Journal of neuroimaging : official journal of the American Society of Neuroimaging
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Comparative Study Observational Study
Correction for Susceptibility Distortions Increases the Performance of Arterial Spin Labeling in Patients with Cerebrovascular Disease.
Arterial spin labeling (ASL) is an MRI technique to measure cerebral blood flow (CBF) without the need of exogenous contrast agents and is thus a promising alternative to the clinical standard dynamic susceptibility-weighted contrast-enhanced (DSC) perfusion imaging. Latest international guidelines encourage its application in the clinical setting. However, susceptibility-induced image distortions impair ASL with fast readout modules (eg Echo Planar Imaging, EPI; gradient and spin echo, GRASE). In the present study, we investigated the benefit of a distortion correction for ASL compared to DSC. ⋯ We showed that susceptibility distortion correction strongly improves the comparability of multi-TI ASL 3D-GRASE to DSC in steno-occlusive disease. We suggest it to be implemented in ASL postprocessing routines.
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Pulsatility index (PI) of the middle cerebral artery is postulated to reflect the vascular resistance in the artery distal of the probe, and has been reported to increase in small vessel disease, diabetes mellitus, ageing, and dementia. Lacunar infarcts are considered to be related to cognitive impairment. We therefore conducted a study to assess the association between cognitive impairment and PI in patients with a lacunar infarct. ⋯ PI was associated with the cognitive performance in patients with lacunar infarcts and a lacunar syndrome. An elevated PI may be related to impairment in several cognitive domains. These findings suggest that transcranial Doppler ultrasonography could be an adjunct tool for early diagnosis of cognitive impairment after stroke.
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Case Reports
Performance of CT Angiography on a Mobile Stroke Treatment Unit: Implications for Triage.
There is a strong inverse relationship between outcome in patients with acute ischemic stroke from emergent large vessel occlusion (ELVO), and time to reperfusion from intra-arterial therapy. Delay in transferring patients to thrombectomy-capable centers is currently a major limitation. The mobile stroke unit (MSU) concept with onboard portable computed tomography (CT) scanner enables rapid performance of CT angiography (CTA) of the intracranial vessels to detect ELVO in the field, and allows for rapid triage of patients to interventional-capable centers. ⋯ CTA is possible on an MSTU, enabling rapid detection and triage of ELVO cases directly to thrombectomy-capable centers, which significantly reduces time to endovascular treatment.
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Comparative Study
The Effect of Endogenous Adenosine on Neuronal Activity in Rats: An FDG PET Study.
2-(18) F-fluorodeoxy-D-glucose (FDG) is a glucose analog that is taken up by cells and phosphorylated. The amount of FDG accumulated by cells is a measure of the rate of glycolysis, which reflects cellular activity. As the levels and actions of the neuromodulator adenosine are dynamically regulated by neuronal activity, this study was designed to test whether endogenous adenosine affects tissue accumulation of FDG as assessed by positron emission tomography (PET) or by postmortem analysis of tissue radioactivity. ⋯ Whole-brain FDG uptake was not affected by drug treatment. Significant regional hypometabolism was detected, particularly in cerebellum, of DPCPX- and ABT-702 treated rats, relative to vehicle-treated rats. Thus, endogenous adenosine can affect FDG accumulation although this effect is modest in quiescent rats.
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The additional information that transcranial Doppler (TCD) can provide as part of a multimodal imaging stroke protocol in the setting of hyper acute strokes has not been evaluated. ⋯ TCD in the first 4.5 hours of acute ischemia can provide additional information to a multimodal acute ischemic stroke imaging protocol, and can induce changes in the management of a proportion of these patients.