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https://www.readbyqxmd.com/read/28345479/imaging-the-physiological-evolution-of-the-ischemic-penumbra-in-acute-ischemic-stroke
#1
Richard Leigh, Linda Knutsson, Jinyuan Zhou, Peter Cm van Zijl
We review the hemodynamic, metabolic and cellular parameters affected during early ischemia and their changes as a function of approximate cerebral blood flow ( CBF) thresholds. These parameters underlie the current practical definition of an ischemic penumbra, namely metabolically affected but still viable brain tissue. Such tissue is at risk of infarction under continuing conditions of reduced CBF, but can be rescued through timely intervention. This definition will be useful in clinical diagnosis only if imaging techniques exist that can rapidly, and with sufficient accuracy, visualize the existence of a mismatch between such a metabolically affected area and regions that have suffered cell depolarization...
January 1, 2017: Journal of Cerebral Blood Flow and Metabolism
https://www.readbyqxmd.com/read/28343848/capillary-dysfunction-is-associated-with-symptom-severity-and-neurodegeneration-in-alzheimer-s-disease
#2
Rune B Nielsen, Lærke Egefjord, Hugo Angleys, Kim Mouridsen, Michael Gejl, Arne Møller, Birgitte Brock, Hans Brændgaard, Hanne Gottrup, Jørgen Rungby, Simon F Eskildsen, Leif Østergaard
INTRODUCTION: We examined whether cortical microvascular blood volume and hemodynamics in Alzheimer's disease (AD) are consistent with tissue hypoxia and whether they correlate with cognitive performance and the degree of cortical thinning. METHODS: Thirty-two AD patients underwent cognitive testing, structural magnetic resonance imaging (MRI), and perfusion MRI at baseline and after 6 months. We measured cortical thickness, microvascular cerebral blood volume (CBV), cerebral blood flow (CBF), mean transit time (MTT), and capillary transit time heterogeneity (CTH) and estimated tissue oxygen tension (PtO2)...
March 23, 2017: Alzheimer's & Dementia: the Journal of the Alzheimer's Association
https://www.readbyqxmd.com/read/28339483/temporal-evolution-of-vasospasm-and-clinical-outcome-after-intra-arterial-vasodilator-therapy-in-patients-with-aneurysmal-subarachnoid-hemorrhage
#3
Laleh Daftari Besheli, Can Ozan Tan, Donnie L Bell, Joshua A Hirsch, Rajiv Gupta
Intra-arterial (IA) vasodilator therapy is one of the recommended treatments to minimize the impact of aneurysmal subarachnoid hemorrhage-induced cerebral vasospasm refractory to standard management. However, its usefulness and efficacy is not well established. We evaluated the effect IA vasodilator therapy on middle cerebral artery blood flow and on discharge outcome. We reviewed records for 115 adults admitted to Neurointensive Care Unit to test whether there was a difference in clinical outcome (discharge mRS) in those who received IA infusions...
2017: PloS One
https://www.readbyqxmd.com/read/28336779/validation-of-the-semi-quantitative-static-suvr-method-for-18-f-av45-pet-by-pharmacokinetic-modeling-with-an-arterial-input-function
#4
Julie Ottoy, Jeroen Verhaeghe, Ellis Niemantsverdriet, Leonie Wyffels, Charisse Somers, Ellen De Roeck, Hanne Struyfs, Femke Soetewey, Steven Deleye, Tobi Van den Bossche, Sara Van Mossevelde, Sarah Ceyssens, Jan Versijpt, Sigrid Stroobants, Sebastiaan Engelborghs, Steven Staelens
Increased brain uptake of [(18)F]-AV45 visualized by PET is a key biomarker for Alzheimer's disease (AD). The standardized uptake value ratio (SUVR) is widely used for quantification, but is subject to variability based on choice of reference region and changes in cerebral blood flow. Here we validate the SUVR method against the gold standard volume of distribution (VT) to assess cross-sectional differences in plaque load. Methods: Dynamic 60-min [(18)F]-AV45 (291 ± 67 MBq) and 1-min [(15)O]-H2O (370 MBq) scans were obtained in 35 age-matched elderly subjects, including 10 probable AD dementia, 15 amnestic mild cognitive impairment (aMCI) and 10 cognitively healthy controls (HC)...
March 23, 2017: Journal of Nuclear Medicine: Official Publication, Society of Nuclear Medicine
https://www.readbyqxmd.com/read/28335828/dha-brain-uptake-and-apoe4-status-a-pet-study-with-1-11-c-dha
#5
Hussein N Yassine, Etienne Croteau, Varun Rawat, Joseph R Hibbeln, Stanley I Rapoport, Stephen C Cunnane, John C Umhau
BACKGROUND: The apolipoprotein E ɛ4 (APOE4) allele is the strongest genetic risk factor identified for developing Alzheimer's disease (AD). Among brain lipids, alteration in the ω-3 polyunsaturated fatty acid docosahexaenoic acid (DHA) homeostasis is implicated in AD pathogenesis. APOE4 may influence both brain DHA metabolism and cognitive outcomes. METHODS: Using positron emission tomography, regional incorporation coefficients (k*), rates of DHA incorporation from plasma into the brain using [1-(11)C]-DHA (J in), and regional cerebral blood flow using [(15)O]-water were measured in 22 middle-aged healthy adults (mean age 35 years, range 19-65 years)...
March 23, 2017: Alzheimer's Research & Therapy
https://www.readbyqxmd.com/read/28335662/performance-of-computed-tomography-angiography-to-determine-anterograde-and-collateral-blood-flow-status-in-patients-with-symptomatic-middle-cerebral-artery-stenosis
#6
Baixue Jia, David S Liebeskind, Ligang Song, Xiaotong Xu, Xuan Sun, Lian Liu, Bo Wang, Zhongrong Miao
Background The purpose of this study was to determine the performance of computed tomography angiography (CTA) by using a scoring system to predict anterograde and collateral blood flow status in patients with symptomatic middle cerebral artery (MCA) stenosis with use of conventional angiography as standard reference. Methods We retrospectively identified all consecutive patients with unilateral symptomatic MCA stenosis in our center who underwent conventional angiography and CTA within 1 month. The anterograde and collateral blood flow (AnCo) scoring system consisted of anterograde score (AnS) and collateral score (CoS)...
January 1, 2017: Interventional Neuroradiology
https://www.readbyqxmd.com/read/28334813/construction-of-ductal-diameter-centiles-in-the-first-24%C3%A2-h-of-life-and-their-relation-to-cerebral-blood-flow-in-neonates-weighing-less-than-1250%C3%A2-g-in-the-first-24%C3%A2-h-of-life
#7
Sunil Pawar, Deepak Sharma, Srinivas Murki, Sreeram Subramaniam, Hemashree Kandraju
Aims and objectives: To evaluate the ductal diameter centiles in the first 24 h of life and their relation to cerebral blood flow in neonates weighing <1250 g in the first 24 h of life. Method and material: This prospective observational cohort study enrolled 44 infants with birth weight <1250 g. Two-dimensional echocardiography and color Doppler were performed within the first 12 h of life and were repeated again in the next 12 h of life to assess the ductal size and middle cerebral artery (MCA) flows [peak systolic velocity (PSV), end diastolic velocity (EDV), mean velocity (MV) and pulsatility index (PI)]...
March 13, 2017: Journal of Tropical Pediatrics
https://www.readbyqxmd.com/read/28328241/perfusion-ct-in-acute-stroke-effectiveness-of-automatically-generated-colour-maps
#8
Maja Ukmar, Ferruccio Degrassi, Roberta Antea Pozzi Mucelli, Francesca Neri, Fabio Pozzi Mucelli, Maria Assunta Cova
OBJECTIVE: To evaluate the accuracy of perfusion CT (pCT) in the definition of the infarcted core and the penumbra, comparing the data obtained from the evaluation of parametric maps [cerebral blood volume (CBV), cerebral blood flow (CBF) and mean transit time (MTT)] with software-generated colour maps. METHODS: A retrospective analysis was performed to identify patients with suspected acute ischaemic strokes and who had undergone unenhanced CT and pCT carried out within 4...
April 2017: British Journal of Radiology
https://www.readbyqxmd.com/read/28326436/reference-region-selection-and-the-association-between-the-rate-of-amyloid-accumulation-over-time-and-the-baseline-amyloid-burden
#9
Janusch Blautzik, Matthias Brendel, Julia Sauerbeck, Sebastian Kotz, Franziska Scheiwein, Peter Bartenstein, John Seibyl, Axel Rominger
Relative quantitative analysis of amyloid plaque burden in Alzheimer's disease (AD) patients can be reported as standardized uptake value ratio (SUVR) from positron emission tomography (PET). Here, the SUVR is the ratio of the mean amyloid radioligand retention in a composite (COMP) neocortical volume of interest (VOI) to that in a reference VOI, such as the cerebellum, brainstem (BST)/pons, or white matter (WM). Some longitudinal PET investigations show that the rate of amyloid accumulation to follow-up has an inverted U relationship with baseline amyloid SUVR relative to cerebellar or brainstem/pons reference VOIs...
March 22, 2017: European Journal of Nuclear Medicine and Molecular Imaging
https://www.readbyqxmd.com/read/28325558/l-citrulline-ameliorates-cerebral-blood-flow-during-cortical-spreading-depression-in-rats-involvement-of-nitric-oxide-and-prostanoids-mediated-pathway
#10
Yuki Kurauchi, Koichi Mokudai, Asami Mori, Kenji Sakamoto, Tsutomu Nakahara, Masahiko Morita, Ayako Kamimura, Kunio Ishii
l-Citrulline is a potent precursor of l-arginine, and exerts beneficial effect on cardiovascular system via nitric oxide (NO) production. Migraine is one of the most popular neurovascular disorder, and imbalance of cerebral blood flow (CBF) observed in cortical spreading depression (CSD) contributes to the mechanism of migraine aura. Here, we investigated the effect of l-citrulline on cardiovascular changes to KCl-induced CSD. in rats. Intravenous injection of l-citrulline prevented the decrease in CBF, monitored by laser Doppler flowmetry, without affecting mean arterial pressure and heart rate during CSD...
February 17, 2017: Journal of Pharmacological Sciences
https://www.readbyqxmd.com/read/28323181/perioperative-changes-in-cerebral-perfusion-territories-assessed-by-arterial-spin-labeling-magnetic-resonance-imaging-are-associated-with-postoperative-increases-in-cerebral-blood-flow-in-patients-with-carotid-stenosis
#11
Daisuke Yamamoto, Kohkichi Hosoda, Yoshito Uchihashi, Atsushi Fujita, Takashi Sasayama, Masahiko Fujii, Kazuro Sugimura, Masaaki Kohta, Eiji Kohmura
OBJECTIVE: MRI technique known as Territorial ASL (TASL) allows for noninvasive visualization of their perfusion territories. The objective of this study was to use TASL to assess the relationship between perioperative changes in the perfusion territories of ICA and CBF after carotid revascularization. METHODS: In 32 patients, ICA perfusion volume (PV) and CBF were measured before and after CEA/CAS using TASL and SPECT, respectively. ICA flow was measured during CEA before and after reconstruction, using an electromagnetic flowmeter...
March 16, 2017: World Neurosurgery
https://www.readbyqxmd.com/read/28320141/functional-magnetic-resonance-imaging-responses-in-cadasil
#12
Ikreet Cheema, Aaron R Switzer, Cheryl R McCreary, Michael D Hill, Richard Frayne, Bradley G Goodyear, Eric E Smith
OBJECTIVES: The magnitude of the blood oxygen dependent level (BOLD) functional MRI (fMRI) response to visual stimulation is reduced in the small vessel disease cerebral amyloid angiopathy (CAA), reflecting impaired vascular reactivity. We determined whether BOLD responses were reduced in another small vessel disease, cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL). METHODS: BOLD fMRI data were collected using a visual stimulus (contrast-reversing checkerboard) and motor task (finger-tapping)...
April 15, 2017: Journal of the Neurological Sciences
https://www.readbyqxmd.com/read/28314624/cerebral-white-matter-hypoperfusion-increases-with-small-vessel-disease-burden-data-from-the-third-international-stroke-trial
#13
Francesco Arba, Grant Mair, Trevor Carpenter, Eleni Sakka, Peter A G Sandercock, Richard I Lindley, Domenico Inzitari, Joanna M Wardlaw
BACKGROUND: Leukoaraiosis is associated with impaired cerebral perfusion, but the effect of individual and combined small-vessel disease (SVD) features on white matter perfusion is unclear. METHODS: We studied patients recruited with perfusion imaging in the Third International Stroke Trial. We rated individual SVD features (leukoaraiosis, lacunes) and brain atrophy on baseline plain computed tomography or magnetic resonance imaging. Separately, we assessed white matter at the level of the lateral ventricles in the cerebral hemisphere contralateral to the stroke for visible areas of hypoperfusion (present or absent) on 4 time-based perfusion imaging parameters...
March 14, 2017: Journal of Stroke and Cerebrovascular Diseases: the Official Journal of National Stroke Association
https://www.readbyqxmd.com/read/28306210/benchmarking-transverse-spin-relaxation-based-oxygenation-measurements-in-the-brain-during-hypercapnia-and-hypoxia
#14
Wendy W Ni, Thomas Christen, Greg Zaharchuk
PURPOSE: To simultaneously assess reproducibility of three MRI transverse relaxation parameters ( R2', R2*, and R2 ) for brain tissue oxygenation mapping and to assess changes in these parameters with inhalation of gases that increase and decrease oxygenation, to identify the most sensitive parameter for imaging brain oxygenation. MATERIALS AND METHODS: Forty-eight healthy subjects (25 male, ages 35 ± 8 years) were scanned at 3.0 Tesla, each with one of four gases (mildly and strongly hypercapnic and hypoxic) administered in a challenge paradigm, using a gas delivery setup designed for patient use...
March 17, 2017: Journal of Magnetic Resonance Imaging: JMRI
https://www.readbyqxmd.com/read/28302764/-18-f-gp1-a-novel-fluorine-18-labeled-tracer-designed-for-pet-imaging-of-thrombi-with-high-detection-sensitivity-and-low-background
#15
Jessica Lohrke, Holger Siebeneicher, Markus Berger, Michael Reinhardt, Mathias Berndt, Andre Mueller, Marion Zerna, Norman Koglin, Felix Oden, Marcus Bauser, Matthias Friebe, Ludger M Dinkelborg, Joachim Huetter, Andrew W Stephens
Thromboembolic diseases such as myocardial infarction, stroke, transient ischemic attacks and pulmonary embolism are major causes of morbidity and mortality worldwide. GPIIb/IIIa is the key receptor involved in platelet aggregation and is a validated target for therapeutic approaches and diagnostic imaging. The aim of this study was to develop and characterize a specific small molecule tracer for positron emission tomography (PET) imaging that binds with high affinity to GPIIb/IIIa receptors and has suitable pharmacokinetic properties to overcome limitations of previous approaches...
March 16, 2017: Journal of Nuclear Medicine: Official Publication, Society of Nuclear Medicine
https://www.readbyqxmd.com/read/28298706/an-assessment-of-fetal-cerebral-and-hepatic-perfusion-in-normal-pregnancy-and-pre-eclampsia-using-three-dimensional-ultrasound
#16
Susan Addley, Amanda Ali, Stephen Ong
BACKGROUND: Pre-eclampsia and placental causes of intrauterine growth restriction (IUGR) are part of the same spectrum of disorders. In IUGR, there is preferential shunting of blood to the fetal brain at the expense of other organs. We wanted to demonstrate that this also occurs in pre-eclampsia using three dimensional (3D) ultrasound. The 3D indices of perfusion are: flow index (FI), vascular index (VI) and vascularisation flow index (VFI) which reflect tissue vascularity and flow intensity...
January 2017: Ulster Medical Journal
https://www.readbyqxmd.com/read/28295523/quantitative-susceptibility-mapping-based-cerebral-metabolic-rate-of-oxygen-mapping-with-minimum-local-variance
#17
Jingwei Zhang, Junghun Cho, Dong Zhou, Thanh D Nguyen, Pascal Spincemaille, Ajay Gupta, Yi Wang
PURPOSE: The objective of this study was to demonstrate the feasibility of a cerebral metabolic rate of oxygen (CMRO2 ) mapping method based on its minimum local variance (MLV) without vascular challenge using quantitative susceptibility mapping (QSM) and cerebral blood flow (CBF). METHODS: Three-dimensional multi-echo gradient echo imaging and arterial spin labeling were performed in 11 healthy subjects to calculate QSM and CBF. Minimum local variance was used to compute whole-brain CMRO2 map from QSM and CBF...
March 10, 2017: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/28293809/a-mesenteric-traction-syndrome-affects-near-infrared-spectroscopy-evaluated-cerebral-oxygenation-because-skin-blood-flow-increases
#18
Niels D Olesen, Henrik Sørensen, Rikard Ambrus, Lars B Svendsen, Anton Lund, Niels H Secher
During abdominal surgery manipulation of internal organs may induce a "mesenteric traction syndrome" (MTS) including a triad of flushing, hypotension, and tachycardia that lasts for about 30 min. We evaluated whether MTS affects near-infrared spectroscopy (NIRS) assessed frontal lobe oxygenation (ScO2) by an increase in forehead skin blood flow (SkBF). The study intended to include 10 patients who developed MTS during pancreaticoduodenectomy and 22 patients were enrolled (age 61 ± 8 years; mean ± SD)...
March 14, 2017: Journal of Clinical Monitoring and Computing
https://www.readbyqxmd.com/read/28292870/regional-comparison-of-multiphase-computed-tomographic-angiography-and-computed-tomographic-perfusion-for-prediction-of-tissue-fate-in-ischemic-stroke
#19
Christopher D d'Esterre, Anurag Trivedi, Pooneh Pordeli, Mari Boesen, Shivanand Patil, Seong Hwan Ahn, Mohamed Najm, Enrico Fainardi, Jai Jai Shiva Shankar, Marta Rubiera, Mohammed A Almekhlafi, Jennifer Mandzia, Alexander V Khaw, Philip Barber, Shelagh Coutts, Michael D Hill, Andrew M Demchuk, Tolulope Sajobi, Nils D Forkert, Mayank Goyal, Ting-Yim Lee, Bijoy K Menon
BACKGROUND AND PURPOSE: Within different brain regions, we determine the comparative value of multiphase computed tomographic angiography (mCTA) and computed tomographic perfusion (CTP) in predicting follow-up infarction. METHODS: Patients with M1-middle cerebral artery occlusions were prospectively included in this multicenter study. Regional analysis was performed for each patient within Alberta Stroke Program Early CT Score regions M2 to M6. Regional pial vessel filling was assessed on mCTA in 3 ways: (1) Washout of contrast within pial vessels; (2) Extent of maximal pial vessel enhancement compared with contralateral hemisphere; (3) Delay in maximal pial vessel enhancement compared with contralateral hemisphere...
April 2017: Stroke; a Journal of Cerebral Circulation
https://www.readbyqxmd.com/read/28287282/cerebrovascular-reactivity-in-acute-hyperoxia-in-patients-with-acute-ischaemic-stroke
#20
Ivana Hegeduš, Jakov Milić, Anita Ćosić, Krunoslav Buljan, Ines Drenjančević
AIM: This study aimed to assess the effect of acute hyperoxia on cerebral and systemic heamodynamics and the plasma concentration of prostacyclin and thromboxane in patients with stroke. METHODS: Mean blood flow velocity (MBFV), pulsatility and resistance indices of the middle cerebral artery using transcranial Doppler ultrasound before and during acute hyperoxia (4 L of 100%O2/15' over facial mask) in 92 participants - 25 patients with acute ischaemic stroke (AIS) that occurred within 72 hours and diabetes mellitus (SPDM), 26 AIS patients without DM (SP) and in 41 healthy controls (HS), were measured...
March 13, 2017: Brain Injury: [BI]
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