow-up remain elusive.