Publications by authors named "Karl Olof Lovblad"

The possible authorisation of new monoclonal antibody therapies for Alzheimer's disease poses challenges for healthcare systems worldwide. In this paper, the Swiss Memory Clinics association (SMC) analyses the available resources and identifies potential health care shortages. Overcoming potential bottlenecks is a challenge that requires action at various levels.

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Background: Ultra-high-field magnetic resonance imaging (MRI) at a field strength of 7 Tesla (T) has marked a significant milestone in diagnostic imaging since it was approved for clinical use in 2017. Despite the potential to improve image analysis by advances in signal-to-noise ratio, and improved spatial resolution and metabolic imaging, the clinical implementation of 7-T MRI remains limited. Factors that contribute to this limited availability are the high price, the operating costs, the need for specifically educated personnel, and lack of evidence of clinical benefit.

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In the cerebral cortex, establishing the precise relationship between functional areas and the macroscopic anatomy of gyri and sulci has a paramount importance for the field of neuroimaging and neurosurgical interventions. The anatomical orientation should start with the identification of anatomical landmarks to set the anatomo-functional boundaries. The human central sulcus region stands out as a well-defined structural and functional unit housing the primary motor and sensory cortices and is considered as key region to be identified during brain surgery.

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Article Synopsis
  • The study investigates the use of contrast-enhanced cone beam CT (CE-CBCT) for better visualization of the distal part of clots during mechanical thrombectomy (MT) for ischemic strokes, as conventional imaging methods face challenges in this regard.!* -
  • Results showed that CE-CBCT significantly outperformed traditional imaging techniques like 3D rotational angiography (3DRA) and digital subtraction angiography (DSA) in visualizing the distal edges of clots and the arteries beyond the blockage.!* -
  • Enhanced visualization with CE-CBCT correlated with improved MT effectiveness, demonstrated by higher rates of successful clot removal and better collateral blood flow, indicating its potential value in stroke treatment.!*
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Functional connectivity patterns in the human brain, like the friction ridges of a fingerprint, can uniquely identify individuals. Does this "brain fingerprint" remain distinct even during Alzheimer's disease (AD)? Using fMRI data from healthy and pathologically ageing subjects, we find that individual functional connectivity profiles remain unique and highly heterogeneous during mild cognitive impairment and AD. However, the patterns that make individuals identifiable change with disease progression, revealing a reconfiguration of the brain fingerprint.

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Direct oral anticoagulants (DOACs) changed stroke prevention and decreased the risk of ischemic and hemorrhagic complications in patients on oral anticoagulation (OAC) therapy. The numbers of patients prescribed DOACs has increased rapidly. Availability of specific reversal agents opened new avenues in the prevention and management of DOAC complications.

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Background: Studies investigating endovascular therapy in vertebro-basilar stroke have led to controversial results in the past, but recent randomized trials seem to show an effectiveness superiority of endovascular therapy versus best medical treatment. However, uncertainty remains concerning many aspects of thrombectomy in acute basilar artery occlusion, notably technical considerations. This study compared the first-pass effect of direct thromboaspiration and combined thrombectomy in the setting of distal basilar occlusion.

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Article Synopsis
  • Arterial spin labeling (ASL) is a noninvasive imaging technique that shows promise for assessing arteriovenous malformations (AVMs) in both children and adults, with its own set of advantages and challenges.
  • While ASL effectively identifies feeder arteries and assesses blood flow, its performance may not always match that of traditional methods like digital subtraction angiography (DSA), particularly in visualizing venous drainage.
  • There are uncertainties regarding its sensitivity for certain AVM features, especially in complex locations, highlighting the need for larger studies to better understand ASL's diagnostic capabilities.
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Background: The identification of specific clot characteristics before mechanical thrombectomy (MTB) might allow the selection of the most effective first-line technique, thus potentially improving the procedural outcome. We aimed to evaluate if the microwire push forces could extrapolate information on clot consistency and extension before MTB, based on clot mechanical properties.

Methods: We measured in vitro the forces exerted on the proximal extremity of the guidewire during the advancement and retrieval of the guidewire through clot analogs of different compositions.

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Background: Mechanical thrombectomy using a double stent retriever technique has recently been described for the treatment of acute ischemic stroke, but its efficacy and safety are not well-established.

Purpose: The aim of this systematic review and meta-analysis was to evaluate reports of the use of a double stent retriever technique during the endovascular treatment of patients with ischemic stroke.

Data Sources: The PubMed, EMBASE, Web of Science, and Scopus databases were searched to identify all studies (clinical trials, cohort series, and case reports) investigating the utility of a double stent retriever technique for the treatment of stroke.

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Background: Despite numerous observations of neuropsychological deficits immediately following severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, little is known about what happens to these deficits over time and whether they are affected by changes in fatigue and any psychiatric symptoms. We aimed to assess the prevalence of neuropsychological deficits at 6-9 months and again at 12-15 months after coronavirus disease 2019 (COVID-19) and to explore whether it was associated with changes in fatigue and psychiatric symptoms.

Methods: We administered a series of neuropsychological tests and psychiatric questionnaires to 95 patients (mean age = 57.

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Objectives: Acute encephalopathy (AE) has been described as a severe complication of COVID-19. Inflammation has been suggested as a pathogenic mechanism, with high-dose glucocorticoids (GC) showing a beneficial effect. Here, we retrospectively analyzed the clinical and radiological features in a group of COVID-19 AE patients who received GC treatment (GT) and in a non-treated (NT) group.

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Purpose: Arterial spin labeling (ASL) represents a noninvasive perfusion biomarker, and, in the study of nonvascular disease, the use of the single-timepoint ASL technique is recommended. However, the obtained cerebral blood flow (CBF) maps may be highly influenced by delayed arterial transit time (ATT). Our aim was to assess the complexity of hemodynamic information of single-timepoint CBF maps using a new visual scale and comparing it with an ATT proxy, the "coefficient of spatial variation" (sCoV).

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Intracranial aneurysms (IAs) are usually incidentally discovered by magnetic resonance imaging (MRI). Once discovered, the risk associated with their treatment must be balanced with the risk of an unexpected rupture. Although clinical observations suggest that the detection of contrast agent in the aneurysm wall using a double-inversion recovery black-blood (BB) sequence may point to IA wall instability, the exact meaning of this observation is not understood.

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Article Synopsis
  • Cerebral small vessel disease (SVD) is a key cause of intracerebral hemorrhage (ICH), and researchers created a new MRI-based classification system, known as CADMUS, to categorize ICH subtypes associated with SVD.
  • A retrospective study analyzed data from two patient cohorts to classify ICH types based on MRI findings, assessing reliability and tracking subsequent strokes or hemorrhages.
  • The findings revealed a diverse distribution of ICH phenotypes among patients, with the CADMUS classification showing good reliability and potential for enhancing clinical and research practices in identifying SVD-related ICH types.
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Background: Focal vasospasm (FV) of the occluded vessel can occur during the endovascular treatment of acute ischemic stroke (AIS). Nimodipine is commonly used to treat vasospasm and can play a role in distinguishing it from artery narrowing due to iatrogenic dissection or residual clot. However, nimodipine administration can result in arterial hypotension and subsequent enlargement of the ischemic core.

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Background: This study evaluates the impact of high risk of obstructive sleep apnea (OSA) on coronavirus disease 2019 (COVID-19) acute encephalopathy (AE).

Methods: Between 3/1/2020 and 11/1/2021, 97 consecutive patients were evaluated at the Geneva University Hospitals with a neurological diagnosis of COVID-19 AE. They were divided in two groups depending on the presence or absence of high risk for OSA based on the modified NOSAS score (mNOSAS, respectively ≥ 8 and < 8).

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Alterations of the limbic system may be present in the chronic phase of SARS-CoV-2 infection. Our aim was to study the long-term impact of this disease on limbic system-related behaviour and its associated brain functional connectivity, according to the severity of respiratory symptoms in the acute phase. To this end, we investigated the multimodal emotion recognition abilities of 105 patients from the Geneva COVID-COG Cohort 223 days on average after SARS-CoV-2 infection (diagnosed between March 2020 and May 2021), dividing them into three groups (severe, moderate or mild) according to respiratory symptom severity in the acute phase.

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Background And Purpose: A mechanical thrombectomy technique using a double stent retriever approach has been reported for the treatment of patients with acute ischemic stroke. The purpose of this study was to perform a benchtop evaluation of the mechanism of action and efficacy of a double-stent retriever approach compared to a single-stent retriever approach.

Materials And Methods: In vitro, mechanical thrombectomy procedures were performed in a vascular phantom reproducing an M1-M2 occlusion with two different clot analog consistencies (soft and hard).

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In acute ischemic stroke, the composition of the occlusive clot can be associated with the underlying pathophysiology and the response to treatment. For these reasons, it is important to characterize the clot composition from clinical scans. We examine the ability of 3T and 7T MRI to distinguish the composition of in vitro clots, using quantitative T and T*, alternatively R*, mapping.

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Amyloid staging models showed that regional abnormality occurs before global positivity. Several studies assumed that the trajectory of amyloid spread is homogeneous, but clinical evidence suggests that it is highly heterogeneous. We tested whether different amyloid-β (Aβ) patterns exist by applying clustering on negative scans and investigating their demographics, clinical, cognitive, and biomarkers correlates, and cognitive trajectories.

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Background: Bilateral and simultaneous occlusion of the anterior circulation is a rare event in patients with acute ischemic stroke. Although endovascular treatment is feasible and safe, the endovascular strategy to be used remains a subject of debate.

Objective: To assess the different endovascular strategies proposed for the treatment of a bilateral, simultaneous anterior circulation occlusion following acute ischemic stroke.

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