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https://www.readbyqxmd.com/read/29923496/sensitivity-and-specificity-of-time-resolved-point-dose-measurements-for-patient-specific-quality-assurance
#1
Benjamin E W Scarlet, Andrew J Williams, Steven Marsh, Robert J W Louwe
This study aimed to quantify the sensitivity and specificity of time-resolved point dose (trPD) measurements. 
 Criteria were defined to assess whether errors would cause a clinically relevant dose deviation during patient treatment. The sensitivity and specificity were determined based on verification measurements of five error-free plans and 84 intentional error plans. Receiver operator characteristic (ROC) analysis was conducted to quantify the efficiency of the method. In addition, the specificity of the method was investigated in more detail by assessing its ability to identify different error modes...
June 20, 2018: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/29923495/dosimetric-verification-and-commissioning-for-a-small-animal-image-guided-irradiator
#2
Yi-Fang Wang, Shih-Chi Lin, Yong Hum Na, Paul J Black, Cheng-Shie Wuu
In recent years, small animal image-guided irradiators have been widely utilized in preclinical studies involving rodent models. However, the dosimetry commissioning of such equipment involving kilovoltage small-field dosimetry has not received as much interest as the megavoltage small-field dosimetry used clinically. For improvement of rodent treatments in the future, this work aims to provide comprehensive and accurate beam data for the small animal radiation research platform (SARRP, Xstrahl) using EBT3 Gafchromic films and Monte Carlo calculation, with submillimeter resolution and accuracy...
June 20, 2018: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/29922951/time-window-and-tissue-window-two-approaches-to-assist-decision-making-in-strokes
#3
REVIEW
XuYing Xiang, Fei Cao
Intravenous alteplase given in an appropriate time window has been recommended in guidelines and effects are on the decline over time. In general, the clinical decision is primarily based on whether ischemic stroke patients are sent to hospitals within the time window. However, some patients sent to the hospital over time limitations are eligible to receive intervention for recanalization due to good collateral circulation. In this dilemma, "tissue window" can be more reliable, which means using the penumbra as a major criterion for patient recruitment...
June 19, 2018: Journal of Neurology
https://www.readbyqxmd.com/read/29910169/proximal-embolization-of-splenic-artery-in-acute-trauma-comparison-between-penumbra-occlusion-device-versus-coils-or-amplatzer-vascular-plug
#4
E Jambon, A Hocquelet, F Petitpierre, Y Le Bras, C Marcelin, V Dubuisson, N Grenier, F Cornelis
PURPOSE: To compare intervention duration and fluoroscopy time for proximal embolization of splenic arteries in acute trauma using the Penumbra occlusion device (POD® ), coils or Amplatzer™ vascular plug (AVP). MATERIAL AND METHODS: A total of 29 patients with splenic injury without vascular injury who were treated by proximal splenic artery embolization using POD® (n=12), coils (n=9) or AVP (n=8) were retrospectively included. There were 25 men and 4 women with a median age of 34 years (range: 10-69 years)...
June 14, 2018: Diagnostic and Interventional Imaging
https://www.readbyqxmd.com/read/29905521/contrast-enhanced-ultrasound-to-visualize-hemodynamic-changes-after-rodent-spinal-cord-injury
#5
Zin Z Khaing, Lindsay N Cates, Dane M DeWees, Alexander Hannah, Pierre Mourad, Matthew Bruce, Christoph P Hofstetter
OBJECTIVE Traumatic spinal cord injury (tSCI) causes an almost complete loss of blood flow at the site of injury (primary injury) as well as significant hypoperfusion in the penumbra of the injury. Hypoperfusion in the penumbra progresses after injury to the spinal cord and is likely to be a major contributor to progressive cell death of spinal cord tissue that was initially viable (secondary injury). Neuroprotective treatment strategies seek to limit secondary injury. Clinical monitoring of the temporal and spatial patterns of blood flow within the contused spinal cord is currently not feasible...
June 15, 2018: Journal of Neurosurgery. Spine
https://www.readbyqxmd.com/read/29904091/naloxone-attenuates-ischemic-brain-injury-in-rats-through-suppressing-the-nik-ikk%C3%AE-nf-%C3%AE%C2%BAb-and-neuronal-apoptotic-pathways
#6
Xuan Wang, Zu-Jun Sun, Jun-Lu Wu, Wen-Qiang Quan, Wei-Dong Xiao, Helen Chew, Cui-Min Jiang, Dong Li
Although naloxone has been documented to exert neuroprotection in animal model of cerebral ischemia, the mechanism is not well understood. In this present study we investigated whether naloxone affected the mitochondrial apoptotic pathway in ischemic brain injury of rats. SD rats were subjected to a permanent middle cerebral artery occlusion surgery, and received naloxone (0.5, 1, 2 mg/kg, i.v.) immediately after ischemia. Neurological deficits were evaluated 24 h after ischemia using the McGraw Stroke Index, and then the rats were killed, and the brains were collected for further analyses...
June 14, 2018: Acta Pharmacologica Sinica
https://www.readbyqxmd.com/read/29896417/sdf-1-cxcr7-chemokine-signaling-is-induced-in-the-peri-infarct-regions-in-patients-with-ischemic-stroke
#7
Yu Zhang, Hongxia Zhang, Siyang Lin, Xudong Chen, Yu Yao, XiaoOu Mao, Bei Shao, Qichuan Zhuge, Kunlin Jin
Stromal-derived factor-1 (SDF-1, also known as CXCL12) and its receptors CXCR4 and CXCR7 play important roles in brain repair after ischemic stroke, as SDF-1/ CXCR4/CXCR7 chemokine signaling is critical for recruiting stem cells to sites of ischemic injury. Upregulation of SDF-1/CXCR4/CXCR7 chemokine signaling in the ischemic regions has been well-documented in the animal models of ischemic stroke, but not in human ischemic brain. Here, we found that protein expression of SDF-1 and CXCR7, but not CXCR4, were significantly increased in the cortical peri-infarct regions (penumbra) after ischemic stroke in human, compared with adjacent normal tissues and control subjects...
April 2018: Aging and Disease
https://www.readbyqxmd.com/read/29896415/clarity-for-high-resolution-imaging-and-quantification-of-vasculature-in-the-whole-mouse-brain
#8
Lin-Yuan Zhang, Pan Lin, Jiaji Pan, Yuanyuan Ma, Zhenyu Wei, Lu Jiang, Liping Wang, Yaying Song, Yongting Wang, Zhijun Zhang, Kunlin Jin, Qian Wang, Guo-Yuan Yang
Elucidating the normal structure and distribution of cerebral vascular system is fundamental for understanding its function. However, studies on visualization and whole-brain quantification of vasculature with cellular resolution are limited. Here, we explored the structure of vasculature at the whole-brain level using the newly developed CLARITY technique. Adult male C57BL/6J mice undergoing transient middle cerebral artery occlusion and Tie2-RFP transgenic mice were used. Whole mouse brains were extracted for CLARITY processing...
April 2018: Aging and Disease
https://www.readbyqxmd.com/read/29895489/shengui-sansheng-san-extraction-is-an-angiogenic-switch-via-regulations-of-akt-mtor-erk1-2-and-notch1-signal-pathways-after-ischemic-stroke
#9
Bowen Liu, Cheng Luo, Zhaoguang Zheng, Zhenyan Xia, Qian Zhang, Chienchih Ke, Renshyan Liu, Yonghua Zhao
BACKGROUND: As a traditional Chinese herbal formula, Shengui Sansheng San (SSS) has been employed for stroke treatment more than 300 years. PURPOSE: We hypothesize that SSS extraction is an angiogenic switch in penumbra post-stroke, and corresponding mechanisms are investigated. METHODS: In present study, rats were subjected to permanent middle cerebral artery occlusion model (MCAo) and were treated with low, middle and high doses of SSS extraction...
May 15, 2018: Phytomedicine: International Journal of Phytotherapy and Phytopharmacology
https://www.readbyqxmd.com/read/29884977/detection-of-neuroinflammation-before-selective-neuronal-loss-appearance-after-mild-focal-ischemia-using-18-f-dpa-714-imaging
#10
Natsumi Miyajima, Miwa Ito, Takemi Rokugawa, Hitoshi Iimori, Sotaro Momosaki, Shigeki Omachi, Eku Shimosegawa, Jun Hatazawa, Kohji Abe
BACKGROUND: Translocator protein (TSPO) imaging can be used to detect neuroinflammation (including microglial activation) after acute cerebral infarction. However, longitudinal changes of TSPO binding after mild ischemia that induces selective neuronal loss (SNL) without acute infarction are not well understood. Here, we performed TSPO imaging with [18 F]DPA-714 to determine the time course of neuroinflammation and SNL after mild focal ischemia. RESULTS: Mild focal ischemia was induced by middle cerebral artery occlusion (MCAO) for 20 min...
June 8, 2018: EJNMMI Research
https://www.readbyqxmd.com/read/29879696/tenacity-of-collateral-perfusion-in-proximal-cerebral-arterial-occlusions-6-12-h-after-onset
#11
Beom Joon Kim, Hyeran Kim, Han-Gil Jeong, Mi Hwa Yang, Cheol Kyu Jung, Moon-Ku Han, Jae Hyoung Kim, Andrew M Demchuk, Hee-Joon Bae
BACKGROUND: Clinical trials have shown that benefits of endovascular recanalization (EVT) for acute ischemic stroke patients with sizable penumbral tissues seems plausible even beyond 6 h after their last seen normal (LSN). Persistency of ischemic penumbra remains unclear in delayed periods. METHODS: From a prospective stroke registry database, we identified 111 acute ischemic stroke patients who had internal carotid artery or middle cerebral artery occlusion with baseline National Institutes of Health Stroke Scale scores ≥6 points and arrived 6-12 h after LSN...
June 7, 2018: Cerebrovascular Diseases
https://www.readbyqxmd.com/read/29858774/docosanoids-promote-neurogenesis-and-angiogenesis-blood-brain-barrier-integrity-penumbra-protection-and-neurobehavioral-recovery-after-experimental-ischemic-stroke
#12
Ludmila Belayev, Sung-Ha Hong, Hemant Menghani, Shawn J Marcell, Andre Obenaus, Raul S Freitas, Larissa Khoutorova, Veronica Balaszczuk, Bokkyoo Jun, Reinaldo B Oriá, Nicolas G Bazan
Docosahexaenoic acid (DHA) and neuroprotectin D1 (NPD1) are neuroprotective after experimental ischemic stroke. To explore underlying mechanisms, SD rats underwent 2 h of middle cerebral artery occlusion (MCAo) and treated with DHA (5 mg/kg, IV) or NPD1 (5 μg/per rat, ICV) and vehicles 1 h after. Neuro-behavioral assessments was conducted on days 1, 2, and 3, and on week 1, 2, 3, or 4. BrdU was injected on days 4, 5, and 6, immunohistochemistry was performed on week 2 or 4, MRI on day 7, and lipidomic analysis at 4 and 5 h after onset of stroke...
June 1, 2018: Molecular Neurobiology
https://www.readbyqxmd.com/read/29858132/dosimetric-characterization-of-a-single-crystal-diamond-detector-in-x-ray-beams-for-preclinical-research
#13
Severin Kampfer, Nathan Cho, Stephanie E Combs, Jan J Wilkens
The aim of this study was to investigate a single crystal diamond detector, the microDiamond detector from PTW (PTW-Freiburg, Freiburg, Germany), concerning the particular requirements in the set-up and energy range used in small animal radiotherapy (RT) research (around 220kV). We tested it to find out the minimal required pre-irradiation dose, the dose linearity, dose rate dependency and the angular response as well as usability in the small animal radiation research platform, SARRP (Xstrahl Ltd., Camberley, UK)...
May 29, 2018: Zeitschrift Für Medizinische Physik
https://www.readbyqxmd.com/read/29803065/fracture-and-embolization-of-distal-guide-catheter-during-neuroendovascular-intervention-case-report
#14
Jason Kim, Yiping Li, Demi Dawkins, Azam Ahmed
We report the clinical details, imaging findings, and management of a 69-year-old woman who underwent elective pipeline embolization of an incidental right para-ophthalmic artery aneurysm and suffered distal embolization of the radiopaque marker from a distal guide catheter (088 Neuron Max, Penumbra, Alameda, CA) used during neuroendovascular intervention. This is the first account of distal embolism from fracture of a neurointerventional catheter.
May 23, 2018: World Neurosurgery
https://www.readbyqxmd.com/read/29802364/observing-kelvin-helmholtz-instability-in-solar-blowout-jet
#15
Xiaohong Li, Jun Zhang, Shuhong Yang, Yijun Hou, Robert Erdélyi
Kelvin-Helmholtz instability (KHI) is a basic physical process in fluids and magnetized plasmas, with applications successfully modelling e.g. exponentially growing instabilities observed at magnetospheric and heliospheric boundaries, in the solar or Earth's atmosphere and within astrophysical jets. Here, we report the discovery of the KHI in solar blowout jets and analyse the detailed evolution by employing high-resolution data from the Interface Region Imaging Spectrograph (IRIS) satellite launched in 2013...
May 25, 2018: Scientific Reports
https://www.readbyqxmd.com/read/29802210/neuroprotection-via-at-2-receptor-agonists-in-ischemic-stroke
#16
REVIEW
Douglas M Bennion, U Muscha Steckelings, Colin Sumners
Stroke is a devastating disease that afflicts millions of people each year worldwide. Ischemic stroke, which accounts for ~88% of cases, occurs when blood supply to the brain is decreased, often because of thromboembolism or atherosclerotic occlusion. This deprives the brain of oxygen and nutrients, causing immediate, irreversible necrosis within the core of the ischemic area, but more delayed and potentially reversible neuronal damage in the surrounding brain tissue, the penumbra. The only currently approved therapies for ischemic stroke, the thrombolytic agent recombinant tissue plasminogen activator (rtPA) and the endovascular clot retrieval/destruction processes, are aimed at restoring blood flow to the infarcted area, but are only available for a minority of patients and are not able in most cases to completely restore neurological deficits...
May 31, 2018: Clinical Science (1979-)
https://www.readbyqxmd.com/read/29794157/a-novel-combined-approach-using-a-penumbra-catheter-and-balloon-catheter-for-cerebral-venous-sinus-thrombosis
#17
Yoshikazu Matsuda, Yoshihiro Owai, Koji Kakishita, Naoyuki Nakao
Cerebral venous sinus thrombosis is sometimes fatal. We describe a case of sinus thrombosis in a 43-year-old woman presenting with generalized seizure, delirium, and a 2 week history of headache and nausea. The patient underwent mechanical thrombectomy using a novel combined approach, in which a Shouryu HR balloon catheter (Kaneka) was anchored in the right transverse sinus (TS), sigmoid sinus (SS), and superior sagittal sinus (SSS), while a Penumbra 5 MAX ACE (Penumbra) catheter was moved back and forth between the right TS, SS, and SSS...
May 24, 2018: Journal of Neurointerventional Surgery
https://www.readbyqxmd.com/read/29790261/-characterization-of-elekta-srs-cone-collimator-using-high-spatial-resolution-monolithic-silicon-detector-array
#18
Khalsa Al Shukaili, Stéphanie Corde, Marco Petasecca, Vladimir Pereveratylo, Michael Lerch, Michael Jackson, Anatoly Rosenfeld
PURPOSE: To investigate the accuracy of the dosimetry of radiation fields produced by small ELEKTA cone collimators used for stereotactic radiosurgery treatments (SRS) using commercially available detectors EBT3 GafchromicTM film, IBA Stereotactic diode (SFD), and the recently developed detector DUO, which is a monolithic silicon orthogonal linear diode array detector. METHODS: These three detectors were used for the measurement of beam profiles, output factors, and percentage depth dose for SRS cone collimators with cone sizes ranging from 5 to 50 mm diameter...
May 22, 2018: Journal of Applied Clinical Medical Physics
https://www.readbyqxmd.com/read/29788552/an-analytical-dose-averaged-let-calculation-algorithm-considering-the-off-axis-let-enhancement-by-secondary-protons-for-spot-scanning-proton-therapy
#19
Shusuke Hirayama, Taeko Matsuura, Ueda Hideaki, Yusuke Fujii, Takaaki Fujii, Seishin Takao, Naoki Miyamoto, Shinichi Shimizu, Rintaro Fujimoto, Kikuo Umegaki, Hiroki Shirato
PURPOSE: To evaluate the biological effects of proton beams as part of daily clinical routine, fast and accurate calculation of dose-averaged linear energy transfer (LETd ) is required. In this study, we have developed the analytical LETd calculation method based on the pencil-beam algorithm (PBA) considering the off-axis enhancement by secondary protons. This algorithm (PBA-dLET) was then validated using Monte Carlo simulation (MCS) results. METHODS: In PBA-dLET, LET values were assigned separately for each individual dose kernel based on the PBA...
May 22, 2018: Medical Physics
https://www.readbyqxmd.com/read/29785469/early-detection-of-cerebral-infarction-after-focal-ischemia-using-a-new-mri-indicator
#20
Yukako Nakajo, Qiang Zhao, Jun-Ichiro Enmi, Hidehiro Iida, Jun C Takahashi, Hiroharu Kataoka, Keiko Yamato, Hiroji Yanamoto
Prolongation of the T2 relaxation time, an increase in T2-weighted signal intensity (T2-SI), and a decrease in the apparent diffusion coefficient (ADC) calculated from diffusion-weighted images (DWI) on magnetic resonance imaging (MRI) are conventional indicators of the vasogenic (interstitial) or cytotoxic (cellular) cerebral edema that develops after ischemic stroke. However, these parameters obtained on stroke imaging have not given us a precise threshold at which we can determine the viability or vulnerability of the tissue, allowing us to decide on an intervention that will help reversible tissue in the acute phase...
May 21, 2018: Molecular Neurobiology
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