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https://www.readbyqxmd.com/read/28821628/frontline-adapt-therapy-to-treat-patients-with-symptomatic-m2-and-m3-occlusions-in-acute-ischemic-stroke-initial-experience-with-the-penumbra-ace-and-3max-reperfusion-system
#1
Jens Altenbernd, Oliver Kuhnt, Svenja Hennigs, Ruediger Hilker, Christian Loehr
BACKGROUND: After a series of positive studies for mechanical thrombectomy in large vessel occlusion acute ischemic stroke, the question remains, can symptomatic patients with distal vessel occlusion benefit from mechanical thrombectomy? PURPOSE: To assess the safety and efficacy of the 3MAX reperfusion system as frontline therapy for M2 and M3 occlusions. METHODS: This study retrospectively collected data on 58 patients treated for M2 and M3 occlusions between January and September 2016...
August 18, 2017: Journal of Neurointerventional Surgery
https://www.readbyqxmd.com/read/28815994/imrt-qa-using-machine-learning-a-multi-institutional-validation
#2
Gilmer Valdes, Maria F Chan, Seng Boh Lim, Ryan Scheuermann, Joseph O Deasy, Timothy D Solberg
PURPOSE: To validate a machine learning approach to Virtual intensity-modulated radiation therapy (IMRT) quality assurance (QA) for accurately predicting gamma passing rates using different measurement approaches at different institutions. METHODS: A Virtual IMRT QA framework was previously developed using a machine learning algorithm based on 498 IMRT plans, in which QA measurements were performed using diode-array detectors and a 3%local/3 mm with 10% threshold at Institution 1...
August 17, 2017: Journal of Applied Clinical Medical Physics
https://www.readbyqxmd.com/read/28790886/molecular-bases-of-brain-preconditioning
#3
Oleg G Deryagin, Svetlana A Gavrilova, Khalil L Gainutdinov, Anna V Golubeva, Vyatcheslav V Andrianov, Guzel G Yafarova, Sergey V Buravkov, Vladimir B Koshelev
Preconditioning of the brain induces tolerance to the damaging effects of ischemia and prevents cell death in ischemic penumbra. The development of this phenomenon is mediated by mitochondrial adenosine triphosphate-sensitive potassium ([Formula: see text]) channels and nitric oxide signaling (NO). The aim of this study was to investigate the dynamics of molecular changes in mitochondria after ischemic preconditioning (IP) and the effect of pharmacological preconditioning (PhP) with the [Formula: see text]-channels opener diazoxide on NO levels after ischemic stroke in rats...
2017: Frontiers in Neuroscience
https://www.readbyqxmd.com/read/28777469/a-method-for-a-priori-estimation-of-best-feasible-dvh-for-organs-at-risk-validation-for-head-and-neck-vmat-planning
#4
Saeed Ahmed, Benjamin Nelms, Dawn Gintz, Jimmy Caudell, Geoffrey Zhang, Eduardo G Moros, Vladimir Feygelman
PURPOSE: Despite improvements in optimization and automation algorithms, the quality of radiation treatment plans still varies dramatically. A tool that allows a priori estimation of the best possible sparing (Feasibility DVH, or FDVH) of an organ at risk (OAR) in high-energy photon planning may help reduce plan quality variability by deriving patient-specific OAR goals prior to optimization. Such a tool may be useful for 1) meaningfully evaluating patient-specific plan quality and 2) supplying best theoretically achievable DVH goals, thus pushing the solution towards automatic Pareto-optimality...
August 4, 2017: Medical Physics
https://www.readbyqxmd.com/read/28776652/trauma-innocence-and-the-core-complex-of-dissociation
#5
Donald E Kalsched
Trauma survivors often lament that they have lost their innocence or lost their souls and that something vulnerable and whole about themselves has been 'broken' or annihilated. Yet when the psychotherapeutic relationship begins, and symbolic material from dreams and the transference emerges, discernible patterns become apparent, indicating that a core of innocence and vitality has not been totally lost or annihilated. On the contrary, it has been 'saved' by dissociation and its system of inner objects and their protective and/or persecutory narrative 'scripts' or 'schemas'...
September 2017: Journal of Analytical Psychology
https://www.readbyqxmd.com/read/28767503/neuroendovascular-surgery-for-the-treatment-of-ischemic-stroke
#6
Arthur Wang, Meic H Schmidt
This review discusses modern therapeutic interventions for acute ischemic stroke with a focus on endovascular therapy. In 2015, the American Heart Association (AHA) made major changes to the guidelines for the endovascular treatment of acute ischemic stroke. The Class IA indications for endovascular therapy of stroke patients include symptom onset within 6 hours, proven large vessel occlusion of an artery in the anterior circulation, and the use of a stent retriever as part of the mechanical thrombectomy. Advanced perfusion imaging helps identify patients with a low ratio of ischemic core to salvageable penumbra...
June 22, 2017: Cardiology in Review
https://www.readbyqxmd.com/read/28761391/the-accuracy-of-treatment-planning-system-dose-modelling-in-the-presence-of-brass-mesh-bolus
#7
Neil Richmond
AIM: This work assesses the dosimetric accuracy of three commercial treatment planning system (TPS) photon dose calculation algorithms in the presence of brass mesh used as a bolus. BACKGROUND: Bolus material is used in radiotherapy to provide dose build-up where superficial tissues require irradiation. They are generally water equivalent but high density materials can also be used. MATERIALS AND METHODS: Dose calculations were performed on Monaco and Masterplan TPS (Elekta AB, Sweden) using phantoms defined by the three DICOM CT image sets of water equivalent blocks (no bolus, 1 layer and 2 layers of brass mesh) exported from the CT scanner...
September 2017: Reports of Practical Oncology and Radiotherapy
https://www.readbyqxmd.com/read/28752790/ph-imaging-reveals-worsened-tissue-acidification-in-diffusion-kurtosis-lesion-than-the-kurtosis-diffusion-lesion-mismatch-in-an-animal-model-of-acute-stroke
#8
Enfeng Wang, Yin Wu, Jerry S Cheung, Iris Yuwen Zhou, Takahiro Igarashi, XiaoAn Zhang, Phillip Zhe Sun
Diffusion weighted imaging (DWI) has been commonly used in acute stroke examination, yet a portion of DWI lesion may be salvageable. Recently, it has been shown that diffusion kurtosis imaging (DKI) defines the most severely damaged DWI lesion that does not renormalize following early reperfusion. We postulated that the diffusion and kurtosis lesion mismatch experience heterogeneous hemodynamic and/or metabolic injury. We investigated tissue perfusion, pH, diffusion, kurtosis and relaxation from regions of the contralateral normal area, diffusion lesion, kurtosis lesion and their mismatch in an animal model of acute stroke...
January 1, 2017: Journal of Cerebral Blood Flow and Metabolism
https://www.readbyqxmd.com/read/28752507/intravenous-alteplase-for-acute-ischemic-stroke-in-taiwan-can-we-expand-the-national-health-insurance-s-reimbursement-criteria
#9
Cheng-Yang Hsieh
lization of intravenous thrombolysis with alteplase was very low in Taiwanese patients with acute ischemic stroke(1). One of the reasons is the strict reimbursement guideline made by the Bureau of National Health Insurance (NHI) in 2004(2). In this issue of the Acta Neurologica Taiwanica, Yu-Hsiang Su and co-authors(3) retrospectively evaluated outcomes of their thrombolysed stroke patients who were "mismatched" between updated clinical practice guideline and NHI reimbursement criteria. They concluded that the outcomes of patients treated according to guidelines were comparable between the reimbursement and non-reimbursement groups...
March 15, 2017: Acta Neurologica Taiwanica
https://www.readbyqxmd.com/read/28751692/ct-perfusion-stroke-imaging-a-threshold-free-probabilistic-approach-to-predict-infarct-volume-compared-to-traditional-ischemic-thresholds
#10
Fabian Flottmann, Gabriel Broocks, Tobias Djamsched Faizy, Marielle Ernst, Nils Daniel Forkert, Malte Grosser, Götz Thomalla, Susanne Siemonsen, Jens Fiehler, André Kemmling
The aim was to evaluate a novel method of threshold-free prediction of brain infarct from computed tomography perfusion (CTP) imaging in comparison to conventional ischemic thresholds. In a multicenter cohort of 161 patients with acute large vessel occlusion who received endovascular therapy, brain infarction was predicted by CTP using (1) optimized parameter cut-off values determined by ROC curve analysis and (2) probabilistic logistic regression threshold-free analysis. Predicted infarct volumes and prediction errors based on four perfusion parameter maps were compared against observed infarcts...
July 27, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28749373/dosimetric-evaluation-of-a-commercial-proton-spot-scanning-monte-carlo-dose-algorithm-comparisons-against-measurements-and-simulations
#11
Jatinder Saini, Dominic Maes, Alexander Egan, Stephen R Bowen, Sara St James, Martin Janson, Tony Wong, Charles Bloch
RaySearch Americas Inc. (NY) has introduced a commercial Monte Carlo dose algorithm (RS-MC) for routine clinical use in proton spot scanning. In this report, we provide a validation of this algorithm against phantom measurements and simulations in GATE/GEANT4 software package. We also compared the performance of RayStation analytical algorithm (RS-PBA) against the RS-MC algorithm. Methods: A beam model (G-MC) for spot scanning gantry at our proton center was implemented in the GATE software package. The model was validated against measurements in a water phantom and was used for benchmarking the RS-MC...
July 27, 2017: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/28738724/neighbor-effect-penumbra-dose-exposed-neighbor-cells-contribute-to-the-enhanced-survival-of-high-dose-targeted-cells
#12
Min-Ho Lee, Ki-Man Lee, Eun-Hee Kim
PURPOSE: In the last decade, new types of 'bystander effect' have been suggested by multiple research groups and have been challenged by others. In this study, we explored a new type of bystander effect, which has been defined in previous studies as the enhancement of the survival of high-dose targeted cells due to the penumbra-dose exposed neighbor cells. Intensity-modulated radiation therapy, which is the most widely used treatment modality, generates local regions of gradient doses between targeted and shielded cells throughout the treatment volume; therefore, we were urged to ascertain whether the new type of effect is real and to suggest a revised treatment planning...
August 16, 2017: International Journal of Radiation Biology
https://www.readbyqxmd.com/read/28736809/dose-evaluation-of-grid-therapy-using-a-6-mv-flattening-filter-free-fff-photon-beam-a-monte-carlo-study
#13
Immaculada Martínez-Rovira, Josep Puxeu, Yolanda Prezado
PURPOSE: Spatially fractionated radiotherapy is a strategy to overcome the main limitation of radiotherapy, i.e., the restrained normal tissue tolerances. A well-known example is Grid Therapy, which is currently performed at some hospitals using megavoltage photon beams delivered by Linacs. Grid Therapy has been successfully used in the management of bulky abdominal tumors with low toxicity. The aim of this work is to evaluate whether an improvement in therapeutic index in Grid Therapy can be obtained by implementing it in a flattening filter-free (FFF) Linac...
July 24, 2017: Medical Physics
https://www.readbyqxmd.com/read/28730951/penumbra-and-re-canalization-acute-computed-tomography-in-ischemic-stroke-evaluation-practise-study-protocol
#14
Salwa El-Tawil, Joanna Wardlaw, Ian Ford, Grant Mair, Tom Robinson, Lalit Kalra, Keith W Muir
Rationale Multimodal imaging, including computed tomography angiography and computed tomography perfusion imaging, yields additional information on intracranial vessels and brain perfusion and can differentiate between ischemic core and penumbra which may affect patient selection for intravenous thrombolysis. Hypothesis The use of multimodal imaging will increase the number of patients receiving intravenous thrombolysis and lead to better treatment outcomes. Sample size 400 patients. Methods and design PRACTISE is a prospective, multicenter, randomized, controlled trial in which patients presenting within 4...
August 2017: International Journal of Stroke: Official Journal of the International Stroke Society
https://www.readbyqxmd.com/read/28727355/-perfusion-imaging-of-acute-ischemic-stroke
#15
Carlo W Cereda, Patrik Michel, Karl-Olof Lovblad, Emmanuel Carrera
Multi-modal imaging in acute ischemic stroke includes structural imaging, perfusion imaging and angiographic assessment of brain arteries. Perfusion imaging discriminates brain tissue that is critically hypo-perfused but salvageable (ischemic penumbra) from irreversibly injured tissue (ischemic core). In acute reperfusion therapies (intravenous or endovascular), patients who have substantial penumbra and a small core (target mismatch pattern) are most likely to have a good clinical outcome. Patient selection based on multi-modal imaging is not proven mandatory for acute treatment in patients admitted within the established time-window...
April 26, 2017: Revue Médicale Suisse
https://www.readbyqxmd.com/read/28727192/current-evidence-for-endovascular-therapy-in-stroke-and-remaining-uncertainties-r1
#16
REVIEW
Ronan Motyer, Hamed Asadi, John Thornton, Patrick Nicholson, Hong Kuan Kok
Class 1 level A evidence now supports endovascular thrombectomy as best practice in the management of large vessel occlusion acute ischemic stroke. However, significant questions pertaining to initial imaging, radiological assessment, patient selection and therapeutic limits remain unanswered. A specific cohort of patients who benefit from endovascular thrombectomy has been established, although current uncertainties regarding selection of those not meeting top-tier evidence criteria may potentially deny certain patients the benefit of intervention...
July 20, 2017: Journal of Internal Medicine
https://www.readbyqxmd.com/read/28725211/critical-evaluation-of-the-lund-concept-for-treatment-of-severe-traumatic-head-injury-25%C3%A2-years-after-its-introduction
#17
REVIEW
Per-Olof Grände
When introduced in 1992, the Lund concept (LC) was the first complete guideline for treatment of severe traumatic brain injury (s-TBI). It was a theoretical approach, based mainly on general physiological principles-i.e., of brain volume control and optimization of brain perfusion and oxygenation of the penumbra zone. The concept gave relatively strict outlines for cerebral perfusion pressure, fluid therapy, ventilation, sedation, nutrition, the use of vasopressors, and osmotherapy. The LC strives for treatment of the pathophysiological mechanisms behind symptoms rather than just treating the symptoms...
2017: Frontiers in Neurology
https://www.readbyqxmd.com/read/28717436/endovascular-management-of-chronic-internal-carotid-occlusion-with-penumbra-system
#18
Masoud Mehrpour
No abstract text is available yet for this article.
January 5, 2017: Iranian Journal of Neurology
https://www.readbyqxmd.com/read/28717354/blood-pressure-and-penumbral-sustenance-in-stroke-from-large-vessel-occlusion
#19
REVIEW
Robert W Regenhardt, Alvin S Das, Christopher J Stapleton, Ronil V Chandra, James D Rabinov, Aman B Patel, Joshua A Hirsch, Thabele M Leslie-Mazwi
The global burden of stroke remains high, and of the various subtypes of stroke, large vessel occlusions (LVOs) account for the largest proportion of stroke-related death and disability. Several randomized controlled trials in 2015 changed the landscape of stroke care worldwide, with endovascular thrombectomy (ET) now the standard of care for all eligible patients. With the proven success of this therapy, there is a renewed focus on penumbral sustenance. In this review, we describe the ischemic penumbra, collateral circulation, autoregulation, and imaging assessment of the penumbra...
2017: Frontiers in Neurology
https://www.readbyqxmd.com/read/28712720/manual-aspiration-thrombectomy-in-patients-with-acute-stroke-related-calcified-cerebral-emboli
#20
Esther Koh, Hyo Sung Kwak, Gyung-Ho Chung
OBJECTIVE: The aim of this study was to evaluate the effectiveness of mechanical aspiration thrombectomy (MAT) in patients with acute ischemic stroke from calcified cerebral emboli. METHODS: Procedural results were reviewed for acute stroke patients with clinically neurological deficits who underwent recanalization from October 2012 through September 2015. Initial imaging studies and cerebral angiography were analyzed. RESULTS: Of the total number of patients with acute stroke, 5 patients were confirmed to have acute ischemic stroke by calcified cerebral emboli...
July 13, 2017: Journal of Stroke and Cerebrovascular Diseases: the Official Journal of National Stroke Association
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