Simulation-based team-training in acute stroke: Is it safe to speed up?

BACKGROUND: In acute ischemic stroke (AIS), rapid treatment with intravenous thrombolysis (IVT) is crucial for good clinical outcome. Weekly simulation-based team-training of the stroke treatment team was implemented, resulting in faster treatment times. The aim of this study was to assess whether this time reduction led to a higher proportion of stroke mimics (SMs) among patients who received IVT for presumed AIS, and whether these SM patients were harmed by intracranial hemorrhage (ICH). METHODS: All suspected AIS patients treated with IVT between January 1, 2015 and December 31, 2020 were prospectively registered. In 2017, weekly in situ simulation-based team-training involving the whole stroke treatment team was introduced. To analyze possible unintended effects of simulation training, the proportion of SMs among patients who received IVT for presumed AIS were identified by clinical and radiological evaluation. Additionally, we identified the extent of symptomatic ICH (sICH) in IVT-treated SM patients. RESULTS: From 2015 to 2020, 959 patients were treated with IVT for symptoms of AIS. After introduction of simulation training, the proportion of patients treated with IVT who were later diagnosed as SMs increased significantly (15.9% vs. 24.4%, p = .003). There were no ICH complications in the SM patients treated before, whereas two SM patients suffered from asymptomatic ICH after introduction of simulation training (p = 1.0). When subgrouping SMs into prespecified categories, only the group diagnosed with peripheral vertigo increased significantly (2.5% vs. 8.6%, p < .001). CONCLUSIONS: Simulation training of the acute stroke treatment team was associated with an increase in the proportion of patients treated with IVT for a suspected AIS who were later diagnosed with peripheral vertigo. The proportion of other SM groups among IVT-treated patients did not change significantly. No sICH was detected in IVT-treated SM patients.

Machine Learning Algorithms Versus Thresholding to Segment Ischemic Regions in Patients With Acute Ischemic Stroke.

OBJECTIVE: Computed tomography (CT) scan is a fast and widely used modality for early assessment in patients with symptoms of a cerebral ischemic stroke. CT perfusion (CTP) is often added to the protocol and is used by radiologists for assessing the severity of the stroke. Standard parametric maps are calculated from the CTP datasets. Based on parametric value combinations, ischemic regions are separated into presumed infarct core (irreversibly damaged tissue) and penumbra (tissue-at-risk). Different thresholding approaches have been suggested to segment the parametric maps into these areas. The purpose of this study is to compare fully-automated methods based on machine learning and thresholding approaches to segment the hypoperfused regions in patients with ischemic stroke. METHODS: We test two different architectures with three mainstream machine learning algorithms. We use parametric maps as input features, and manual annotations made by two expert neuroradiologists as ground truth. RESULTS: The best results are produced with random forest (RF) and Single-Step approach; we achieve an average Dice coefficient of 0.68 and 0.26, respectively for penumbra and core, for the three groups analysed. We also achieve an average in volume difference of 25.1 ml for penumbra and 7.8 ml for core. CONCLUSIONS: Our best RF-based method outperforms the classical thresholding approaches, to segment both the ischemic regions in a group of patients regardless of the severity of vessel occlusion. SIGNIFICANCE: A correct visualization of the ischemic regions will guide treatment decisions better.

Headache and MRI Changes after Endovascular Treatment of a Cerebral Aneurysm.

BACKGROUND: The main complications after endovascular therapy of intracranial aneurysms are aneurysm rupture and thromboembolic events. Yet, the widespread use of magnetic resonance imaging (MRI) in follow-up of these patients also demonstrates other, rarely known complications such as aseptic meningitis and foreign body reaction. CASE PRESENTATION: A small aneurysm in the right posterior communicating artery was treated with endovascular therapy in a 65 year old woman. Two weeks after successful interventional treatment, the patient developed a headache. On MRI performed five months after intervention, vasogenic edema was seen in the vascular territory of the right internal carotid artery. The edema and the symptoms diminished without specific treatment within a year. INTERPRETATION: The clinical and radiological presentation of this case are suggestive of a foreign body reaction, a treatable condition that radiologists and clinicians should be aware of.