Journal of neuroimaging : official journal of the American Society of Neuroimaging
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Quantitative CT perfusion (CTP) thresholds for assessing the extent of ischemia in patients with acute ischemic stroke (AIS) have been established; relative cerebral blood flow (rCBF) <30% is typically used for estimating estimated ischemic core volume and Tmax (time to maximum) >6 seconds for critical hypoperfused volume in AIS patients with large vessel occlusion (LVO). In this study, we aimed to identify the optimal threshold values for patients presenting with AIS secondary to distal medium vessel occlusions (DMVOs). ⋯ In AIS patients with DMVOs, longer Tmax delays than Tmax > 6 seconds, most notably, Tmax > 10 seconds, best predict FIV in unsuccessfully recanalized patients. No CTP threshold reliably predicts FIV in the successfully recanalized group nor significantly outperformed rCBF < 30%.
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Neurologists in both the inpatient and outpatient settings are increasingly using ultrasound to diagnose and manage common neurological diseases. Advantages include cost-effectiveness, the lack of exposure to ionizing radiation, and the ability to perform at the bedside to provide real-time data. There is a growing body of literature that supports using ultrasonography to improve diagnostic accuracy and aid in performing procedures. ⋯ This includes neuromuscular diseases such as motor neuron disorders, focal neuropathies, and muscular dystrophy as well as vascular conditions such as stroke and vasospasm in subarachnoid hemorrhage. We also address ultrasound's use in critically ill patients to aid in identifying increased intracranial pressure, hemodynamics, and arterial and/or venous catheterization. Finally, we address the importance of standardized ultrasound curricula in trainee education and make recommendations for the future directions of research and competency guidelines within our specialty.
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Cerebral hypoperfusion has been described in both severe and mild forms of symptomatic Coronavirus Disease 2019 (COVID-19) infection. The purpose of this study was to investigate global and regional cerebral blood flow (CBF) in asymptomatic COVID-19 patients. ⋯ In this study, lower WM CBF, as well as widespread regional CBF changes identified using quantitative MRI, was found in mild COVID-19 patients. Further studies are needed to determine the reliability of this newly identified COVID-19 brain imaging marker and determine what drives these CBF changes.
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Several studies in the literature have attempted to subjectively assess the degree of visualization of different neurovascular structures using different contrast agents and concentrations. Given the recent contrast shortages, we aim to objectively compare the radiopacity achieved with four angiographic contrast agents used in clinical practice. ⋯ Isovue 370 provides the highest HU radiopacity and the most accurate aneurysm measurements. Angiographic measurements obtained with Isovue 300 may underestimate the actual aneurysmal dimensions. Visipaque 320 and Omnipaque 300 at 100% concentration have similar mean HUs and are beneficial for patients with chronic kidney or cardiac disease.
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Review
The role of brain perfusion SPECT in the diagnosis of frontotemporal dementia: A systematic review.
Frontotemporal dementia (FTD) is the second most common cause of presenile dementia. The clinical distinction between FTD, Alzheimer's disease (AD), and other dementias is a clinical challenge. Brain perfusion SPECT may contribute to the diagnosis of FTD, but its value is unclear. ⋯ Brain perfusion SPECT has a limited value in the diagnostic framework of FTD. SPECT can be performed when FDG-PET is not available. SPECT is recommended only for selected cases when the diagnosis is challenging using conventional methods.