Journal of neuroimaging : official journal of the American Society of Neuroimaging
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The significance of a bright vessel sign (BVS) at the site of a large vessel occlusion (LVO) on MR arterial spin labeling (ASL) sequence is not widely reported. We compared the utility of the ASL BVS to the gradient echo (GRE) susceptibility vessel sign (SVS) in heralding and localizing LVOs in a large cohort; most underwent digital subtraction angiography (DSA) and endovascular therapy for acute stroke. ⋯ ASL BVS is significantly more sensitive than GRE SVS for identification of LVO on both MRA and DSA.
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Randomized Controlled Trial
Tapentadol and oxycodone affect resting-state functional brain connectivity: A randomized, placebo-controlled trial.
The changes in functional brain connectivity induced by treatment with analgesics are poorly investigated. Unfortunately, results from clinical studies investigating treatments in patients with pain are often confounded by co-medication and comorbidity. Thalamus is central in sensory processing, and we hypothesized that functional connectivity between thalamus and other brain areas in healthy volunteers was different in treatment with oxycodone, representing a pure opioid, compared to treatment with tapentadol, which has a dual effect on the opioidergic and adrenergic systems. ⋯ This study has shown that the functional connectivity between thalamus and other brain areas central in pain processing was different for the tapentadol and oxycodone treatments compared to placebo. This supports that the two treatments exert different mechanism of action. Further studies with larger sample sizes need to be carried out in order to validate this.
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Dynamic contrast-enhanced MRI (DCE-MRI) can be employed to assess the blood-brain barrier (BBB) integrity. Detection of BBB leakage at lower field strengths (≤3T) is cumbersome as the signal is noisy, while leakage can be subtle. Utilizing the increased signal-to-noise ratio at higher field strengths, we explored the application of 7T DCE-MRI for assessing BBB leakage. ⋯ We demonstrate how a dual-time resolution DCE-MRI protocol at 7T, with administration of half the clinically used contrast agent dose, can be used for assessing subtle BBB leakage. Although the feasibility of DCE-MRI for assessing the BBB integrity at 3T is well known, we showed that a continuous sampling DCE-MRI method tailored for 7T is also capable of assessing leakage with a high sensitivity over a range of Ki values.
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Neurodegeneration of the substantia nigra in Lewy body disease is associated with iron deposition, which increases the magnetic susceptibility of the substantia nigra on MRI. Our objective was to measure iron deposition in the substantia nigra in patients with probable dementia with Lewy bodies (pDLB) and patients who are at risk for pDLB by quantitative susceptibility mapping (QSM). ⋯ Our data suggested that QSM is sensitive to the increased magnetic susceptibility due to higher iron content in the substantia nigra in pDLB. The trend of increasing susceptibility from controls to iRBD and MCI-LB, and to pDLB suggests that iron deposition in the substantia nigra starts to increase as early as the prodromal stage in DLB and continues to increase as the disease progresses, independent of parkinsonism severity.
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Observational Study
Intracranial dolichoectasia in patients with symptomatic intracranial atherosclerotic disease: Results from the MYRIAD study.
It is unknown whether intracranial atherosclerotic disease (ICAD), in addition to causing stenosis, also associates with abnormal arterial enlargement, a condition known as intracranial dolichoectasia (IDE). Across symptomatic ICAD patients, we aim to determine IDE prevalence and IDE impact on cerebral hemodynamics and recurrent cerebral ischemia. ⋯ IDE was common among symptomatic ICAD patients. IDE was not associated with stroke recurrence. Instead, increased diameter and tortuosity correlated with improved blood flow across the stenotic artery, suggesting that IDE may originate as an adaptive mechanism in ICAD.