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Sample records for breath-hold multi-echo fast

  1. Comparison of multi-echo dixon methods with volume interpolated breath-hold gradient magnetic resonance imaging in fat-signal fraction quantification of paravaertebral muscle

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    Yoo, Yeon Hwa; Kim, Hak Sun; Lee, Young Han [Dept. of Radiology, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul (Korea, Republic of); and others

    2015-10-15

    To assess whether multi-echo Dixon magnetic resonance (MR) imaging with simultaneous T2{sup *} estimation and correction yields more accurate fat-signal fraction (FF) measurement of the lumbar paravertebral muscles, in comparison with non-T2{sup *}-corrected two-echo Dixon or T2{sup *}-corrected three-echo Dixon, using the FF measurements from single-voxel MR spectroscopy as the reference standard. Sixty patients with low back pain underwent MR imaging with a 1.5T scanner. FF mapping images automatically obtained using T2{sup *}-corrected Dixon technique with two (non-T2{sup *}-corrected), three, and six echoes, were compared with images from single-voxel MR spectroscopy at the paravertebral muscles on levels L4 through L5. FFs were measured directly by two radiologists, who independently drew the region of interest on the mapping images from the three sequences. A total of 117 spectroscopic measurements were performed either bilaterally (57 of 60 subjects) or unilaterally (3 of 60 subjects). The mean spectroscopic FF was 14.3 ± 11.7% (range, 1.9-63.7%). Interobserver agreement was excellent between the two radiologists. Lin's concordance correlation between the spectroscopic findings and all the imaging-based FFs were statistically significant (p < 0.001). FFs obtained from the T2*-corrected six-echo Dixon sequences showed a significantly better concordance with the spectroscopic data, with its concordance correlation coefficient being 0.99 and 0.98 (p < 0.001), as compared with two- or three-echo methods. T2{sup *}-corrected six-echo Dixon sequence would be a better option than two- or three-echo methods for noninvasive quantification of lumbar muscle fat quantification.

  2. Fast 3-Breath-Hold 3-Dimensional Tagging Cardiac Magnetic Resonance in Patients with Hypertrophic Myocardial Diseases: A Feasibility Study

    Directory of Open Access Journals (Sweden)

    Yasuo Amano

    2016-01-01

    Full Text Available Tagging CMR has been established as the standard reference for measurement of myocardial strain. The current 2D tagging technique requires multiple breath-holds to cover the whole heart and cannot show the 3D motions of the left ventricle. We performed fast 3-breath-hold 3D tagging with localized tagging preparation and complementary spatial modulation of magnetization in 10 patients with hypertrophic myocardial diseases and 6 normal volunteers. The left wall motion was observed at any view angle, which allowed for the identification of regional and global hypokinesis using the fast 3D tagging. Although a decrease in the circumferential strain and LGE were observed at the basal septum in hypertrophic cardiomyopathy, they were not located together in each patient. In hypertensive heart disease, the decrease in circumferential strain was observed more widely than LGE, and the summed strain of all segments was significantly decreased. The decrease in strain and LGE were observed diffusely in cardiac amyloidosis. In conclusion, fast 3-breath-hold 3D tagging is feasible for the regional and global strain analysis. The location of reduced circumferential strain is not necessarily the same as that of LGE and is related to the global cardiac function in patients with hypertrophic myocardial diseases.

  3. T2-weighted MRI of the uterus: fast spin echo vs. breath-hold fast spin echo.

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    Ascher, S M; O'Malley, J; Semelka, R C; Patt, R H; Rajan, S; Thomasson, D

    1999-03-01

    This study compared one routine T2-weighted fast spin echo (T2FSE) sequence with a breath-hold T2FSE (BH T2FSE) sequence of the female pelvis for image quality, uterine anatomy, lesion detection, and signal intensity measurements. Thirty-two consecutive women (mean age 41.7 years) were imaged at 1.5 T with one high-resolution routine T2FSE sequence and one BH T2FSE sequence in the sagittal plane as part of comprehensive pelvic magnetic resonance imaging. The different image sets were rated separately for imaging characteristics (overall image quality, uterine anatomy definition, lesion detection, and free fluid conspicuity) and then compared side by side. The image sets were also compared for artifacts (ghosting, blurring, pulsatility, and chemical shift misregistration). Signal-to-noise (S/N) and signal difference-to-noise (SD/N) ratios were calculated for the different uterine zones, uterine abnormalities, free fluid, rectus abdominis muscle, and bladder. Contrast-to-noise ratios (CNRs) were calculated for uterine abnormalities. Twenty-eight uterine abnormalities were detected in 20 patients and included leiomyomata (13 patients), adenomyosis (7 patients), benign endometrial polyps (6 patients), endometrial carcinoma (1 patient), and pregnancy (1 patient). BH T2FSE was superior or equivalent to T2FSE for overall image quality in 23/32 patients (71.8%), uterine anatomy definition in 19/32 patients (59.3%), and lesion detection in 13/20 patients (65%). BH T2FSE performed less well than T2FSE for free fluid conspicuity in 5/5 (100%) patients. BH T2FSE was equivalent to or less affected than T2FSE for ghosting artifact in 24/32 patients (75%) and blurring artifact in 29/32 patients (90.6%). Pulsatility and chemical shift artifacts were not problematic for either image set. S/N and SD/N were higher for all BH T2FSE determinations compared with T2FSE. For the endometrium, junctional zone, myometrium, and bladder, these differences were statistically significant. There

  4. Single breath-hold magnetic resonance cine imaging for fast assessment of global and regional left ventricular function in clinical routine

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    Nassenstein, Kai; Heilmaier, Christina; Schlosser, Thomas [University Hospital Essen, Department of Diagnostic and Interventional Radiology and Neuroradiology, Essen (Germany); Eberle, Holger; Jensen, Christoph J.; Bruder, Oliver [Elisabeth Hospital Essen, Department of Cardiology and Angiology, Essen (Germany); Maderwald, Stefan [University Hospital Essen, Department of Diagnostic and Interventional Radiology and Neuroradiology, Essen (Germany); University Duisburg-Essen, Erwin L. Hahn Institute for Magnetic Resonance Imaging, Essen (Germany)

    2010-10-15

    To evaluate a TGRAPPA (temporal parallel acquisition technique)-accelerated, single breath-hold multi-slice cine imaging approach for the assessment of left ventricular (LV) function. One hundred eleven patients were examined at 1.5 T. Cine imaging was performed with single-slice breath-hold acquisitions in short-axis orientation using a SSFP (TR 2.63 ms, TE 1.12 ms, FA 72 ) sequence and a TGRAPPA SSFP (TR 2.66 ms, TE 1.11 ms, FA 72 , AF 3) sequence, which covered the entire LV in multiple short-axis slices during a single breath-hold. End-diastolic (EDV), end-systolic (ESV), stroke volumes (SV), ejection fraction (EF), muscle mass (MM) and regional wall motion were assessed for both data sets. Single breath-hold imaging was feasible in 108 patients. Excellent correlations were observed for all volumetric parameters derived from both data sets (all r > 0.97). While EDV and ESV showed marginally lower values for single breath-hold imaging (EDV: -1.6 {+-} 7.9 ml; ESV: -1.8 {+-} 6.0 ml, p < 0.05), no differences were observed for SV, EF, MM and regional wall motion assessment. Single breath-hold imaging required significant shorter acquisition times (28 {+-} 6 s vs. 335 {+-} 87 s). TGRAPPA-accelerated multi-slice SSPF imaging allows for fast and accurate assessment of regional and global LV function within a single breath-hold. (orig.)

  5. Analysis of Heart Rate Variability During Breath-Holding Using Fast and Continuous Calculation Method of Frequency and Power

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    Yoshida, Yutaka; Yokoyama, Kiyoko; Ishii, Naohiro

    Many reports show that dominant frequency of high frequency component(HF:0.15∼0.4Hz) of heart rate time series is synchronized with the respiratory frequency. In this paper, we proposed the method for estimating the condition of respiration continuously using dominant frequency and power of HF (HFP) of heart rate time series. Dominant frequency and HFP is calculated from the interval of the neighboring two extreme points and the subtraction of the neighboring two extremals.In the experimental results, high frequency components did not disappear completely during breath-holding. This fact is different from the previous study. Subjects were classified into two groups. In one group, dominant frequency of the HF is significant increased during breath-holding compared with normal breathing. In the other group, this phenomenon was not observed. On the other hand, HFP of total subjects significantly decreased during breath-holding compared with normal breathing. Correct rate during breath-holding and error rate during rest and recovery are calculated using HFP. In the results, average and S. D. of correct rate during breath-holding were 65.0±26.3%. Correct rate of 18 subjects was 80.0±14.1% and correct rate of other 8 subjects was 31.5±11.9%. Our method is expected to apply to the development of the respiratory monitor which can measure respiratory condition with non-restricted in continuously.

  6. Diagnosing Lung Nodules on Oncologic MR/PET Imaging: Comparison of Fast T1-Weighted Sequences and Influence of Image Acquisition in Inspiration and Expiration Breath-Hold

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    Schwenzer, Nina F.; Seith, Ferdinand; Gatidis, Sergios [Department of Diagnostic and Interventional Radiology, University Hospital of Tuebingen, Tuebingen 72076 (Germany); Brendle, Cornelia [Department of Diagnostic and Interventional Radiology, University Hospital of Tuebingen, Tuebingen 72076 (Germany); Department of Diagnostic and Interventional Neuroradiology, University Hospital of Tuebingen, Tuebingen 72076 (Germany); Schmidt, Holger; Pfannenberg, Christina A. [Department of Diagnostic and Interventional Radiology, University Hospital of Tuebingen, Tuebingen 72076 (Germany); Fougère, Christian la [Department of Nuclear Medicine, University Hospital of Tuebingen, Tuebingen 72076 (Germany); Nikolaou, Konstantin; Schraml, Christina [Department of Diagnostic and Interventional Radiology, University Hospital of Tuebingen, Tuebingen 72076 (Germany)

    2016-11-01

    First, to investigate the diagnostic performance of fast T1-weighted sequences for lung nodule evaluation in oncologic magnetic resonance (MR)/positron emission tomography (PET). Second, to evaluate the influence of image acquisition in inspiration and expiration breath-hold on diagnostic performance. The study was approved by the local Institutional Review Board. PET/CT and MR/PET of 44 cancer patients were evaluated by 2 readers. PET/CT included lung computed tomography (CT) scans in inspiration and expiration (CTin, CTex). MR/PET included Dixon sequence for attenuation correction and fast T1-weighted volumetric interpolated breath-hold examination (VIBE) sequences (volume interpolated breath-hold examination acquired in inspiration [VIBEin], volume interpolated breath-hold examination acquired in expiration [VIBEex]). Diagnostic performance was analyzed for lesion-, lobe-, and size-dependence. Diagnostic confidence was evaluated (4-point Likert-scale; 1 = high). Jackknife alternative free-response receiver-operating characteristic (JAFROC) analysis was performed. Seventy-six pulmonary lesions were evaluated. Lesion-based detection rates were: CTex, 77.6%; VIBEin, 53.3%; VIBEex, 51.3%; and Dixon, 22.4%. Lobe-based detection rates were: CTex, 89.6%; VIBEin, 58.3%; VIBEex, 60.4%; and Dixon, 31.3%. In contrast to CT, inspiration versus expiration did not alter diagnostic performance in VIBE sequences. Diagnostic confidence was best for VIBEin and CTex and decreased in VIBEex and Dixon (1.2 ± 0.6; 1.2 ± 0.7; 1.5 ± 0.9; 1.7 ± 1.1, respectively). The JAFROC figure-of-merit of Dixon was significantly lower. All patients with malignant lesions were identified by CTex, VIBEin, and VIBEex, while 3 patients were false-negative in Dixon. Fast T1-weighted VIBE sequences allow for identification of patients with malignant pulmonary lesions. The Dixon sequence is not recommended for lung nodule evaluation in oncologic MR/PET patients. In contrast to CT, inspiration versus

  7. Diagnosing lung nodules on oncologic MR/PET imaging: Comparison of fast T1-weighted sequences and influence of image acquisition in inspiration and expiration breath-hold

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    Schwenzer, Nina F.; Seith, Ferdinand; Gatidis, Sergios; Brendle, Cornelia; Schmidt, Holger; Pfannenberg, Christina A; LaFougère, Christian; Nikolaou, Konstantin; Schraml, Christina [University Hospital of Tuebingen, Tuebingen (Germany)

    2016-09-15

    First, to investigate the diagnostic performance of fast T1-weighted sequences for lung nodule evaluation in oncologic magnetic resonance (MR)/positron emission tomography (PET). Second, to evaluate the influence of image acquisition in inspiration and expiration breath-hold on diagnostic performance. The study was approved by the local Institutional Review Board. PET/CT and MR/PET of 44 cancer patients were evaluated by 2 readers. PET/CT included lung computed tomography (CT) scans in inspiration and expiration (CTin, CTex). MR/PET included Dixon sequence for attenuation correction and fast T1-weighted volumetric interpolated breath-hold examination (VIBE) sequences (volume interpolated breath-hold examination acquired in inspiration [VIBEin], volume interpolated breath-hold examination acquired in expiration [VIBEex]). Diagnostic performance was analyzed for lesion-, lobe-, and size-dependence. Diagnostic confidence was evaluated (4-point Likert-scale; 1 = high). Jackknife alternative free-response receiver-operating characteristic (JAFROC) analysis was performed. Seventy-six pulmonary lesions were evaluated. Lesion-based detection rates were: CTex, 77.6%; VIBEin, 53.3%; VIBEex, 51.3%; and Dixon, 22.4%. Lobe-based detection rates were: CTex, 89.6%; VIBEin, 58.3%; VIBEex, 60.4%; and Dixon, 31.3%. In contrast to CT, inspiration versus expiration did not alter diagnostic performance in VIBE sequences. Diagnostic confidence was best for VIBEin and CTex and decreased in VIBEex and Dixon (1.2 ± 0.6; 1.2 ± 0.7; 1.5 ± 0.9; 1.7 ± 1.1, respectively). The JAFROC figure-of-merit of Dixon was significantly lower. All patients with malignant lesions were identified by CTex, VIBEin, and VIBEex, while 3 patients were false-negative in Dixon. Fast T1-weighted VIBE sequences allow for identification of patients with malignant pulmonary lesions. The Dixon sequence is not recommended for lung nodule evaluation in oncologic MR/PET patients. In contrast to CT, inspiration versus

  8. Automatically gated image-guided breath-hold IMRT is a fast, precise, and dosimetrically robust treatment for lung cancer patients

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    Simeonova-Chergou, Anna; Jahnke, Anika; Siebenlist, Kerstin; Stieler, Florian; Mai, Sabine; Boda-Heggemann, Judit; Wenz, Frederik; Lohr, Frank; Jahnke, Lennart [University Medical Center Mannheim, University of Heidelberg, Department of Radiotherapy and Oncology, Mannheim (Germany)

    2016-03-15

    High-dose radiotherapy of lung cancer is challenging. Tumors may move by up to 2 cm in craniocaudal and anteroposterior directions as a function of breathing cycle. Tumor displacement increases with treatment time, which consequentially increases the treatment uncertainty. This study analyzed whether automatically gated cone-beam-CT (CBCT)-controlled intensity modulated fast deep inspiration breath hold (DIBH) stereotactic body radiation therapy (SBRT) in flattening filter free (FFF) technique and normofractionated lung DIBH intensity-modulated radiotherapy (IMRT)/volumetric-modulated arc therapy (VMAT) treatments delivered with a flattening filter can be applied with sufficient accuracy within a clinically acceptable timeslot. Plans of 34 patients with lung tumors were analyzed. Of these patients, 17 received computer-controlled fast DIBH SBRT with a dose of 60 Gy (5 fractions of 12 Gy or 12 fractions of 5 Gy) in an FFF VMAT technique (FFF-SBRT) every other day and 17 received conventional VMAT with a flattening filter (conv-VMAT) and 2-Gy daily fractional doses (cumulative dose 50-70 Gy). FFF-SBRT plans required more monitor units (MU) than conv-VMAT plans (2956.6 ± 885.3 MU for 12 Gy/fraction and 1148.7 ± 289.2 MU for 5 Gy/fraction vs. 608.4 ± 157.5 MU for 2 Gy/fraction). Total treatment and net beam-on times were shorter for FFF-SBRT plans than conv-VMAT plans (268.0 ± 74.4 s vs. 330.2 ± 93.6 s and 85.8 ± 25.3 s vs. 117.2 ± 29.6 s, respectively). Total slot time was 13.0 min for FFF-SBRT and 14.0 min for conv-VMAT. All modalities could be delivered accurately despite multiple beam-on/-off cycles and were robust against multiple interruptions. Automatically gated CBCT-controlled fast DIBH SBRT in VMAT FFF technique and normofractionated lung DIBH VMAT can be applied with a low number of breath-holds in a short timeslot, with excellent dosimetric accuracy. In clinical routine, these approaches combine optimally reduced lung tissue irradiation with maximal

  9. Functional Analysis and Intervention for Breath Holding.

    Science.gov (United States)

    Kern, Lee; And Others

    1995-01-01

    A functional analysis of breath-holding episodes in a 7-year-old girl with severe mental retardation and Cornelia-de-Lange syndrome indicated that breath holding served an operant function, primarily to gain access to attention. Use of extinction, scheduled attention, and a picture card communication system decreased breath holding. (Author/SW)

  10. Breath-holding and its breakpoint.

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    Parkes, M J

    2006-01-01

    This article reviews the basic properties of breath-holding in humans and the possible causes of the breath at breakpoint. The simplest objective measure of breath-holding is its duration, but even this is highly variable. Breath-holding is a voluntary act, but normal subjects appear unable to breath-hold to unconsciousness. A powerful involuntary mechanism normally overrides voluntary breath-holding and causes the breath that defines the breakpoint. The occurrence of the breakpoint breath does not appear to be caused solely by a mechanism involving lung or chest shrinkage, partial pressures of blood gases or the carotid arterial chemoreceptors. This is despite the well-known properties of breath-hold duration being prolonged by large lung inflations, hyperoxia and hypocapnia and being shortened by the converse manoeuvres and by increased metabolic rate. Breath-holding has, however, two much less well-known but important properties. First, the central respiratory rhythm appears to continue throughout breath-holding. Humans cannot therefore stop their central respiratory rhythm voluntarily. Instead, they merely suppress expression of their central respiratory rhythm and voluntarily 'hold' the chest at a chosen volume, possibly assisted by some tonic diaphragm activity. Second, breath-hold duration is prolonged by bilateral paralysis of the phrenic or vagus nerves. Possibly the contribution to the breakpoint from stimulation of diaphragm muscle chemoreceptors is greater than has previously been considered. At present there is no simple explanation for the breakpoint that encompasses all these properties.

  11. Fast and tissue-optimized mapping of magnetic susceptibility and T2* with multi-echo and multi-shot spirals.

    Science.gov (United States)

    Wu, Bing; Li, Wei; Avram, Alexandru Vlad; Gho, Sung-Min; Liu, Chunlei

    2012-01-02

    Gradient-echo MRI of resonance-frequency shift and T2* values exhibit unique tissue contrast and offer relevant physiological information. However, acquiring 3D-phase images and T2* maps with the standard spoiled gradient echo (SPGR) sequence is lengthy for routine imaging at high-spatial resolution and whole-brain coverage. In addition, with the standard SPGR sequence, optimal signal-to-noise ratio (SNR) cannot be achieved for every tissue type given their distributed resonance frequency and T2* value. To address these two issues, a SNR optimized multi-echo sequence with a stack-of-spiral acquisition is proposed and implemented for achieving fast and simultaneous acquisition of image phase and T2* maps. The analytical behavior of the phase SNR is derived as a function of resonance frequency, T2* and echo time. This relationship is utilized to achieve tissue optimized SNR by combining phase images with different echo times. Simulations and in vivo experiments were designed to verify the theoretical predictions. Using the multi-echo spiral acquisition, whole-brain coverage with 1 mm isotropic resolution can be achieved within 2.5 min, shortening the scan time by a factor of 8. The resulting multi-echo phase map shows similar SNR to that of the standard SPGR. The acquisition can be further accelerated with non-Cartesian parallel imaging. The technique can be readily extended to other multi-shot readout trajectories besides spiral. It may provide a practical acquisition strategy for high resolution and simultaneous 3D mapping of magnetic susceptibility and T2*.

  12. The physiology and pathophysiology of human breath-hold diving.

    Science.gov (United States)

    Lindholm, Peter; Lundgren, Claes E G

    2009-01-01

    This is a brief overview of physiological reactions, limitations, and pathophysiological mechanisms associated with human breath-hold diving. Breath-hold duration and ability to withstand compression at depth are the two main challenges that have been overcome to an amazing degree as evidenced by the current world records in breath-hold duration at 10:12 min and depth of 214 m. The quest for even further performance enhancements continues among competitive breath-hold divers, even if absolute physiological limits are being approached as indicated by findings of pulmonary edema and alveolar hemorrhage postdive. However, a remarkable, and so far poorly understood, variation in individual disposition for such problems exists. Mortality connected with breath-hold diving is primarily concentrated to less well-trained recreational divers and competitive spearfishermen who fall victim to hypoxia. Particularly vulnerable are probably also individuals with preexisting cardiac problems and possibly, essentially healthy divers who may have suffered severe alternobaric vertigo as a complication to inadequate pressure equilibration of the middle ears. The specific topics discussed include the diving response and its expression by the cardiovascular system, which exhibits hypertension, bradycardia, oxygen conservation, arrhythmias, and contraction of the spleen. The respiratory system is challenged by compression of the lungs with barotrauma of descent, intrapulmonary hemorrhage, edema, and the effects of glossopharyngeal insufflation and exsufflation. Various mechanisms associated with hypoxia and loss of consciousness are discussed, including hyperventilation, ascent blackout, fasting, and excessive postexercise O(2) consumption. The potential for high nitrogen pressure in the lungs to cause decompression sickness and N(2) narcosis is also illuminated.

  13. Decompression sickness following breath-hold diving.

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    Schipke, J D; Gams, E; Kallweit, Oliver

    2006-01-01

    Despite convincing evidence of a relationship between breath-hold diving and decompression sickness (DCS), the causal connection is only slowly being accepted. Only the more recent textbooks have acknowledged the risks of repetitive breath-hold diving. We compare four groups of breath-hold divers: (1) Japanese and Korean amas and other divers from the Pacific area, (2) instructors at naval training facilities, (3) spear fishers, and (4) free-dive athletes. While the number of amas is likely decreasing, and Scandinavian Navy training facilities recorded only a few accidents, the number of spear fishers suffering accidents is on the rise, in particular during championships or using scooters. Finally, national and international associations (e.g., International Association of Free Drives [IAFD] or Association Internationale pour Le Developpment De L'Apnee [AIDA]) promote free-diving championships including deep diving categories such as constant weight, variable weight, and no limit. A number of free-diving athletes, training for or participating in competitions, are increasingly accident prone as the world record is presently set at a depth of 171 m. This review presents data found after searching Medline and ISI Web of Science and using appropriate Internet search engines (e.g., Google). We report some 90 cases in which DCS occurred after repetitive breath-hold dives. Even today, the risk of suffering from DCS after repetitive breath-hold diving is often not acknowledged. We strongly suggest that breath-hold divers and their advisors and physicians be made aware of the possibility of DCS and of the appropriate therapeutic measures to be taken when DCS is suspected. Because the risk of suffering from DCS increases depending on depth, bottom time, rate of ascent, and duration of surface intervals, some approaches to assess the risks are presented. Regrettably, none of these approaches is widely accepted. We propose therefore the development of easily manageable

  14. Single Breath-Hold Physiotherapy Technique: Effective tool for T2* magnetic resonance imaging in young patients with thalassaemia major

    OpenAIRE

    2016-01-01

    Magnetic resonance imaging using T2* (MRI T2*) is a highly sensitive and non-invasive technique for the detection of tissue iron load. Although the single breath-hold multi-echo T2* technique has been available at the Sultan Qaboos University Hospital (SQUH), Muscat, Oman, since 2006, it could not be performed on younger patients due to their inability to hold their breath after expiration. This study was carried out between May 2007 and May 2015 and assessed 50 SQUH thalassaemic patients age...

  15. Sports-related lung injury during breath-hold diving

    Directory of Open Access Journals (Sweden)

    Tanja Mijacika

    2016-12-01

    Full Text Available The number of people practising recreational breath-hold diving is constantly growing, thereby increasing the need for knowledge of the acute and chronic effects such a sport could have on the health of participants. Breath-hold diving is potentially dangerous, mainly because of associated extreme environmental factors such as increased hydrostatic pressure, hypoxia, hypercapnia, hypothermia and strenuous exercise. In this article we focus on the effects of breath-hold diving on pulmonary function. Respiratory symptoms have been reported in almost 25% of breath-hold divers after repetitive diving sessions. Acutely, repetitive breath-hold diving may result in increased transpulmonary capillary pressure, leading to noncardiogenic oedema and/or alveolar haemorrhage. Furthermore, during a breath-hold dive, the chest and lungs are compressed by the increasing pressure of water. Rapid changes in lung air volume during descent or ascent can result in a lung injury known as pulmonary barotrauma. Factors that may influence individual susceptibility to breath-hold diving-induced lung injury range from underlying pulmonary or cardiac dysfunction to genetic predisposition. According to the available data, breath-holding does not result in chronic lung injury. However, studies of large populations of breath-hold divers are necessary to firmly exclude long-term lung damage.

  16. Sports-related lung injury during breath-hold diving.

    Science.gov (United States)

    Mijacika, Tanja; Dujic, Zeljko

    2016-12-01

    The number of people practising recreational breath-hold diving is constantly growing, thereby increasing the need for knowledge of the acute and chronic effects such a sport could have on the health of participants. Breath-hold diving is potentially dangerous, mainly because of associated extreme environmental factors such as increased hydrostatic pressure, hypoxia, hypercapnia, hypothermia and strenuous exercise.In this article we focus on the effects of breath-hold diving on pulmonary function. Respiratory symptoms have been reported in almost 25% of breath-hold divers after repetitive diving sessions. Acutely, repetitive breath-hold diving may result in increased transpulmonary capillary pressure, leading to noncardiogenic oedema and/or alveolar haemorrhage. Furthermore, during a breath-hold dive, the chest and lungs are compressed by the increasing pressure of water. Rapid changes in lung air volume during descent or ascent can result in a lung injury known as pulmonary barotrauma. Factors that may influence individual susceptibility to breath-hold diving-induced lung injury range from underlying pulmonary or cardiac dysfunction to genetic predisposition.According to the available data, breath-holding does not result in chronic lung injury. However, studies of large populations of breath-hold divers are necessary to firmly exclude long-term lung damage.

  17. Piracetam in severe breath holding spells.

    Science.gov (United States)

    Azam, Matloob; Bhatti, Nasera; Shahab, Naheed

    2008-01-01

    Breath holding spells (BHS) are apparently frightening events occurring in otherwise healthy children. Generally, no medical treatment is recommended and parental reassurance is believed to be enough, however, severe BHS can be very stressful for the parents and a pharmacological agent may be desired in some of these children. In this prospective study aim was to determine the usefulness of piracetam as prophylactic treatment for severe BHS. Children were recruited from Neurology Clinic in Children's Hospital, Islamabad between January 2002 to December 2004. Diagnosis of BHS was based on characteristic history and normal physical examination. Piracetam was prescribed to those children who were diagnosed as severe BHS in a dose ranging from 50-100 mg/kg/day. Iron supplements were added if hemoglobin was less than 10 gm%. Patients were seen at 2-4 weeks interval and follow-up was continued until 3 months after the cessation of drug therapy. Fifty-two children were enrolled in the study, 34 boys and 18 girls. Ages ranged from 4 weeks to 5 years with mean age of 17 months. In 81% of children, spells disappeared completely and in 9% frequency was reduced to less than one per month and of much lesser intensity. Prophylaxis was given for 3-6 months (mean 5) duration. Piracetam is an effective prophylactic treatment for severe BHS.

  18. Acute effects of cannabis on breath-holding duration.

    Science.gov (United States)

    Farris, Samantha G; Metrik, Jane

    2016-08-01

    Distress intolerance (an individual's perceived or actual inability to tolerate distressing psychological or physiological states) is associated with cannabis use. It is unknown whether a biobehavioral index of distress intolerance, breath-holding duration, is acutely influenced (increased or decreased) by cannabis. Such information may further inform understanding of the expression of psychological or physiological distress postcannabis use. This within-subjects study examined whether smoked marijuana with 2.7%-3.0% delta-9-tetrahydrocannabinol (THC), relative to placebo, acutely changed duration of breath holding. Participants (n = 88; 65.9% male) were nontreatment-seeking frequent cannabis users who smoked placebo or active THC cigarette on two separate study days and completed a breath-holding task postsmoking. Controlling for baseline breath-holding duration and participant sex, THC produced significantly shorter breath-holding durations relative to placebo. There was a significant interaction of drug administration × frequency of cannabis use, such that THC decreased breath-holding time among less frequent but not among more frequent users. Findings indicate that cannabis may exacerbate distress intolerance (via shorter breath-holding durations). As compared to less frequent cannabis users, frequent users display tolerance to cannabis' acute effects including increased ability to tolerate respiratory distress when holding breath. Objective measures of distress intolerance are sensitive to contextual factors such as acute drug intoxication, and may inform the link between cannabis use and the expression of psychological distress. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

  19. Single-breath-hold 3-D CINE imaging of the left ventricle using Cartesian sampling.

    Science.gov (United States)

    Wetzl, Jens; Schmidt, Michaela; Pontana, François; Longère, Benjamin; Lugauer, Felix; Maier, Andreas; Hornegger, Joachim; Forman, Christoph

    2017-05-26

    Our objectives were to evaluate a single-breath-hold approach for Cartesian 3-D CINE imaging of the left ventricle with a nearly isotropic resolution of [Formula: see text] and a breath-hold duration of [Formula: see text]19 s against a standard stack of 2-D CINE slices acquired in multiple breath-holds. Validation is performed with data sets from ten healthy volunteers. A Cartesian sampling pattern based on the spiral phyllotaxis and a compressed sensing reconstruction method are proposed to allow 3-D CINE imaging with high acceleration factors. The fully integrated reconstruction uses multiple graphics processing units to speed up the reconstruction. The 2-D CINE and 3-D CINE are compared based on ventricular function parameters, contrast-to-noise ratio and edge sharpness measurements. Visual comparisons of corresponding short-axis slices of 2-D and 3-D CINE show an excellent match, while 3-D CINE also allows reformatting to other orientations. Ventricular function parameters do not significantly differ from values based on 2-D CINE imaging. Reconstruction times are below 4 min. We demonstrate single-breath-hold 3-D CINE imaging in volunteers and three example patient cases, which features fast reconstruction and allows reformatting to arbitrary orientations.

  20. Single breath-hold assessment of cardiac function using an accelerated 3D single breath-hold acquisition technique - comparison of an intravascular and extravascular contrast agent

    Directory of Open Access Journals (Sweden)

    Makowski Marcus R

    2012-07-01

    Full Text Available Abstract Background Cardiovascular magnetic resonance (CMR is the current gold standard for the assessment of left ventricular (LV function. Repeated breath-holds are needed for standard multi-slice 2D cine steady-state free precession sequences (M2D-SSFP. Accelerated single breath-hold techniques suffer from low contrast between blood pool and myocardium. In this study an intravascular contrast agent was prospectively compared to an extravascular contrast agent for the assessment of LV function using a single-breath-hold 3D-whole-heart cine SSFP sequence (3D-SSFP. Methods LV function was assessed in fourteen patients on a 1.5 T MR-scanner (Philips Healthcare using 32-channel coil technology. Patients were investigated twice using a 3D-SSFP sequence (acquisition time 18–25 s after Gadopentetate dimeglumine (GdD, day 1 and Gadofosveset trisodium (GdT, day 2 administration. Image acquisition was accelerated using sensitivity encoding in both phase encoding directions (4xSENSE. CNR and BMC were both measured between blood and myocardium. The CNR incorporated noise measurements, while the BMC represented the coeffiancy between the signal from blood and myocardium [1]. Contrast to noise ratio (CNR, blood to myocardium contrast (BMC, image quality, LV functional parameters and intra-/interobserver variability were compared. A M2D-SSFP sequence was used as a reference standard on both days. Results All 3D-SSFP sequences were successfully acquired within one breath-hold after GdD and GdT administration. CNR and BMC were significantly (p vs. 23.7 and regression analysis showed a stronger correlation to the reference standard (R2 = 0.92 vs. R2 = 0.71, compared to 3D-SSFP with GdD. Conclusions A single-breath-hold 3D-whole-heart cine SSFP sequence in combination with 32-channel technology and an intravascular contrast agent allows for the accurate and fast assessment of LV function. Trial registration The study was approved by the local

  1. CAIPIRINHA-Dixon-TWIST (CDT)-volume-interpolated breath-hold examination (VIBE): a new technique for fast time-resolved dynamic 3-dimensional imaging of the abdomen with high spatial resolution.

    Science.gov (United States)

    Michaely, Henrik J; Morelli, John N; Budjan, Johannes; Riffel, Philipp; Nickel, Dominik; Kroeker, Randall; Schoenberg, Stefan O; Attenberger, Ulrike I

    2013-08-01

    The purpose of this study was to assess the feasibility and image quality of a novel, highly accelerated T1-weighted sequence for time-resolved imaging of the abdomen during the first pass of contrast media transit using controlled aliasing in parallel imaging results in higher acceleration (CAIPIRINHA) under sampling, view-sharing techniques, and Dixon water-fat separation (CAIPRINHA-Dixon-time-resolved imaging with interleaved stochastic trajectories-volumetric interpolated breath-hold examination [CDT-VIBE]). In this retrospective, institutional review board-approved study, 47 patients (median age, 62 years; 25 men, 22 women) scanned on a 3.0-T magnetic resonance system (Skyra; Siemens) were included. The CDT-VIBE (repetition time/echo time1/echo time2, 4.1/1.33/2.56 milliseconds; acquisition time, 29 seconds) was used in place of the standard arterial phase acquisition and started 15 seconds after the injection of 0.1 mmol/kg Gd-DOTA (Dotarem, Guerbet). Within 29 seconds, 14 high spatial resolution (1.2 × 1.2 × 3 mm) 3-dimensional data sets were acquired and reconstructed using view sharing (temporal resolution, 2.1 seconds). The CDT-VIBE images were evaluated independently by 2 blinded, experienced radiologists with regard to image quality and the number of hepatic arterial-dominant phases present on an ordinal 5-point scale (5, excellent; 1, nondiagnostic). Added diagnostic information with CDT-VIBE relative to portal venous phase VIBE was assessed. In all patients, CDT-VIBE measurements were successfully acquired. The image quality was diagnostic in 46 of the 47 patients. Both readers assessed the highest image quality present in the data sets with a median score of 4 (range, 3-5 for both readers; κ, 0.789) and the worst image quality with a median score of 3 (range, 1-4 for both readers; κ, 0.689). With a range between 1 and 8 (median, 5), hepatic arterial-dominant data sets (of the 14 acquired) were obtained in each case. There was an added diagnostic

  2. Single Breath-Hold Physiotherapy Technique: Effective tool for T2* magnetic resonance imaging in young patients with thalassaemia major.

    Science.gov (United States)

    Mevada, Surekha T; Al-Mahruqi, Najma; El-Beshlawi, Ismail; El-Shinawy, Mohamed; Zachariah, Mathew; Al-Rawas, Abdul H; Daar, Shahina; Wali, Yasser

    2016-02-01

    Magnetic resonance imaging using T2* (MRI T2*) is a highly sensitive and non-invasive technique for the detection of tissue iron load. Although the single breath-hold multi-echo T2* technique has been available at the Sultan Qaboos University Hospital (SQUH), Muscat, Oman, since 2006, it could not be performed on younger patients due to their inability to hold their breath after expiration. This study was carried out between May 2007 and May 2015 and assessed 50 SQUH thalassaemic patients aged 7-17 years old. Seven of these patients underwent baseline and one-year follow-up MRI T2* scans before receiving physiotherapy training. Subsequently, all patients were trained by a physiotherapist to hold their breath for approximately 15-20 seconds at the end of expiration before undergoing baseline and one-year follow-up MRI T2* scans. Failure rates for the pre- and post-training groups were 6.0% and 42.8%, respectively. These results indicate that the training of thalassaemic patients in breath-hold techniques is beneficial and increases rates of compliance for MRI T2* scans.

  3. Clinical and Laboratory Findings of Patients with Breath Holding Spells

    Directory of Open Access Journals (Sweden)

    Özlem Özdemir

    2009-09-01

    Full Text Available Aim: The aim of this prospective study was to evaluate the clinical characteristics; physical findings, cardiological, hematological and neurological problems; treatment approaches; and the prognosis of children with breath holding spells.Materials and Method: Seventhy patients were included in this study. All patients were evaluated with detailed history and physical examination. Complete blood count, serum iron and iron binding capacity were studied; cardiological (telecardiography, electrocardiography, if necessary echocardiography and event recorder and neurological investigations (electroencephalography were done during the admission. Patients with iron deficiency anemia and iron deficiency were treated with ferrous sulphate orally. In patients with normal hematological values, no medication was used. After a two-month treatment period patients underwent control hematological evaluation. Frequency of the spells, age of disappearance of spells (defined as 6 months without spells, disappearance ratios between the three groups were compared. Results: The percentage of cyanotic, palloric and mixt type of breath holding spells of 70 patients included in the study were 67.1, 14.3 and 18.6, respectively. It was determined that psychogenic factors played a role in 77.1% of our patients. There were iron deficiency anemia in 39 (55.7%, iron deficiency in 12 (17.2% and normal hematological parameters in 19 (27.1% of 70 patients. The QTc values were normal in all of them. EEG’s were normal in 56 (80%, dysrhythmic in 11 (15.7% and pathologic in (4.3%. There was a positive family history of breath holding spells in 44.3% of those with breath holding spells. Conclusion: We determined that there was a correlation between the iron levels and the frequency of spells. The lower the iron levels the higher the frequency of spells. There was a dramatic decrease of 92% in spells with low doses of iron supplementation especially in the anemic group. (Journal of

  4. Deep inspiration breath-hold radiotherapy for lung cancer

    DEFF Research Database (Denmark)

    Josipovic, Mirjana; Persson, Gitte F; Bangsgaard, Jens P

    2016-01-01

    OBJECTIVE: We investigated the impact of deep inspiration breath-hold (DIBH) and tumour baseline shifts on image quality and registration uncertainty in image-guided DIBH radiotherapy (RT) for locally advanced lung cancer. METHODS: Patients treated with daily cone beam CT (CBCT)-guided free...... ≤2 mm did not affect the CBCT image quality considerably. CONCLUSION: DIBH CBCT improved image quality and reduced registration uncertainty in the craniocaudal direction in image-guided RT of locally advanced lung cancer. Baseline shifts ≤2 mm in DIBH during CBCT acquisition did not affect image...

  5. Energy cost and optimisation in breath-hold diving.

    Science.gov (United States)

    Trassinelli, M

    2016-05-07

    We present a new model for calculating locomotion costs in breath-hold divers. Starting from basic mechanics principles, we calculate the work that the diver must provide through propulsion to counterbalance the action of drag, the buoyant force and weight during immersion. Compared to those in previous studies, the model presented here accurately analyses breath-hold divers which alternate active swimming with prolonged glides during the dive (as is the case in mammals). The energy cost of the dive is strongly dependent on these prolonged gliding phases. Here we investigate the length and impacts on energy cost of these glides with respect to the diver characteristics, and compare them with those observed in different breath-hold diving species. Taking into account the basal metabolic rate and chemical energy to propulsion transformation efficiency, we calculate optimal swim velocity and the corresponding total energy cost (including metabolic rate) and compare them with observations. Energy cost is minimised when the diver passes through neutral buoyancy conditions during the dive. This generally implies the presence of prolonged gliding phases in both ascent and descent, where the buoyancy (varying with depth) is best used against the drag, reducing energy cost. This is in agreement with past results (Miller et al., 2012; Sato et al., 2013) where, when the buoyant force is considered constant during the dive, the energy cost was minimised for neutral buoyancy. In particular, our model confirms the good physical adaption of dolphins for diving, compared to other breath-hold diving species which are mostly positively buoyant (penguins for example). The presence of prolonged glides implies a non-trivial dependency of optimal speed on maximal depth of the dive. This extends previous findings (Sato et al., 2010; Watanabe et al., 2011) which found no dependency of optimal speed on dive depth for particular conditions. The energy cost of the dive can be further

  6. Clinical Efficacy of Piracetam on Breath Holding Spells in Children

    Directory of Open Access Journals (Sweden)

    F. Ashrafzadeh

    2004-07-01

    Full Text Available Breath holding spells (BHS is a type of syncope in children , most commonly encontered in the early years of life. Although these athacks don't damage the brain , if these are frequent or prolonged cause , parents frighten , so physician should intervent. In this study we evaluated clinical efficacy of piracetam on B.H.S of children in Mashhad Ghaem Hospital during 2001-2002.In this double blind placebo control study , piracetam or placebo on a randomized basis was administered to children with 40 mg/kg/day in 2 divided doses for 2 months. From the 41 children that were enrolled , 21 cases received piracetam and 20 cases received placebo. Parents denoted the numbers of spells two months before and two months after taking drug. Control of breath holding spells were observed in 90.5% of patients in the group taking piracetam as compared with 40% in the group taking placebo (P = 0.002. Of the all patients 10 cases had iron deficiency anemia so they had taken elemental Fe too. The side effects were the same in these two groups. The results of this study indicated that piracetam was efficient for the treatment of children with B.H.S without greater incidence adverse effects than placebo.

  7. SU-E-J-62: Breath Hold for Left-Sided Breast Cancer: Visually Monitored Deep Inspiration Breath Hold Amplitude Evaluated Using Real-Time Position Management

    Energy Technology Data Exchange (ETDEWEB)

    Conroy, L; Quirk, S; Smith, WL [The University of Calgary, Calgary, AB (Canada); Tom Baker Cancer Centre, Calgary, AB (Canada); Yeung, R; Phan, T [The University of Calgary, Calgary, AB (Canada); Hudson, A [Tom Baker Cancer Centre, Calgary, AB (Canada)

    2015-06-15

    Purpose: We used Real-Time Position Management (RPM) to evaluate breath hold amplitude and variability when gating with a visually monitored deep inspiration breath hold technique (VM-DIBH) with retrospective cine image chest wall position verification. Methods: Ten patients with left-sided breast cancer were treated using VM-DIBH. Respiratory motion was passively collected once weekly using RPM with the marker block positioned at the xiphoid process. Cine images on the tangent medial field were acquired on fractions with RPM monitoring for retrospective verification of chest wall position during breath hold. The amplitude and duration of all breath holds on which treatment beams were delivered were extracted from the RPM traces. Breath hold position coverage was evaluated for symmetric RPM gating windows from ± 1 to 5 mm centered on the average breath hold amplitude of the first measured fraction as a baseline. Results: The average (range) breath hold amplitude and duration was 18 mm (3–36 mm) and 19 s (7–34 s). The average (range) of amplitude standard deviation per patient over all breath holds was 2.7 mm (1.2–5.7 mm). With the largest allowable RPM gating window (± 5 mm), 4 of 10 VM-DIBH patients would have had ≥ 10% of their breath hold positions excluded by RPM. Cine verification of the chest wall position during the medial tangent field showed that the chest wall was greater than 5 mm from the baseline in only 1 out of 4 excluded patients. Cine images verify the chest wall/breast position only, whether this variation is acceptable in terms of heart sparing is a subject of future investigation. Conclusion: VM-DIBH allows for greater breath hold amplitude variability than using a 5 mm gating window with RPM, while maintaining chest wall positioning accuracy within 5 mm for the majority of patients.

  8. Comparison of left and right ventricular ejection and filling parameters by fast cine MR imaging in breath-hold technique: clinical study of 42 patients with cardiomyopathy and coronary heart disease; Vergleich links- und rechtsventrikulaerer Auswurf- und Fuellungsparameter des Herzens mittels Cine MRT in Atemanhaltetechnik: klinische Studie an 42 Patienten mit Kardiomyopathie und koronarer Herzerkrankung

    Energy Technology Data Exchange (ETDEWEB)

    Rominger, M.B.; Bachmann, G.F.; Geuer, M.; Puzik, M.; Rau, W.S. [Giessen Univ. (Germany). Diagnostische Radiologie; Ricken, W.W. [Kerckhoff-Klinik GmbH, Bad Nauheim (Germany). Abt. Kardiologie

    1999-06-01

    Purpose: Quantification of left and right ventricular filling and ejection of localized and diffuse heart diseases with fast cine MR imaging in breath-hold technique. Methods: 42 patients (14 idiopathic dilated cardiomyopathies (DCM), 13 hypertrophic cardiomyopathies (HCM) and 15 coronary artery diseases (CAD)) and 10 healthy volunteers were examined. Time-volume-curves of three left ventricular and one right ventricular slices were evaluated and peak ejection and filling rates (PER, PFR end-diastolic volume (EDV)/s) time to PER and PFR (TPER, TPFR ms) and time of end-systole (TSYS in % RR-intervall) were calculated. Results: There were significant regional and left-/right-sided differences of the filling and ejection of both ventricles within and between the different groups. In DCM the left ventricular PFR was reduced (DCM 3.1 EDV/s; volunteers 4.9 EDV/s) and Z-SYS prolonged (DCM 50.1%; volunteers 35.4%). In CAD there were localized decreased filling rates in comparison to the normal volunteer group (left ventricle: basal: 2.9 and 6.3 EDV/s, apical: 4.4 and 6.3 EDV/s; right ventricle: 3.6 and 5.7 EDV/s). HCM typically showed an isovolumetric lengthening of the endsystole. Conclusions: Cardiac MR imaging in breath-hold technique is suitable for measuring contraction and relaxation disturbances of localized and diffuse heart diseases by means of ejection and filling volume indices. (orig.) [Deutsch] Ziel: Quantifizierung der links- und rechtsventrikulaeren Fuellung und des Auswurfs bei umschriebenen und diffusen Herzerkrankungen mittels schneller Cine MR Bildgebung in Atemanhaltetechnik. Methoden: Untersucht wurden 42 Patienten (14 dilatative Kardiomyopathien (DCM), 13 hypertrophe obstruktive Kardiomyopathien (HCM) und 15 koronare Herzerkrankungen (KHK)) und 10 Probanden. Von drei linksventrikulaeren und einer rechtsventrikulaeren Einzelschicht wurden Zeit-Volumen-Kurven erstellt, aus denen die maximale Auswurf- und Fuellrate (MAR) (MFR eddiastolisches Volumen (EDV

  9. Single Breath-Hold Physiotherapy Technique; Effective tool for T2* magnetic resonance imaging in young patients with thalassaemia major

    Directory of Open Access Journals (Sweden)

    Surekha T. Mevada

    2016-02-01

    Full Text Available Magnetic resonance imaging using T2* (MRI T2* is a highly sensitive and non-invasive technique for the detection of tissue iron load. Although the single breath-hold multi-echo T2* technique has been available at the Sultan Qaboos University Hospital (SQUH, Muscat, Oman, since 2006, it could not be performed on younger patients due to their inability to hold their breath after expiration. This study was carried out between May 2007 and May 2015 and assessed 50 SQUH thalassaemic patients aged 7‒17 years old. Seven of these patients underwent baseline and one-year follow-up MRI T2* scans before receiving physiotherapy training. Subsequently, all patients were trained by a physiotherapist to hold their breath for approximately 15‒20 seconds at the end of expiration before undergoing baseline and one-year follow-up MRI T2* scans. Failure rates for the pre- and post-training groups were 6.0% and 42.8%, respectively. These results indicate that the training of thalassaemic patients in breathhold techniques is beneficial and increases rates of compliance for MRI T2* scans.

  10. Comparative study of fast T 2-weighted images using respiratory triggered, breath-hold, fat suppression and phased array multi coil for liver evaluation by magnetic resonance imaging; Estudo comparativo das sequencias rapidas ponderadas em T2, utilizando-se sincronizacao respiratoria, apneia, supressao de gordura, bobina de corpo e bobina de sinergia para a avaliacao do figado pela ressonancia magnetica

    Energy Technology Data Exchange (ETDEWEB)

    Abbehusen, Cristiane L.; D' Ippolito, Giuseppe; Palacio, Glaucia A.S.; Szejnfeld, Jacob [Universidade Federal de Sao Paulo (UNIFESP), SP (Brazil). Escola Paulista de Medicina (EPM). Dept. de Diagnostico por Imagem]. E-mail: cabbehusen@hotmail.com

    2003-10-01

    The objective of this study was to compare both qualitatively and quantitatively six T 2-weighted turbo spin-echo sequences varying the respiratory compensation technique, associating or not fat tissue suppression and using different types of coils. We performed a prospective study of 71 consecutive patients that were submitted to MRI of the liver using a 1.5 T magnet. The six following pulse sequences were used: fat-suppressed respiratory triggered with conventional body coil; breath-hold fat-suppressed with conventional body coil; non-suppressed respiratory triggered with conventional body coil; breath-hold non fat-suppressed with conventional body coil; fat-suppressed respiratory triggered with phased-array multi coil; breath-hold fat-suppressed with phased-array multi coil. Images were analyzed quantitatively by measuring the signal-to-noise ratios and qualitatively by evaluating the sharpness of hepatic contours, visibility of intrahepatic vessels and other segmental landmarks, and the presence of artifacts. Results: the qualitative analysis showed that the mean values obtained with the six sequences were 7.8, 4.6, 7.9, 5.2, 6.7 and 4.6 respectively. The respiratory-triggered sequences were better than the breath-hold sequences in both qualitative and quantitative analysis (p < 0.001). No significant differences in the values of signal-to-noise ratios and in overall image quality were found between the sequences with and without fat suppression (p . 0.05). The sequences using the body coil were similar in terms of image quality (p . 0.05) and better regarding signal-to-noise ratios than those obtained with the phased=array multi coil (p ,0.001). Our qualitative and quantitative results suggest that the best MRI sequences for the valuation of the liver are the sequences with respiratory triggering using a conventional body coil, with or without fat suppression. (author)

  11. Qualitative assessment of contrast-enhanced magnetic resonance angiography using breath-hold and non-breath-hold techniques in the portal venous system

    Science.gov (United States)

    Goo, Eun-Hoe; Kim, Sun-Ju; Dong, Kyung-Rae; Kim, Kwang-Choul; Chung, Woon-Kwan

    2016-09-01

    The purpose of this study is to evaluate the image quality in delineation of the portal venous systems with two different methods, breath-hold and non-breath-hold by using the 3D FLASH sequence. We used a 1.5 T system to obtain magnetic resonance(MR)images. Arterial and portal phase 3D FLASH images were obtained with breath-hold after a bolus injection of GD-DOTA. The detection of PVS on the MR angiograms was classified into three grades. First, the angiograms of the breath-hold method showed well the portal vein, the splenic vein and the superior mesenteric vein systems in 13 of 15 patients (86%) and the inferior mesenteric vein system in 6 of 15 patients (40%), Second, MR angiograms of the non-breath-hold method demonstrated the PVS and the SMV in 12 of 15 patients (80%) and the IMV in 5 of 15 patients (33%). Our study showed contrast-enhanced 3D FLASH MR angiography, together with the breath-hold technique, may provide reliable and accurate information on the portal venous system.

  12. The Ins and Outs of Breath Holding: Simple Demonstrations of Complex Respiratory Physiology

    Science.gov (United States)

    Skow, Rachel J.; Day, Trevor A.; Fuller, Jonathan E.; Bruce, Christina D.; Steinback, Craig D.

    2015-01-01

    The physiology of breath holding is complex, and voluntary breath-hold duration is affected by many factors, including practice, psychology, respiratory chemoreflexes, and lung stretch. In this activity, we outline a number of simple laboratory activities or classroom demonstrations that illustrate the complexity of the integrative physiology…

  13. Audiovisual biofeedback guided breath-hold improves lung tumor position reproducibility and volume consistency

    Directory of Open Access Journals (Sweden)

    Danny Lee, PhD

    2017-07-01

    Conclusions: This study demonstrated that audiovisual biofeedback can be used to improve the reproducibility and consistency of breath-hold lung tumor position and volume, respectively. These results may provide a pathway to achieve more accurate lung cancer radiation treatment in addition to improving various medical imaging and treatments by using breath-hold procedures.

  14. Role of cerebral blood flow in extreme breath holding

    Directory of Open Access Journals (Sweden)

    Bain Anthony R.

    2016-01-01

    Full Text Available The role of cerebral blood flow (CBF on a maximal breath-hold (BH in ultra-elite divers was examined. Divers (n = 7 performed one control BH, and one BH following oral administration of the non-selective cyclooxygenase inhibitor indomethacin (1.2 mg/kg. Arterial blood gases and CBF were measured prior to (baseline, and at BH termination. Compared to control, indomethacin reduced baseline CBF and cerebral delivery of oxygen (CDO2 by about 26% (p < 0.01. Indomethacin reduced maximal BH time from 339 ± 51 to 319 ± 57 seconds (p = 0.04. In both conditions, the CDO2 remained unchanged from baseline to the termination of apnea. At BH termination, arterial oxygen tension was higher following oral administration of indomethacin compared to control (4.05 ± 0.45 vs. 3.44 ± 0.32 kPa. The absolute increase in CBF from baseline to the termination of apnea was lower with indomethacin (p = 0.01. These findings indicate that the impact of CBF on maximal BH time is likely attributable to its influence on cerebral H+ washout, and therefore central chemoreceptive drive to breathe, rather than to CDO2.

  15. Diverse Presentation of Breath Holding Spells: Two Case Reports with Literature Review

    Directory of Open Access Journals (Sweden)

    Geetanjali Rathore

    2013-01-01

    Full Text Available Breath holding spells are a common and dramatic form of syncope and anoxic seizure in infancy. They are usually triggered by an emotional stimuli or minor trauma. Based on the color change, they are classified into 3 types, cyanotic, pallid, and mixed. Pallid breath holding spells result from exaggerated, vagally-mediated cardiac inhibition, whereas the more common, cyanotic breathholding spells are of more complex pathogenesis which is not completely understood. A detailed and accurate history is the mainstay of diagnosis. An EKG should be strongly considered to rule out long QT syndrome. Spontaneous resolution of breath-holding spells is usually seen, without any adverse developmental and intellectual sequelae. Rare cases of status epilepticus, prolonged asystole, and sudden death have been reported. Reassurance and education is the mainstay of therapy. Occasionally, pharmacologic intervention with iron, piracetam; atropine may be of benefit. Here we present 2 cases, one of each, pallid and cyanotic breath holding spells.

  16. Cardiac Repolarization Changes in the Children with Breath-Holding Spells

    Science.gov (United States)

    Amoozgar, Hamid; Saleh, Fazl; Farhani, Nahal; Rafiei, Mohammad; Inaloo, Soroor; Asadipooya, Ali-Akbar

    2013-01-01

    Objective Breath-holding spells are known as benign attacks, frequencies of which decrease by the development of the autonomic nervous system. The present study aims to compare the electrocardiographic repolarization in children with breath-holding spells. Methods In this study, QT dispersion, QTc dispersion, T peak to T end dispersion, and P wave dispersion of the twelve-lead surface electrocardiography of fifty children who had breath-holding spells were measured and compared with normal children from April 2011 to August 2012. Findings Forty-four (88%) patients had cyanotic spells, while 6 (12%) had pallid spells. QTc dispersion was increased in the patients with breath-holding spells (148.2±33.1) compared to the healthy children (132±27.3) and the difference was statically significant (P = 0.01). Meanwhile, no statistically significant differences were observed between the patients and the control subjects regarding the other parameters (P > 0.05). Conclusion QTc dispersion was significantly increased in the patients with breath-holding spells compared to normal children and this is a sign of cardiac repolarization abnormality as well as the increased risk of cardiac arrhythmia in patients with breath-holding spells. PMID:24910749

  17. SU-E-J-223: A BOLD Contrast Imaging Sequence to Evaluate Oxygenation Changes Due to Breath Holding for Breast Radiotherapy: A Pilot Study

    Energy Technology Data Exchange (ETDEWEB)

    Adamson, J; Chang, Z; Cai, J; Palta, M; Horton, J; Yin, F; Blitzblau, R [Duke University Medical Center, Durham, NC (United States)

    2015-06-15

    Purpose: To develop a robust MRI sequence to measure BOLD breath hold induced contrast in context of breast radiotherapy. Methods: Two sequences were selected from prior studies as candidates to measure BOLD contrast attributable to breath holding within the breast: (1) T2* based Gradient Echo EPI (TR/TE = 500/41ms, flip angle = 60°), and (2) T2 based Single Shot Fast Spin Echo (SSFSE) (TR/TE = 3000/60ms). We enrolled ten women post-lumpectomy for breast cancer who were undergoing treatment planning for whole breast radiotherapy. Each session utilized a 1.5T GE MRI and 4 channel breast coil with the subject immobilized prone on a custom board. For each sequence, 1–3 planes of the lumpectomy breast were imaged continuously during a background measurement (1min) and intermittent breath holds (20–40s per breath hold, 3–5 holds per sequence). BOLD contrast was quantified as correlation of changes in per-pixel intensity with the breath hold schedule convolved with a hemodynamic response function. Subtle motion was corrected using a deformable registration algorithm. Correlation with breath-holding was considered significant if p<0.001. Results: The percentage of the breast ROI with positive BOLD contrast measured by the two sequences were in agreement with a correlation coefficient of R=0.72 (p=0.02). While both sequences demonstrated areas with strong BOLD response, the response was more systematic throughout the breast for the SSFSE (T2) sequence (% breast with response in the same direction: 51.2%±0.7% for T2* vs. 68.1%±16% for T2). In addition, the T2 sequence was less prone to magnetic susceptibility artifacts, especially in presence of seroma, and provided a more robust image with little distortion or artifacts. Conclusion: A T2 SSFSE sequence shows promise for measuring BOLD contrast in the context of breast radiotherapy utilizing a breath hold technique. Further study in a larger patient cohort is warranted to better refine this novel technique.

  18. A hybrid breath hold and continued respiration-triggered technique for time-resolved 3D MRI perfusion studies in lung cancer

    Energy Technology Data Exchange (ETDEWEB)

    Hintze, C. [Deutsches Krebsforschungszentrum (DKFZ), Heidelberg (Germany). Radiologie; Stemmer, A. [Siemens AG (Germany). Healthcare Sector; Bock, M. [Deutsches Krebsforschungszentrum (DKFZ), Heidelberg (DE). Medizinische Physik in der Radiologie] (and others)

    2010-01-15

    Assessment of lung cancer perfusion is impaired by respiratory motion. Imaging times for contrast agent wash-out studies often exceed breath hold capabilities, and respiration triggering reduces temporal resolution. Temporally resolved volume acquisition of entire tumors is required to assess heterogeneity. Therefore, we developed and evaluated an MR measurement technique that exceeds a single breath hold, and provides a variable temporal resolution during acquisition while suspending breath-dependent motion. 20 patients with suspected lung cancer were subjected to perfusion studies using a spoiled 3D gradient echo sequence after bolus injection of 0.07 mmol/kg body weight of Gd-DTPA. 10 acquisitions in expiratory breath hold were followed by 50 navigator-triggered acquisitions under free breathing. Post-processing allowed for co-registration of the 3D data sets. An ROI-based visualization of the signal-time curves was performed. In all cases motion-suspended, time-resolved volume data sets (40 x 33 x 10 cm{sup 3}, voxel size: 2.1 x 2.1 x 5.0 mm{sup 3}) were generated with a variable, initially high temporal resolution (2.25 sec) that was synchronized with the breath pattern and covered up to 8(1)/(2) min. In 7 / 20 cases a remaining offset could be reduced by rigid co-registration. The tumors showed fast wash-in, followed by rapid signal decay (8 / 20) or a plateau. The feasibility of a perfusion study with hybrid breath hold and navigator-triggered time-resolved 3D MRI which combines high initial temporal resolution during breath hold with a long wash-out period under free breathing was demonstrated. (orig.)

  19. Risk of Neurological Insult in Competitive Deep Breath-Hold Diving.

    Science.gov (United States)

    Tetzlaff, Kay; Schöppenthau, Holger; Schipke, Jochen D

    2017-02-01

    It has been widely believed that tissue nitrogen uptake from the lungs during breath-hold diving would be insufficient to cause decompression stress in humans. With competitive free diving, however, diving depths have been ever increasing over the past decades. A case is presented of a competitive free-diving athlete who suffered stroke-like symptoms after surfacing from his last dive of a series of 3 deep breath-hold dives. A literature and Web search was performed to screen for similar cases of subjects with serious neurological symptoms after deep breath-hold dives. A previously healthy 31-y-old athlete experienced right-sided motor weakness and difficulty speaking immediately after surfacing from a breathhold dive to a depth of 100 m. He had performed 2 preceding breath-hold dives to that depth with surface intervals of only 15 min. The presentation of symptoms and neuroimaging findings supported a clinical diagnosis of stroke. Three more cases of neurological insults were retrieved by literature and Web search; in all cases the athletes presented with stroke-like symptoms after single breath-hold dives of depths exceeding 100 m. Two of these cases only had a short delay to recompression treatment and completely recovered from the insult. This report highlights the possibility of neurological insult, eg, stroke, due to cerebral arterial gas embolism as a consequence of decompression stress after deep breath-hold dives. Thus, stroke as a clinical presentation of cerebral arterial gas embolism should be considered another risk of extreme breath-hold diving.

  20. Mean heart dose variation over a course of breath-holding breast cancer radiotherapy.

    Science.gov (United States)

    Dunkerley, Nicolle; Bartlett, Frederick R; Kirby, Anna M; Evans, Philip M; Donovan, Ellen M

    2016-11-01

    The purpose of the work was to estimate the dose received by the heart throughout a course of breath-holding breast radiotherapy. 113 cone-beam CT (CBCT) scans were acquired for 20 patients treated within the HeartSpare 1A study, in which both an active breathing control (ABC) device and a voluntary breath-hold (VBH) method were used. Predicted mean heart doses were obtained from treatment plans. CBCT scans were imported into a treatment planning system, heart outlines defined, images registered to the CT planning scan and mean heart dose recorded. Two observers outlined two cases three times each to assess interobserver and intraobserver variation. There were no statistically significant differences between ABC and VBH heart dose data from CT planning scans, or in the CBCT-based estimates of heart dose, and no effect from the order of the breath-hold method. Variation in mean heart dose per fraction over the three imaged fractions was heart doses were heart dose was at an acceptable level over the duration of breath-holding radiotherapy and was well predicted by the planning system. Advances in knowledge: Mean heart dose was not adversely affected by fraction-to-fraction variations throughout a course of heart-sparing radiotherapy using two well-established breath-holding methods.

  1. Magnetic Resonance Imaging in Breath-Hold Divers with Cerebral Decompression Sickness

    Directory of Open Access Journals (Sweden)

    Ryu Matsuo

    2014-01-01

    Full Text Available The mechanism of cerebral decompression sickness (DCS is still unclear. We report 2 cases of breath-hold divers with cerebral DCS in whom magnetic resonance imaging (MRI demonstrated distinctive characteristics. One case presented right hemiparesthesia, diplopia, and gait disturbance after breath-hold diving into the sea at a depth of 20 m. Brain MRI with fluid-attenuated inversion recovery (FLAIR sequence revealed multiple hyperintense lesions in the right frontal lobe, bilateral thalamus, pons, and right cerebellar hemisphere. The second case presented visual and gait disturbance after repetitive breath-hold diving into the sea. FLAIR imaging showed hyperintense areas in the bilateral occipito-parietal lobes. In both cases, diffusion-weighted imaging and apparent diffusion coefficient mapping revealed hyperintense areas in the lesions identified by FLAIR. Moreover, follow-up MRI showed attenuation of the FLAIR signal abnormalities. These findings are suggestive of transient hyperpermeability in the microvasculature as a possible cause of cerebral DCS.

  2. Effects of Piracetam on Pediatric Breath Holding Spells: A Randomized Double Blind Controlled Trial

    OpenAIRE

    2012-01-01

    How to cite this article:Abbaskhanian A, Ehteshami S, Sajjadi S, Rezai MS. Effects of Piracetam on Pediatric Breath Holding Spells: A Randomized Double Blind Controlled Trial. Iran J Child Neurol Autumn 2012; 6(4): 9-15. Abstarct:Objective Breath holding spells (BHS) are common paroxysmal non-epileptic eventsin the pediatric population which are very stressfull despite their harmlessnature. There has been no specific treatment found for the spells yet. The aimof this study was to evaluate the...

  3. Effects of Piracetam on Pediatric Breath Holding Spells: A Randomized Double Blind Controlled Trial

    Directory of Open Access Journals (Sweden)

    Ali ABBASKHANIAN

    2013-01-01

    Full Text Available How to cite this article:Abbaskhanian A, Ehteshami S, Sajjadi S, Rezai MS. Effects of Piracetam on Pediatric Breath Holding Spells: A Randomized Double Blind Controlled Trial. Iran J Child Neurol Autumn 2012; 6(4: 9-15. Abstarct:Objective Breath holding spells (BHS are common paroxysmal non-epileptic eventsin the pediatric population which are very stressfull despite their harmlessnature. There has been no specific treatment found for the spells yet. The aimof this study was to evaluate the efficacy of piracetam (2-oxo-l-pyrrolidineon these children.Materials & MethodsIn this randomized double blind clinical trial study, 150 children with severe BHS referred to our pediatric outpatient service were enrolled from August2011 to July 2012. The patients were randomized into two equal groups.One received 40mg/kg/day piracetam and the other group received placebo,twice daily. Patients were followed monthly for three months. The numberof attacks/month before and after treatment were documented.ResultsOf the enrolled patients, 86 were boys. The mean age of the patients was17 months (range, 6 to 24 months. In the piracetam group, 1 month after treatment an 81% response to treatment was found. In the placebo group,none of the patients had complete remission and 7% of the cases had partialremission. Overall, control of breath-holding spells was observed in 91%of the patients in the group taking piracetam as compared with 16% in the group taking placebo at the end of the study. There wasd nosignificant difference detected between the groups regarding the prevalenceof drug side effects.ConclusionA significant difference was detected between piracetam and placebo in prevention and controlling BHS. Piracetam (40mg/kg/day had a good effecton our patients. ReferencesDi Mario FJ Jr. Prospective study of children with cyanotic and pallid breath-holding spells. Pediatrics. 2001 Feb;107(2:265-9.Kotagal P, Costa M, Wyllie E, Wolgamuth B. Paroxysmal non epileptic

  4. MR coronary angiography with breath-hold targeted volumes: preliminary clinical results

    NARCIS (Netherlands)

    R.J.M. van Geuns (Robert Jan); P.A. Wielopolski (Piotr); H.G. de Bruin (Hein); B.J.W.M. Rensing (Benno); M. Hulshoff (Maarten); P.M.A. van Ooijen (Peter); P.J. de Feyter (Pim); M. Oudkerk (Matthijs)

    2000-01-01

    textabstractPURPOSE: To assess the clinical value of a magnetic resonance (MR) coronary angiography strategy involving a small targeted volume to image one coronary segment in a single breath hold for the detection of greater than 50% stenosis. MATERIALS AND METHODS:

  5. MR coronary angiography with breath-hold targeted volumes : Preliminary clinical results

    NARCIS (Netherlands)

    van Geuns, R J; Wielopolski, P A; de Bruin, Hein G.; Rensing, B J; Hulshoff, Marc; van Ooijen, P M; de Feyter, P J; Oudkerk, M

    2000-01-01

    PURPOSE: To assess the clinical value of a magnetic resonance (MR) coronary angiography strategy involving a small targeted volume to image one coronary segment in a single breath hold for the detection of greater than 50% stenosis. MATERIALS AND METHODS: Thirty-eight patients referred for elective

  6. Accelerated partial breast irradiation (APBI): are breath-hold and volumetric radiation therapy techniques useful?

    NARCIS (Netherlands)

    Essers, M.; Osman, S.O.; Hol, S.; Donkers, T.; Poortmans, P.M.P.

    2014-01-01

    BACKGROUND: In a selective group of patients accelerated partial breast irradiation (APBI) might be applied after conservative breast surgery to reduce the amount of irradiated healthy tissue. The role of volumetric modulated arc therapy (VMAT) and voluntary moderately deep inspiration breath-hold (

  7. Assessment of heart rate variability in breath holding children by 24 hour Holter monitoring.

    Science.gov (United States)

    Yilmaz, Osman; Ciftel, Murat; Ozturk, Kezban; Kilic, Omer; Kahveci, Hasan; Laloğlu, Fuat; Ceylan, Ozben

    2015-02-01

    Previous studies have shown that the underlying pathophysiologic mechanism in children with breath holding may be generalised autonomic dysregulation. Thus, we performed cardiac rhythm and heart rate variability analyses using 24-hour Holter monitoring to evaluate the cardiac effects of autonomic dysregulation in children with breath-holding spells. We performed cardiac rhythm and heart rate analyses using 24-hour Holter monitors to evaluate the cardiac effects of autonomic dysregulation in children during a breath-holding spell. Our study group consisted of 68 children with breath-holding spells - 56 cyanotic type and 12 pallid type - and 39 healthy controls. Clinical and heart rate variability results were compared between each spell type - cyanotic or pallid - and the control group; significant differences (p50 ms, and square root of the mean of the sum of squares of the differences between adjacent NN intervals values were found between the pallid and cyanotic groups. Holter monitoring for 24 hours and heart rate variability parameters, particularly in children with pallid spells, are crucial for evaluation of cardiac rhythm changes.

  8. Effect of breath holding on cerebrovascular hemodynamics in normal pregnancy and preeclampsia

    NARCIS (Netherlands)

    van Veen, Teelkien R.; Panerai, Ronney B.; Haeri, Sina; Zeeman, Gerda G.; Belfort, Michael A.

    2015-01-01

    Preeclampsia (PE) is associated with endothelial dysfunction and impaired autonomic function, which is hypothesized to cause cerebral hemodynamic abnormalities. Our aim was to test this hypothesis by estimating the difference in the cerebrovascular response to breath holding (BH; known to cause symp

  9. Real time transit dosimetry for the breath-hold radiotherapy technique: An initial experience

    Energy Technology Data Exchange (ETDEWEB)

    Piermattei, Angelo; Cilla, Savino; Grimaldi, Luca (Istituto di Fisica, Universitagrave Cattolica S. Cuore, Roma (Italy)) (and others)

    2008-08-15

    Introduction. The breath-hold is one of the techniques to obtain the dose escalation for lung tumors. However, the change of the patient's breath pattern can influence the stability of the inhaled air volume, IAV, used in this work as a surrogate parameter to assure the tumor position reproducibility during dose delivery. Materials. and method. In this paper, an Elekta active breathing coordinator has been used for lung tumor irradiation. This device is not an absolute spirometer and the feasibility study here presented developed (i) the possibility to select a specific range epsilon of IAV values comfortable for the patient and (ii) the ability of a transit signal rate, obtained by a small ion-chamber positioned on the portal image device, to supply in real time the in vivo isocenter dose reproducibility. Indeed, while the selection of the IAV range depends on the patient's ability to follow instructions for breath-hold, the monitoring can supply to the radiation therapist a surrogate of the tumor irradiation reproducibility. Results. The detection of the (image) in real time during breath-hold was used to determine the interfraction isocenter dose variations due to the reproducibility of the patient's breathing pattern. The agreement between the reconstructed and planned isocenter dose in breath-hold at the interfraction level was well within 1.5%, while in free breathing a disagreement up to 8% was observed. The standard deviation of the [image omitted] in breath-hold observed at the intrafraction level is a bit higher than the one obtained without the patient and this can be justified by the presence of a small residual tumor motion as heartbeat. Conclusion. The technique is simple and can be implemented for routine use in a busy clinic

  10. Treatment of Chronic Breath-Holding in an Adult with Severe Mental Retardation: A Clinical Case Study

    Science.gov (United States)

    Reed, Derek D.; Martens, Brian K.

    2008-01-01

    We describe a clinical case study surrounding the behavioral assessment and operant treatment of, an adult with severe mental retardation who engaged in chronic breath-holding. In this clinical case, previous neurological and medical testing had ruled out biological bases for the individual's breath-holding. A functional behavioral assessment…

  11. Evaluation of pulmonary function using single-breath-hold dual-energy computed tomography with xenon

    Science.gov (United States)

    Kyoyama, Hiroyuki; Hirata, Yusuke; Kikuchi, Satoshi; Sakai, Kosuke; Saito, Yuriko; Mikami, Shintaro; Moriyama, Gaku; Yanagita, Hisami; Watanabe, Wataru; Otani, Katharina; Honda, Norinari; Uematsu, Kazutsugu

    2017-01-01

    Abstract Xenon-enhanced dual-energy computed tomography (xenon-enhanced CT) can provide lung ventilation maps that may be useful for assessing structural and functional abnormalities of the lung. Xenon-enhanced CT has been performed using a multiple-breath-hold technique during xenon washout. We recently developed xenon-enhanced CT using a single-breath-hold technique to assess ventilation. We sought to evaluate whether xenon-enhanced CT using a single-breath-hold technique correlates with pulmonary function testing (PFT) results. Twenty-six patients, including 11 chronic obstructive pulmonary disease (COPD) patients, underwent xenon-enhanced CT and PFT. Three of the COPD patients underwent xenon-enhanced CT before and after bronchodilator treatment. Images from xenon-CT were obtained by dual-source CT during a breath-hold after a single vital-capacity inspiration of a xenon–oxygen gas mixture. Image postprocessing by 3-material decomposition generated conventional CT and xenon-enhanced images. Low-attenuation areas on xenon images matched low-attenuation areas on conventional CT in 21 cases but matched normal-attenuation areas in 5 cases. Volumes of Hounsfield unit (HU) histograms of xenon images correlated moderately and highly with vital capacity (VC) and total lung capacity (TLC), respectively (r = 0.68 and 0.85). Means and modes of histograms weakly correlated with VC (r = 0.39 and 0.38), moderately with forced expiratory volume in 1 second (FEV1) (r = 0.59 and 0.56), weakly with the ratio of FEV1 to FVC (r = 0.46 and 0.42), and moderately with the ratio of FEV1 to its predicted value (r = 0.64 and 0.60). Mode and volume of histograms increased in 2 COPD patients after the improvement of FEV1 with bronchodilators. Inhalation of xenon gas caused no adverse effects. Xenon-enhanced CT using a single-breath-hold technique depicted functional abnormalities not detectable on thin-slice CT. Mode, mean, and volume of HU histograms of xenon images

  12. In vivo proton MRS of normal pancreas metabolites during breath-holding and free-breathing

    Energy Technology Data Exchange (ETDEWEB)

    Su, T.-H. [Department of Radiology, Beijing Friendship Hospital, Capital Medical University, 95 Yong-An Road, Beijing (China); Jin, E.-H., E-mail: erhujin1@hotmail.com [Department of Radiology, Beijing Friendship Hospital, Capital Medical University, 95 Yong-An Road, Beijing (China); Shen, H. [GE China Company Ltd, Healthcare, General Electric Company, Beijing (China); Zhang, Y.; He, W. [Department of Radiology, Beijing Friendship Hospital, Capital Medical University, 95 Yong-An Road, Beijing (China)

    2012-07-15

    Aim: To characterize normal pancreas metabolites using in vivo proton magnetic resonance spectroscopy ({sup 1}H MRS) at 3 T under conditions of breath-holding and free-breathing. Materials and methods: The pancreases of 32 healthy volunteers were examined using {sup 1}H MRS during breath-holding and free-breathing acquisitions in a single-voxel point-resolved selective spectroscopy sequence (PRESS) technique using a 3 T MRI system. Resonances were compared between paired spectra of the two breathing modes. Furthermore, correlations between lipid (Lip) content and age, body-mass index (BMI), as well as choline (Cho) peak visibility of the normal pancreas were analysed during breath-holding. Results: Twenty-nine pairs of spectra were successfully obtained showing three major resonances, Lip, Cho, cholesterol and the unsaturated parts of the olefinic region of fatty acids (Chol + Unsat). Breath-hold spectra were generally better, with higher signal-to-noise ratios (SNR; Z=-2.646, p = 0.008) and Cho peak visible status (Z=-2.449, p = 0.014). Correlations were significant between spectra acquired by the two breathing modes, especially for Lip height, Lip area, and the area of other peaks at 1.9-4.1 ppm. However, the Lip resonance was significantly different between the spectra of the two breathing modes (p < 0.05). In the breath-holding spectra, there were significant positive correlations between Lip peak height, area, and age (r = 0.491 and 0.521, p = 0.007 and 0.004), but not between Lip peak area and BMI. There was no statistical difference in Cho resonances between males and females. The Lip peak height and area were significantly higher in the Cho peak invisible group than in the Cho peak visible group (t = 2.661 and 2.353, p = 0.030 and 0.043). Conclusion: In vivo{sup 1}H MRS of the normal pancreas at 3 T is technically feasible and can characterize several metabolites. {sup 1}H MRS during breath-holding acquisition is superior to that during free

  13. Review of deep inspiration breath-hold techniques for the treatment of breast cancer

    Energy Technology Data Exchange (ETDEWEB)

    Latty, Drew, E-mail: drew.latty@health.nsw.gov.au [Crown Princess Mary Cancer Centre, Westmead Hospital, Sydney, New South Wales (Australia); Stuart, Kirsty E [Crown Princess Mary Cancer Centre, Westmead Hospital, Sydney, New South Wales (Australia); Westmead Breast Cancer Institute, Sydney, New South Wales (Australia); Wang, Wei [Crown Princess Mary Cancer Centre, Westmead Hospital, Sydney, New South Wales (Australia); Westmead Breast Cancer Institute, Sydney, New South Wales (Australia); Nepean Cancer Care Centre, Sydney, New South Wales (Australia); Ahern, Verity [Crown Princess Mary Cancer Centre, Westmead Hospital, Sydney, New South Wales (Australia)

    2015-03-15

    Radiation treatment to the left breast is associated with increased cardiac morbidity and mortality. The deep inspiration breath-hold technique (DIBH) can decrease radiation dose delivered to the heart and this may facilitate the treatment of the internal mammary chain nodes. The aim of this review is to critically analyse the literature available in relation to breath-hold methods, implementation, utilisation, patient compliance, planning methods and treatment verification of the DIBH technique. Despite variation in the literature regarding the DIBH delivery method, patient coaching, visual feedback mechanisms and treatment verification, all methods of DIBH delivery reduce radiation dose to the heart. Further research is required to determine optimum protocols for patient training and treatment verification to ensure the technique is delivered successfully.

  14. Facial immersion in cold water enhances cerebral blood velocity during breath-hold exercise in humans

    DEFF Research Database (Denmark)

    Kjeld, Thomas; Pott, Frank C; Secher, Niels H

    2009-01-01

    180-W exercise (from 47 to 53 cm/s), and this increment became larger with facial immersion (76 cm/s, approximately 62%; P brain with a >100% increase in MCA V(mean), largely...... perfusion evaluated as the middle cerebral artery mean flow velocity (MCA V(mean)) during exercise in nine male subjects. At rest, a breath hold of maximum duration increased the arterial carbon dioxide tension (Pa(CO(2))) from 4.2 to 6.7 kPa and MCA V(mean) from 37 to 103 cm/s (mean; approximately 178%; P...... exercise, a breath hold increased Pa(CO(2)) from 5.9 to 8.2 kPa (P

  15. Assessment of voluntary deep inspiration breath-hold with CINE imaging for breast radiotherapy.

    Science.gov (United States)

    Estoesta, Reuben Patrick; Attwood, Lani; Naehrig, Diana; Claridge-Mackonis, Elizabeth; Odgers, David; Martin, Darren; Pham, Melissa; Toohey, Joanne; Carroll, Susan

    2017-10-01

    Deep Inspiration Breath-Hold (DIBH) techniques for breast cancer radiation therapy (RT) have reduced cardiac dose compared to Free Breathing (FB). Recently, a voluntary deep inspiration breath-hold (vDIBH) technique was established using in-room lasers and skin tattoos to monitor breath-hold. An in-house quality assessment of positional reproducibility during RT delivery with vDIBH in patients with left-sided breast cancer was evaluated. The electronic portal imaging device (EPID) was used in cinematographic (CINE) mode to capture a sequence of images during beam delivery. Weekly CINE images were retrospectively assessed for 20 left-sided breast cancer patients receiving RT in vDIBH, and compared with CINE images of 20 patients treated in FB. The intra-beam motion was assessed and the distance from the beam central axis (CA) to the internal chest wall (ICW) was measured on each CINE image. These were then compared to the planned distance on digitally reconstructed radiograph (DRR). The maximum intra-beam motion for any one patient measurement was 0.30 cm for vDIBH and 0.20 cm for FB. The mean difference between the distance from the CA to ICW on DRR and the equivalent distance on CINE imaging (as treated) was 0.28 cm (SD 0.17) for vDIBH patients and 0.25 cm (SD 0.14) for FB patients (P = 0.458). The measured values were comparable for patients undergoing RT in vDIBH, and for those in FB. This quality assessment showed that using in-room lasers and skin tattoos to independently monitor breath-hold in vDIBH as detected by 'on-treatment' CINE imaging is safe and effective. © 2017 The Royal Australian and New Zealand College of Radiologists.

  16. Facial immersion in cold water enhances cerebral blood velocity during breath-hold exercise in humans

    DEFF Research Database (Denmark)

    Kjeld, Thomas; Pott, Frank C; Secher, Niels H

    2009-01-01

    perfusion evaluated as the middle cerebral artery mean flow velocity (MCA V(mean)) during exercise in nine male subjects. At rest, a breath hold of maximum duration increased the arterial carbon dioxide tension (Pa(CO(2))) from 4.2 to 6.7 kPa and MCA V(mean) from 37 to 103 cm/s (mean; approximately 178%; P...

  17. Functional Mechanism of Lung Mosaic CT Attenuation: Assessment with Deep-Inspiration Breath-Hold Perfusion SPECT-CT Fusion Imaging and Non-Breath-Hold Technegas SPECT

    Energy Technology Data Exchange (ETDEWEB)

    Suga, K.; Yasuhiko, K. (Dept. of Radiology, St. Hill Hospital, Ube, Yamaguchi (Japan)); Iwanaga, H.; Tokuda, O.; Matsunaga, N. (Dept. of Radiology, Yamaguchi Univ. School of Medicine, Ube, Yamaguchi (Japan))

    2009-01-15

    Background: The functional mechanism of lung mosaic computed tomography attenuation (MCA) in pulmonary vascular disease (PVD) and obstructive airway disease (OAD) has not yet been fully clarified. Purpose: To clarify the mechanism of MCA in these diseases by assessing the relationship between regional lung function and CT attenuation change at MCA sites with the use of automated deep-inspiratory breath-hold (DIBrH) perfusion single-photon emission computed tomography (SPECT)-CT fusion images and non-breath-hold Technegas SPECT. Material and Methods: Subjects were 42 PVD patients (31 pulmonary thromboembolism, four primary/two secondary pulmonary hypertension, and five Takayasu arteritis), 12 OAD patients (five acute asthma, four obliterative bronchiolitis, and three bronchiectasis), and 12 normal controls, all of whom had MCA on DIBrH CT. The relationship between regional lung function and CT attenuation change at the lung slices with MCA was assessed using DIBrH perfusion SPECT-CT fusion images and non-breath-hold Technegas SPECT. The severity of perfusion defects with or without MCA was quantified by regions-of-interest analysis. Results: On DIBrH CT and perfusion SPECT, in contrast to no noticeable CT attenuation abnormality and fairly uniform perfusion in controls, 60 MCA and 274 perfusion defects in PVD patients, and 18 MCA and 61 defects in OAD patients were identified, with a total of 77 ventilation defects on Technegas SPECT in all patients. SPECT-CT correlation showed that, throughout the 78 MCA sites of all patients, lung perfusion was persistently decreased at low CT attenuation and preserved at intervening high CT attenuation, while lung ventilation was poorly correlated with CT attenuation change. The radioactivity ratios of reduced perfusion and the intervening preserved perfusion at the 78 perfusion defects with MCA were significantly lower than those at the remaining 257 defects without MCA (P<0.0001). Conclusion: Although further validation is

  18. [Hemodynamic and respiratory changes in athletes during deep breath-hold diving].

    Science.gov (United States)

    Gentile, C; La Scala, S

    2001-12-01

    The study analysed the hemodynamic and respiratory aspects of deep breath-hold diving. One male (59-year-old) and one female (32-year-old) subject were enrolled. They were both champion deep breath-hold divers. The dives were performed in the wet compartment of the hyperbaric chamber, first in thermoneutral (35 degrees C) and then cool (25 degrees C) water. The subjects were monitored using ECG recordings; percentage cannulation of the right radial artery using an aseptic technique. Stroke volume (SV) and cardiac output (CO) were measured using impedance cardiography (Bomed). Variations were observed in heart rhythm, cardiac output, arterial blood pressure and breathing. Both bradycardia and many hemodynamically effective dysrhythmias influenced CO, which showed a tendency to decrease in the diver in cool water. Changes in CO were caused by concomitant changes in HR as SV showed no significant variations. During breath-hold diving, a drop in intra-thoracic pressure is likely to enhance redistribution of blood from the periphery to the chest, which might distend the heart even more, contributing to dysrhythmogenesis. The observation that dysrhythmias were more frequent in cool water is in line with these concepts. Only two leading divers were recruited in this study and observed for hemodynamic and respiratory changes. However, these findings are in line with similar studies carried out by other authors.

  19. Panic disorder in a breath-holding challenge test: a simple tool for a better diagnosis

    Directory of Open Access Journals (Sweden)

    Nardi Antonio E.

    2003-01-01

    Full Text Available OBJECTIVE: Our aim was to observe if anxiety disorder patients - DSM-IV - respond in a similar way to the induction of panic attacks by a breath-holding challenge test. METHOD: We randomly selected 29 panic disorder (PD patients, 27 social anxiety disorder (SAD patients, 21 generalized anxiety disorder (GAD patients. They were induced to breath-hold for as long as possible four times with two-minute interval between them. Anxiety scales were applied before and after the test. RESULTS: A total of 44.8% (n=13 PD patients, 14.8% (n=4 SAD patients, 9.5% (n=2 GAD patients had a panic attack after the test (c²= 21.44, df= 2, p=0.001. There was no heart rate or anxiety levels difference among the groups before and after the test. CONCLUSION: In this breath-holding challenge test the panic disorder patients were more sensitive than other anxiety disorder patients.

  20. Multi-center transferability of a breath-hold T2 technique for myocardial iron assessment

    Directory of Open Access Journals (Sweden)

    Chan Godfrey CF

    2008-02-01

    Full Text Available Abstract Background Cardiac iron overload is the leading cause of death in thalassemia major and is usually assessed using myocardial T2* measurements. Recently a cardiovascular magnetic resonance (CMR breath-hold T2 sequence has been developed as a possible alternative. This cardiac T2 technique has good interstudy reproducibility, but its transferability to different centres has not yet been investigated. Methods and Results The breath-hold black blood spin echo T2 sequence was installed and validated on 1.5T Siemens MR scanners at 4 different centres across the world. Using this sequence, 5–10 thalassemia patients from each centre were scanned twice locally within a week for local interstudy reproducibility (n = 34 and all were rescanned within one month at the standardization centre in London (intersite reproducibility. The local interstudy reproducibility (coefficient of variance and mean difference were 4.4% and -0.06 ms. The intersite reproducibility and mean difference between scanners were 5.2% and -0.07 ms. Conclusion The breath-hold myocardial T2 technique is transferable between Siemens scanners with good intersite and local interstudy reproducibility. This technique may have value in the diagnosis and management of patients with iron overload conditions such as thalassemia.

  1. Effect of breath-hold on blood gas analysis in captive Pacific white-sided dolphins (Lagenorhynchus obliquidens).

    Science.gov (United States)

    Terasawa, Fumio; Ohizumi, Hiroshi; Ohshita, Isao

    2010-09-01

    The effect of a breath-hold on blood gas was evaluated in captive Pacific white-sided dolphins (Lagenorhynchus obliquidens). Serial blood collections were performed from a vessel on the ventral surface of the flukes during breath-hold. In total, 178 blood samples were taken from three dolphins for five trials in each animal. During a breath-hold, partial pressure of oxygen (Po₂) decreased from 152.5 to 21.8 mmHg and partial pressure of carbon dioxide (Po₂) conversely increased from 31.8 to 83.6 mmHg. The range of pH was 7.54 to 7.25, suggesting drastic change from alkalemia to acidemia. These wide ranges of blood gas imply a considerable change of oxygen affinity caused by the Bohr effect during breath-hold, which enable effective uptake and distribution of oxygen to metabolizing tissues.

  2. Prospective phase II trial of image-guided radiotherapy in Hodgkin lymphoma: Benefit of deep inspiration breath-hold

    National Research Council Canada - National Science Library

    Petersen, Peter M; Aznar, Marianne C; Berthelsen, Anne K; Loft, Annika; Schut, Deborah A; Maraldo, Maja; Josipovic, Mirjana; Klausen, Thomas L; Andersen, Flemming L; Specht, Lena

    2015-01-01

    .... In this prospective study we investigate whether radiotherapy with deep inspiration breath-hold (DIBH) can reduce radiation doses to the lungs, heart, and cardiac structures without compromising the target dose...

  3. Optimization of single shot 3D breath-hold non-enhanced MR angiography of the renal arteries

    Directory of Open Access Journals (Sweden)

    Tan Huan

    2012-05-01

    Full Text Available Abstract Background Cardiac and navigator-gated, inversion-prepared non-enhanced magnetic resonance angiography techniques can accurately depict the renal arteries without the need for contrast administration. However, the scan time and effectiveness of navigator-gated techniques depend on the subject respiratory pattern, which at times results in excessively prolonged scan times or suboptimal image quality. A single-shot 3D magnetization-prepared steady-state free precession technique was implemented to allow the full extent of the renal arteries to be depicted within a single breath-hold. Methods Technical optimization of the breath-hold technique was performed with fourteen healthy volunteers. An alternative magnetization preparation scheme was tested to maximize inflow signal. Quantitative and qualitative comparisons were made between the breath-hold technique and the clinically accepted navigator-gated technique in both volunteers and patients on a 1.5 T scanner. Results The breath-hold technique provided an average of seven fold reduction in imaging time, without significant loss of image quality. Comparable single-to-noise and contrast-to-noise ratios of intra- and extra-renal arteries were found between the breath-hold and the navigator-gated techniques in volunteers. Furthermore, the breath-hold technique demonstrated good image quality for diagnostic purposes in a small number of patients in a pilot study. Conclusions The single-shot, breath-hold technique offers an alternative to navigator-gated methods for non-enhanced renal magnetic resonance angiography. The initial results suggest a potential supplementary clinical role for the breath-hold technique in the evaluation of suspected renal artery diseases.

  4. The Influence of Age on Interaction between Breath-Holding Test and Single-Breath Carbon Dioxide Test.

    Science.gov (United States)

    Trembach, Nikita; Zabolotskikh, Igor

    2017-01-01

    Introduction. The aim of the study was to compare the breath-holding test and single-breath carbon dioxide test in evaluation of the peripheral chemoreflex sensitivity to carbon dioxide in healthy subjects of different age. Methods. The study involved 47 healthy volunteers between ages of 25 and 85 years. All participants were divided into 4 groups according to age: 25 to 44 years (n = 14), 45 to 60 years (n = 13), 60 to 75 years (n = 12), and older than 75 years (n = 8). Breath-holding test was performed in the morning before breakfast. The single-breath carbon dioxide (SB-CO2) test was performed the following day. Results. No correlation was found between age and duration of breath-holding (r = 0.13) and between age and peripheral chemoreflex sensitivity to CO2 (r = 0.07). In all age groups there were no significant differences in the mean values from the breath-holding test and peripheral chemoreflex sensitivity tests. In all groups there was a strong significant inverse correlation between breath-holding test and SB-CO2 test. Conclusion. A breath-holding test reflects the sensitivity of the peripheral chemoreflex to carbon dioxide in healthy elderly humans. Increasing age alone does not alter the peripheral ventilatory response to hypercapnia.

  5. Chronic adaptations of lung function in breath-hold diving fishermen

    Directory of Open Access Journals (Sweden)

    Cristiane Diniz

    2014-04-01

    Full Text Available Objectives: The aim of this study was to verify and analyze the existence of chronic adaptations of lung function in freediving fishermen whose occupation is artisanal fishing. Material and Methods: This was a cross-sectional study involving 11 breath-hold diving fishermen and 10 non-breath-hold diving fishermen (control from the village of Bitupitá in the municipality of Barroquinha (Ceará - Brazil. Anthropometric measurements, chest and abdominal circumferences as well as spirometric and respiratory muscle strength tests were conducted according to the specifications of the American Thoracic Society/European Respiratory Society (ATS/ERS. In order to compare the measured values versus the predicted values, Student t test was used in the case of parametric test and Wilcoxon test in the case of nonparametric test. To compare the inter-group means Student t test was used for parametric test and Mann-Whitney test for the nonparametric one. The level of significance was set at α = 5%. Results: The forced vital capacity (FVC (4.9±0.6 l vs. 4.3±0.4 l and forced expiratory volume in 1 s (FEV1 (4.0±0.5 l vs. 3.6±0.3 l were, respectively, higher in the group of divers compared to the control group (p ≤ 0.05. Furthermore, in the group of free divers, the measured FVC, FEV1 and FEV1/FVC ratios were significantly greater than the predicted ones. No differences were found between the measured respiratory pressures. Conclusions: These results indicate that breath-hold diving seems to produce chronic adaptations of the respiratory system, resulting in elevated lung volumes with no airway obstruction.

  6. 3D late gadolinium enhancement in a single prolonged breath-hold using supplemental oxygenation and hyperventilation.

    Science.gov (United States)

    Roujol, Sébastien; Basha, Tamer A; Akçakaya, Mehmet; Foppa, Murilo; Chan, Raymond H; Kissinger, Kraig V; Goddu, Beth; Berg, Sophie; Manning, Warren J; Nezafat, Reza

    2014-09-01

    To evaluate the feasibility of three-dimensional (3D) single breath-hold late gadolinium enhancement (LGE) of the left ventricle (LV) using supplemental oxygen and hyperventilation and compressed-sensing acceleration. Breath-hold metrics [breath-hold duration, diaphragmatic/LV position drift, and maximum variation of R wave to R wave (RR) interval] without and with supplemental oxygen and hyperventilation were assessed in healthy adult subjects using a real-time single shot acquisition. Ten healthy subjects and 13 patients then underwent assessment of the proposed 3D breath-hold LGE acquisition (field of view = 320 × 320 × 100 mm(3) , resolution = 1.6 × 1.6 × 5.0 mm(3) , acceleration rate of 4) and a free-breathing acquisition with right hemidiaphragm navigator (NAV) respiratory gating. Semiquantitative grading of overall image quality, motion artifact, myocardial nulling, and diagnostic value was performed by consensus of two blinded observers. Supplemental oxygenation and hyperventilation increased the breath-hold duration (35 ± 11 s to 58 ± 21 s; P  0.01). LGE images were of similar quality when compared with free-breathing acquisitions, but with reduced total scan time (85 ± 22 s to 35 ± 6 s; P < 0.001). Supplemental oxygenation and hyperventilation allow for prolonged breath-holding and enable single breath-hold 3D accelerated LGE with similar image quality as free breathing with NAV. Copyright © 2013 Wiley Periodicals, Inc.

  7. Muscle characteristics in career breath-hold divers: effect of water temperature.

    Science.gov (United States)

    Park, Jeong Bae; Kim, Hyo Jeong; Kim, Jae Cheol; Lutan, Rusli; Kim, Chang Keun

    2005-12-01

    In a previous study we reported that Korean female breath-hold divers (BHD) with life-long experience of diving in cold water (10-12 degrees C in winter and 25-27 degrees C in summer) had reduced muscle fiber size and increased capillary density. The hypothesis tested in the present study was whether prolonged habitual diving at a moderate water temperature (MWT, 29-30 degrees C all year round) similarly caused a reduction in muscle fiber size. The subjects were 14 Indonesian BHDs with long experience of diving at MWT, and a control group of 10 age-matched non-diving Indonesian men (CON), selected from the same tribe among which the BHDs lived. Muscle samples obtained from the middle portion of the vastus lateralis muscle were analyzed for muscle morphology by histochemical analysis and the levels of vascular endothelial growth factor (VEGF) protein by Western blotting. Muscle fiber type composition was identical in both groups, and no difference in cross-sectional area (CSA), VEGF protein, or capillarity between the BHD and the CON was observed. The present study demonstrated that prolonged habitual breath-hold diving at MWT does not cause any alteration in muscle fiber composition, fiber size, or capillarity.

  8. Multi-slice CT for visualization of acute pulmonary embolism: single breath-hold subtraction technique

    Energy Technology Data Exchange (ETDEWEB)

    Wildberger, J.E.; Mahnken, A.H.; Spuentrup, E.; Guenther, R.W. [Dept. of Diagnostic Radiology, Univ. of Technology, Aachen (Germany); Klotz, E.; Ditt, H. [Siemens Medical Solutions, Computed Tomography, Forchheim (Germany)

    2005-01-01

    Purpose: the purpose of our preliminary animal study was to evaluate the feasibility of a new subtraction technique for visualization of perfusion defects within the lung parenchyma in segmental and subsegmental pulmonary embolism (PE). Materials and methods: in three healthy pigs, PE were artificially induced by fresh human clot material. Within a single breath-hold, CT angiography (CTA) was performed on a 16-slice multi-slice CT scanner (SOMATOM Sensation 16; Siemens, Forchheim, Germany) before and after intravenous application of 80 mL of contrast-medium, followed by a saline chaser. Scan parameters were 120 kV and 100 mAs{sub eff.}, using a collimation of 16 x 1.5 mm and a table speed/rot. of 36 mm (pitch: 1.5; rotation time: 0.5 s). A new 3D subtraction technique was developed, which is based on automated segmentation, non-linear spatial filtering and non-rigid registration. Data were analysed using a color-encoded ''compound view'' of parenchymal enhancement and CTA information displayed in axial, coronal and sagittal orientation. Results: subtraction was technically feasible in all three data sets. The mean scan time for each series was 4.7 s, interscan delay was 14.7 s, respectively. Therefore, an average breath-hold of approximately 24 s was required for the overall scanning procedure. Downstream of occluded segmental and subsegmental arteries, perfusion defects were clearly assessable, showing lower or missing enhancement compared to normally perfused lung parenchyma. In all pigs, additional peripheral areas with triangular shaped perfusion defects were delineated, considered typical for PE. Conclusions: our initial results from the animal model studied slow that perfusion imaging of PE is feasible within a single breath-hold. It allows a comprehensive assessment of perfusion deficits as the direct proof of a pulmonary embolus, can be combined with an indirect visual quantification of the density changes in the adjacent lung tissue

  9. Computer tomography guided lung biopsy using interactive breath-hold control

    DEFF Research Database (Denmark)

    Ashraf, Haseem; Krag-Andersen, Shella; Naqibullah, Matiullah

    2017-01-01

    BACKGROUND: Interactive breath-hold control (IBC) may improve the accuracy and decrease the complication rate of computed tomography (CT)-guided lung biopsy, but this presumption has not been proven in a randomized study. METHODS: Patients admitted for CT-guided lung biopsy were randomized...... to biopsy either with (N=201) or without (N=206) IBC. Biopsy accuracy, procedure time, radiation, and complications were compared in the two groups. Predictors for pneumothorax were analyzed. RESULTS: Procedures performed with the use of IBC (N=130) did not show higher biopsy accuracy (P=0.979) but were...... associated with a higher risk of pneumothorax (P=0.022) compared to procedures without the use of IBC (N=171). Overall, 50% of the biopsies were malignant, 13% were benign, and 33% were inconclusive (4% missing). Long needle time (P=0.037) and small nodule size (P=0.001) were predictors of pneumothorax...

  10. Release of erythropoietin and neuron-specific enolase after breath holding in competing free divers

    DEFF Research Database (Denmark)

    Kjeld, Thomas; Jattu, T; Nielsen, Henrik

    2015-01-01

    Free diving is associated with extreme hypoxia. This study evaluated the combined effect of maximal static breath holding and underwater swimming on plasma biomarkers of tissue hypoxemia: erythropoietin, neuron-specific enolase and S100B, C-reactive protein, pro-atrial natriuretic peptide......, and troponin T. Venous blood samples were obtained from 17 competing free divers before and 3 h after sessions of static apnea and underwater swimming. The heart was evaluated by echocardiography. Static apnea for 293 ± 78 s (mean ± SD) and subsequent 88 ± 21 m underwater swimming increased plasma...... = 0.549), and troponin T (P = 0.125) remained unchanged and, as assessed by echocardiography, the heart was not affected. In competitive free divers, bouts of static and dynamic apnea increase plasma erythropoietin and neuron-specific enolase, suggesting that renal and neural tissue, rather than...

  11. Geometric uncertainties in voluntary deep inspiration breath hold radiotherapy for locally advanced lung cancer

    DEFF Research Database (Denmark)

    Josipovic, Mirjana; Persson, Gitte Bjørnsen Fredberg; Dueck, Jenny;

    2016-01-01

    BACKGROUND AND PURPOSE: Deep inspiration breath hold (DIBH) increases lung volume and can potentially reduce treatment-related toxicity in locally advanced lung cancer. We estimated geometric uncertainties in visually guided voluntary DIBH and derived the appropriate treatment margins for different...... image-guidance strategies. MATERIAL AND METHODS: Seventeen patients were included prospectively. An optical marker-based respiratory monitoring with visual guidance enabled comfortable DIBHs, adjusted to each patient's performance. All patients had three consecutive DIBH CTs at each of the treatment...... fractions 2, 16 and 31. DIBH reproducibility was evaluated as inter- and intra-fractional variations in lung volume, tumour position and differential motion between primary tumour and mediastinal lymph nodes. RESULTS: Lung volume increased by median 60% in DIBH. Inter- and intra-fractional lung volume...

  12. Breath holding duration as a measure of distress tolerance: examining its relation to measures of executive control.

    Science.gov (United States)

    Sütterlin, Stefan; Schroijen, Mathias; Constantinou, Elena; Smets, Elyn; Van den Bergh, Omer; Van Diest, Ilse

    2013-01-01

    Recent research considers distress (in)tolerance as an essential component in the development of various forms of psychopathology. A behavioral task frequently used to assess distress tolerance is the breath holding task. Although breath holding time (BHT) has been associated with behavioral outcomes related to inhibitory control (e.g., smoking cessation), the relationship among breath holding and direct measures of executive control has not yet been thoroughly examined. The present study aims to assess (a) the BHT-task's test-retest reliability in a 1-year follow-up and (b) the relationship between a series of executive function tasks and breath holding duration. One hundred and thirteen students completed an initial BHT assessment, 58 of which also completed a series of executive function tasks [the Wisconsin Card Sorting Test (WCST), the Parametric Go/No-Go task and the N-back memory updating task]. A subsample of these students (N = 34) repeated the breath holding task in a second session 1 year later. Test-retest reliability of the BHT-task over a 1-year period was high (r = 0.67, p BHT. The rather moderate levels of unpleasantness induced by breath holding in our sample may suggest that other processes (physiological, motivational) besides distress tolerance influence BHT. Overall, the current findings do not support the assumption of active inhibitory control in the BHT-task in a healthy sample. Our findings suggest that individual differences (e.g., in interoceptive or anxiety sensitivity) should be taken into account when examining the validity of BHT as a measure of distress tolerance.

  13. Effects of Piracetam on Pediatric Breath Holding Spells: A Randomized Double Blind Controlled Trial

    Directory of Open Access Journals (Sweden)

    Mohammad Sadegh REZAI

    2012-10-01

    Full Text Available ObjectiveBreath holding spells (BHS are common paroxysmal non-epileptic events in the pediatric population which are very stressful despite their harmless nature. There has been no specific treatment found for the spells yet. The aim of this study was to evaluate the efficacy of piracetam (2-oxo-l-pyrrolidineon these children.Materials & MethodsIn this randomized double blind clinical trial study, 150 children with severe BHS referred to our pediatric outpatient service were enrolled from August 2011 to July 2012. The patients were randomized into two equal groups.One received 40mg/kg/day piracetam and the other group received placebo,twice daily. Patients were followed monthly for three months. The number of attacks/month before and after treatment were documented.Results Of the enrolled patients, 86 were boys. The mean age of the patients was 17 months (range, 6 to 24 months. In the piracetam group, 1 month after treatment an 81% response to treatment was found. In the placebo group,none of the patients had complete remission and 7% of the cases had partial remission. Overall, control of breath-holding spells was observed in 91%of the patients in the group taking piracetam as compared with 16% in the group taking placebo at the end of the study. There was nosignificant difference detected between the groups regarding the prevalence of drug side effects.ConclusionA significant difference was detected between piracetam and placebo in prevention and controlling BHS. Piracetam (40mg/kg/day had a good effect on our patients.

  14. SU-E-T-450: How Important Is a Reproducible Breath Hold for DIBH Breast Radiotherapy?

    Energy Technology Data Exchange (ETDEWEB)

    Liu, H; Wentworth, S; Sintay, B; Wiant, D [Cone Health Cancer Center, Greensboro, NC (United States)

    2015-06-15

    Purpose: Deep inspiration breath hold (DIBH) for left-sided breast cancer has been shown to reduce heart dose. Surface imaging helps to ensure accurate breast positioning, but does not guarantee a reproducible breath hold (BH) at DIBH treatments. We examine the effects of variable BH positions for DIBH treatments. Methods: Twenty-Five patients with free breathing (FB) and DIBH scans were reviewed. Four plans were created for each patient: 1) FB, 2) DIBH, 3) FB-DIBH – the DIBH plans were copied to the FB images and recalculated (image registration was based on breast tissue), and 4) P-DIBH – a partial BH with the heart shifted midway between the FB and DIBH positions. The FB-DIBH plans give “worst case” scenarios for surface imaging DIBH, where the breast is aligned by surface imaging but the patient is not holding their breath. Students t-tests were used to compare dose metrics. Results: The DIBH plans gave lower heart dose and comparable breast coverage versus FB in all cases. The FB-DIBH plans showed no significant difference versus FB plans for breast coverage, mean heart dose, or maximum heart dose (p >= 0.10). The mean heart dose differed between FB-DIBH and FB by < 2 Gy for all cases, the maximum heart dose differed by < 2 Gy for 21 cases. The P-DIBH plans showed significantly lower mean heart dose than FB (p = 0.01). The mean heart doses for the P-DIBH plans were < FB for 22 cases, the maximum dose < FB for 18 cases. Conclusions: A DIBH plan delivered to a FB patient set-up with surface imaging will yield similar dosimetry to a plan created and delivered FB. A DIBH plan delivered with even a partial BH can give reduced heart dose compared to FB techniques when the breast tissue is well aligned.

  15. Cardiac output in exercise by impedance cardiography during breath holding and normal breathing.

    Science.gov (United States)

    Du Quesnay, M C; Stoute, G J; Hughson, R L

    1987-01-01

    Estimation of cardiac output by impedance cardiography (QZ) in exercise during normal breathing (NB) has been limited by motion artifact. Our objective was to obtain readable impedance cardiograms on five subjects during upright cycle exercise at 0, 50, 100, 150, and 200 W to permit comparisons of QZ during NB, expiratory breath hold (EXP) and inspiratory breath hold (INSP). Q was also determined using an equilibration CO2 rebreathing method [Q(RB)]. QZ during NB exceeded EXP QZ at 100, 150, and 200 W, and exceeded INSP QZ at 100 W (P less than 0.05). The low EXP QZ values were due to a significantly lower stroke volume at 100, 150, and 200 W (P less than 0.05). For the INSP QZ at 100 W, heart rate was lower than during EXP (P less than 0.05). Regression of QZ (NB) against Q(RB) resulted in a linear relationship (r = 0.93) over the range of Q = 7-26 1/min. The slope of the regression differed significantly from 1.0 (P less than 0.05). We conclude that QZ values obtained during EXP or INSP should not be assumed to represent QZ during NB, at least at work rates greater than 50 W. A consequence of the linear relationship between QZ(NB) and Q(RB) over the range of 0-200 W is that estimates of CO2 rebreathing cardiac output can be obtained by impedance cardiography if QZ is adjusted using an appropriate empirical factor.

  16. Effects of Piracetam on Pediatric Breath Holding Spells: A Randomized Double Blind Controlled Trial

    Science.gov (United States)

    ABBASKHANIAN, Ali; EHTESHAMI, Sara; SAJJADI, Sadegh; REZAI, Mohammad Sadegh

    2012-01-01

    Objective Breath holding spells (BHS) are common paroxysmal non-epileptic events in the pediatric population which are very stressfull despite their harmless nature. There has been no specific treatment found for the spells yet. The aim of this study was to evaluate the efficacy of piracetam (2-oxo-l-pyrrolidine) on these children. Materials & Methods In this randomized double blind clinical trial study, 150 children with severe BHS referred to our pediatric outpatient service were enrolled from August 2011 to July 2012. The patients were randomized into two equal groups. One received 40mg/kg/day piracetam and the other group received placebo, twice daily. Patients were followed monthly for three months. The number of attacks/month before and after treatment were documented. Results Of the enrolled patients, 86 were boys. The mean age of the patients was 17 months (range, 6 to 24 months). In the piracetam group, 1 month after treatment an 81% response to treatment was found. In the placebo group, none of the patients had complete remission and 7% of the cases had partial remission. Overall, control of breath-holding spells was observed in 91% of the patients in the group taking piracetam as compared with 16% in the group taking placebo at the end of the study. There was no significant difference detected between the groups regarding the prevalence of drug side effects. Conclusion A significant difference was detected between piracetam and placebo in prevention and controlling BHS. Piracetam (40mg/kg/day) had a good effect on our patients. PMID:24665274

  17. Iron supplementation reduces the frequency and severity of breath-holding attacks in non-anaemic children

    Directory of Open Access Journals (Sweden)

    Anthony Zehetner

    2011-11-01

    Full Text Available Iron supplementation reduces the frequency and severity of breath-holding attacks (BHAs, particularly in children with iron deficiency. The issue of iron supplementation is less clear for Westernized children with BHAs who present to an outpatient community clinic and are not iron-deficient. This is the first reported case series of iron-replete children with frequent and disabling breath-holding attacks who have responded to a course of oral iron supplementation. This intervention is safe, improves quality of life for both child and carer, and is significantly cost-effective in terms of health resource utilization.

  18. Volumetric modulated arc therapy and breath-hold in image-guided locoregional left-sided breast irradiation

    NARCIS (Netherlands)

    Osman, S.O.; Hol, S.; Poortmans, P.M.P.; Essers, M.

    2014-01-01

    PURPOSE: To investigate the effects of using volumetric modulated arc therapy (VMAT) and/or voluntary moderate deep inspiration breath-hold (vmDIBH) in the radiation therapy (RT) of left-sided breast cancer including the regional lymph nodes. MATERIALS AND METHODS: For 13 patients, four treatment co

  19. Volumetric modulated arc therapy and breath-hold in image-guided locoregional left-sided breast irradiation

    NARCIS (Netherlands)

    Osman, S.O.; Hol, S.; Poortmans, P.M.P.; Essers, M.

    2014-01-01

    PURPOSE: To investigate the effects of using volumetric modulated arc therapy (VMAT) and/or voluntary moderate deep inspiration breath-hold (vmDIBH) in the radiation therapy (RT) of left-sided breast cancer including the regional lymph nodes. MATERIALS AND METHODS: For 13 patients, four treatment

  20. [The use of Pantogam syrup in treating small children's breath holding spells].

    Science.gov (United States)

    Polskaya, A V; Chutko, L S; Jakovenko, E V

    To study the efficacy of pantogam syrup 10% (hopantenic acid) in the treatment of breath-holding spells (BHS). Sixty children, aged from 2 to 4 years, with BHS were studied. The evaluation of clinical manifestations and anxiety level was performed. Results of neurophysiological examination (long-term video-EEG-monitoring) were analyzed. Children were divided into 2 groups: main, in which the patients received pantogam syrup, and control group, in which only psychological methods were used. The results of the clinical and neurophysiological studies performed after the treatment, showed the clinical improvement in 73.3% of patients of the main group compared with similar data from the children in the control group (16.7%). The anxiety level significantly decreased after the neuroprotective therapy. A comparative analysis of electroencephalographic indicators demonstrated a significant (рrhythms and manifestations of functional immaturity of the brain in patients of the main group. These results give evidence for the high efficacy of pantogam syrup in the treatment of children with BHS.

  1. Development of a deep inspiration breath-hold system for radiotherapy utilizing a laser distance measurer.

    Science.gov (United States)

    Jensen, Christer Andre; Skottner, Nils; Frengen, Jomar; Lund, Jo-Åsmund

    2017-01-01

    Deep inspiration breath-hold (DIBH) is a technique for treating left-sided breast cancer (LSBC). In modern radiotherapy, one of the main aims is to exclude the heart from the beam aperture with an individualized beam design for LSBC. A deep inhalation will raise the chest wall while the volume of the lungs increase, this will again push the heart away from the breast to be treated. There are a few commercial DIBH systems, both invasive and noninvasive. We present an alternative noninvasive DIBH system based upon an industrial laser distance measurer. This system can be installed in a treatment room at a low cost; it is very easy to use and requires limited amount of training for the personnel and the patient. The system is capable of measuring the position of the chest wall with high frequency and precision in real time. The patient views its breathing curve through video glasses, and gets instructions during the treatment session. The system is well tolerated by test subjects due to its noninvasiveness. © 2016 The Authors. Journal of Applied Clinical Medical Physics published by Wiley Periodicals, Inc. on behalf of American Association of Physicists in Medicine.

  2. Assessment of reproducibility and stability of different breath-hold maneuvres by dynamic MRI: comparison between healthy adults and patients with pulmonary hypertension

    Energy Technology Data Exchange (ETDEWEB)

    Plathow, Christian [German Cancer Research Center Heidelberg, Department of Radiology, Heidelberg (Germany); Eberhard-Karls-University Tuebingen, Department of Diagnostic Radiology, Tuebingen (Germany); Ley, Sebastian; Zaporozhan, Julia; Puderbach, Michael; Eichinger, Monika; Zuna, Ivan; Kauczor, Hans-Ulrich [German Cancer Research Center Heidelberg, Department of Radiology, Heidelberg (Germany); Schoebinger, Max; Meinzer, Hans-Peter [German Cancer Research Center Heidelberg, Department of Medical and Biological Informatics, Heidelberg (Germany); Gruenig, Ekkehard [University of Heidelberg, Department of Internal Medicine III, Heidelberg (Germany)

    2006-01-01

    To assess the stability and reproducibility of different breath-hold levels in healthy volunteers and patients using dynamic MRI (dMRI). In ten healthy volunteers and ten patients with pulmonary hypertension (PH) and normal lung function craniocaudal intrathoracic distances (CCD) were measured during inspiratory and expiratory breath-hold (15 s) (in healthy volunteers additionally at a self-chosen mid-inspiratory breath-hold) using dMRI (trueFISP, three images/s). To evaluate stability and intraobserver reproducibility of the different breath-hold levels, CCDs, time-distance curves, confidence intervals (CIs), Mann-Witney U test and regression equations were calculated. In healthy volunteers there was a substantial decrease of the CCD during the inspiratory breath-hold in contrast to the expiratory breath-hold. The CI at inspiration was 2.84{+-}1.28 in the right and 2.1{+-}0.68 in the left hemithorax. At expiration the CI was 2.54{+-}1.18 and 2.8{+-}1.48. Patients were significantly less able to hold their breath at inspiration than controls (P<0.05). In patients CI was 4.53{+-}4.06 and 3.46{+-}2.21 at inspiration and 4.45{+-}4.23 and 4.76{+-}3.73 at expiration. Intraobserver variability showed no significant differences either in patients or in healthy subjects. Reproducibility was significantly lower at a self-chosen breath-hold level of the healthy volunteers. DMRI is able to differentiate stability and reproducibility of different breath-hold levels. Expiratory breath-hold proved to be more stable than inspiratory breath-hold in healthy volunteers and patients. (orig.)

  3. SU-E-T-383: Evaluation of Deep Inspiration Breath-Hold Technique for Post-Mastectomy Proton Pencil Beam Scanning Therapy

    Energy Technology Data Exchange (ETDEWEB)

    Depauw, N; Patel, S; MacDonald, S; Lu, H [Massachusetts General Hospital, Boston, MA (United States)

    2015-06-15

    Purpose: Deep inspiration breath-hold techniques (DIBH) have been shown to carry significant dosimetric advantages in conventional radiotherapy of left-sided breast cancer. The purpose of this study is to evaluate the use of DIBH techniques for post-mastectomy radiation therapy (PMRT) using proton pencil beam scanning (PBS). Method: Ten PMRT patients, with or without breast implant, underwent two helical CT scans: one with free breathing and the other with deep inspiration breath-hold. A prescription of 50.4 Gy(RBE) to the whole chest wall and lymphatics (axillary, supraclavicular, and intramammary nodes) was considered. PBS plans were generated for each patient’s CT scan using Astroid, an in-house treatment planning system, with the institution conventional clinical PMRT parameters; that is, using a single en-face field with a spot size varying from 8 mm to 14 mm as a function of energy. Similar optimization parameters were used in both plans in order to ensure appropriate comparison. Results: Regardless of the technique (free breathing or DIBH), the generated plans were well within clinical acceptability. DIBH allowed for higher target coverage with better sparing of the cardiac structures. The lung doses were also slightly improved. While the use of DIBH techniques might be of interest, it is technically challenging as it would require a fast PBS delivery, as well as the synchronization of the beam delivery with a gating system, both of which are not currently available at the institution. Conclusion: DIBH techniques display some dosimetric advantages over free breathing treatment for PBS PMRT patients, which warrants further investigation. Plans will also be generated with smaller spot sizes (2.5 mm to 5.5 mm and 5 mm to 9 mm), corresponding to new generation machines, in order to further quantify the dosimetric advantages of DIBH as a function of spot size.

  4. UNDERWATER STROKE KINEMATICS DURING BREATHING AND BREATH-HOLDING FRONT CRAWL SWIMMING

    Directory of Open Access Journals (Sweden)

    Nickos Vezos

    2007-03-01

    Full Text Available The aim of the present study was to determine the effects of breathing on the three - dimensional underwater stroke kinematics of front crawl swimming. Ten female competitive freestyle swimmers participated in the study. Each subject swam a number of front crawl trials of 25 m at a constant speed under breathing and breath-holding conditions. The underwater motion of each subject's right arm was filmed using two S-VHS cameras, operating at 60 Hz, which were positioned behind two underwater viewing windows. The spatial coordinates of selected points were calculated using the DLT procedure with 30 control points and after the digital filtering of the raw data with a cut-off frequency of 6 Hz, the hand's linear displacements and velocities were calculated. The results revealed that breathing caused significantly increases in the stroke duration (t9 = 2.764; p < 0.05, the backward hand displacement relative to the water (t9 = 2.471; p<0.05 and the lateral displacement of the hand in the X - axis during the downsweep (t9 = 2.638; p < 0.05. On the contrary, the peak backward hand velocity during the insweep (t9 = 2.368; p < 0.05 and the displacement of the hand during the push phase (t9 = -2.297; p < 0.05 were greatly reduced when breathing was involved. From the above, it was concluded that breathing action in front crawl swimming caused significant modifications in both the basic stroke parameters and the overall motor pattern were, possibly due to body roll during breathing

  5. SU-E-T-177: Clinical Experience with Spirometer Guided Breath Hold Lung SBRT

    Energy Technology Data Exchange (ETDEWEB)

    Liu, H; Manning, M; Sintay, B; Maurer, J; Hayes, L; Wiant, D [Cone Health Cancer Center, Greensboro, NC (United States)

    2015-06-15

    Purpose: Tumor motion in lung SBRT is typically managed by creating an internal target volume (ITV) based on 4D-CT information. Another option, which may reduce lung dose and imaging artifact, is to use a breath hold (BH) during simulation and delivery. Here we evaluate the reproducibility of tumor position at repeated BH using a newly released spirometry system. Methods: Three patients underwent multiple BH CT’s at simulation. All patients underwent a BH cone beam CT (CBCT) prior to each treatment. All image sets were registered to a patient’s first simulation CT based on local bony anatomy. The gross tumor volume (GTV), and the diaphragm or the apex of the lung were contoured on the first image set and expanded in 1 mm increments until the GTVs and diaphragms on all image sets were included inside an expanded structure. The GTV and diaphragm margins necessary to encompass the structures were recorded. Results: The first patient underwent 2 BH CT’s and fluoroscopy at simulation, the remaining patients underwent 3 BH CT’s at simulation. In all cases the GTV’s remained within 1 mm expansions and the diaphragms remained within 2 mm expansions on repeat scans. Each patient underwent 3 daily BH CBCT’s. In all cases the GTV’s remained within a 2 mm expansions, and the diaphragms (or lung apex in one case) remained within 2 mm expansions at daily BH imaging. Conclusions: These case studies demonstrate spirometry as an effective tool for limiting tumor motion (and imaging artifact) and facilitating reproducible tumor positioning over multiple set-ups and BH’s. This work was partially supported by Qfix.

  6. SU-C-19A-01: A Simple Deep Inspiration Breath Hold System

    Energy Technology Data Exchange (ETDEWEB)

    Rasmussen, B; Kaznowski, L; Blackburn, J; Chu, K [Marquette General Hospital, Marquette, MI (United States); Duelge, J; Baldwin, B; Valenti, M; Hunsader, A [Dickinson County Healthcare System, Iron Mountain, MI (United States)

    2014-06-15

    Purpose: Deep Inspiration Breath Hold (DIBH) Radiation therapy for left sided breast can reduce dose to the lungs and heart. The purpose of this work is to illustrate how to implement a simple method of DIBH for simulation and treatment using equipment readily available in most radiation oncology clinics. Methods: For simulation and treatment, a foam block is placed on the patient's abdomen or chest and a horizontal laser mounted on a movable slide is aimed at the center of the foam block. After a coaching session the block is marked at the average free breathing position and average DIBH position. The position of block relative to laser can be seen by the patient via prism glasses as well as the radiation therapists via a video camera system. Simulation CT scans and treatment delivery are performed under DIBH conditions. Imaging and treatment are performed by manually turning the beam on once the patient has achieved DIBH after being given verbal instructions. Results: Manually triggered imaging was used daily to verify DIBH reproducibility for all patients treated using this system. Sets of before and during port images were used to ensure patient position was appropriate for treatment. Results of the laser on block method were compared to a sister facility using surface mapping techniques for DIBH and the two methods were found to have clinically equivalent reproducibility. Conclusion: The laser and block system was found to be simple to implement and robust during patient treatment. This system can be created from readily available materials at low cost and provides adequate feedback to patient and therapists. During treatment images document the reproducibility of setup and give confidence to clinicians that this method is reproducible from day to day.

  7. Pacemaker in complicated and refractory breath-holding spells: when to think about it?

    Science.gov (United States)

    Sartori, Stefano; Nosadini, Margherita; Leoni, Loira; de Palma, Luca; Toldo, Irene; Milanesi, Ornella; Cerutti, Alessia; Suppiej, Agnese

    2015-01-01

    Breath-holding spells (BHS) are benign non-epileptic paroxysmal events of infancy, rarely occurring with high frequency and complicated by prolonged syncope, convulsions and even status epilepticus. In these cases response to medical treatment is often unsatisfactory. Pacemaker implantation is a possible therapeutic option, but its indications, efficacy and complications have not been clarified yet. To report a new case of BHS treated with pacemaker and to review its indications and efficacy in patients with severe BHS. We extensively searched the literature in PubMed on cardiac pacing in patients with BHS and we described a new case. A previously healthy boy presented at the age of 4 months with frequent BHS inconstantly associated to prolonged syncope and post-anoxic non-epileptic and epileptic seizures. Parental reassurance, iron supplementation and piracetam were ineffective. After cardiac pacing at the age of 16 months, BHS and their complications disappeared. We identified 47 patients with BHS treated with pacemaker in the literature. Based on the available data, in all patients asystole or marked bradycardia were documented during BHS or stimulating maneuvers; syncope complicated BHS in 100% of cases and post-anoxic convulsions in 78.3%. Medical treatment before pacing, when administered, was ineffective or poorly tolerated. After pacing, BHS complications disappeared in 86.4% of cases, and decreased in 13.6%. Technical problems with the device were reported in 25.7% of patients and mild medical complications in 11.4%. Pacemaker could be reasonably considered in subjects with frequent and severe BHS, poor response to medications, and demonstration of cardioinhibition during spells. Copyright © 2014 The Japanese Society of Child Neurology. Published by Elsevier B.V. All rights reserved.

  8. Optical measures of changes in cerebral vascular tone during voluntary breath holding and a Sternberg memory task.

    Science.gov (United States)

    Tan, Chin Hong; Low, Kathy A; Schneider-Garces, Nils; Zimmerman, Benjamin; Fletcher, Mark A; Maclin, Edward L; Chiarelli, Antonio M; Gratton, Gabriele; Fabiani, Monica

    2016-07-01

    The human cerebral vasculature responds to changes in blood pressure and demands for oxygenation via cerebral autoregulation. Changes in cerebrovascular tone (vasoconstriction and vasodilation) also mediate the changes in blood flow measured by the BOLD fMRI signal. This cerebrovascular reactivity is known to vary with age. In two experiments, we demonstrate that cerebral pulse parameters measured using optical imaging can quantify changes in cerebral vascular tone, both globally and locally. In experiment 1, 51 older adults (age range=55-87) performed a voluntary breath-holding task while cerebral pulse amplitude measures were taken. We found significant pulse amplitude variations across breath-holding periods, indicating vasodilation during, and vasoconstriction after breath holding. The breath-holding index (BHI), a measure of cerebrovascular reactivity (CVR) was derived and found to correlate with age. BHI was also correlated with performance in the Modified Mini-Mental Status Examination, even after controlling for age and education. In experiment 2, the same participants performed a Sternberg task, and changes in regional pulse amplitude between high (set-size 6) and low (set-size 2) task loads were compared. Only task-related areas in the fronto-parietal network (FPN) showed significant reduction in pulse amplitude, indicating vasodilation. Non-task-related areas such as the somatosensory and auditory cortices did not show such reductions. Taken together, these experiments suggest that optical pulse parameters can index changes in brain vascular tone both globally and locally, using both physiological and cognitive load manipulations. Copyright © 2016 Elsevier B.V. All rights reserved.

  9. Accuracy of Dose Delivery in Multiple Breath-Hold Segmented Volumetric Modulated Arc Therapy: A Static Phantom Study

    Directory of Open Access Journals (Sweden)

    Kimiya Noto

    2014-01-01

    Full Text Available Purpose. Accuracy of dose delivery in multiple breath-hold segmented volumetric modulated arc therapy (VMAT was evaluated in comparison to noninterrupted VMAT using a static phantom. Material and Methods. Five VMAT plans were evaluated. A Synergy linear accelerator (Elekta AB, Stockholm, Sweden was employed. A VMAT delivery sequence was divided into multiple segments according to each of the predefined breath-hold periods (10, 15, 20, 30, and 40 seconds. The segmented VMAT delivery was compared to noninterrupted VMAT delivery in terms of the isocenter dose and pass rates of a dose difference of 1% with a dose threshold of 10% of the maximum dose on a central coronal plane using a two-dimensional dosimeter, MatriXX Evolution (IBA Dosimetry, Schwarzenbruck, Germany. Results. Means of the isocenter dose differences were 0.5%, 0.2%, 0.2%, 0.0%, and 0.0% for the beam-on-times between interrupts of 10, 15, 20, 30, and 40 seconds, respectively. Means of the pass rates were 85%, 99.9%, 100%, 100%, and 100% in the same order as the above. Conclusion. Our static phantom study indicated that the multiple breath-hold segmented VMAT maintains stable and accurate dose delivery when the beam-on-time between interrupts is 15 seconds or greater.

  10. Double-blind, placebo-controlled trial on the effect of piracetam on breath-holding spells.

    Science.gov (United States)

    Sawires, Happy; Botrous, Osama

    2012-07-01

    Breath-holding spells (BHS) are apparently frightening events occurring in otherwise healthy children.The aim of this study was to evaluate the efficacy of piracetam in the treatment of breath-holding spells. Forty patients with BHS (who were classified into two groups)were involved in a double-blinded placebo-controlled prospective study. Piracetam was given to group A while group B received placebo. Patients were followed monthly for a total period of 4 months. The numbers of attacks/month before and monthly after treatment were documented, and the overall number of attacks/month after treatment was calculated in both groups. The median number of attacks/month before treatment in the two groups was 5.5 and 5,respectively, while after the first month of treatment, it was 2 and 5, respectively. The median overall number of attacks/month after treatment in both groups was 1 and 5, respectively.There was a significant decline of number of attacks after piracetam treatment compared to placebo (p valuepiracetam throughout the study period. In conclusion, piracetam is a safe and effective drug for the treatment of breath-holding spells in children.

  11. Real-time breath-hold triggering of myocardial perfusion imaging with a novel cadmium-zinc-telluride detector gamma camera

    Energy Technology Data Exchange (ETDEWEB)

    Buechel, Ronny R.; Pazhenkottil, Aju P.; Herzog, Bernhard A.; Husmann, Lars; Nkoulou, Rene N.; Burger, Irene A.; Valenta, Ines; Wyss, Christophe A.; Ghadri, Jelena R. [University Hospital Zurich, Cardiac Imaging, Zurich (Switzerland); Kaufmann, Philipp A. [University Hospital Zurich, Cardiac Imaging, Zurich (Switzerland); University of Zurich, Zurich Center for Integrative Human Physiology (ZIHP), Zurich (Switzerland)

    2010-10-15

    The aim of this study was to assess the ability of real-time breath-hold-triggered myocardial perfusion imaging (MPI) using a novel cadmium-zinc-telluride (CZT) gamma camera to discriminate artefacts from true perfusion defects. A group of 40 patients underwent a 1-day {sup 99m}Tc-tetrofosmin pharmacological stress/rest imaging protocol on a conventional dual detector SPECT gamma camera with and without attenuation correction (AC), immediately followed by scanning on an ultrafast CZT camera with and without real-time breath-hold triggering (instead of AC) by intermittent scanning confined to breath-hold at deep inspiration (using list mode acquisition). We studied the use of breath-hold triggering on the CZT camera and its ability to discriminate artefacts from true perfusion defects using AC SPECT MPI as the reference standard. Myocardial tracer uptake (percent of maximum) from CZT was compared to AC SPECT MPI by intraclass correlation and by calculating Bland-Altman limits of agreement. AC of SPECT MPI identified 19 apparent perfusion defects as artefacts. Of these, 13 were correctly identified and 4 were partially unmasked (decrease in extent and/or severity) by breath-hold triggering of the CZT scan. All perfusion defects verified by SPECT MPI with AC were appropriately documented by CZT with and without breath-hold triggering. This was supported by the quantitative analysis, as the correlation (r) of myocardial tracer uptake between CZT and AC SPECT improved significantly from 0.81 to 0.90 (p<0.001) when applying breath-hold triggering. Similarly, Bland-Altman limits of agreement were narrower for CZT scans with breath-hold triggering. This novel CZT camera allows real-time breath-hold triggering as a potential alternative to AC to assist in the discrimination of artefacts from true perfusion defects. (orig.)

  12. SU-E-J-236: Audiovisual Biofeedback Improves Breath-Hold Lung Tumor Position Reproducibility Measured with 4D MRI

    Energy Technology Data Exchange (ETDEWEB)

    Lee, D; Pollock, S; Keall, P [Radiation Physics Laboratory, Sydney Medical School, The University of Sydney, NSW (Australia); Greer, P [School of Mathematical and Physical Sciences, The University of Newcastle, Newcastle, NSW (Australia); Department of Radiation Oncology, Calvary Mater Newcastle, Newcastle, NSW (Australia); Lapuz, C; Ludbrook, J [Department of Radiation Oncology, Calvary Mater Newcastle, Newcastle, NSW (Australia); Kim, T [Radiation Physics Laboratory, Sydney Medical School, The University of Sydney, NSW (Australia); Department of Radiation Oncology, University of Virginia Health System, Charlottesville, VA (United States)

    2015-06-15

    Purpose: Audiovisual biofeedback breath-hold (AVBH) was employed to reproduce tumor position on inhale and exhale breath-holds for 4D tumor information. We hypothesize that lung tumor position will be more consistent using AVBH compared with conventional breath-hold (CBH). Methods: Lung tumor positions were determined for seven lung cancer patients (age: 25 – 74) during to two separate 3T MRI sessions. A breathhold training session was performed prior to the MRI sessions to allow patients to become comfortable with AVBH and their exhale and inhale target positions. CBH and AVBH 4D image datasets were obtained in the first MRI session (pre-treatment) and the second MRI session (midtreatment) within six weeks of the first session. Audio-instruction (MRI: Siemens Skyra) in CBH and verbal-instruction (radiographer) in AVBH were used. A radiation oncologist contoured the lung tumor using Eclipse (Varian Medical Systems); tumor position was quantified as the centroid of the contoured tumor after rigid registration based on vertebral anatomy across two MRI sessions. CBH and AVBH were compared in terms of the reproducibility assessed via (1) the difference between the two exhale positions for the two sessions and the two inhale positions for the sessions. (2) The difference in amplitude (exhale to inhale) between the two sessions. Results: Compared to CBH, AVBH improved the reproducibility of two exhale (or inhale) lung tumor positions relative to each other by 33%, from 6.4±5.3 mm to 4.3±3.0 mm (p=0.005). Compared to CBH, AVBH improved the reproducibility of exhale and inhale amplitude by 66%, from 5.6±5.9 mm to 1.9±1.4 mm (p=0.005). Conclusions: This study demonstrated that audiovisual biofeedback can be utilized for improving the reproducibility of breath-hold lung tumor position. These results are advantageous towards achieving more accurate emerging radiation treatment planning methods, in addition to imaging and treatment modalities utilizing breath-hold

  13. Fourier modeling of the BOLD response to a breath-hold task: Optimization and reproducibility.

    Science.gov (United States)

    Pinto, Joana; Jorge, João; Sousa, Inês; Vilela, Pedro; Figueiredo, Patrícia

    2016-07-15

    Cerebrovascular reactivity (CVR) reflects the capacity of blood vessels to adjust their caliber in order to maintain a steady supply of brain perfusion, and it may provide a sensitive disease biomarker. Measurement of the blood oxygen level dependent (BOLD) response to a hypercapnia-inducing breath-hold (BH) task has been frequently used to map CVR noninvasively using functional magnetic resonance imaging (fMRI). However, the best modeling approach for the accurate quantification of CVR maps remains an open issue. Here, we compare and optimize Fourier models of the BOLD response to a BH task with a preparatory inspiration, and assess the test-retest reproducibility of the associated CVR measurements, in a group of 10 healthy volunteers studied over two fMRI sessions. Linear combinations of sine-cosine pairs at the BH task frequency and its successive harmonics were added sequentially in a nested models approach, and were compared in terms of the adjusted coefficient of determination and corresponding variance explained (VE) of the BOLD signal, as well as the number of voxels exhibiting significant BOLD responses, the estimated CVR values, and their test-retest reproducibility. The brain average VE increased significantly with the Fourier model order, up to the 3rd order. However, the number of responsive voxels increased significantly only up to the 2nd order, and started to decrease from the 3rd order onwards. Moreover, no significant relative underestimation of CVR values was observed beyond the 2nd order. Hence, the 2nd order model was concluded to be the optimal choice for the studied paradigm. This model also yielded the best test-retest reproducibility results, with intra-subject coefficients of variation of 12 and 16% and an intra-class correlation coefficient of 0.74. In conclusion, our results indicate that a Fourier series set consisting of a sine-cosine pair at the BH task frequency and its two harmonics is a suitable model for BOLD-fMRI CVR measurements

  14. Modeled risk of ischemic heart disease following left breast irradiation with deep inspiration breath hold.

    Science.gov (United States)

    Eldredge-Hindy, Harriet B; Duffy, Danielle; Yamoah, Kosj; Simone, Nicole L; Skowronski, Jenna; Dicker, Adam P; Anne, Pramila R

    2015-01-01

    Deep inspiration breath hold (DIBH) dramatically reduces radiation dose to the heart during radiation therapy (RT) for left-sided breast cancer, but the subsequent risk of radiation-related ischemic heart disease (IHD) is unknown. Our primary objective was to quantify the risk of IHD following RT with DIBH using modeled risk estimates (MRE). Patients with stage 0-III left-sided breast cancer who received RT with DIBH were retrospectively studied. Computed tomography simulations were performed with DIBH and during free breathing (FB) for comparison of dosimetry. Patients were classified as high risk, at risk, or at optimal risk for IHD and baseline risk estimates for IHD were obtained from historic controls. The excess relative risk of IHD because of left breast RT was calculated using patient-specific dosimetry and an existing dose-effect model. MRE were determined from the sum of baseline risk estimates and excess risk. Between 2002 and 2011, 111 patients were treated using DIBH and 104 were available for analysis. MRE for 10-year risk of IHD with DIBH and FB were 3.25% (interquartile range [IQR], 1.20-3.44) and 3.64% (IQR, 1.43-3.81) (P < .0001), respectively. MRE for lifetime risk of IHD with DIBH and FB were 9.71% (IQR, 1.98-16.62) and 10.28% (IQR, 2.05-16.97) (P < .0001), respectively. MRE were significantly reduced by use of DIBH in all risk groups. The largest absolute risk reduction resulting from the DIBH technique was observed in patients at high risk for IHD. The median relative risk reduction in MRE resulting from DIBH was 11.4% (range, 0-32.0) and 6.4% (range, 0-23.4) at 10 years and throughout the patients' lifetime, respectively. After a median follow-up of 7.0 years (range, 1.3-11.2), the estimated 10-year freedom from IHD was 99.0% (95% confidence interval 93.4-99.8). RT with DIBH may provide breast cancer survivors a clinically significant reduction in the risk of IHD. Copyright © 2015 American Society for Radiation Oncology. Published by

  15. Incorporating breath holding and image guidance in the adjuvant gastric cancer radiotherapy: a dosimetric study

    Directory of Open Access Journals (Sweden)

    Hu Weigang

    2012-06-01

    Full Text Available Abstract Background The respiratory related target motion and setup error will lead to a large margin in the gastric radiotherapy. The purpose of this study is to investigate the dosimetric benefit and the possibility of incorporating the breath-hold (BH technique with online image-guided radiotherapy in the adjuvant gastric cancer radiotherapy. Methods Setup errors and target motions of 22 post-operative gastric cancer patients with surgical clips were analyzed. Clips movement was recorded using the digital fluoroscopics and the probability distribution functions (pdf of the target motions were created for both the free breathing (FB and BH treatment. For dosimetric comparisons, two intensity-modulated radiotherapy (IMRT treatment plans, i.e. the free breathing treatment plan (IMRTFB and the image-guided BH treatment plan (IMRTIGBH using the same beam parameters were performed among 6 randomly selected patients. Different margins for FB and BH plans were derived. The plan dose map was convoluted with various pdfs of the setup errors and the target motions. Target coverage and dose to organs at risk were compared and the dose-escalation probability was assessed. Results The mean setup errors were 1.2 mm in the superior-inferior (SI, 0.0 mm in the left-right (LR, and 1.4 mm in the anterior-posterior (AP directions. The mean target motion for the free breathing (vs. BH was 11.1 mm (vs. 2.2 mm, 1.9 mm (vs. 1.1 mm, and 5.5 mm (vs. 1.7 mm in the SI, LR, and AP direction, respectively. The target coverage was comparable for all the original plans. IMRTIGBH showed lower dose to the liver compared with IMRTFB (p = 0.01 but no significant difference in the kidneys. Convolved IMRTIGBH showed better sparing in kidneys (p  Conclusions Combining BH technique with online image guided IMRT can minimize the organ motion and improve the setup accuracy. The dosimetric comparison showed the dose could be escalated to 54 Gy without

  16. Free-breathing radial volumetric interpolated breathhold examination vs breath-hold cartesian volumetric interpolated breath-hold examination magnetic resonance imaging of the liver at 1.5T

    Institute of Scientific and Technical Information of China (English)

    Sireesha Yedururi; HyunSeon C Kang; Wei Wei; Nicolaus A Wagner-Bartak; Leonardo P Marcal; R Jason Stafford; Brandy J Willis; Janio Szklaruk

    2016-01-01

    AIM: To compare breath-hold cartesian volumetric interpolated breath-hold examination(cVIBE) and freebreathing radial VIBE(rVIBE) and determine whether rVIBE could replace cVIBE in routine liver magnetic resonance imaging(MRI).METHODS: In this prospective study, 15 consecutive patients scheduled for routine MRI of the abdomen underwent pre- and post-contrast breath-hold cVIBE imaging(19 s acquisition time) and free-breathing rVIBE imaging(111 s acquisition time) on a 1.5T Siemens scanner. Three radiologists with 2, 4, and 8 years post-fellowship experience in abdominal imaging evaluated all images. The radiologists were blinded to the sequence types, which were presented in a random order for each patient. For each sequence, the radiologists scored the cVIBE and rVIBE images for liver edge sharpness, hepatic vessel clarity, presence of artifacts, lesion conspicuity, fat saturation, and overall image quality using a five-point scale. RESULTS: Compared to rVIBE, cVIBE yielded significantly(P < 0.001) higher scores for liver edge sharpness(mean score, 3.87 vs 3.37), hepatic-vessel clarity(3.71 vs 3.18), artifacts(3.74 vs 3.06), lesion conspicuity(3.81 vs 3.2), and overall image quality(3.91 vs 3.24). cVIBE and rVIBE did not significantly differ in quality of fat saturation(4.12 vs 4.03, P = 0.17). The inter-observer variability with respect to differences between rVIBE and cVIBE scores was close to zero compared to random error and inter-patient variation. Quality of rVIBE images was rated as acceptable for all parameters. CONCLUSION: rVIBE cannot replace cVIBE in routine liver MRI. At 1.5T, free-breathing rVIBE yields acceptable, although slightly inferior image quality compared to breath-hold cVIBE.

  17. Less increase of CT-based calcium scores of the coronary arteries : Effect three years after breast-conserving radiotherapy using breath-hold.

    Science.gov (United States)

    Mast, M E; Heijenbrok, M W; van Kempen-Harteveld, M L; Petoukhova, A L; Scholten, A N; Wolterbeek, R; Schreur, J H M; Struikmans, H

    2016-10-01

    The aim of this prospective longitudinal study was to compare coronary artery calcium (CAC) scores determined before the start of whole breast irradiation with those determined 3 years afterwards. Changes in CAC scores were analysed in 99 breast cancer patients. Three groups were compared: patients receiving left- and right-sided radiotherapy, and those receiving left-sided radiotherapy with breath-hold. We analysed overall CAC scores and left anterior descending (LAD) and right coronary artery (RCA) CAC scores. Between the three groups, changes of the value of the LAD minus the RCA CAC scores of each individual patient were also compared. Three years after breath-hold-based whole breast irradiation, a less pronounced increase of CAC scores was noted. Furthermore, LAD minus RCA scores in patients treated for left-sided breast cancer without breath-hold were higher when compared to LAD minus RCA scores of patients with right-sided breast cancers and those with left-sided breast cancer treated with breath-hold. Breath-hold in breast-conserving radiotherapy leads to a less pronounced increase of CT-based CAC scores. Therefore, breath-hold probably prevents the development of radiation-induced coronary artery disease. However, the sample size of this study is limited and the follow-up period relatively short.

  18. Single breath hold 3D cardiac cine MRI using kat-ARC: preliminary results at 1.5T.

    Science.gov (United States)

    Jeong, Daniel; Schiebler, Mark L; Lai, Peng; Wang, Kang; Vigen, Karl K; François, Christopher J

    2015-04-01

    Validation of a new single breath-hold, three-dimensional, cine balanced steady-state free precession (3D cine bSSFP) cardiac magnetic resonance (CMR) sequence for left ventricular function. CMR examinations were performed on fifteen patients and three healthy volunteers on a clinical 1.5T scanner using a two-dimensional (2D) cine balanced SSFP CMR sequence (2D cine bSSFP) followed by an investigational 3D cine bSSFP pulse sequence acquired within a single breath hold. Left ventricular end diastolic volume (LVEDV), end systolic volume (LVESV), ejection fraction (LVEF), and myocardial mass were independently segmented on a workstation by two experienced radiologists. Blood pool to myocardial contrast was evaluated in consensus using a Likert scale. Bland-Altman analysis was used to compare these quantitative and nominal measurements for the two sequences. The average acquisition time was significantly shorter for the 3D cine bSSFP than for 2D cine bSSFP (0.36 ± 0.03 vs. 8.5 ± 2.3 min) p = 0.0002. Bland-Altman analyses [bias and (limits of agreement)] of the data derived from these two methods revealed that the LVEF 0.9% (-4.7, 6.4), LVEDV 4.9 ml (-23.0, 32.8), LVESV -0.2 ml (-22.4, 21.9), and myocardial mass -0.4 g (-23.8, 23.0) were not significantly different. There was excellent intraclass correlation for intra-observer variability (0.981, 0.989, 0.997, 0.985) and inter-observer variability (0.903, 0.954, 0.970, 0.842) for LVEF, LVEDV, LVESV, and myocardial mass respectively. 3D cine bSSFP allows for accurate single breath-hold volumetric cine CMR which enables substantial improvements in scanner time efficiency without sacrificing diagnostic accuracy.

  19. Determination of ethane, pentane and isoprene in exhaled air--effects of breath-holding, flow rate and purified air.

    Science.gov (United States)

    Lärstad, M A E; Torén, K; Bake, B; Olin, A-C

    2007-01-01

    Exhaled ethane, pentane and isoprene have been proposed as biomarkers of oxidative stress. The objectives were to explore whether ethane, pentane and isoprene are produced within the airways and to explore the effect of different sampling parameters on analyte concentrations. The flow dependency of the analyte concentrations, the concentrations in dead-space and alveolar air after breath-holding and the influence of inhaling purified air on analyte concentrations were investigated. The analytical method involved thermal desorption from sorbent tubes and gas chromatography. The studied group comprised 13 subjects with clinically stable asthma and 14 healthy controls. Ethane concentrations decreased slightly, but significantly, at higher flow rates in subjects with asthma (P = 0.0063) but not in healthy controls. Pentane levels were increased at higher flow rates both in healthy and asthmatic subjects (P = 0.022 and 0.0063 respectively). Isoprene levels were increased at higher flow rates, but only significantly in healthy subjects (P = 0.0034). After breath-holding, no significant changes in ethane levels were observed. Pentane and isoprene levels increased significantly after 20 s of breath-holding. Inhalation of purified air before exhalation resulted in a substantial decrease in ethane levels, a moderate decrease in pentane levels and an increase in isoprene levels. The major fractions of exhaled ethane, pentane and isoprene seem to be of systemic origin. There was, however, a tendency for ethane to be flow rate dependent in asthmatic subjects, although to a very limited extent, suggesting that small amounts of ethane may be formed in the airways.

  20. “Lung packing” in breath hold-diving: An impressive case of pulmo–cardiac interaction

    Directory of Open Access Journals (Sweden)

    Jochen D. Schipke

    2015-01-01

    Full Text Available There is a complex interaction between the heart and the lungs. We report on a healthy female who performs breath hold diving at a high, international level. In order to optimize pressure equalization during diving and to increase oxygen available, apneists employed a special breathing maneuver, so called “lung packing”. Based on cardiac MRI we could demonstrate impressive effects of this maneuver on left ventricular geometry and hemodynamics. Beyond the fact, that our findings support the concept of pulmonary –cardiac interrelationship, it should be emphasized, that the reported, extreme breathing maneuver could have detrimental consequences due to reduction of stroke volume and cardiac output.

  1. Passive flooding of paranasal sinuses and middle ears as a method of equalisation in extreme breath-hold diving.

    Science.gov (United States)

    Germonpré, Peter; Balestra, Costantino; Musimu, Patrick

    2011-06-01

    Breath-hold diving is both a recreational activity, performed by thousands of enthusiasts in Europe, and a high-performance competitive sport. Several 'disciplines' exist, of which the 'no-limits' category is the most spectacular: using a specially designed heavy 'sled,' divers descend to extreme depths on a cable, and then reascend using an inflatable balloon, on a single breath. The current world record for un-assisted descent stands at more than 200 m of depth. Equalising air pressure in the paranasal sinuses and middle-ear cavities is a necessity during descent to avoid barotraumas. However, this requires active insufflations of precious air, which is thus unavailable in the pulmonary system. The authors describe a diver who, by training, is capable of allowing passive flooding of the sinuses and middle ear with (sea) water during descent, by suppressing protective (parasympathetic) reflexes during this process. Using this technique, he performed a series of extreme-depth breath-hold dives in June 2005, descending to 209 m of sea water on one breath of air.

  2. BREATH-HOLD CINE-MRI DURING DIPYRIDAMOLE STRESS FOR IDENTIFICATION OF SEVERE CORONARY ARTERY STENOSIS:A PRELIMINARY REPORT

    Institute of Scientific and Technical Information of China (English)

    赵世华; DidierRevel; PierreCroisille; JeanP.Roux; MarcJanier; IsabelleMagnin

    1998-01-01

    Breath-hold cine MRI was employed for the identification of severe coronary artery stenoscs after 0.56mg/kg of dipyridamole was infused. Fourteen patients without myocardial infarction but with ≥70% diameter narrowing of 1. or 2 major coronary artaries were studied. Each patient tmderwent coronary angiography, MRI at rest and during stress. Segmental wall motion abnormalities were visually assessed in a cine loop, followed by quantitative analysis by calculation of percent systolic wall thickening(%SWth). The results showed that the sensitivities of 70% and 90% were present for the qualitative and quantitative analyses, respectively, in respect to the approximate specificities(82% & 86%). Further quantitative analysis showed that sensitivities and specifieities were 88% and 88% for 1-vessel disease versus 92% and 83% for 2-vessd disease; 86% and 100% for LAD, 100% and 70% for LCX, 89% and 100% for RCA. We concloded that quantitative analysis is significantly superior to qualitative analysis for the identification of severe coronary stenosis while dipyridamole-induced wall motion abnormalities were assessed by breath-hold cine MRI.

  3. Whole-heart magnetic resonance coronary angiography with multiple breath-holds and automatic breathing-level tracking

    Science.gov (United States)

    Kuhara, Shigehide; Ninomiya, Ayako; Okada, Tomohisa; Kanao, Shotaro; Kamae, Toshikazu; Togashi, Kaori

    2010-05-01

    Whole-heart (WH) magnetic resonance coronary angiography (MRCA) studies are usually performed during free breathing while monitoring the position of the diaphragm with real-time motion correction. However, this results in a long scan time and the patient's breathing pattern may change, causing the study to be aborted. Alternatively, WH MRCA can be performed with multiple breath-holds (mBH). However, one problem in the mBH method is that patients cannot hold their breath at the same position every time, leading to image degradation. We have developed a new WH MRCA imaging method that employs both the mBH method and automatic breathing-level tracking to permit automatic tracking of the changes in breathing or breath-hold levels. Evaluation of its effects on WH MRCA image quality showed that this method can provide high-quality images within a shorter scan time. This proposed method is expected to be very useful in clinical WH MRCA studies.

  4. Breath-holding spells: Prevalence and risk factors in under 6-year old children at south of Tehran

    Directory of Open Access Journals (Sweden)

    P. Tootoonchi

    2001-05-01

    Full Text Available To determine breath- holding spells (BHS prevalence and risk factors in under 6- year- old children, we interviewed mothers of 400 children in a cross- sectional study in 5 health centers at south of Tehran in autumn 1999. 33 children (8.25% had history of BHS (Male: 19, Female: 14 25 cases were between 2-4 years old (mean: 40±17 months. Seventy percent of cases (23 had onset of attacks after 6 months of age (mean: 10 monthis and the commonest frequency was one spell per month (78.79%. Painful experience and falling and striking the head wee the common triggering factors (79% and 76% respectively and there was significant association between BHS and history of fallin and severe striking of the head. There was no significant associations between BHS and sex, birth weight, birth order, delivery method, type of labor initiating and duration of labor.

  5. Accuracy Evaluation of a 3-Dimensional Surface Imaging System for Guidance in Deep-Inspiration Breath-Hold Radiation Therapy

    Energy Technology Data Exchange (ETDEWEB)

    Alderliesten, Tanja; Sonke, Jan-Jakob; Betgen, Anja; Honnef, Joeri; Vliet-Vroegindeweij, Corine van [Department of Radiation Oncology, The Netherlands Cancer Institute-Antoni van Leeuwenhoek Hospital, Amsterdam (Netherlands); Remeijer, Peter, E-mail: p.remeijer@nki.nl [Department of Radiation Oncology, The Netherlands Cancer Institute-Antoni van Leeuwenhoek Hospital, Amsterdam (Netherlands)

    2013-02-01

    Purpose: To investigate the applicability of 3-dimensional (3D) surface imaging for image guidance in deep-inspiration breath-hold radiation therapy (DIBH-RT) for patients with left-sided breast cancer. For this purpose, setup data based on captured 3D surfaces was compared with setup data based on cone beam computed tomography (CBCT). Methods and Materials: Twenty patients treated with DIBH-RT after breast-conserving surgery (BCS) were included. Before the start of treatment, each patient underwent a breath-hold CT scan for planning purposes. During treatment, dose delivery was preceded by setup verification using CBCT of the left breast. 3D surfaces were captured by a surface imaging system concurrently with the CBCT scan. Retrospectively, surface registrations were performed for CBCT to CT and for a captured 3D surface to CT. The resulting setup errors were compared with linear regression analysis. For the differences between setup errors, group mean, systematic error, random error, and 95% limits of agreement were calculated. Furthermore, receiver operating characteristic (ROC) analysis was performed. Results: Good correlation between setup errors was found: R{sup 2}=0.70, 0.90, 0.82 in left-right, craniocaudal, and anterior-posterior directions, respectively. Systematic errors were {<=}0.17 cm in all directions. Random errors were {<=}0.15 cm. The limits of agreement were -0.34-0.48, -0.42-0.39, and -0.52-0.23 cm in left-right, craniocaudal, and anterior-posterior directions, respectively. ROC analysis showed that a threshold between 0.4 and 0.8 cm corresponds to promising true positive rates (0.78-0.95) and false positive rates (0.12-0.28). Conclusions: The results support the application of 3D surface imaging for image guidance in DIBH-RT after BCS.

  6. The assessment of the breath hold and the free breath methods about the blood flow evaluation by using phase contrast MRI

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Seong Ho [Dept. of Radiology, Konkuk Medical center, Seoul (Korea, Republic of)

    2016-06-15

    Measurement of cardiac blood flow using the magnetic resonance imaging has been limited due to breathing and involuntary movements of the heart. The present study attempted to improve the accuracy of cardiac blood flow testing through phase contrast magnetic resonance imaging by presenting the adequate breathing method and imaging variables by comparing the measurement values of cardiac blood flow. Each was evaluated by comparing the breath hold retrospective 1NEX and non breath hold retrospective 1-3NEX in the ascending aorta and descending aorta. As a result, the average blood flow amount/ velocity of the breath hold retrosepctive 1NEX method in the ascending aorta were 96.17±19.12 ml/sec, 17.04±4.12 cm/sec respectively, which demonstrates a statistically significant difference(p<0.05) with the non-breath hold retrospective method 1NEX of 72.31±13.27 ml and 12.32±3.85. On the other hand, the average 2NEX blood flow and mean flow velocity is 101.90±24.09, 16.84±4.32, 3NEX 103.06±25.49, 16.88±4.19 did not show statistically significant differences(p>0.05).The average blood flow amount/ velocity of the breath hold retrospective 1NEX method in the descending aorta were 76.68±19.72 ml/s, and 22.23±4.8, which did not demonstrate a significant difference in comparison to non-breath hold retrospective method 1-3 NEX. Therefore, the non breath hold retrospective method does not significantly differ in terms of cardiac blood flow in comparison with the breath hold retrospective method in accordance with the increase of NEX, so pediatric patients or patients who are not able to breathe well must have the diagnostic value of their cardiac blood flow tests improved.

  7. SU-F-BRB-03: Quantifying Patient Motion During Deep-Inspiration Breath-Hold Using the ABC System with Simultaneous Surface Photogrammetry

    Energy Technology Data Exchange (ETDEWEB)

    Cheung, Y; Rahimi, A; Sawant, A [UT Southwestern Medical Center, Dallas, TX (United States)

    2015-06-15

    Purpose: Active breathing control (ABC) has been used to reduce treatment margin due to respiratory organ motion by enforcing temporary breath-holds. However, in practice, even if the ABC device indicates constant lung volume during breath-hold, the patient may still exhibit minor chest motion. Consequently, therapists are given a false sense of security that the patient is immobilized. This study aims at quantifying such motion during ABC breath-holds by monitoring the patient chest motion using a surface photogrammetry system, VisionRT. Methods: A female patient with breast cancer was selected to evaluate chest motion during ABC breath-holds. During the entire course of treatment, the patient’s chest surface was monitored by a surface photogrammetry system, VisionRT. Specifically, a user-defined region-of-interest (ROI) on the chest surface was selected for the system to track at a rate of ∼3Hz. The surface motion was estimated by rigid image registration between the current ROI image captured and a reference image. The translational and rotational displacements computed were saved in a log file. Results: A total of 20 fractions of radiation treatment were monitored by VisionRT. After removing noisy data, we obtained chest motion of 79 breath-hold sessions. Mean chest motion in AP direction during breath-holds is 1.31mm with 0.62mm standard deviation. Of the 79 sessions, the patient exhibited motion ranging from 0–1 mm (30 sessions), 1–2 mm (37 sessions), 2–3 mm (11 sessions) and >3 mm (1 session). Conclusion: Contrary to popular assumptions, the patient is not completely still during ABC breath-hold sessions. In this particular case studied, the patient exhibited chest motion over 2mm in 14 out of 79 breath-holds. Underestimating treatment margin for radiation therapy with ABC could reduce treatment effectiveness due to geometric miss or overdose of critical organs. The senior author receives research funding from NIH, VisionRT, Varian Medical Systems

  8. Simultaneous Quantitative MRI Mapping of T1, T2* and Magnetic Susceptibility with Multi-Echo MP2RAGE

    Science.gov (United States)

    Kober, Tobias; Möller, Harald E.; Schäfer, Andreas

    2017-01-01

    The knowledge of relaxation times is essential for understanding the biophysical mechanisms underlying contrast in magnetic resonance imaging. Quantitative experiments, while offering major advantages in terms of reproducibility, may benefit from simultaneous acquisitions. In this work, we demonstrate the possibility of simultaneously recording relaxation-time and susceptibility maps with a prototype Multi-Echo (ME) Magnetization-Prepared 2 RApid Gradient Echoes (MP2RAGE) sequence. T1 maps can be obtained using the MP2RAGE sequence, which is relatively insensitive to inhomogeneities of the radio-frequency transmit field, B1+. As an extension, multiple gradient echoes can be acquired in each of the MP2RAGE readout blocks, which permits the calculation of T2* and susceptibility maps. We used computer simulations to explore the effects of the parameters on the precision and accuracy of the mapping. In vivo parameter maps up to 0.6 mm nominal resolution were acquired at 7 T in 19 healthy volunteers. Voxel-by-voxel correlations and the test-retest reproducibility were used to assess the reliability of the results. When using optimized paramenters, T1 maps obtained with ME-MP2RAGE and standard MP2RAGE showed excellent agreement for the whole range of values found in brain tissues. Simultaneously obtained T2* and susceptibility maps were of comparable quality as Fast Low-Angle SHot (FLASH) results. The acquisition times were more favorable for the ME-MP2RAGE (≈ 19 min) sequence as opposed to the sum of MP2RAGE (≈ 12 min) and FLASH (≈ 10 min) acquisitions. Without relevant sacrifice in accuracy, precision or flexibility, the multi-echo version may yield advantages in terms of reduced acquisition time and intrinsic co-registration, provided that an appropriate optimization of the acquisition parameters is performed. PMID:28081157

  9. Breath-hold after forced expiration before removal of the biopsy needle decreased the rate of pneumothorax in CT-guided transthoracic lung biopsy

    Energy Technology Data Exchange (ETDEWEB)

    Min, Lingfeng; Xu, Xingxiang [Subei People' s Hospital of Jiangsu Province, Clinical Medical School of Yangzhou University, Yangzhou 225001, Jiangsu (China); Song, Yong [Jinling Hospital, Nanjing University School of Medical, Nanjing 210002, Jiangsu (China); Issahar, Ben-Dov [Pulmonary Institute, Sheba Medical Center, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv (Israel); Wu, Jingtao; Zhang, Le; Huang, Qian [Subei People' s Hospital of Jiangsu Province, Clinical Medical School of Yangzhou University, Yangzhou 225001, Jiangsu (China); Chen, Mingxiang, E-mail: chenmx1129@126.com [Subei People' s Hospital of Jiangsu Province, Clinical Medical School of Yangzhou University, Yangzhou 225001, Jiangsu (China)

    2013-01-15

    Purpose: To assess the effect of a breath-hold after forced expiration on the rate of pneumothorax after computed tomography (CT)-guided transthoracic needle biopsy of pulmonary lesions. Materials and methods: Between January 2008 and December 2011, percutaneous CT-guided lung biopsy was performed in 440 patients. Two hundred and twenty-one biopsies were performed without (control group) and two hundred and nineteen biopsies were performed with (study group) the study maneuver – a breath-hold after forced expiratory approach. Multivariate analysis was performed between groups for risk factors for pneumothorax, including patient demographics, lesion characteristics, and biopsy technique. Results: A reduced number of pneumothoraces (18 [8.2%] vs 35 [15.8%]; P = 0.014) but no significant difference in rate of drainage catheter insertions (2 [0.9%] vs (4 [1.8%]; P = 0.418) were noted in the study group as compared with the control group. By logistic regression analysis, three factors significantly and independently affected the risk for pneumothorax including lesion size (transverse and longitudinal diameter), distance from pleura and utilizing or avoiding the breath-hold after deep expiration maneuver. Conclusion: Breath-holding after forced expiration before removal of the biopsy needle during the percutaneous CT-guided transthoracic lung biopsy almost halved the rate of overall pneumothorax. Small lesion size (longitudinal diameter) and the distance from pleura were also predictors of pneumothorax in our study.

  10. Robustness of the Voluntary Breath-Hold Approach for the Treatment of Peripheral Lung Tumors Using Hypofractionated Pencil Beam Scanning Proton Therapy

    DEFF Research Database (Denmark)

    Dueck, Jenny; Knopf, Antje-Christin; Lomax, Antony

    2016-01-01

    PURPOSE: The safe clinical implementation of pencil beam scanning (PBS) proton therapy for lung tumors is complicated by the delivery uncertainties caused by breathing motion. The purpose of this feasibility study was to investigate whether a voluntary breath-hold technique could limit the delivery...

  11. Adaptation requirements due to anatomical changes in free-breathing and deep-inspiration breath-hold for standard and dose-escalated radiotherapy of lung cancer patients

    DEFF Research Database (Denmark)

    Sibolt, Patrik; Ottosson, Wiviann; Sjöström, David;

    2015-01-01

    Background. Radiotherapy of lung cancer patients is subject to uncertainties related to heterogeneities, anatomical changes and breathing motion. Use of deep-inspiration breath-hold (DIBH) can reduce the treated volume, potentially enabling dose-escalated (DE) treatments. This study was designed...

  12. Set-up verification and 2-dimensional electronic portal imaging device dosimetry during breath hold compared with free breathing in breast cancer radiation therapy

    NARCIS (Netherlands)

    Brouwers, Patricia J A M; Lustberg, Tim; Borger, Jacques H.; van Baardwijk, Angela A W; Jager, Jos J.; Murrer, Lars H P; Nijsten, Sebastian M J J G; Reymen, Bart H.; van Loon, Judith G M; Boersma, Liesbeth J.

    2015-01-01

    Purpose: To compare set-up and 2-dimensional (2D) electronic portal imaging device (EPID) dosimetry data of breast cancer patients treated during voluntary moderately deep inspiration breath hold (vmDIBH) and free breathing (FB). Methods and materials: Set-up data were analyzed for 29 and 51 consecu

  13. High-pitch coronary CT angiography in dual-source CT during free breathing vs. breath holding in patients with low heart rates

    Energy Technology Data Exchange (ETDEWEB)

    Bischoff, Bernhard, E-mail: bernhard.bischoff@med.uni-muenchen.de [Institute for Clinical Radiology, Ludwig-Maximilians-University Hospital Munich (Germany); DZHK (German Centre for Cardiovascular Research), Partner Site Munich Heart Alliance, Munich (Germany); Meinel, Felix G. [Institute for Clinical Radiology, Ludwig-Maximilians-University Hospital Munich (Germany); DZHK (German Centre for Cardiovascular Research), Partner Site Munich Heart Alliance, Munich (Germany); Del Prete, Alessandra [Department of Radiology Magrassi-Lanzara, Second University of Naples, Naples (Italy); Reiser, Maximilian F.; Becker, Hans-Christoph [Institute for Clinical Radiology, Ludwig-Maximilians-University Hospital Munich (Germany); DZHK (German Centre for Cardiovascular Research), Partner Site Munich Heart Alliance, Munich (Germany)

    2013-12-01

    Background: Coronary CT angiography (CCTA) is usually performed during breath holding to reduce motion artifacts caused by respiration. However, some patients are not able to follow the breathing commands adequately due to deafness, hearing impairment, agitation or pulmonary diseases. The aim of this study was to evaluate the potential of high-pitch CCTA in free breathing patients when compared to breath holding patients. Methods: In this study we evaluated 40 patients (20 free breathing and 20 breath holding patients) with a heart rate of 60 bpm or below referred for CCTA who were examined on a 2nd generation dual-source CT system. Image quality of each coronary artery segment was rated using a 4-point grading scale (1: non diagnostic–4: excellent). Results: Mean heart rate during image acquisition was 52 ±5 bpm in both groups. There was no significant difference in mean image quality, slightly favoring image acquisition during breath holding (mean image quality score 3.76 ± 0.32 in breath holding patients vs. 3.61 ± 0.45 in free breathing patients; p = 0.411). Due to a smaller amount of injected contrast medium, there was a trend for signal intensity to be slightly lower in free breathing patients, but this was not statistically significant (435 ± 123 HU vs. 473 ± 117 HU; p = 0.648). Conclusion: In patients with a low heart rate who are not able to hold their breath adequately, CCTA can also be acquired during free breathing without substantial loss of image quality when using a high pitch scan mode in 2nd generation dual-source CT.

  14. Optimising diffusion-weighted MR imaging for demonstrating pancreatic cancer: a comparison of respiratory-triggered, free-breathing and breath-hold techniques

    Energy Technology Data Exchange (ETDEWEB)

    Kartalis, Nikolaos; Loizou, Louiza; Edsborg, Nick; Albiin, Nils [Karolinska University Hospital, Division of Medical Imaging and Technology, Department of Clinical Science, Intervention and Technology (CLINTEC), Karolinska Institutet, Stockholm (Sweden); Segersvaerd, Ralf [Karolinska University Hospital, Division of Surgery, Department of Clinical Science, Intervention and Technology (CLINTEC), Karolinska Institutet, Stockholm (Sweden)

    2012-10-15

    To compare respiratory-triggered, free-breathing, and breath-hold DWI techniques regarding (1) image quality, and (2) signal intensity (SI) and ADC measurements in pancreatic ductal adenocarcinoma (PDAC). Fifteen patients with histopathologically proven PDAC underwent DWI prospectively at 1.5 T (b = 0, 50, 300, 600 and 1,000 s/mm{sup 2}) with the three techniques. Two radiologists, independently and blindly, assigned total image quality scores [sum of rating diffusion images (lesion detection, anatomy, presence of artefacts) and ADC maps (lesion characterisation, overall image quality)] per technique and ranked them. The lesion SI, signal-to-noise ratio, mean ADC and coefficient of variation (CV) were compared. Total image quality scores for respiratory-triggered, free-breathing and breath-hold techniques were 17.9, 16.5 and 17.1 respectively (respiratory-triggered was significantly higher than free-breathing but not breath-hold). The respiratory-triggered technique had a significantly higher ranking. Lesion SI on all b-values and signal-to-noise ratio on b300 and b600 were significantly higher for the respiratory-triggered technique. For respiratory-triggered, free-breathing and breath-hold techniques the mean ADCs were 1.201, 1.132 and 1.253 x 10{sup -3} mm{sup 2}/s, and mean CVs were 8.9, 10.8 and 14.1 % respectively (respiratory-triggered and free-breathing techniques had a significantly lower mean CV than the breath-hold technique). In both analyses, respiratory-triggered DWI showed superiority and seems the optimal DWI technique for demonstrating PDAC. (orig.)

  15. Advantage of deep inspiration breath hold in left-sided breast cancer patients treated with 3D conformal radiotherapy.

    Science.gov (United States)

    Lastrucci, Luciana; Borghesi, Simona; Bertocci, Silvia; Gasperi, Chiara; Rampini, Andrea; Buonfrate, Giovanna; Pernici, Paola; De Majo, Roberta; Gennari, Pietro Giovanni

    2017-01-21

    To compare 3D-conformal radiotherapy (3D-CRT) treatment plans based on free-breathing (FB) and deep inspiration breath hold (DIBH) and investigated whether DIBH technique enables a decrease of cardiac left anterior descending coronary artery (LADCA) and lungs dose with respect to the FB. Twenty-three left-sided breast cancer patients referred for breast radiotherapy were included. The planning target volume (PTV) encompassed the breast and organs at risk including heart, LADCA, lungs, and contralateral breast, which were contoured in FB and DIBH CT scans. Dose to PTV was 50 Gy in 25 fractions. Two treatment plans were generated for each patient: FB-3D-CRT and DIBH-3D-CRT. Dosimetry parameters were obtained from dose volume histograms. Data were compared using the paired-sample Wilcoxon signed rank test. For heart, LADCA, and left lung, a significant dose reduction was found using DIBH technique. By using DIBH, an average reduction of 25% was observed in LADCA for the volume receiving 20 Gy and of 48% considering the mean heart dose. The DIBH technique results in a significant decrease of dose to the heart, LADCA, and left lung compared to FB.

  16. Effects of low oxygen dead space ventilation and breath-holding test in evaluating cerebrovascular reactivity: A comparative observation.

    Science.gov (United States)

    Ju, Ke-Ju; Zhong, Ling-Ling; Ni, Xiao-Yu; Xia, Lei; Xue, Liu-Jun; Cheng, Guan-Liang

    2017-01-01

    This study aims to explore the application prospect of low oxygen dead space ventilation (LODSV) in evaluating vasomotor reactivity (VMR) by comparison between LODSV and breath-holding test (BHT). Outpatient or inpatient patients who underwent transcranial Doppler sonography (TCD) were enrolled into this study. These patients successively underwent BHT and LODSV. The cooperation degree, tolerance conditions and adverse reactions in patients were recorded, and VMR was calculated, compared and analyzed. Patients had poor cooperation during BHT. Except for compensatory tachypnea after BHT, patients basically had no adverse reaction. The main manifestations of patients undergoing LODSV were deepened breathing and accelerated frequency in the end of the ventilation, and increased heart rate and a slight decline in pulse oxygen that rapidly recovered after ventilation. The increase rate of blood flow velocity in patients undergoing LODSV was significantly higher than in BHT (PBHT (PBHT revealed a monophasic curve that slightly descends and rapidly increases, and LODSV revealed a curve that descends for a short time and slowly increases with a platform. LODSV can effectively eliminate the affect of poor cooperation in patients, and avoid intolerance caused by hypoxia. Hence, VMR value is more accurate than that determined by BHT; and this can reflect the maximum reaction ability of the blood vessels. Therefore, this method has higher clinical application value.

  17. Nonrigid groupwise registration for motion estimation and compensation in compressed sensing reconstruction of breath-hold cardiac cine MRI.

    Science.gov (United States)

    Royuela-del-Val, Javier; Cordero-Grande, Lucilio; Simmross-Wattenberg, Federico; Martín-Fernández, Marcos; Alberola-López, Carlos

    2016-04-01

    Compressed sensing methods with motion estimation and compensation techniques have been proposed for the reconstruction of accelerated dynamic MRI. However, artifacts that naturally arise in compressed sensing reconstruction procedures hinder the estimation of motion from reconstructed images, especially at high acceleration factors. This work introduces a robust groupwise nonrigid motion estimation technique applied to the compressed sensing reconstruction of dynamic cardiac cine MRI sequences. A spatio-temporal regularized, groupwise, nonrigid registration method based on a B-splines deformation model and a least squares metric is used to estimate and to compensate the movement of the heart in breath-hold cine acquisitions and to obtain a quasistatic sequence with highly sparse representation in temporally transformed domains. Short axis in vivo datasets are used for validation, both original multicoil as well as DICOM data. Fully sampled data were retrospectively undersampled with various acceleration factors and reconstructions were compared with the two well-known methods k-t FOCUSS and MASTeR. The proposed method achieves higher signal to error ratio and structure similarity index for medium to high acceleration factors. Reconstruction methods based on groupwise registration show higher quality reconstructions for cardiac cine images than the pairwise counterparts tested. © 2015 Wiley Periodicals, Inc.

  18. The cardiac dose-sparing benefits of deep inspiration breath-hold in left breast irradiation: a systematic review

    Energy Technology Data Exchange (ETDEWEB)

    Smyth, Lloyd M, E-mail: lloyd.smyth@epworth.org.au [Epworth Radiation Oncology, Level 4, The Epworth Centre, Richmond, Victoria (Australia); Department of Medical Imaging and Radiation Sciences, Faculty of Medicine, School of Biomedical Sciences, Nursing and Health Sciences, Monash University, Clayton, Victoria (Australia); Knight, Kellie A [Department of Medical Imaging and Radiation Sciences, Faculty of Medicine, School of Biomedical Sciences, Nursing and Health Sciences, Monash University, Clayton, Victoria (Australia); Aarons, Yolanda K; Wasiak, Jason [Epworth Radiation Oncology, Level 4, The Epworth Centre, Richmond, Victoria (Australia)

    2015-03-15

    Despite technical advancements in breast radiation therapy, cardiac structures are still subject to significant levels of irradiation. As the use of adjuvant radiation therapy after breast-conserving surgery continues to improve survival for early breast cancer patients, the associated radiation-induced cardiac toxicities become increasingly relevant. Our primary aim was to evaluate the cardiac-sparing benefits of the deep inspiration breath-hold (DIBH) technique. An electronic literature search of the PubMed database from 1966 to July 2014 was used to identify articles published in English relating to the dosimetric benefits of DIBH. Studies comparing the mean heart dose of DIBH and free breathing treatment plans for left breast cancer patients were eligible to be included in the review. Studies evaluating the reproducibility and stability of the DIBH technique were also reviewed. Ten studies provided data on the benefits of DIBH during left breast irradiation. From these studies, DIBH reduced the mean heart dose by up to 3.4 Gy when compared to a free breathing approach. Four studies reported that the DIBH technique was stable and reproducible on a daily basis. According to current estimates of the excess cardiac toxicity associated with radiation therapy, a 3.4 Gy reduction in mean heart dose is equivalent to a 13.6% reduction in the projected increase in risk of heart disease. DIBH is a reproducible and stable technique for left breast irradiation showing significant promise in reducing the late cardiac toxicities associated with radiation therapy.

  19. Less increase of CT-based calcium scores of the coronary arteries. Effect three years after breast-conserving radiotherapy using breath-hold

    Energy Technology Data Exchange (ETDEWEB)

    Mast, M.E.; Kempen-Harteveld, M.L. van; Petoukhova, A.L. [Centre West, Radiotherapy, The Hague (Netherlands); Heijenbrok, M.W. [Medical Center Haaglanden, Department of Radiology, The Hague (Netherlands); Scholten, A.N. [Netherlands Cancer Institute - Antoni van Leeuwenhoek Hospital, Department of Radiation Oncology, Amsterdam (Netherlands); Wolterbeek, R. [Leiden University Medical Centre, Department of Medical Statistics and Bioinformatics, Leiden (Netherlands); Schreur, J.H.M. [Medical Center Haaglanden, Department of Cardiology, The Hague (Netherlands); Struikmans, H. [Centre West, Radiotherapy, The Hague (Netherlands); Leiden University Medical Centre, Department of Clinical Oncology, Leiden (Netherlands)

    2016-10-15

    The aim of this prospective longitudinal study was to compare coronary artery calcium (CAC) scores determined before the start of whole breast irradiation with those determined 3 years afterwards. Changes in CAC scores were analysed in 99 breast cancer patients. Three groups were compared: patients receiving left- and right-sided radiotherapy, and those receiving left-sided radiotherapy with breath-hold. We analysed overall CAC scores and left anterior descending (LAD) and right coronary artery (RCA) CAC scores. Between the three groups, changes of the value of the LAD minus the RCA CAC scores of each individual patient were also compared. Three years after breath-hold-based whole breast irradiation, a less pronounced increase of CAC scores was noted. Furthermore, LAD minus RCA scores in patients treated for left-sided breast cancer without breath-hold were higher when compared to LAD minus RCA scores of patients with right-sided breast cancers and those with left-sided breast cancer treated with breath-hold. Breath-hold in breast-conserving radiotherapy leads to a less pronounced increase of CT-based CAC scores. Therefore, breath-hold probably prevents the development of radiation-induced coronary artery disease. However, the sample size of this study is limited and the follow-up period relatively short. (orig.) [German] Das Ziel dieser prospektiven Langzeitstudie war der Vergleich der Coronary-Artery-Calcium-(CAC-)Werte vor Beginn der Brustbestrahlung mit den Werten nach 3 Jahren. Aenderungen der CAC-Werte wurden bei 99 Brustkrebspatienten analysiert. Drei Gruppen wurden untersucht: Patienten nach links- und rechtsseitiger Strahlentherapie sowie mit Bestrahlung unter Atemanhalt. Wir analysierten die Gesamt-CAC-Werte sowie die CAC-Werte der vorderen linken absteigenden (''left anterior descending'', LAD) und der rechten Koronararterie (''right coronary artery'', RCA). Zwischen den drei Gruppen wurden auch die Veraenderungen

  20. Hypofractionated image-guided breath-hold SABR (Stereotactic Ablative Body Radiotherapy of liver metastases – clinical results

    Directory of Open Access Journals (Sweden)

    Boda-Heggemann Judit

    2012-06-01

    Full Text Available Abstract Purpose Stereotactic Ablative Body Radiotherapy (SABR is a non-invasive therapy option for inoperable liver oligometastases. Outcome and toxicity were retrospectively evaluated in a single-institution patient cohort who had undergone ultrasound-guided breath-hold SABR. Patients and methods 19 patients with liver metastases of various primary tumors consecutively treated with SABR (image-guidance with stereotactic ultrasound in combination with computer-controlled breath-hold were analysed regarding overall-survival (OS, progression-free-survival (PFS, progression pattern, local control (LC, acute and late toxicity. Results PTV (planning target volume-size was 108 ± 109cm3 (median 67.4 cm3. BED2 (Biologically effective dose in 2 Gy fraction was 83.3 ± 26.2 Gy (median 78 Gy. Median follow-up and median OS were 12 months. Actuarial 2-year-OS-rate was 31%. Median PFS was 4 months, actuarial 1-year-PFS-rate was 20%. Site of first progression was predominantly distant. Regression of irradiated lesions was observed in 84% (median time to detection of regression was 2 months. Actuarial 6-month-LC-rate was 92%, 1- and 2-years-LC-rate 57%, respectively. BED2 influenced LC. When a cut-off of BED2 = 78 Gy was used, the higher BED2 values resulted in improved local control with a statistical trend to significance (p = 0.0999. Larger PTV-sizes, inversely correlated with applied dose, resulted in lower local control, also with a trend to significance (p-value = 0.08 when a volume cut-off of 67 cm3 was used. No local relapse was observed at PTV-sizes 3 and BED2 > 78 Gy. No acute clinical toxicity > °2 was observed. Late toxicity was also ≤ °2 with the exception of one gastrointestinal bleeding-episode 1 year post-SABR. A statistically significant elevation in the acute phase was observed for alkaline-phosphatase; in the chronic phase for alkaline-phosphatase, bilirubine, cholinesterase and C

  1. Minimizing Late Effects for Patients With Mediastinal Hodgkin Lymphoma: Deep Inspiration Breath-Hold, IMRT, or Both?

    Energy Technology Data Exchange (ETDEWEB)

    Aznar, Marianne C., E-mail: marianne.camille.aznar@regionh.dk [Department of Oncology, Section of Radiotherapy, Rigshospitalet, University of Copenhagen, Copenhagen (Denmark); Faculty of Sciences, Niels Bohr Institute, and Faculty of Health Sciences, University of Copenhagen, Copenhagen (Denmark); Maraldo, Maja V.; Schut, Deborah A. [Department of Oncology, Section of Radiotherapy, Rigshospitalet, University of Copenhagen, Copenhagen (Denmark); Lundemann, Michael [Department of Oncology, Section of Radiotherapy, Rigshospitalet, University of Copenhagen, Copenhagen (Denmark); Faculty of Sciences, Niels Bohr Institute, and Faculty of Health Sciences, University of Copenhagen, Copenhagen (Denmark); Brodin, N Patrik [Department of Oncology, Section of Radiotherapy, Rigshospitalet, University of Copenhagen, Copenhagen (Denmark); Institute of Onco-Physics, Albert Einstein College of Medicine of Yeshiva University, Bronx, New York (United States); Vogelius, Ivan R. [Department of Oncology, Section of Radiotherapy, Rigshospitalet, University of Copenhagen, Copenhagen (Denmark); Berthelsen, Anne K. [Department of Oncology, Section of Radiotherapy, Rigshospitalet, University of Copenhagen, Copenhagen (Denmark); Department of Clinical Physiology, Nuclear Medicine and PET, Rigshospitalet, University of Copenhagen, Copenhagen (Denmark); Specht, Lena; Petersen, Peter M. [Department of Oncology, Section of Radiotherapy, Rigshospitalet, University of Copenhagen, Copenhagen (Denmark)

    2015-05-01

    Purpose: Hodgkin lymphoma (HL) survivors have an increased risk of cardiovascular disease (CD), lung cancer, and breast cancer. We investigated the risk for the development of CD and secondary lung, breast, and thyroid cancer after radiation therapy (RT) delivered with deep inspiration breath-hold (DIBH) compared with free-breathing (FB) using 3-dimensional conformal RT (3DCRT) and intensity modulated RT (IMRT). The aim of this study was to determine which treatment modality best reduced the combined risk of life-threatening late effects in patients with mediastinal HL. Methods and Materials: Twenty-two patients with early-stage mediastinal HL were eligible for the study. Treatment plans were calculated with both 3DCRT and IMRT on both DIBH and FB planning computed tomographic scans. We reported the estimated dose to the heart, lung, female breasts, and thyroid and calculated the estimated life years lost attributable to CD and to lung, breast, and thyroid cancer. Results: DIBH lowered the estimated dose to heart and lung regardless of delivery technique (P<.001). There was no significant difference between IMRT-FB and 3DCRT-DIBH in mean heart dose, heart V20Gy, and lung V20Gy. The mean breast dose was increased with IMRT regardless of breathing technique. Life years lost was lowest with DIBH and highest with FB. Conclusions: In this cohort, 3DCRT-DIBH resulted in lower estimated doses and lower lifetime excess risks than did IMRT-FB. Combining IMRT and DIBH could be beneficial for a subgroup of patients.

  2. Investigation of dose homogeneity for loose helical tomotherapy delivery in the context of breath-hold radiation therapy

    Science.gov (United States)

    Kim, Bryan; Kron, Tomas; Battista, Jerry; Van Dyk, Jake

    2005-05-01

    Loose helical delivery is a potential solution to account for respiration-driven tumour motion in helical tomotherapy (HT). In this approach, a treatment is divided into a set of interlaced 'loose' helices commencing at different gantry angles. Each loose helix covers the entire target length in one gantry rotation during a single breath-hold. The dosimetric characteristics of loose helical delivery were investigated by delivering a 6 MV photon beam in a HT-like manner. Multiple scenarios of conventional 'tight' HT and loose helical deliveries were modelled in treatment planning software, and carried out experimentally with Kodak EDR2 film. The advantage of loose helical delivery lies in its ability to produce a more homogeneous dose distribution by eliminating the 'thread' effect—an inherent characteristic of HT, which results in dose modulations away from the axis of gantry rotation. However, loose helical delivery was also subjected to undesirable dose modulations in the direction of couch motion (termed 'beating' effect), when the ratio between the number of beam projections per gantry rotation (n) and pitch factor (p) was a non-integer. The magnitude of dose modulations decreased with an increasing n/p ratio. The results suggest that for the current HT unit (n = 51), dose modulations could be kept under 5% by selecting a pitch factor smaller than 7. A pitch factor of this magnitude should be able to treat a target up to 30 cm in length. Loose helical delivery should increase the total session time only by a factor of 2, while the planning time should stay the same since the total number of beam projections remains unchanged. Considering its dosimetric advantage and clinical practicality, loose helical delivery is a promising solution for the future HT treatments of respiration-driven targets.

  3. Evaluation of Vasomotor Reactivity by Transcranial Doppler Sonography: Age and Sex Related Differences in Breath Holding Index in Iranian Population

    Directory of Open Access Journals (Sweden)

    SA Mousavi

    2005-03-01

    Full Text Available Background: The assessment of cerebral vasoreactivity can provide information regarding the reserve capacity of cerebral circulation. Reduction of this property has been found in association with situations predisposing one toward cerebrovascular disease. In this study, we defined the vasoreactivity of brain vesseles according to age and sex of the patients. Methods: In this descriptive study, 289 healthy subjects (without hypertension, diabetes mellitus, obesity, smoking, CHF, CHD, were admitted from January 2004 to June 2004. The population was divided to four groups, according to age and sex (women and men more and less than 30. After determination of each patient’s flow velocity of middle cerebral artery (MCA by mean of a transcranial doppler instrument (TCD, before and after 30s apnea, breath holding index (BHI was calculated. Data was analyzed, using SPSS software. Results: BHI was significantly higher in women than men (0.918±0.40 versus 0.637±0.22; P<0.001. BHI was significantly lower in older (age > 30 women (0.812±0.31 than in younger ( ≤ 30 years women (0.995±0.44; P<0.001 but there was no significant difference between older (age > 30 men (0.62±0.23 and younger ( ≤ 30 years men (0.65±0.20; P > 0.05. Conclusion: The average of BHI was lower in men than in women in total and in all age subgroups. BHI was relatively constant in all age subgroups in men but there was significant decline in BHI by increasing age in women. So despite of many physiologic changes related to aging, vasomotor reactivity remains relatively constant in men but decreases in women. Findings of our study suggest that changes of cerebrovascular vasomotor reactivity in healthy subjects may be related to aging, but they are probably mainly influenced by sex. Keywords: vasomotor reactivity, BHI, TCD

  4. Initial clinical results for breath-hold CT-based processing of respiratory-gated PET acquisitions

    Energy Technology Data Exchange (ETDEWEB)

    Fin, Loic; Daouk, Joel; Morvan, Julie; Esper, Isabelle El; Saidi, Lazhar; Meyer, Marc-Etienne [Amiens University Hospital, Nuclear Medicine Department, Amiens (France); Bailly, Pascal [Amiens University Hospital, Nuclear Medicine Department, Amiens (France); CHU d' Amiens, Service de Medecine Nucleaire, unite TEP, Hopital Sud, Amiens cedex (France)

    2008-11-15

    Respiratory motion causes uptake in positron emission tomography (PET) images of chest structures to spread out and misregister with the CT images. This misregistration can alter the attenuation correction and thus the quantisation of PET images. In this paper, we present the first clinical results for a respiratory-gated PET (RG-PET) processing method based on a single breath-hold CT (BH-CT) acquisition, which seeks to improve diagnostic accuracy via better PET-to-CT co-registration. We refer to this method as ''CT-based'' RG-PET processing. Thirteen lesions were studied. Patients underwent a standard clinical PET protocol and then the CT-based protocol, which consists of a 10-min List Mode RG-PET acquisition, followed by a shallow end-expiration BH-CT. The respective performances of the CT-based and clinical PET methods were evaluated by comparing the distances between the lesions' centroids on PET and CT images. SUV{sub MAX} and volume variations were also investigated. The CT-based method showed significantly lower (p=0.027) centroid distances (mean change relative to the clinical method =-49%; range =-100% to 0%). This led to higher SUV{sub MAX} (mean change =+33%; range =-4% to 69%). Lesion volumes were significantly lower (p=0.022) in CT-based PET volumes (mean change =-39%: range =-74% to -1%) compared with clinical ones. A CT-based RG-PET processing method can be implemented in clinical practice with a small increase in radiation exposure. It improves PET-CT co-registration of lung lesions and should lead to more accurate attenuation correction and thus SUV measurement. (orig.)

  5. A Voluntary Breath-Hold Treatment Technique for the Left Breast With Unfavorable Cardiac Anatomy Using Surface Imaging

    Energy Technology Data Exchange (ETDEWEB)

    Gierga, David P., E-mail: dgierga@partners.org [Department of Radiation Oncology, Massachusetts General Hospital, Boston, Massachusetts (United States); Harvard Medical School, Boston, Massachusetts (United States); Turcotte, Julie C. [Department of Radiation Oncology, Massachusetts General Hospital, Boston, Massachusetts (United States); Sharp, Gregory C. [Department of Radiation Oncology, Massachusetts General Hospital, Boston, Massachusetts (United States); Harvard Medical School, Boston, Massachusetts (United States); Sedlacek, Daniel E.; Cotter, Christopher R. [Department of Radiation Oncology, Massachusetts General Hospital, Boston, Massachusetts (United States); Taghian, Alphonse G. [Department of Radiation Oncology, Massachusetts General Hospital, Boston, Massachusetts (United States); Harvard Medical School, Boston, Massachusetts (United States)

    2012-12-01

    Purpose: Breath-hold (BH) treatments can be used to reduce cardiac dose for patients with left-sided breast cancer and unfavorable cardiac anatomy. A surface imaging technique was developed for accurate patient setup and reproducible real-time BH positioning. Methods and Materials: Three-dimensional surface images were obtained for 20 patients. Surface imaging was used to correct the daily setup for each patient. Initial setup data were recorded for 443 fractions and were analyzed to assess random and systematic errors. Real time monitoring was used to verify surface placement during BH. The radiation beam was not turned on if the BH position difference was greater than 5 mm. Real-time surface data were analyzed for 2398 BHs and 363 treatment fractions. The mean and maximum differences were calculated. The percentage of BHs greater than tolerance was calculated. Results: The mean shifts for initial patient setup were 2.0 mm, 1.2 mm, and 0.3 mm in the vertical, longitudinal, and lateral directions, respectively. The mean 3-dimensional vector shift was 7.8 mm. Random and systematic errors were less than 4 mm. Real-time surface monitoring data indicated that 22% of the BHs were outside the 5-mm tolerance (range, 7%-41%), and there was a correlation with breast volume. The mean difference between the treated and reference BH positions was 2 mm in each direction. For out-of-tolerance BHs, the average difference in the BH position was 6.3 mm, and the average maximum difference was 8.8 mm. Conclusions: Daily real-time surface imaging ensures accurate and reproducible positioning for BH treatment of left-sided breast cancer patients with unfavorable cardiac anatomy.

  6. Assessment of renal artery stenosis: Comparison of captopril renography and gadolinium-enhanced breath-hold MR angiography

    Energy Technology Data Exchange (ETDEWEB)

    Bongers, V.; Bakker, J.; Beutler, J.J.; Beek, F.J.A.; De Klerk, J.M.H

    2000-05-01

    AIM: To determine the accuracy of captopril renography (CR) and gadolinium-enhanced breath-hold magnetic resonance (MR) angiography in the diagnosis of 50-99% renal artery stenosis (RAS). MATERIALS AND METHODS: Forty-three patients with possible RAS, of whom 53% had renal function impairment (creatinine >130 {mu}mol/l), were included.{sup 99m}Tc-mercaptoacetyl triglycine (MAG{sub 3}) renography was performed after an oral dose of 25 mg captopril. Gadolinium-enhanced MR angiography was performed on a standard 1.5 Tesla system: TR 13.5, TE 3.5, flip angle 60 deg. , matrix 195 x 512. Intra-arterial digital subtraction angiography (DSA) was the standard of reference. RESULTS: Captropril renography accurately categorized 22 of 26 patients who had either uni- or bilateral RAS of 50-99%. The sensitivity and specificity of CR for the detection of 50-99% stenosis were 85 and 71%, respectively. With MR angiography one occluded artery was incorrectly diagnosed as a stenosis. Sensitivity and specificity were 100 and 94%, respectively. The difference between the accuracies of MR angiography and CR was statistically significant (P = 0.02). The accuracy of CR was lower in patients with renal impairment (70%) than in those with normal renal function (90%). CONCLUSION: MR angiography showed a high accuracy in diagnosing RAS of between 50 and 99%. CR was less accurate than MR angiography, especially in patients with renal function impairment. In patients with normal renal function, however, CR remains a useful diagnostic test. Bongers, V. (2000)

  7. Classifying geometric variability by dominant eigenmodes of deformation in regressing tumours during active breath-hold lung cancer radiotherapy

    Science.gov (United States)

    Badawi, Ahmed M.; Weiss, Elisabeth; Sleeman, William C., IV; Hugo, Geoffrey D.

    2012-01-01

    The purpose of this study is to develop and evaluate a lung tumour interfraction geometric variability classification scheme as a means to guide adaptive radiotherapy and improve measurement of treatment response. Principal component analysis (PCA) was used to generate statistical shape models of the gross tumour volume (GTV) for 12 patients with weekly breath hold CT scans. Each eigenmode of the PCA model was classified as ‘trending’ or ‘non-trending’ depending on whether its contribution to the overall GTV variability included a time trend over the treatment course. Trending eigenmodes were used to reconstruct the original semi-automatically delineated GTVs into a reduced model containing only time trends. Reduced models were compared to the original GTVs by analyzing the reconstruction error in the GTV and position. Both retrospective (all weekly images) and prospective (only the first four weekly images) were evaluated. The average volume difference from the original GTV was 4.3% ± 2.4% for the trending model. The positional variability of the GTV over the treatment course, as measured by the standard deviation of the GTV centroid, was 1.9 ± 1.4 mm for the original GTVs, which was reduced to 1.2 ± 0.6 mm for the trending-only model. In 3/13 cases, the dominant eigenmode changed class between the prospective and retrospective models. The trending-only model preserved GTV and shape relative to the original GTVs, while reducing spurious positional variability. The classification scheme appears feasible for separating types of geometric variability by time trend.

  8. Changes in Respiratory Parameters and Fin-Swimming Performance Following a 16-Week Training Period with Intermittent Breath Holding

    Directory of Open Access Journals (Sweden)

    Stavrou Vasileios

    2015-12-01

    Full Text Available The purpose of this study was to examine the effects of training with intermittent breath holding (IBH on respiratory parameters, arterial oxygen saturation (SpO2 and performance. Twenty-eight fin-swimming athletes were randomly divided into two groups and followed the same training for 16 weeks. About 40% of the distance of each session was performed with self-selected breathing frequency (SBF group or IBH (IBH group. Performance time of 50 and 400 m at maximum intensity was recorded and forced expired volume in 1 s (FEV1, forced vital capacity (FVC, peak expiratory flow (PEF and SpO2 were measured before and after the 50 m test at baseline and post-training. Posttraining, the respiratory parameters were increased in the IBH but remained unchanged in the SBF group (FEV1: 17 ±15% vs. -1 ±11%; FVC: 22 ±13% vs. 1 ±10%; PEF: 9 ±14% vs. -4 ±15%; p<0.05. Pre compared to post-training SpO2 was unchanged at baseline and decreased post-training following the 50 m test in both groups (p<0.05. The reduction was higher in the IBH compared to the SBF group (p<0.05. Performance in the 50 and 400 m tests improved in both groups, however, the improvement was greater in the IBH compared to the SBF group in both 50 and 400 m tests (p<0.05. The use of IBH is likely to enhance the load on the respiratory muscles, thus, contributing to improvement of the respiratory parameters. Decreased SpO2 after IBH is likely due to adaptation to hypoventilation. IBH favours performance improvement at 50 and 400 m fin-swimming.

  9. Influences of prolonged apnea and oxygen inhalation on pulmonary hemodynamics during breath holding: Quantitative assessment by velocity-encoded MR imaging with SENSE technique

    Energy Technology Data Exchange (ETDEWEB)

    Nogami, Munenobu [Department of Radiology, Kobe University Graduate School of Medicine, 7-5-2 Kusunoki-cho, Chuo-ku, Kobe, Hyogo 650-0017 (Japan)], E-mail: aznogami@med.kobe-u.ac.jp; Ohno, Yoshiharu [Department of Radiology, Kobe University Graduate School of Medicine, 7-5-2 Kusunoki-cho, Chuo-ku, Kobe, Hyogo 650-0017 (Japan); Higashino, Takanori [Department of Radiology, Kobe University Graduate School of Medicine, 7-5-2 Kusunoki-cho, Chuo-ku, Kobe, Hyogo 650-0017 (Japan); Department of Radiology, Tenri Hospital, Tenri, Nara (Japan); Takenaka, Daisuke [Department of Radiology, Kobe University Graduate School of Medicine, 7-5-2 Kusunoki-cho, Chuo-ku, Kobe, Hyogo 650-0017 (Japan); Yoshikawa, Takeshi [Department of Radiology, Kobe University Graduate School of Medicine, 7-5-2 Kusunoki-cho, Chuo-ku, Kobe, Hyogo 650-0017 (Japan); Department of Radiology, Konan Hospital, Kobe, Hyogo (Japan); Koyama, Hisanobu [Department of Radiology, Kobe University Graduate School of Medicine, 7-5-2 Kusunoki-cho, Chuo-ku, Kobe, Hyogo 650-0017 (Japan); Kawamitsu, Hideaki [Division of Radiology, Kobe University Hospital, Kobe, Hyogo (Japan); Fujii, Masahiko [Department of Radiology, Kobe University Graduate School of Medicine, 7-5-2 Kusunoki-cho, Chuo-ku, Kobe, Hyogo 650-0017 (Japan); Division of Radiology, Kobe University Hospital, Kobe, Hyogo (Japan); Sugimura, Kazuro [Department of Radiology, Kobe University Graduate School of Medicine, 7-5-2 Kusunoki-cho, Chuo-ku, Kobe, Hyogo 650-0017 (Japan)

    2007-12-15

    Purpose: The purpose of our study was to assess the influence of prolonged apnea and administration of oxygen on pulmonary hemodynamics during breath holding (BH) by using velocity-encoded MR imaging combined with the SENSE technique (velocity MRI). Materials and methods: Ten healthy male volunteers underwent velocity MRI during BH with and without O{sub 2} inhalation. All velocity MRI data sets were obtained continuously with the 2D cine phase-contrast method during a single BH period. The data were then divided into three BH time phases as follows: first, second and third. To evaluate the influence of prolonged apnea on hemodynamics, stroke volume (SV) and maximal change in flow rate during ejection (MCFR) of second and third phases were statistically compared with those of first phase by using the ANOVA followed by Turkey's HSD multiple comparison test. To assess the influence of O{sub 2} on hemodynamics, SV and MCFR with or without O{sub 2} were compared by the paired t-test. To assess the measuring agreement of hemodynamic indices during prolonged breath holding, Bland-Altman's analysis was performed. Results: Prolonged apnea had no significant influence on SV and MCFR regardless of administration of O{sub 2} (p > 0.05). Mean MCFR for all phases was significantly lower with administration of O{sub 2} than without (p < 0.05). The limits of agreement for MCFR with O{sub 2} were smaller than without. Conclusion: O{sub 2} inhalation modulated maximal change in flow rate during ejection, and did not influence stroke volume during breath holding. Influence of O{sub 2} inhalation should be considered for MR measurements of pulmonary hemodynamics during breath holding.

  10. SU-E-T-361: Clinical Benefit of Automatic Beam Gating Mixed with Breath Hold in Radiation Therapy of Left Breast

    Energy Technology Data Exchange (ETDEWEB)

    Wu, J; Hill, G; Spiegel, J [Swedish Cancer Institute, Issaquah, Washington (United States); Ye, J [Swedish Cancer Institute, Edmond, Washington (United States); Mehta, V [Swedish Cancer Institute, Seattle, WA (United States)

    2014-06-01

    Purpose: To investigate the clinical and dosimetric benefits of automatic gating of left breast mixed with breath-hold technique. Methods: Two Active Breathing Control systems, ABC2.0 and ABC3.0, were used during simulation and treatment delivery. The two systems are different such that ABC2.0 is a breath-hold system without beam control capability, while ABC3.0 has capability in both breath-hold and beam gating. At simulation, each patient was scanned twice: one with free breathing (FB) and one with breath hold through ABC. Treatment plan was generated on the CT with ABC. The same plan was also recalculated on the CT with FB. These two plans were compared to assess plan quality. For treatments with ABC2.0, beams with MU > 55 were manually split into multiple subfields. All subfields were identical and shared the total MU. For treatment with ABC3.0, beam splitting was unnecessary. Instead, treatment was delivered in gating mode mixed with breath-hold technique. Treatment delivery efficiency using the two systems was compared. Results: The prescribed dose was 50.4Gy at 1.8Gy/fraction. The maximum heart dose averaged over 10 patients was 46.0±2.5Gy and 24.5±12.2Gy for treatments with FB and with ABC respectively. The corresponding heart V10 was 13.2±3.6% and 1.0±1.6% respectively. The averaged MUs were 99.8±7.5 for LMT, 99.2±9.4 for LLT. For treatment with ABC2.0, normally the original beam was split into 2 subfields. The averaged total time to delivery all beams was 4.3±0.4min for treatments with ABC2.0 and 3.3±0.6min for treatments with ABC3.0 in gating mode. Conclusion: Treatment with ABC tremendously reduced heart dose. Compared to treatments with ABC2.0, gating with ABC3.0 reduced the total treatment time by 23%. Use of ABC3.0 improved the delivery efficiency, and eliminated the possibility of mistreatments. The latter may happen with ABC2.0 where beam is not terminated when breath signal falls outside of the treatment window.

  11. Rank Awareness in Group-Sparse Recovery of Multi-Echo MR Images

    Directory of Open Access Journals (Sweden)

    Rabab Ward

    2013-03-01

    Full Text Available This work addresses the problem of recovering multi-echo T1 or T2 weighted images from their partial K-space scans. Recent studies have shown that the best results are obtained when all the multi-echo images are reconstructed by simultaneously exploiting their intra-image spatial redundancy and inter-echo correlation. The aforesaid studies either stack the vectorised images (formed by row or columns concatenation as columns of a Multiple Measurement Vector (MMV matrix or concatenate them as a long vector. Owing to the inter-image correlation, the thus formed MMV matrix or the long concatenated vector is row-sparse or group-sparse respectively in a transform domain (wavelets. Consequently the reconstruction problem was formulated as a row-sparse MMV recovery or a group-sparse vector recovery. In this work we show that when the multi-echo images are arranged in the MMV form, the thus formed matrix is low-rank. We show that better reconstruction accuracy can be obtained when the information about rank-deficiency is incorporated into the row/group sparse recovery problem. Mathematically, this leads to a constrained optimization problem where the objective function promotes the signal’s groups-sparsity as well as its rank-deficiency; the objective function is minimized subject to data fidelity constraints. The experiments were carried out on ex vivo and in vivo T2 weighted images of a rat's spinal cord. Results show that this method yields considerably superior results than state-of-the-art reconstruction techniques.

  12. Multi-Echo-Based Echo-Planar Spectroscopic Imaging Using a 3T MRI Scanner

    Directory of Open Access Journals (Sweden)

    Jon K. Furuyama

    2011-10-01

    Full Text Available The use of spin-echoes has been employed in an Echo-Planar Spectroscopic Imaging (EPSI sequence to collect multiple phase encoded lines within a single TR in a Multi-Echo-based Echo-Planar Spectroscopic Imaging technique (MEEPSI. Despite the T2 dependence on the amplitude of the spin-echoes, the Full Width at Half Maximum (FWHM of the derived multi-echo Point Spread Function (PSF is shown to decrease, indicating an improved overall spatial resolution without requiring any additional scan time. The improved spatial resolution is demonstrated in the one-dimensional (1D spatial profiles of the N-Acetyl Aspartate (NAA singlet along the phase encode dimension in a gray matter phantom. Although the improved spatial resolution comes at the expense of spectral resolution, it is shown in vivo that peak broadening due to T2* decay is more significant than the loss of resolution from using spin-echoes and therefore does not affect the ability to quantify metabolites using the LCModel fitting algorithm.

  13. Evaluation of pancreatic cancer by multiple breath-hold dynamic contrast-enhanced magnetic resonance imaging at 3.0 T

    Energy Technology Data Exchange (ETDEWEB)

    Yao, Xiuzhong, E-mail: yao.xiuzhong@zs-hospital.sh.cn [Department of Radiology, Zhongshan Hospital of Fudan University and Department of Medical Image, Shanghai Medical College of Fudan University, No. 138, Fenglin Road, Xuhui District, Shanghai 200032 (China); Zeng, Mengsu, E-mail: zengmengsu@gmail.com [Department of Radiology, Zhongshan Hospital of Fudan University and Department of Medical Image, Shanghai Medical College of Fudan University, No. 138, Fenglin Road, Xuhui District, Shanghai 200032 (China); Wang, He, E-mail: herry258@hotmail.com [Global Applied Science Laboratory of GE Healthcare, No. 1, Huatuo Road, Zhangjiang Hi-tech Park, Pudong District, Shanghai 201203 (China); Sun, Fei, E-mail: fei.sun@med.ge.com [Global Applied Science Laboratory of GE Healthcare, No. 1, Huatuo Road, Zhangjiang Hi-tech Park, Pudong District, Shanghai 201203 (China); Rao, Shengxiang, E-mail: rao.shengxiang@zs-hospital.sh.cn [Department of Radiology, Zhongshan Hospital of Fudan University and Department of Medical Image, Shanghai Medical College of Fudan University, No. 138, Fenglin Road, Xuhui District, Shanghai 200032 (China); Ji, Yuan, E-mail: Ji.yuan@zs-hospital.sh.cn [Department of Pathology, Zhongshan Hospital of Fudan University, No. 138, Fenglin Road, Xuhui District, Shanghai 200032 (China)

    2012-08-15

    Objective: To investigate the microcirculation in pancreatic cancer by pharmacokinetic analysis of multiple breath-hold dynamic contrast-enhanced magnetic resonance imaging at 3.0 T. Materials and methods: Multiple breath-hold dynamic contrast-enhanced magnetic resonance imaging was performed in 40 healthy volunteers and 40 patients with pancreatic cancer proven by histopathology using an axial three-dimensions fat-saturated T1-weighted spoiled-gradient echo sequence at 3.0 T. A two compartment model with T1 correction was used to quantify the transfer constant, the rate constant of backflux from the extravascular extracellular space to the plasma and the extravascular extracellular space fractional volume in pancreatic cancer, obstructive pancreatitis distal to the malignant tumor, adjacent pancreatic tissue proximal to the tumor and normal pancreas. All parameters were statistically analyzed. Results: Statistical differences were noticed in both the transfer constant (p = 0.000075) and the rate constant of backflux (p = 0.006) among different tissues. Both the transfer constant and the rate constant of backflux in pancreatic cancer were statistically lower than those in normal pancreas and adjacent pancreatic tissue (p < 0.05). Both the transfer constant and the rate constant of backflux in obstructive pancreatitis were statistically lower than those in normal pancreas and adjacent pancreatic tissue (p < 0.05). The extravascular extracellular space fractional volume in pancreatic cancer was statistically lager than that in normal pancreas (p = 0.002). Conclusion: Multiple breath-hold dynamic contrast-enhanced magnetic resonance imaging offers a useful technique to evaluate the microenvironment in pancreatic cancer at 3.0 T. Compared to normal pancreas, pancreatic cancer has lower transfer constant, rate constant of backflux and larger extravascular extracellular space fractional volume.

  14. Can multi-slice or navigator-gated R2* MRI replace single-slice breath-hold acquisition for hepatic iron quantification?

    Energy Technology Data Exchange (ETDEWEB)

    Loeffler, Ralf B.; McCarville, M.B.; Song, Ruitian; Hillenbrand, Claudia M. [St. Jude Children' s Research Hospital, Diagnostic Imaging, Memphis, TN (United States); Wagstaff, Anne W. [St. Jude Children' s Research Hospital, Diagnostic Imaging, Memphis, TN (United States); Rhodes College, Memphis, TN (United States); University of Alabama at Birmingham School of Medicine, Birmingham, AL (United States); Smeltzer, Matthew P. [St. Jude Children' s Research Hospital, Department of Biostatistics, Memphis, TN (United States); University of Memphis, Division of Epidemiology, Biostatistics, and Environmental Health, School of Public Health, Memphis, TN (United States); Krafft, Axel J. [St. Jude Children' s Research Hospital, Diagnostic Imaging, Memphis, TN (United States); University Hospital Center Freiburg, Department of Radiology, Freiburg (Germany); Hankins, Jane S. [St. Jude Children' s Research Hospital, Department of Hematology, Memphis, TN (United States)

    2017-01-15

    Liver R2* values calculated from multi-gradient echo (mGRE) magnetic resonance images (MRI) are strongly correlated with hepatic iron concentration (HIC) as shown in several independently derived biopsy calibration studies. These calibrations were established for axial single-slice breath-hold imaging at the location of the portal vein. Scanning in multi-slice mode makes the exam more efficient, since whole-liver coverage can be achieved with two breath-holds and the optimal slice can be selected afterward. Navigator echoes remove the need for breath-holds and allow use in sedated patients. To evaluate if the existing biopsy calibrations can be applied to multi-slice and navigator-controlled mGRE imaging in children with hepatic iron overload, by testing if there is a bias-free correlation between single-slice R2* and multi-slice or multi-slice navigator controlled R2*. This study included MRI data from 71 patients with transfusional iron overload, who received an MRI exam to estimate HIC using gradient echo sequences. Patient scans contained 2 or 3 of the following imaging methods used for analysis: single-slice images (n = 71), multi-slice images (n = 69) and navigator-controlled images (n = 17). Small and large blood corrected region of interests were selected on axial images of the liver to obtain R2* values for all data sets. Bland-Altman and linear regression analysis were used to compare R2* values from single-slice images to those of multi-slice images and navigator-controlled images. Bland-Altman analysis showed that all imaging method comparisons were strongly associated with each other and had high correlation coefficients (0.98 ≤ r ≤ 1.00) with P-values ≤0.0001. Linear regression yielded slopes that were close to 1. We found that navigator-gated or breath-held multi-slice R2* MRI for HIC determination measures R2* values comparable to the biopsy-validated single-slice, single breath-hold scan. We conclude that these three R2* methods can be

  15. Monte Carlo calculations support organ sparing in Deep-Inspiration Breath-Hold intensity-modulated radiotherapy for locally advanced lung cancer

    DEFF Research Database (Denmark)

    Ottosson, Wiviann; Sibolt, Patrik; Larsen, Christina

    2015-01-01

    Background and purpose: Studies indicate that Deep-Inspiration Breath-Hold (DIBH) is advantageous over Free-Breathing (FB) for locally advanced lung cancer radiotherapy. However, these studies were based on simplified dose calculation algorithms, potentially critical due to the heterogeneous nature......) for intensity-modulated-radio therapy or volumetric-modulated-arc-therapy using 66 Gy in 33 fractions. All plans were re-calculated with MC. Results: Relative to FB, the total lung volume increased 86.8% in DIBH, while the gross tumor volume decreased 14.8%. MC revealed equally under- and over...

  16. The advantage of deep-inspiration breath-hold and cone-beam CT based soft-tissue registration for locally advanced lung cancer radiotherapy

    DEFF Research Database (Denmark)

    Ottosson, Wiviann; Rahma, Fatma; Sjöström, David

    2016-01-01

    Background and purpose: Three cone-beam computed tomography (CBCT) registration strategies combined with deep-inspiration breath-hold (DIBH) and free-breathing (FB) were explored, in terms of obtaining the smallest planning target volume (PTV). Material and methods: CBCT images were acquired pre...... uncertainties compared to FB, DIBH resulted in smaller PTV-Totals for all registration methods. Soft-tissue registrations were superior to bony registration, independently of FB and DIBH. During DIBH, undesirable arching of the back was identified. Daily CBCT pre-treatment target verification is advised....

  17. Compressed sensing real-time cine cardiovascular magnetic resonance: accurate assessment of left ventricular function in a single-breath-hold.

    Science.gov (United States)

    Kido, Tomoyuki; Kido, Teruhito; Nakamura, Masashi; Watanabe, Kouki; Schmidt, Michaela; Forman, Christoph; Mochizuki, Teruhito

    2016-08-24

    Cardiovascular cine magnetic resonance (CMR) accelerated by compressed sensing (CS) is used to assess left ventricular (LV) function. However, it is difficult for prospective CS cine CMR to capture the complete end-diastolic phase, which can lead to underestimation of the end-diastolic volume (EDV), stroke volume (SV), and ejection fraction (EF), compared to retrospective standard cine CMR. This prospective study aimed to evaluate the diagnostic quality and accuracy of single-breath-hold full cardiac cycle CS cine CMR, acquired over two heart beats, to quantify LV volume in comparison to multi-breath-hold standard cine CMR. Eighty-one participants underwent standard segmented breath-hold cine and CS real-time cine CMR examinations to obtain a stack of eight contiguous short-axis images with same high spatial (1.7 × 1.7 mm(2)) and temporal resolution (41 ms). Two radiologists independently performed qualitative analysis of image quality (score, 1 [i.e., "nondiagnostic"] to 5 [i.e., "excellent"]) and quantitative analysis of the LV volume measurements. The total examination time was 113 ± 7 s for standard cine CMR and 24 ± 4 s for CS cine CMR (p cine image quality was slightly lower than standard cine (4.8 ± 0.5 for standard vs. 4.4 ± 0.5 for CS; p cine were above 4 (i.e., good). No significant differences existed between standard and CS cine MR for all quantitative LV measurements. The mean differences with 95 % confidence interval (CI), based on Bland-Altman analysis, were 1.3 mL (95 % CI, -14.6 - 17.2) for LV end-diastolic volume, 0.2 mL (95 % CI, -9.8 to10.3) for LV end-systolic volume, 1.1 mL (95 % CI, -10.5 to 12.7) for LV stroke volume, 1.0 g (95 % CI, -11.2 to 13.3) for LV mass, and 0.4 % (95 % CI, -4.8 - 5.6) for LV ejection fraction. The interobserver and intraobserver variability for CS cine MR ranged from -4.8 - 1.6 % and from -7.3 - 9.3 %, respectively, with slopes of the regressions ranging 0.88-1.0 and 0

  18. Dual-pathway multi-echo sequence for simultaneous frequency and T2 mapping

    Science.gov (United States)

    Cheng, Cheng-Chieh; Mei, Chang-Sheng; Duryea, Jeffrey; Chung, Hsiao-Wen; Chao, Tzu-Cheng; Panych, Lawrence P.; Madore, Bruno

    2016-04-01

    Purpose: To present a dual-pathway multi-echo steady state sequence and reconstruction algorithm to capture T2, T2∗ and field map information. Methods: Typically, pulse sequences based on spin echoes are needed for T2 mapping while gradient echoes are needed for field mapping, making it difficult to jointly acquire both types of information. A dual-pathway multi-echo pulse sequence is employed here to generate T2 and field maps from the same acquired data. The approach might be used, for example, to obtain both thermometry and tissue damage information during thermal therapies, or susceptibility and T2 information from a same head scan, or to generate bonus T2 maps during a knee scan. Results: Quantitative T2, T2∗ and field maps were generated in gel phantoms, ex vivo bovine muscle, and twelve volunteers. T2 results were validated against a spin-echo reference standard: A linear regression based on ROI analysis in phantoms provided close agreement (slope/R2 = 0.99/0.998). A pixel-wise in vivo Bland-Altman analysis of R2 = 1/T2 showed a bias of 0.034 Hz (about 0.3%), as averaged over four volunteers. Ex vivo results, with and without motion, suggested that tissue damage detection based on T2 rather than temperature-dose measurements might prove more robust to motion. Conclusion: T2, T2∗ and field maps were obtained simultaneously, from the same datasets, in thermometry, susceptibility-weighted imaging and knee-imaging contexts.

  19. The Effect of Inhalation Volume and Breath-Hold Duration on the Retention of Nicotine and Solanesol in the Human Respiratory Tract and on Subsequent Plasma Nicotine Concentrations During Cigarette Smoking

    Directory of Open Access Journals (Sweden)

    Armitage AK

    2014-12-01

    Full Text Available The influence of inhalation depth and breath-hold duration on the retention of nicotine and solanesol in the human respiratory tract and on nicotine uptake was studied in ten cigarette smokers. In a first series of experiments, the subjects took seven puffs from a 10 mg ‘tar’ yield, test cigarette and a fixed volume of air (0, 75, 250, 500 or 1000 mL, as required by the protocol was inhaled after each puff in order to give a controlled ‘depth’ of inhalation. The inhalation was drawn from a bag containing the required volume of air. Following a 2 s breath-hold, subjects exhaled normally, with the first exhalation after each puff passing through a single acidified filter pad for collection of the non-retained nicotine and solanesol. Blood samples were taken before and at intervals during and after smoking for the sessions with 0, 75 and 500 mL inhalation volumes for determination of plasma nicotine and carboxyhaemoglobin levels. Another series of experiments was conducted with a fixed inhalation volume (500 mL and two further breath-hold durations (0 and 10 s in addition to 2 s from above. Nicotine and solanesol retentions were measured for each breath-hold condition. The amounts of nicotine retained within the respiratory system, expressed as a percentage of the amount taken into the mouth, were consistently higher than the corresponding values for solanesol in all five inhalation conditions (0-1000 mL, 2 s breath-hold. Nicotine retention increased from 46.5% at zero inhalation to 99.5% at 1000 mL inhalation (2 s breath-hold and from 98.0% at zero breath-hold to 99.9% at 10 s breath-hold (500 mL inhalation. Solanesol retention increased from 34.2% at zero inhalation volume to 71.9% at 1000 mL inhalation (2 s breath-hold and from 51.8% at zero breath-hold to 87.6% at 10 s breath-hold (500 mL inhalation. Plasma nicotine decreased from pre-smoking levels after zero inhalation indicating that the nicotine retained within the mouth was poorly

  20. Whole-heart cine MRI in a single breath-hold. A compressed sensing accelerated 3D acquisition technique for assessment of cardiac function

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    Wech, T.; Koestler, H. [Wuerzburg Univ. (Germany). Inst. of Radiology; Wuerzburg Univ. (Germany). Comprehensive Heart Failure Center; Pickl, W.; Tran-Gia, J.; Ritter, C.; Hahn, D. [Wuerzburg Univ. (Germany). Inst. of Radiology; Beer, M. [Wuerzburg Univ. (Germany). Inst. of Radiology; Graz Univ. (Austria). University Hospital Radiology

    2014-01-15

    Purpose: The aim of this study was to perform functional MR imaging of the whole heart in a single breath-hold using an undersampled 3 D trajectory for data acquisition in combination with compressed sensing for image reconstruction. Materials and Methods: Measurements were performed using an SSFP sequence on a 3 T whole-body system equipped with a 32-channel body array coil. A 3 D radial stack-of-stars sampling scheme was utilized enabling efficient undersampling of the k-space and thereby accelerating data acquisition. Compressed sensing was applied for the reconstruction of the missing data. A validation study was performed based on a fully sampled dataset acquired by standard Cartesian cine imaging of 2 D slices on a healthy volunteer. The results were investigated with regard to systematic errors and resolution losses possibly introduced by the developed reconstruction. Subsequently, the proposed technique was applied for in-vivo functional cardiac imaging of the whole heart in a single breath-hold of 27 s. The developed technique was tested on three healthy volunteers to examine its reproducibility. Results: By means of the results of the simulation (temporal resolution: 47 ms, spatial resolution: 1.4 x 1.4 x 8 mm, 3 D image matrix: 208 x 208 x 10), an overall acceleration factor of 10 has been found where the compressed sensing reconstructed image series shows only very low systematic errors and a slight in-plane resolution loss of 15 %. The results of the in-vivo study (temporal resolution: 40.5 ms, spatial resolution: 2.1 x 2.1 x 8 mm, 3 D image matrix: 224 x 224 x 12) performed with an acceleration factor of 10.7 confirm the overall good image quality of the presented technique for undersampled acquisitions. Conclusion: The combination of 3 D radial data acquisition and model-based compressed sensing reconstruction allows high acceleration factors enabling cardiac functional imaging of the whole heart within only one breath-hold. The image quality in the

  1. Effect of Maximal Apnoea Easy-Going and Struggle Phases on Subarachnoid Width and Pial Artery Pulsation in Elite Breath-Hold Divers.

    Directory of Open Access Journals (Sweden)

    Pawel J Winklewski

    Full Text Available The aim of the study was to assess changes in subarachnoid space width (sas-TQ, the marker of intracranial pressure (ICP, pial artery pulsation (cc-TQ and cardiac contribution to blood pressure (BP, cerebral blood flow velocity (CBFV and cc-TQ oscillations throughout the maximal breath hold in elite apnoea divers. Non-invasive assessment of sas-TQ and cc-TQ became possible due to recently developed method based on infrared radiation, called near-infrared transillumination/backscattering sounding (NIR-T/BSS.The experimental group consisted of seven breath-hold divers (six men. During testing, each participant performed a single maximal end-inspiratory breath hold. Apnoea consisted of the easy-going and struggle phases (characterised by involuntary breathing movements (IBMs. Heart rate (HR was determined using a standard ECG. BP was assessed using the photoplethysmography method. SaO2 was monitored continuously with pulse oximetry. A pneumatic chest belt was used to register thoracic and abdominal movements. Cerebral blood flow velocity (CBFV was estimated by a 2-MHz transcranial Doppler ultrasonic probe. sas-TQ and cc-TQ were measured using NIR-T/BSS. Wavelet transform analysis was performed to assess cardiac contribution to BP, CBFV and cc-TQ oscillations.Mean BP and CBFV increased compared to baseline at the end of the easy phase and were further augmented by IBMs. cc-TQ increased compared to baseline at the end of the easy phase and remained stable during the IBMs. HR did not change significantly throughout the apnoea, although a trend toward a decrease during the easy phase and recovery during the IBMs was visible. Amplitudes of BP, CBFV and cc-TQ were augmented. sas-TQ and SaO2 decreased at the easy phase of apnoea and further decreased during the IBMs.Apnoea increases intracranial pressure and pial artery pulsation. Pial artery pulsation seems to be stabilised by the IBMs. Cardiac contribution to BP, CBFV and cc-TQ oscillations does not

  2. Multiple breath-hold proton spectroscopy of human liver at 3T: Relaxation times and concentrations of glycogen, choline, and lipids.

    Science.gov (United States)

    Weis, Jan; Kullberg, Joel; Ahlström, Håkan

    2017-04-17

    To evaluate the feasibility of an expiration multiple breath-hold (1) H-MRS technique to measure glycogen (Glycg), choline-containing compounds (CCC), and lipid relaxation times T1 , T2 , and their concentrations in normal human liver. Thirty healthy volunteers were recruited. Experiments were performed at 3T. Multiple expiration breath-hold single-voxel point-resolved spectroscopy (PRESS) technique was used for localization. Water-suppressed spectra were used for the estimation of Glycg, CCC, lipid methylene (CH2 )n relaxation times and concentrations. Residual water lines were removed by the Hankel Lanczos singular value decomposition filter. After phase correction and frequency alignment, spectra were averaged and processed by LCModel. Summed signals of Glycg resonances H2H4', H3, and H5 between 3.6 and 4 ppm were used to estimate their apparent relaxation times and concentration. Glycg, CCC, and lipid content were estimated from relaxation corrected spectral intensity ratios to unsuppressed water line. Relaxation times were measured for liver Glycg (T1 , 892 ± 126 msec; T2 , 13 ± 4 msec), CCC (T1 , 842 ± 75 msec; T2 , 50 ± 5 msec), lipid (CH2 )n (T1 , 402 ± 19 msec; T2 , 52 ± 3 msec), and water (T1 , 990 ± 89 msec; T2 , 30 ± 2 msec). Mean CCC and lipid concentrations of healthy liver were 7.8 ± 1.3 mM and 15.8 ± 23.6 mM, respectively. Glycg content was found lower in the morning (48 ± 21 mM) compared to the afternoon (145 ± 50 mM). Multiple breath-hold (1) H-MRS together with dedicated postprocessing is a feasible technique for the quantification of liver Glycg, CCC, and lipid relaxation times and concentrations. 1 J. Magn. Reson. Imaging 2017. © 2017 International Society for Magnetic Resonance in Medicine.

  3. Rapid MR assessment of left ventricular systolic function after acute myocardial infarction using single breath-hold cine imaging with the temporal parallel acquisition technique (TPAT) and 4D guide-point modelling analysis of left ventricular function

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    Eberle, Holger C.; Jensen, Christoph J.; Sabin, Georg V.; Naber, Christoph K.; Bruder, Oliver [Elisabeth Hospital, Department of Cardiology and Angiology, Essen (Germany); Nassenstein, Kai; Schlosser, Thomas [University of Duisburg-Essen, Department of Diagnostic and Interventional Radiology and Neuroradiology, University Hospital Essen, Essen (Germany)

    2010-01-15

    We compared four-dimensional guide-point modelling left ventricular function analysis (4DVF) results of cine images in four short-axis and two long-axis slices acquired in a single breath-hold, obtained with the temporal parallel acquisition technique (TPAT), with standard left ventricular function (LVF) analysis results determined by the summation of discs method, in patients who had recently suffered myocardial infarction. Despite wall motion abnormalities, 4DVF yields results for left ventricular ejection fractions and end-diastolic and end-systolic volumes that are in excellent agreement with standard LVF analysis results in these patients. A shortened cardiac magnetic resonance (CMR) protocol using single breath-hold cine image acquisition could facilitate the assessment of left ventricular function soon after myocardial infarction in critically ill patients who are unable to comply with the multiple breath-holds required for standard LVF analysis. (orig.)

  4. Quantification of early fatty infiltration of the rotator cuff muscles: comparison of multi-echo Dixon with single-voxel MR spectroscopy

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    Agten, Christoph A.; Rosskopf, Andrea B.; Pfirrmann, Christian W.A. [Balgrist University Hospital, Radiology, Zurich (Switzerland); University of Zurich, Faculty of Medicine, Zurich (Switzerland); Gerber, Christian [Balgrist University Hospital, Orthopaedic Surgery, Zurich (Switzerland); University of Zurich, Faculty of Medicine, Zurich (Switzerland)

    2016-10-15

    To evaluate quantification of early fatty infiltration in supraspinatus muscles with magnetic resonance (MR) imaging using a T2*-corrected multi-echo 3D-gradient-echo Dixon-based sequence (multi-echo Dixon) and compare it to proton-MR-spectroscopy. Sixty subjects (mean age 46 years, 41 men) with good supraspinatus muscle quality on 1.5 T MR imaging were included. Fat percentage (FP) in the supraspinatus muscle was quantified using a multi-echo Dixon compared to single-voxel MR spectroscopy as reference standard. In 18 subjects the multi-echo Dixon was repeated to assess test-retest reliability. Measurements based on multi-echo Dixon were performed by two independent readers by placing regions-of-interest (ROIs) in the supraspinatus muscle corresponding to the MR-spectroscopy voxel. Intraclass and concordance correlation coefficients (ICC/CCC) were used for statistical analysis. Test-retest reliability was substantial for reader 1 (ICC = 0.757) and almost perfect for reader 2 (ICC = 0.873). Inter-reader reliability for multi-echo Dixon was almost perfect (ICC = 0.893, P <.0005). Mean FP in all 60 subjects with multi-echo Dixon was 3.5 ± 1.6 for reader 1, 3.7 ± 1.8 for reader 2, and 2.8 ± 1.4 with MR spectroscopy. Correlation between multi-echo Dixon and MR spectroscopy was moderate (CCC = 0.641). The multi-echo Dixon sequence is a reliable method and comparable to MR-spectroscopy for quantification of low levels of fatty infiltration in the supraspinatus muscle. (orig.)

  5. A study of reduction in breath-holding time in smokers and recovery among ex-smokers in bus depot workers

    Directory of Open Access Journals (Sweden)

    Bakthavathsalam Sreenivas Sudha

    2012-01-01

    Full Text Available Background: Smoking has deleterious effects on breath-holding time (BHT, which has been used in respiratory physiology as a measure of ventilatory response. Evidences regarding assessment of the reversibility of the impact of smoking on BHT and recovery in ex-smokers are ambiguous. Hence, this study was conducted to quantify the reduction in BHT and to assess the reversibility of the same. Materials and Methods: A cross-sectional study was conducted on 84 bus-depot workers consisting of equal number of smokers, ex-smokers, and non-smokers. Breath-holding time was recorded using the mouth piece attached to the mercury manometer where the subjects were advised to blow through the mouth piece after full inspiration as long as possible till the breaking point following standard methods and precautions. Comparisons among 3 groups were performed employing one-way ANOVA and post-hoc tests. The significance of difference in BHT between the 2 categories of frequency and duration of smoking was tested using Student′s t-test for independent samples. Results: BHT was found to be significantly reduced among smokers compared to non-smokers. Almost complete recovery of BHT was observed in ex-smokers. There was deterioration in BHT with increase in BMI, and a statistically significant negative correlation was observed when BHT was correlated with age, especially in smokers. Conclusion: Present study has demonstrated considerable reduction of BHT in smokers and indications of recovery in ex-smokers. Further detailed study with larger sample size, stricter definition of ex-smokers, and considering physical activity is recommended.

  6. Multi-echo fMRI: A review of applications in fMRI denoising and analysis of BOLD signals.

    Science.gov (United States)

    Kundu, Prantik; Voon, Valerie; Balchandani, Priti; Lombardo, Michael V; Poser, Benedikt A; Bandettini, Peter A

    2017-07-01

    In recent years the field of fMRI research has enjoyed expanded technical abilities related to resolution, as well as use across many fields of brain research. At the same time, the field has also dealt with uncertainty related to many known and unknown effects of artifact in fMRI data. In this review we discuss an emerging fMRI technology, called multi-echo (ME)-fMRI, which focuses on improving the fidelity and interpretability of fMRI. Where the essential problem of standard single-echo fMRI is the indeterminacy of sources of signals, whether BOLD or artifact, this is not the case for ME-fMRI. By acquiring multiple echo images per slice, the ME approach allows T2* decay to be modeled at every voxel at every time point. Since BOLD signals arise by changes in T2* over time, an fMRI experiment sampling the T2* signal decay can be analyzed to distinguish BOLD from artifact signal constituents. While the ME approach has a long history of use in theoretical and validation studies, modern MRI systems enable whole-brain multi-echo fMRI at high resolution. This review covers recent multi-echo fMRI acquisition methods, and the analysis steps for this data to make fMRI at once more principled, straightforward, and powerful. After a brief overview of history and theory, T2* modeling and applications will be discussed. These applications include T2* mapping and combining echoes from ME data to increase BOLD contrast and mitigate dropout artifacts. Next, the modeling of fMRI signal changes to detect signal origins in BOLD-related T2* versus artifact-related S0 changes will be reviewed. A focus is on the use of ME-fMRI data to extract and classify components from spatial ICA, called multi-echo ICA (ME-ICA). After describing how ME-fMRI and ME-ICA lead to a general model for analysis of fMRI signals, applications in animal and human imaging will be discussed. Applications include removing motion artifacts in resting state data at subject and group level. New imaging methods such

  7. T2{sup *} mapping from multi-echo dixon sequence on gadoxetic acid-enhanced magnetic resonance imaging for the hepatic fat quantification: Can it be used for hepatic function assessment?

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    Yoo, Hyun Suk; Lee, Jeong Min; Yoon, Jeong Hee; Kang, Hyo Jin; Lee, Sang Min; Yang, Hyun Kyung; Han, Joon Koo [Dept. of Radiology, Seoul National University Hospital, Seoul (Korea, Republic of)

    2017-08-01

    To evaluate the diagnostic value of T2{sup *} mapping using 3D multi-echo Dixon gradient echo acquisition on gadoxetic acid-enhanced liver magnetic resonance imaging (MRI) as a tool to evaluate hepatic function. This retrospective study was approved by the IRB and the requirement of informed consent was waived. 242 patients who underwent liver MRIs, including 3D multi-echo Dixon fast gradient-recalled echo (GRE) sequence at 3T, before and after administration of gadoxetic acid, were included. Based on clinico-laboratory manifestation, the patients were classified as having normal liver function (NLF, n = 50), mild liver damage (MLD, n = 143), or severe liver damage (SLD, n = 30). The 3D multi-echo Dixon GRE sequence was obtained before, and 10 minutes after, gadoxetic acid administration. Pre- and post-contrast T2{sup *} values, as well as T2{sup *} reduction rates, were measured from T2{sup *} maps, and compared among the three groups. There was a significant difference in T2{sup *} reduction rates between the NLF and SLD groups (−0.2 ± 4.9% vs. 5.0 ± 6.9%, p = 0.002), and between the MLD and SLD groups (3.2 ± 6.0% vs. 5.0 ± 6.9%, p = 0.003). However, there was no significant difference in both the pre- and post-contrast T2{sup *} values among different liver function groups (p = 0.735 and 0.131, respectively). A receiver operating characteristic (ROC) curve analysis showed that the area under the ROC curve for using T2{sup *} reduction rates to differentiate the SLD group from the NLF group was 0.74 (95% confidence interval: 0.63–0.83). Incorporation of T2{sup *} mapping using 3D multi-echo Dixon GRE sequence in gadoxetic acid-enhanced liver MRI protocol may provide supplemental information for liver function deterioration in patients with SLD.

  8. Magnitude of shift of tumor position as a function of moderated deep inspiration breath-hold: An analysis of pooled data of lung patients with active breath control in image-guided radiotherapy

    Directory of Open Access Journals (Sweden)

    Muralidhar K

    2008-01-01

    Full Text Available The purpose of this study was to evaluate the reproducibility and magnitude of shift of tumor position by using active breathing control and iView-GT for patients with lung cancer with moderate deep-inspiration breath-hold (mDIBH technique. Eight patients with 10 lung tumors were studied. CT scans were performed in the breath-holding phase. Moderate deep-inspiration breath-hold under spirometer-based monitoring system was used. Few important bony anatomic details were delineated by the radiation oncologist. To evaluate the interbreath-hold reproducibility of the tumor position, we compared the digital reconstruction radiographs (DRRs from planning system with the DRRs from the iView-GT in the machine room. We measured the shift in x, y, and z directions. The reproducibility was defined as the difference between the bony landmarks from the DRR of the planning system and those from the DRR of the iView-GT. The maximum shift of the tumor position was 3.2 mm, 3.0 mm, and 2.9 mm in the longitudinal, lateral, and vertical directions. In conclusion, the moderated deep-inspiration breath-hold method using a spirometer is feasible, with relatively good reproducibility of the tumor position for image-guided radiotherapy in lung cancers.

  9. Single breath-hold 3D measurement of left atrial volume using compressed sensing cardiovascular magnetic resonance and a non-model-based reconstruction approach.

    Science.gov (United States)

    Vardoulis, Orestis; Monney, Pierre; Bermano, Amit; Vaxman, Amir; Gotsman, Craig; Schwitter, Janine; Stuber, Matthias; Stergiopulos, Nikolaos; Schwitter, Juerg

    2015-06-11

    Left atrial (LA) dilatation is associated with a large variety of cardiac diseases. Current cardiovascular magnetic resonance (CMR) strategies to measure LA volumes are based on multi-breath-hold multi-slice acquisitions, which are time-consuming and susceptible to misregistration. To develop a time-efficient single breath-hold 3D CMR acquisition and reconstruction method to precisely measure LA volumes and function. A highly accelerated compressed-sensing multi-slice cine sequence (CS-cineCMR) was combined with a non-model-based 3D reconstruction method to measure LA volumes with high temporal and spatial resolution during a single breath-hold. This approach was validated in LA phantoms of different shapes and applied in 3 patients. In addition, the influence of slice orientations on accuracy was evaluated in the LA phantoms for the new approach in comparison with a conventional model-based biplane area-length reconstruction. As a reference in patients, a self-navigated high-resolution whole-heart 3D dataset (3D-HR-CMR) was acquired during mid-diastole to yield accurate LA volumes. Phantom studies. LA volumes were accurately measured by CS-cineCMR with a mean difference of -4.73 ± 1.75 ml (-8.67 ± 3.54%, r2 = 0.94). For the new method the calculated volumes were not significantly different when different orientations of the CS-cineCMR slices were applied to cover the LA phantoms. Long-axis "aligned" vs "not aligned" with the phantom long-axis yielded similar differences vs the reference volume (-4.87 ± 1.73 ml vs. -4.45 ± 1.97 ml, p = 0.67) and short-axis "perpendicular" vs. "not-perpendicular" with the LA long-axis (-4.72 ± 1.66 ml vs. -4.75 ± 2.13 ml; p = 0.98). The conventional bi-plane area-length method was susceptible for slice orientations (p = 0.0085 for the interaction of "slice orientation" and "reconstruction technique", 2-way ANOVA for repeated measures). To use the 3D-HR-CMR as the reference for LA volumes

  10. SU-E-J-55: End-To-End Effectiveness Analysis of 3D Surface Image Guided Voluntary Breath-Holding Radiotherapy for Left Breast

    Energy Technology Data Exchange (ETDEWEB)

    Lin, M; Feigenberg, S [University of Maryland School of Medicine, Baltimore, MD (United States)

    2015-06-15

    Purpose To evaluate the effectiveness of using 3D-surface-image to guide breath-holding (BH) left-side breast treatment. Methods Two 3D surface image guided BH procedures were implemented and evaluated: normal-BH, taking BH at a comfortable level, and deep-inspiration-breath-holding (DIBH). A total of 20 patients (10 Normal-BH and 10 DIBH) were recruited. Patients received a BH evaluation using a commercialized 3D-surface- tracking-system (VisionRT, London, UK) to quantify the reproducibility of BH positions prior to CT scan. Tangential 3D/IMRT plans were conducted. Patients were initially setup under free-breathing (FB) condition using the FB surface obtained from the untaged CT to ensure a correct patient position. Patients were then guided to reach the planned BH position using the BH surface obtained from the BH CT. Action-levels were set at each phase of treatment process based on the information provided by the 3D-surface-tracking-system for proper interventions (eliminate/re-setup/ re-coaching). We reviewed the frequency of interventions to evaluate its effectiveness. The FB-CBCT and port-film were utilized to evaluate the accuracy of 3D-surface-guided setups. Results 25% of BH candidates with BH positioning uncertainty > 2mm are eliminated prior to CT scan. For >90% of fractions, based on the setup deltas from3D-surface-trackingsystem, adjustments of patient setup are needed after the initial-setup using laser. 3D-surface-guided-setup accuracy is comparable as CBCT. For the BH guidance, frequency of interventions (a re-coaching/re-setup) is 40%(Normal-BH)/91%(DIBH) of treatments for the first 5-fractions and then drops to 16%(Normal-BH)/46%(DIBH). The necessity of re-setup is highly patient-specific for Normal-BH but highly random among patients for DIBH. Overall, a −0.8±2.4 mm accuracy of the anterior pericardial shadow position was achieved. Conclusion 3D-surface-image technology provides effective intervention to the treatment process and ensures

  11. Abdominal 4D flow MR imaging in a breath hold: combination of spiral sampling and dynamic compressed sensing for highly accelerated acquisition.

    Science.gov (United States)

    Dyvorne, Hadrien; Knight-Greenfield, Ashley; Jajamovich, Guido; Besa, Cecilia; Cui, Yong; Stalder, Aurélien; Markl, Michael; Taouli, Bachir

    2015-04-01

    To develop a highly accelerated phase-contrast cardiac-gated volume flow measurement (four-dimensional [4D] flow) magnetic resonance (MR) imaging technique based on spiral sampling and dynamic compressed sensing and to compare this technique with established phase-contrast imaging techniques for the quantification of blood flow in abdominal vessels. This single-center prospective study was compliant with HIPAA and approved by the institutional review board. Ten subjects (nine men, one woman; mean age, 51 years; age range, 30-70 years) were enrolled. Seven patients had liver disease. Written informed consent was obtained from all participants. Two 4D flow acquisitions were performed in each subject, one with use of Cartesian sampling with respiratory tracking and the other with use of spiral sampling and a breath hold. Cartesian two-dimensional (2D) cine phase-contrast images were also acquired in the portal vein. Two observers independently assessed vessel conspicuity on phase-contrast three-dimensional angiograms. Quantitative flow parameters were measured by two independent observers in major abdominal vessels. Intertechnique concordance was quantified by using Bland-Altman and logistic regression analyses. There was moderate to substantial agreement in vessel conspicuity between 4D flow acquisitions in arteries and veins (κ = 0.71 and 0.61, respectively, for observer 1; κ = 0.71 and 0.44 for observer 2), whereas more artifacts were observed with spiral 4D flow (κ = 0.30 and 0.20). Quantitative measurements in abdominal vessels showed good equivalence between spiral and Cartesian 4D flow techniques (lower bound of the 95% confidence interval: 63%, 77%, 60%, and 64% for flow, area, average velocity, and peak velocity, respectively). For portal venous flow, spiral 4D flow was in better agreement with 2D cine phase-contrast flow (95% limits of agreement: -8.8 and 9.3 mL/sec, respectively) than was Cartesian 4D flow (95% limits of agreement: -10.6 and 14.6 m

  12. Anatomy, variants, and pathologies of the superior glenohumeral ligament: Magnetic resonance imaging with three-dimensional volumetric interpolated breath-hold examination sequence and conventional magnetic resonance arthrography

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    Ogul, Hayri; Karaca, Leyla; Emre, Cahit; Pirimoglu, Berhan; Tuncer, Kutsi; Topai, Murat; Okur, Aylin; Kantarci, Mecit [Medical Faculty, Ataturk University, Erzurum (Turkmenistan)

    2014-08-15

    The purpose of this review was to demonstrate magnetic resonance (MR) arthrography findings of anatomy, variants, and pathologic conditions of the superior glenohumeral ligament (SGHL). This review also demonstrates the applicability of a new MR arthrography sequence in the anterosuperior portion of the glenohumeral joint. The SGHL is a very important anatomical structure in the rotator interval that is responsible for stabilizing the long head of the biceps tendon. Therefore, a torn SGHL can result in pain and instability. Observation of the SGHL is difficult when using conventional MR imaging, because the ligament may be poorly visualized. Shoulder MR arthrography is the most accurately established imaging technique for identifying pathologies of the SGHL and associated structures. The use of three dimensional (3D) volumetric interpolated breath-hold examination (VIBE) sequences produces thinner image slices and enables a higher in-plane resolution than conventional MR arthrography sequences. Therefore, shoulder MR arthrography using 3D VIBE sequences may contribute to evaluating of the smaller intraarticular structures such as the SGHL.

  13. Using surface imaging and visual coaching to improve the reproducibility and stability of deep-inspiration breath hold for left-breast-cancer radiotherapy

    Science.gov (United States)

    Cerviño, Laura I.; Gupta, Sonia; Rose, Mary A.; Yashar, Catheryn; Jiang, Steve B.

    2009-11-01

    Late cardiac complications may arise after left-breast radiation therapy. Deep-inspiration breath hold (DIBH) allows reduction of the irradiated heart volume at the same time as it reduces tumor bed motion and increases lung sparing. In the present study, we have evaluated the improvement in reproducibility and stability of the DIBH for left-breast-cancer treatment when visual coaching is provided with the aid of 3D video surface imaging and video goggles. Five left-breast-cancer patients and fifteen healthy volunteers were asked to perform a series of DIBHs without and with visual coaching. Reproducibility and stability of DIBH were measured for each individual with and without visual coaching. The average reproducibility and stability changed from 2.1 mm and 1.5 mm, respectively, without visual feedback to 0.5 mm and 0.7 mm with visual feedback, showing a significant statistical difference (p 2 mm) in reproducibility and stability were observed in 35% and 15% of the subjects, respectively. The average chest wall excursion of the DIBH with respect to the free breathing preceding the DIBH was found to be 11.3 mm. The reproducibility and stability of the DIBH improve significantly from the visual coaching provided to the patient, especially in those patients with poor reproducibility and stability.

  14. Quantitative assessment of irradiated lung volume and lung mass in breast cancer patients treated with tangential fields in combination with deep inspiration breath hold (DIBH)

    Energy Technology Data Exchange (ETDEWEB)

    Kapp, Karin Sigrid [Univ. Clinic of Therapeutic Radiology and Oncology, Medical Univ. of Graz (Austria); Zurl, Brigitte; Stranzl, Heidi; Winkler, Peter

    2010-03-15

    Purpose: Comparison of the amount of irradiated lung tissue volume and mass in patients with breast cancer treated with an optimized tangential-field technique with and without a deep inspiration breath-hold (DIBH) technique and its impact on the normal-tissue complication probability (NTCP). Material and Methods: Computed tomography datasets of 60 patients in normal breathing (NB) and subsequently in DIBH were compared. With a Real-Time Position Management Respiratory Gating System (RPM), anteroposterior movement of the chest wall was monitored and a lower and upper threshold were defined. Ipsilateral lung and a restricted tangential region of the lung were delineated and the mean and maximum doses calculated. Irradiated lung tissue mass was computed based on density values. NTCP for lung was calculated using a modified Lyman-Kutcher-Burman (LKB) model. Results: Mean dose to the ipsilateral lung in DIBH versus NB was significantly reduced by 15%. Mean lung mass calculation in the restricted area receiving {<=} 20 Gy (M{sub 20}) was reduced by 17% in DIBH but associated with an increase in volume. NTCP showed an improvement in DIBH of 20%. The correlation of individual breathing amplitude with NTCP proved to be independent. Conclusion: The delineation of a restricted area provides the lung mass calculation in patients treated with tangential fields. DIBH reduces ipsilateral lung dose by inflation so that less tissue remains in the irradiated region and its efficiency is supported by a decrease of NTCP. (orig.)

  15. Use of expiratory CT pulmonary angiography to reduce inspiration and breath-hold associated artefact: Contrast dynamics and implications for scan protocol

    Energy Technology Data Exchange (ETDEWEB)

    Mortimer, A.M., E-mail: alex_mortimer@hotmail.com [Department of Radiology, Bristol Royal Infirmary, Bristol (United Kingdom); Singh, R.K.; Hughes, J.; Greenwood, R.; Hamilton, M.C.K. [Department of Radiology, Bristol Royal Infirmary, Bristol (United Kingdom)

    2011-12-15

    Aim: To investigate the effects of scanning in expiration during computed tomography pulmonary angiography (CTPA). Materials and methods: One hundred and eighty-one consecutive expiratory CTPA examinations were compared with 145 inspiratory CTPA examinations performed using a standardized protocol through assessment of attenuation seen in the cardiac chambers, pulmonary artery (PA), and ascending aorta. Results: Expiratory scans showed greater attenuation at the pulmonary trunk, right PA, left PA, lobar and segmental PAs (p < 0.05). Expiratory scans showed a lower incidence of transient contrast medium interruption (p < 0.001) and generalized unsatisfactory PA opacification (p < 0.05). Scans with generalized low PA attenuation had lower attenuation in the right ventricle, left heart, and ascending aorta (p < 0.001) suggesting that contrast medium delivery or dilution prior to contrast medium entry into the PA is responsible. Expiratory scans showed lower quality scores (p < 0.001) for depiction of lung parenchyma. Conclusion: Expiratory scanning could be used as an optimal protocol for dedicated PA imaging. However, it suffers from inferior parenchymal imaging and should probably be reserved for failed inspiratory breath-hold CTPA.

  16. Registration and Summation of Respiratory-Gated or Breath-Hold PET Images Based on Deformation Estimation of Lung from CT Image

    Directory of Open Access Journals (Sweden)

    Hideaki Haneishi

    2016-01-01

    Full Text Available Lung motion due to respiration causes image degradation in medical imaging, especially in nuclear medicine which requires long acquisition times. We have developed a method for image correction between the respiratory-gated (RG PET images in different respiration phases or breath-hold (BH PET images in an inconsistent respiration phase. In the method, the RG or BH-PET images in different respiration phases are deformed under two criteria: similarity of the image intensity distribution and smoothness of the estimated motion vector field (MVF. However, only these criteria may cause unnatural motion estimation of lung. In this paper, assuming the use of a PET-CT scanner, we add another criterion that is the similarity for the motion direction estimated from inhalation and exhalation CT images. The proposed method was first applied to a numerical phantom XCAT with tumors and then applied to BH-PET image data for seven patients. The resultant tumor contrasts and the estimated motion vector fields were compared with those obtained by our previous method. Through those experiments we confirmed that the proposed method can provide an improved and more stable image quality for both RG and BH-PET images.

  17. Role of EPI in diagnosing cavernous hemangioma and small HCC : comparison with fast T2-weighted MR Imaging

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Suk; Lee, Jun Woo; Kim, Chang Won; Jung, Hyun Woo; Choi, Sang Yoel; Lee, Suck Hong; Kim, Byung Soo [Pusan National Univeraty Hospital, Pusan (Korea, Republic of)

    1998-05-01

    The purpose of this study is to compare single-shot echo-planar MR imaging (EPI) with breath-hold fast T2-weighted imaging (HASTE or Turbo spin-echo T2WI) for evaluation of the role of EPI in distinguishing small hepatocellular carcinoma from cavernous hemangioma. We retrospectively evaluated MR images of 35 patients (21 cases of small HCC and 14 cases of cavernous hemangioma). EPI and breath-hold fast T2WI images were obtained and compared on the basis of lesion detection sensitivity, lesion-to-liver signal intensity ratio (SIR), contrast ratio (CR), and lesion-to-liver contrast to noise ratio (CNR). For the detection of small HCC, the sensitivity of EPI and breath-hold fast T2WI were equal in 14 of 21 cases (71.4%). The detection sensitivity of cavernous hemangioma with EPI and breath-hold fast T2WI was 100 % (14/14). Mean SIR on breath-hold fast T2WI was 2.02 {+-} 0.45 for small HCC and 3.65 {+-} 0.97 for cavernous hemangioma; on EPI, the corresponding figures were 2.91 {+-} 0.57 for cavernous hemangioma; On EPI, the figures obtained were 2.27 {+-} 0.52 and 6.26 {+-} 2.19, respectively. Mean CNR on breath-hold fast T2WI was 14.24 {+-} 4.098 for small HCC and 50.28 {+-} 10.96 for cavernous hemangioma, while on EPI, the corresponding figures were 13.84 {+-} 3.02 and 45.44 {+-} 11.21. In detecting focal hepatic mass, the sensitivity of EPI and breath-hold fast T2WI are comparable for the diagnosis of small HCC and cavernous hemangioma, EPI can provided additional information. (author). 20 refs., 2 tabs., 4 figs.

  18. A 4D ultrasound real-time tracking system for external beam radiotherapy of upper abdominal lesions under breath-hold

    Energy Technology Data Exchange (ETDEWEB)

    Sihono, Dwi Seno Kuncoro; Vogel, Lena; Thoelking, Johannes; Wenz, Frederik; Boda-Heggemann, Judit; Wertz, Hansjoerg [University of Heidelberg, Department of Radiation Oncology, University Medical Center Mannheim, Mannheim (Germany); Weiss, Christel [University of Heidelberg, Department of Biomathematics and Medical Statistics, University Medical Center Mannheim, Mannheim (Germany); Lohr, Frank [University of Heidelberg, Department of Radiation Oncology, University Medical Center Mannheim, Mannheim (Germany); Az. Ospedaliero-Universitaria di Modena, Struttura Complessa di Radioterapia, Dipartimento di Oncologia, Modena (Italy)

    2017-03-15

    To evaluate a novel four-dimensional (4D) ultrasound (US) tracking system for external beam radiotherapy of upper abdominal lesions under computer-controlled deep-inspiration breath-hold (DIBH). The tracking accuracy of the research 4D US system was evaluated using two motion phantoms programmed with sinusoidal and breathing patterns to simulate free breathing and DIBH. Clinical performance was evaluated with five healthy volunteers. US datasets were acquired in computer-controlled DIBH with varying angular scanning angles. Tracked structures were renal pelvis (spherical structure) and portal/liver vein branches (non-spherical structure). An external marker was attached to the surface of both phantoms and volunteers as a secondary object to be tracked by an infrared camera for comparison. Phantom measurements showed increased accuracy of US tracking with decreasing scanning range/increasing scanning frequency. The probability of lost tracking was higher for small scanning ranges (43.09% for 10 and 13.54% for 20 ).The tracking success rates in healthy volunteers during DIBH were 93.24 and 89.86% for renal pelvis and portal vein branches, respectively. There was a strong correlation between marker motion and US tracking for the majority of analyzed breath-holds: 84.06 and 88.41% of renal pelvis target results and 82.26 and 91.94% of liver vein target results in anteroposterior and superoinferior directions, respectively; Pearson's correlation coefficient was between 0.71 and 0.99. The US system showed a good tracking performance in 4D motion phantoms. The tracking capability of surrogate structures for upper abdominal lesions in DIBH fulfills clinical requirements. Further investigation in a larger cohort of patients is underway. (orig.) [German] Evaluation eines neuen vierdimensionalen (4D) Ultraschall(US)-Tracking-Systems fuer die externe Strahlentherapie von Oberbauchlaesionen unter computergesteuertem tiefem Atemanhalt (DIBH). Die Tracking-Genauigkeit des 4D

  19. Purine metabolism in response to hypoxic conditions associated with breath-hold diving and exercise in erythrocytes and plasma from bottlenose dolphins (Tursiops truncatus).

    Science.gov (United States)

    del Castillo Velasco-Martínez, Iris; Hernández-Camacho, Claudia J; Méndez-Rodríguez, Lía C; Zenteno-Savín, Tania

    2016-01-01

    In mammalian tissues under hypoxic conditions, ATP degradation results in accumulation of purine metabolites. During exercise, muscle energetic demand increases and oxygen consumption can exceed its supply. During breath-hold diving, oxygen supply is reduced and, although oxygen utilization is regulated by bradycardia (low heart rate) and peripheral vasoconstriction, tissues with low blood flow (ischemia) may become hypoxic. The goal of this study was to evaluate potential differences in the circulating levels of purine metabolism components between diving and exercise in bottlenose dolphins (Tursiops truncatus). Blood samples were taken from captive dolphins following a swimming routine (n=8) and after a 2min dive (n=8). Activity of enzymes involved in purine metabolism (hypoxanthine guanine phosphoribosyl transferase (HGPRT), inosine monophosphate deshydrogenase (IMPDH), xanthine oxidase (XO), purine nucleoside phosphorylase (PNP)), and purine metabolite (hypoxanthine (HX), xanthine (X), uric acid (UA), inosine monophosphate (IMP), inosine, nicotinamide adenine dinucleotide (NAD(+)), adenosine, adenosine monophosphate (AMP), adenosine diphosphate (ADP), ATP, guanosine diphosphate (GDP), guanosine triphosphate (GTP)) concentrations were quantified in erythrocyte and plasma samples. Enzymatic activity and purine metabolite concentrations involved in purine synthesis and degradation, were not significantly different between diving and exercise. Plasma adenosine concentration was higher after diving than exercise (p=0.03); this may be related to dive-induced ischemia. In erythrocytes, HGPRT activity was higher after diving than exercise (p=0.007), suggesting an increased capacity for purine recycling and ATP synthesis from IMP in ischemic tissues of bottlenose dolphins during diving. Purine recycling and physiological adaptations may maintain the ATP concentrations in bottlenose dolphins after diving and exercise.

  20. Deep Inspiration Breath Hold [(18)F]FDG PET-CT on 4-rings scanners in evaluating lung lesions: evidences from a phantom and a clinical study.

    Science.gov (United States)

    Caobelli, Federico; Puta, Erinda; Kaiser, Stefano Ren; Massetti, Valentina; Andreoli, Michela; Mostarda, Angelica; Soffientini, Alberto; Pizzocaro, Claudio; Guerra, Ugo Paolo

    2014-01-01

    To investigate the clinical feasibility of a Deep Inspiration Breath Hold (DIBH) (18)F-FDG PET-CT acquisition in apnea and compare the results obtained between these acts of acquisition in apnea and in Free Breathing in the evaluation of lung lesions. A pre-clinical phantom study was performed to evaluate the shortest simulated DIBH time according to the minimum detectable lesion that can be detected by our ultrasound scanner. This study was conducted by changing acquisition time and sphere-to-background activity ratio values and by using radioactivity densities similar to those generally found in clinical examinations. In the clinical study, 25 patients with pulmonary lesions underwent a standard whole body (18)F-FDG PET-CT scan in free breathing followed by a 20s single thorax acquisition PET/CT in DIBH acquisition. The phantom study indicated that a 20-s acquisition time provides an accurate evaluation of smallest sphere shaped lesions. In the clinical study, PET-CT scans obtained in DIBH studies showed a significant reduction of misalignment between the PET and CT scan images and an increase of SUVmax compared to free breathing acquisitions. A correlation between the %BH-index and lesion displacement between PET and CT images in FB acquisition was demonstrated, significantly higher for lesions with a displacement>8mm. The single 20s acquisition of DIBH PET-CT is a feasible technique for lung lesion detection in the clinical setting. It only requires a minor increase in examination time without special patient training. 20s DIBH scan provided a more precise measurement of SUVmax, especially for lesions in the lower lung lobes which usually show greater displacement between PET and CT scan images in FB acquisition. Copyright © 2013 Elsevier España, S.L. and SEMNIM. All rights reserved.

  1. SU-E-J-32: Calypso(R) and Laser-Based Localization Systems Comparison for Left-Sided Breast Cancer Patients Using Deep Inspiration Breath Hold

    Energy Technology Data Exchange (ETDEWEB)

    Robertson, S [Northwest Medical Physics Center, Lynnwood, WA (United States); Kaurin, D; Sweeney, L [Northwest Medical Physics Center, Lynnwood, WA (United States); Seattle Cancer Care Alliance, Seattle, WA (United States); Kim, J; Fang, L; Tran, A [Seattle Cancer Care Alliance, Seattle, WA (United States); University of Washington Medical Center, Seattle, WA (United States); Holloway, K [Seattle Cancer Care Alliance, Seattle, WA (United States)

    2014-06-01

    Purpose: Our institution uses a manual laser-based system for primary localization and verification during radiation treatment of left-sided breast cancer patients using deep inspiration breath hold (DIBH). This primary system was compared with sternum-placed Calypso(R) beacons (Varian Medical Systems, CA). Only intact breast patients are considered for this analysis. Methods: During computed tomography (CT) simulation, patients have BB and Calypso(R) surface beacons positioned sternally and marked for free-breathing and DIBH CTs. During dosimetry planning, BB longitudinal displacement between free breathing and DIBH CT determines laser mark (BH mark) location. Calypso(R) beacon locations from the DIBH CT are entered at the Tracking Station. During Linac simulation and treatment, patients inhale until the cross-hair and/or lasers coincide with the BH Mark, which can be seen using our high quality cameras (Pelco, CA). Daily Calypso(R) displacement values (difference from the DIBH-CT-based plan) are recorded.The displacement mean and standard deviation was calculated for each patient (77 patients, 1845 sessions). An aggregate mean and standard deviation was calculated weighted by the number of patient fractions.Some patients were shifted based on MV ports. A second data set was calculated with Calypso(R) values corrected by these shifts. Results: Mean displacement values indicate agreement within 1±3mm, with improvement for shifted data (Table). Conclusion: Both unshifted and shifted data sets show the Calypso(R) system coincides with the laser system within 1±3mm, demonstrating either localization/verification system will Resultin similar clinical outcomes. Displacement value uncertainty unilaterally reduces when shifts are taken into account.

  2. Deep inspiration breath-hold technique for left-sided breast cancer: An analysis of predictors for organ-at-risk sparing

    Energy Technology Data Exchange (ETDEWEB)

    Register, Steven; Takita, Cristiane [Department of Radiation Oncology, University of Miami Sylvester Comprehensive Cancer Center, Miami, FL (United States); Reis, Isildinha; Zhao, Wei [Department of Public Health Sciences, University of Miami, Miami, FL (United States); Amestoy, William [Department of Radiation Oncology, University of Miami Sylvester Comprehensive Cancer Center, Miami, FL (United States); Wright, Jean, E-mail: jwrigh71@jhmi.edu [Department of Radiation Oncology, University of Miami Sylvester Comprehensive Cancer Center, Miami, FL (United States); Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins University, Baltimore, MD (United States)

    2015-04-01

    To identify anatomic and treatment characteristics that correlate with organ-at-risk (OAR) sparing with deep inspiration breath-hold (DIBH) technique to guide patient selection for this technique. Anatomic and treatment characteristics and radiation doses to OARs were compared between free-breathing and DIBH plans. Linear regression analysis was used to identify factors independently predicting for cardiac sparing. We identified 64 patients: 44 with intact breast and 20 postmastectomy. For changes measured directly on treatment planning scans, DIBH plans decreased heart-chest wall length (6.5 vs 5.0 cm, p < 0.001), and increased lung volume (1074.4 vs 1881.3 cm{sup 3}, p < 0.001), and for changes measured after fields are set, they decreased maximum heart depth (1.1 vs 0.3 cm, p < 0.001) and heart volume in field (HVIF) (9.1 vs 0.9 cm{sup 3}, p < 0.001). DIBH reduced the mean heart dose (3.4 vs 1.8 Gy, p < 0.001) and lung V{sub 20} (19.6% vs 15.3%, p < 0.001). Regression analysis found that only change in HVIF independently predicted for cardiac sparing. We identified patients in the bottom quartile of the dosimetric benefits seen with DIBH and categorized the cause of this “minimal benefit.” Overall, 29% of patients satisfied these criteria for minimal benefit with DIBH and the most common cause was favorable baseline anatomy. Only the reduction in HVIF predicted for reductions in mean heart dose; no specific anatomic surrogate for the dosimetric benefits of DIBH technique could be identified. Most patients have significant dosimetric benefit with DIBH, and this technique should be planned and evaluated for all patients receiving left-sided breast/chest wall radiation.

  3. SU-F-BRB-02: Towards Quantitative Clinical Decision On Deep Inspiration Breath Hold (DIBH) Or Prone for Left-Sided Breast Irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Lin, H; Gao, Y [Rensselaer Polytechnic Institute, Troy, NY (United States); Liu, T [Memorial Sloan Kettering West Harrison, West Harrison, New York (United States); Gelblum, D; Ho, A [Memorial Sloan Lettering Cancer Center, New York City, New York (United States); Powell, S [Memorial Sloan Kettering Cancer Center, New York, NY (United States); Tang, X [Memorial Sloan Kettering Cancer Center, West Harrison, NY (United States); Xu, X [Rensselaer Polytechnic Inst., Troy, NY (United States)

    2015-06-15

    Purpose: To develop quantitative clinical guidelines between supine Deep Inspiratory Breath Hold (DIBH) and prone free breathing treatments for breast patients, we applied 3D deformable phantoms to perform Monte Carlo simulation to predict corresponding Dose to the Organs at Risk (OARs). Methods: The RPI-adult female phantom (two selected cup sizes: A and D) was used to represent the female patient, and it was simulated using the MCNP6 Monte Carlo code. Doses to OARs were investigated for supine DIBH and prone treatments, considering two breast sizes. The fluence maps of the 6-MV opposed tangential fields were exported. In the Monte Carlo simulation, the fluence maps allow each simulated photon particle to be weighed in the final dose calculation. The relative error of all dose calculations was kept below 5% by simulating 3*10{sup 7} photons for each projection. Results: In terms of dosimetric accuracy, the RPI Adult Female phantom with cup size D in DIBH positioning matched with a DIBH treatment plan of the patient. Based on the simulation results, for cup size D phantom, prone positioning reduced the cardiac dose and the dose to other OARs, while cup size A phantom benefits more from DIBH positioning. Comparing simulation results for cup size A and D phantom, dose to OARs was generally higher for the large breast size due to increased scattering arising from a larger portion of the body in the primary beam. The lower dose that was registered for the heart in the large breast phantom in prone positioning was due to the increase of the distance between the heart and the primary beam when the breast was pendulous. Conclusion: Our 3D deformable phantom appears an excellent tool to predict dose to the OARs for the supine DIBH and prone positions, which might help quantitative clinical decisions. Further investigation will be conducted. National Institutes of Health R01EB015478.

  4. SU-E-J-140: Availability of Using Diaphragm Matching in Stereotactic Body Radiotherapy (SBRT) at the Time in Breath-Holding SBRT for Liver Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Kawahara, D; Tsuda, S. [Course of Medical and Dental Sciences, Graduate School of Biomedical ' Health Sciences, Hiroshima University (Japan); Section of Radiation Therapy, Department of Clinical Support, Hiroshima University Hospital Health (Japan); Ozawa, S; Ohno, Y.; Kimura, T.; Nagata, Y. [Department of Radiation Oncology, Institute of Biomedical ' Health Science, Hiroshima University (Japan); Nakashima, T.; Aita, M.; Ochi, Y.; Okumura, T.; Masuda, H. [Section of Radiation Therapy, Department of Clinical Support, Hiroshima University Hospital Health (Japan)

    2014-06-01

    Purpose: IGRT based on the bone matching may produce a larger target positioning error in terms of the reproducibility of the expiration breath hold. Therefore, the feasibility of the 3D image matching between planning CT image and pretreatment CBCT image based on the diaphragm matching was investigated. Methods: In fifteen-nine liver SBRT cases, Lipiodol, uptake after TACE was outlined as the marker of the tumor. The relative coordinate of the isocenter obtained by the contrast matching was defined as the reference coordinate. The target positioning difference between diaphragm matching and bone matching were evaluated by the relative coordinate of the isocenter from the reference coordinate obtained by each matching technique. In addition, we evaluated PTV margins by van Herk setup margin formula. Results: The target positioning error by the diaphragm matching and the bone matching was 1.31±0.83 and 3.10±2.80 mm in the cranial-caudal(C-C) direction, 1.04±0.95 and 1.62±1.02 mm in the anterior-posterior(A-P) direction, 0.93±1.19 and 1.12±0.94 mm in the left-right(L-R) direction, respectively. The positioning error by the diaphragm matching was significantly smaller than the bone matching in the C-C direction (p<0.05). The setup margin of diaphragm matching and bone matching that we had calculated based on van Herk margin formula was 4.5mm and 6.2mm(C-C), and 3.6mm and 6.3mm(A-P), and 2.6mm and 4.5mm(L-R), respectively. Conclusion: IGRT based on a diaphragm matching could be one alternative image matching technique for the positioning of the patients with liver tumor.

  5. A comparative analysis of 3D conformal deep inspiratory–breath hold and free-breathing intensity-modulated radiation therapy for left-sided breast cancer

    Energy Technology Data Exchange (ETDEWEB)

    Reardon, Kelli A.; Read, Paul W.; Morris, Monica M. [Department of Radiation Oncology, University of Virginia, Charlottesville, VA (United States); Reardon, Michael A. [Department of Radiology, University of Virginia, Charlottesville, VA (United States); Geesey, Constance [Department of Radiation Oncology, University of Virginia, Charlottesville, VA (United States); Wijesooriya, Krishni, E-mail: kw5wx@hscmail.mcc.virginia.edu [Department of Radiation Oncology, University of Virginia, Charlottesville, VA (United States)

    2013-07-01

    Patients undergoing radiation for left-sided breast cancer have increased rates of coronary artery disease. Free-breathing intensity-modulated radiation therapy (FB-IMRT) and 3-dimensional conformal deep inspiratory–breath hold (3D-DIBH) reduce cardiac irradiation. The purpose of this study is to compare the dose to organs at risk in FB-IMRT vs 3D-DIBH for patients with left-sided breast cancer. Ten patients with left-sided breast cancer had 2 computed tomography scans: free breathing and voluntary DIBH. Optimization of the IMRT plan was performed on the free-breathing scan using 6 noncoplanar tangential beams. The 3D-DIBH plan was optimized on the DIBH scan and used standard tangents. Mean volumes of the heart, the left anterior descending coronary artery (LAD), the total lung, and the right breast receiving 5% to 95% (5% increments) of the prescription dose were calculated. Mean volumes of the heart and the LAD were lower (p<0.05) in 3D-DIBH for volumes receiving 5% to 80% of the prescription dose for the heart and 5% for the LAD. Mean dose to the LAD and heart were lower in 3D-DIBH (p≤0.01). Mean volumes of the total lung were lower in FB-IMRT for dose levels 20% to 75% (p<0.05), but mean dose was not different. Mean volumes of the right breast were not different for any dose; however, mean dose was lower for 3D-DIBH (p = 0.04). 3D-DIBH is an alternative approach to FB-IMRT that provides a clinically equivalent treatment for patients with left-sided breast cancer while sparing organs at risk with increased ease of implementation.

  6. Reproducibility Evaluation of Deep inspiration breath-hold(DIBH) technique by respiration data and heart position analysis during radiation therapy for Left Breast cancer patients

    Energy Technology Data Exchange (ETDEWEB)

    Jo, Jae Young; Bae, Sun Myung; Yoon, In Ha; Lee, Ho Yeon; Kang, Tae Young; Baek, Geum Mun; Bae, Jae Beom [Dept. of Radiation Oncology, Asan Medical Center, Seoul (Korea, Republic of)

    2014-12-15

    The purpose of this study is reproducibility evaluation of deep inspiration breath-hold(DIBH) technique by respiration data and heart position analysis in radiation therapy for Left Breast cancer patients. Free breathing(FB) Computed Tomography(CT) images and DIBH CT images of three left breast cancer patients were used to evaluate the heart volume and dose during treatment planing system( Eclipse version 10.0, Varian, USA ). The signal of RPM (Real-time Position Management) Respiratory Gating System (version 1.7.5, Varian, USA) was used to evaluate respiration stability of DIBH during breast radiation therapy. The images for measurement of heart position were acquired by the Electronic portal imaging device(EPID) cine acquisition mode. The distance of heart at the three measuring points(A, B, C) on each image was measured by Offline Review (ARIA 10, Varian, USA). Significant differences were found between the FB and DIBH plans for mean heart dose (6.82 vs. 1.91 Gy), heart V{sub 30} (68.57 vs. 8.26 cm{sup 3}), V{sub 20} (76.43 vs. 11.34 cm{sup 3}). The standard deviation of DIBH signal of each patient was ±0.07 cm, ±0.04cm, 0.13 cm{sup 3}, respectively. The Maximum and Minimum heart distance on EPID images were measured as 0.32 m and 0.00 cm. Consequently, using the DIBH technique with radiation therapy for left breast cancer patients is very useful to establish the treatment plan and to reduce the heart dose. In addition, it is beneficial to using the Cine acquisition mode of EPID for the reproducibility evaluation of DIBH.

  7. Breath-hold imaging of the coronary arteries using Quiescent-Interval Slice-Selective (QISS) magnetic resonance angiography: pilot study at 1.5 Tesla and 3 Tesla.

    Science.gov (United States)

    Edelman, Robert R; Giri, S; Pursnani, A; Botelho, M P F; Li, W; Koktzoglou, I

    2015-11-23

    Coronary magnetic resonance angiography (MRA) is usually obtained with a free-breathing navigator-gated 3D acquisition. Our aim was to develop an alternative breath-hold approach that would allow the coronary arteries to be evaluated in a much shorter time and without risk of degradation by respiratory motion artifacts. For this purpose, we implemented a breath-hold, non-contrast-enhanced, quiescent-interval slice-selective (QISS) 2D technique. Sequence performance was compared at 1.5 and 3 Tesla using both radial and Cartesian k-space trajectories. The left coronary circulation was imaged in six healthy subjects and two patients with coronary artery disease. Breath-hold QISS was compared with T2-prepared 2D balanced steady-state free-precession (bSSFP) and free-breathing, navigator-gated 3D bSSFP. Approximately 10 2.1-mm thick slices were acquired in a single ~20-s breath-hold using two-shot QISS. QISS contrast-to-noise ratio (CNR) was 1.5-fold higher at 3 Tesla than at 1.5 Tesla. Cartesian QISS provided the best coronary-to-myocardium CNR, whereas radial QISS provided the sharpest coronary images. QISS image quality exceeded that of free-breathing 3D coronary MRA with few artifacts at either field strength. Compared with T2-prepared 2D bSSFP, multi-slice capability was not restricted by the specific absorption rate at 3 Tesla and pericardial fluid signal was better suppressed. In addition to depicting the coronary arteries, QISS could image intra-cardiac structures, pericardium, and the aortic root in arbitrary slice orientations. Breath-hold QISS is a simple, versatile, and time-efficient method for coronary MRA that provides excellent image quality at both 1.5 and 3 Tesla. Image quality exceeded that of free-breathing, navigator-gated 3D MRA in a much shorter scan time. QISS also allowed rapid multi-slice bright-blood, diastolic phase imaging of the heart, which may have complementary value to multi-phase cine imaging. We conclude that, with further clinical

  8. Quantitative analysis of the breath-holding half-Fourier acquisition single-shot turbo spin-echo technique in abdominal MRI

    Science.gov (United States)

    Dong, Kyung-Rae; Goo, Eun-Hoe; Lee, Jae-Seung; Chung, Woon-Kwan

    2013-01-01

    A consecutive series of 50 patients (28 males and 22 females) who underwent hepatic magnetic resonance imaging (MRI) from August to December 2011 were enrolled in this study. The appropriate parameters for abdominal MRI scans were determined by comparing the images (TE = 90 and 128 msec) produced using the half-Fourier acquisition single-shot turbo spin-echo (HASTE) technique at different signal acquisition times. The patients consisted of 15 normal patients, 25 patients with a hepatoma and 10 patients with a hemangioma. The TE in a single patient was set to either 90 msec or 128 msec. This was followed by measurements using the four normal rendering methods of the biliary tract system and the background signal intensity using the maximal signal intensity techniques in the liver, spleen, pancreas, gallbladder, fat, muscles and hemangioma. The signal-to-noise and the contrast-to-noise ratios were obtained. The image quality was assessed subjectively, and the results were compared. The signal-to-noise and the contrast-to-noise ratios were significantly higher at TE = 128 msec than at TE = 90 when diseases of the liver, spleen, pancreas, gallbladder, and fat and muscles, hepatocellular carcinomas and hemangiomas, and rendering the hepatobiliary tract system based on the maximum signal intensity technique were involved (p < 0.05). In addition, the presence of artifacts, the image clarity and the overall image quality were excellent at TE = 128 msec (p < 0.05). In abdominal MRI, the breath-hold half-Fourier acquisition single-shot turbo spin-echo (HASTE) was found to be effective in illustrating the abdominal organs for TE = 128 msec. Overall, the image quality at TE = 128 msec was better than that at TE = 90 msec due to the improved signal-to-noise (SNR) and contrast-to-noise (CNR) ratios. Overall, the HASTE technique for abdominal MRI based on a high-magnetic field (3.0 T) at a TE of 128 msec can provide useful data.

  9. SU-C-210-04: Considerable Pancreatic Tumor Motion During Breath-Hold Measured Using Intratumoral Fiducials On Fluoroscopic Movies

    Energy Technology Data Exchange (ETDEWEB)

    Lens, E; Horst, A van der; Versteijne, E; Tienhoven, G van; Bel, A [Academic Medical Center, Amsterdam (Netherlands)

    2015-06-15

    Purpose: Using a breath hold (BH) technique during radiotherapy of pancreatic tumors is expected to reduce intra-fractional motion. The aim of this study was to evaluate the tumor motion during BH. Methods: In this pilot study, we included 8 consecutive pancreatic cancer patients. All had 2– 4 intratumoral gold fiducials. Patients were asked to perform 3 consecutive 30-second end-inhale BHs on day 5, 10 and 15 of their three-week treatment. During BH, airflow through a mouthpiece was measured using a spirometer. Any inadvertent flow of air during BH was monitored for all patients. We measured tumor motion on lateral fluoroscopic movies (57 in total) made during BH. In each movie the fiducials as a group were tracked over time in superior-inferior (SI) and anterior-posterior (AP) direction using 2-D image correlation between consecutive frames. We determined for each patient the range of intra-BH motion over all movies; we also determined the absolute means and standard deviations (SDs) for the entire patient group. Additionally, we investigated the relation between inadvertent airflow during BH and the intra-BH motion. Results: We found intra-BH tumor motion of up to 12.5 mm (range, 1.0–12.5 mm) in SI direction and up to 8.0 mm (range, 1.0–8.0 mm) in AP direction. The absolute mean motion over the patient population was 4.7 (SD: 3.0) mm and 2.8 (SD: 1.2) mm in the SI and AP direction, respectively. Patients were able to perform stable consecutive BHs; during only 20% of the movies we found very small airflows (≤ 65 ml). These were mostly stepwise in nature and could not explain the continuous tumor motions we observed. Conclusion: We found substantial (up to 12.5 mm) pancreatic tumor motion during BHs. We found minimal inadvertent airflow, seen only during a minority of BHs, and this did not explain the obtained results. This work was supported by the foundation Bergh in het Zadel through the Dutch Cancer Society (KWF Kankerbestrijding) project No. UVA 2011-5271.

  10. Contribution of the deep-inspiration breath-hold technique in patients treated for a left breast cancer by mono-isocentric conformational irradiation; Apport du blocage inspiratoire profond chez des patientes traitees pour un cancer du sein gauche par irradiation conformationnelle mono-isocentrique

    Energy Technology Data Exchange (ETDEWEB)

    Zioueche, A.; Mege, A.; Bodez, V.; Rauglaudre, G. de [Institut Sainte-Catherine, Avignon (France)

    2011-10-15

    The authors report a study which aimed at assessing the benefit of a deep-inspiration-breath-hold on heart sparing in 31 women treated in the left breast or wall and locoregional ganglionary areas by three-dimensional conformational irradiation with field-in-field optimization. All heart and lung parameters (delivered doses) have been significantly improved by a deep-inspiration-breath-hold. Short communication

  11. Deep inspiration breath-hold (DIBH) radiotherapy in left-sided breast cancer. Dosimetrical comparison and clinical feasibility in 20 patients

    Energy Technology Data Exchange (ETDEWEB)

    Hepp, Rodrigo; Ammerpohl, Mark; Morgenstern, Christina; Erichsen, Patricia [Evangelische Kliniken Gelsenkirchen, Klinik fuer Strahlentherapie und Radioonkologie, Gelsenkirchen (Germany); Nielinger, Lisa [Evangelische Kliniken Gelsenkirchen, Klinik fuer Strahlentherapie und Radioonkologie, Gelsenkirchen (Germany); Hochschule Hamm-Lippstadt, Lippstadt (Germany); Abdallah, Abdallah [Evangelische Kliniken Gelsenkirchen, Klinik fuer Senologie, Gelsenkirchen (Germany); Galalae, Razvan [Evangelische Kliniken Gelsenkirchen, Klinik fuer Strahlentherapie und Radioonkologie, Gelsenkirchen (Germany); Christian-Albrechts-Universitaet zu Kiel, Medizinische Fakultaet, Kiel (Germany)

    2015-09-15

    Adjuvant radiotherapy after breast-conserving surgery (BCS) for breast cancer (BC) is a well-established indication. The risk of ischaemic heart disease after radiotherapy for BC increases linearly with the heart mean dose with no apparent threshold. Radiotherapy to the left breast in deep inspiration breath-hold (DIBH) reduces the dose to the heart. A new linac system with an integrated surface scanner (SS) for DIBH treatments was recently installed in our department. We tested it for potential benefits, safety, patients' acceptance/compliance and associated additional workload. Twenty consecutive patients following BCS for breast carcinoma of the left side were enrolled in our institutional DIBH protocol. We compared dose to the heart and ipsilateral lung (IL) between plans in DIBH and free breathing (FB) using standard defined parameters: mean dose, maximal dose to a volume of 2 cm{sup 3} (D{sub 2} {sub cm} {sup 3}), volume receiving ≥ 5 Gy (V{sub 5}), 10 Gy (V{sub 10}), 15 Gy (V{sub 15}) and 20 Gy (V{sub 20}). Comparison of median calculated dose values was performed using a two-tailed Wilcoxon signed rank test. DIBH was associated with a statistically significant reduction (p < 0.001) in all studied parameters for the heart and the IL. In 16 of 20 patients the heart D{sub 2} {sub cm} {sup 3} was less than 42 Gy in DIBH. In FB the heart D{sub 2} {sub cm} {sup 3} was ≥ 42 Gy in 17 of 20 patients. The median daily treatment time was 9 min. Radiotherapy of the left breast in DIBH using a SS could easily be incorporated into daily routine and is associated with significant dose reduction to the heart and IL. (orig.) [German] Die adjuvante Strahlentherapie nach brusterhaltener Operation (BCS) bei Brustkrebs (BC) ist eine seit langem anerkannte Behandlungsform. Das postradiogene Risiko einer kardialen Ischaemie steigt linear ohne erkennbaren Schwellenwert mit der mittleren Herzdosis. Die Bestrahlung der linken Brust in tiefer Inspiration unter Anhalten der

  12. Advantage of using deep inspiration breath hold with active breathing control and image-guided radiation therapy for patients treated with lung cancers

    Directory of Open Access Journals (Sweden)

    KR Muralidhar

    2015-01-01

    Full Text Available Purpose: The aim of this study was to evaluate the irradiated volume and doses to the target, heart, left lung, right lung and spinal cord, the number of segments and treatment time by using moderated deep inspiration breath hold (mDIBH with active breathing control (ABC and image-guided radiotherapy (IGRT for patients treated with lung cancers.Methods: The suitability of this technique for lung patient treated with ABC was investigated and the solutions to achieve better treatments were discussed. Eleven lung cancer patients (3 left-sided and 8 right sided lesions with stages I-III underwent standard free breath (FB and ABC computed tomography (CT scans in the treatment supine position. This can be achieved by applying respiratory manoeuvres, such as mDIBH, during which the threshold volume utilized is defined as 75-80% of the maximum aspiratory capacity. Five to seven, 6-MV photon beams with optimized gantry angles were designed according to the tumor location to conform to the PTV while sparing as much heart, spinal cord, and contra lateral lung as possible. For eleven patients, treatment planning using mDIBH CT data with intensity modulated radiation therapy (IMRT was then reoptimized on the free breathing data set for comparison. The studied parameters of the plans for each patient were evaluated based on the average of the minimum, mean, and maximum difference in dose, the range of difference, and the p-value using two-tailed paired t test assuming equal variance.Results: The average volume of the planning target volume (PTV in 11 patients increased to 1.32% in ABC compared to FB. The average volume of heart in 11 patients decreased to 2.9% in ABC compared to free breathing IMRT. In the case of lungs, the volume increased to 27.5% and 25.85% for left and right lungs, respectively. The range of mean difference in dose to the PTV in 11 patients was -54 cGy to 230 cGy with ABC technique when compared with free breathing. The range of mean

  13. Reduction of cardiac and coronary artery doses in irradiation of left-sided breast cancer during inspiration breath hold. A planning study

    Energy Technology Data Exchange (ETDEWEB)

    Schoenecker, S.; Heinz, C.; Soehn, M.; Haimerl, W.; Corradini, S.; Pazos, M.; Belka, C.; Scheithauer, H. [University Hospital of Ludwig-Maximilian-University, Department of Radiation Oncology, Munich (Germany)

    2016-11-15

    The radiation dose received by the heart during adjuvant left-sided breast irradiation plays a crucial role in development of late toxicity. Although the absolute risk of cardiotoxicity can be reduced with modern irradiation techniques, cardiotoxic chemotherapy increases the risk of late damage. Thus, the radiation dose to the heart should be minimized. This study evaluated the influence of different amplitudes of inspiration breath hold (IBH) during simulated left-sided breast irradiation on cardiac doses compared to free breathing (FB). CT data of 11 lung cancer patients were retrospectively used as left-sided pseudo-breast cancer cases. Two CT scans were used, one during IBH and one during FB, and two treatment plans were generated. Relevant heart, lung, and left anterior descending artery (LAD) parameters were derived from dose-volume histograms. The normal tissue complication probabilities (NTCPs) for the heart were calculated based on the relative seriality model. Inspiration depth was quantified using chest volume and diameter, and correlated thereafter to a possible sparing of heart tissue. Mean reduction of heart dose for IBH compared to FB was 40 % (1.65 vs. 0.99 Gy; p = 0.007). Maximum dose to the heart and LAD could be decreased by 33 % (p = 0.011) and 43 % (p = 0.024), respectively. The mean anteroposterior shift was 5 mm (range 0.9-9.5 mm). Significant negative correlations between the relative change in LAD mean dose and the mean thoracic diameter and volume change, as well as with the absolute change in thoracic diameter were seen. The NTCP for cardiac mortality could be decreased by about 78 % (p = 0.017). For left-sided breast cancer patients, cardiac doses can be significantly decreased with tangential irradiation and IBH. (orig.) [German] Die Herzdosisbelastung spielt eine entscheidende Rolle in der Entwicklung einer kardialen Spaettoxizitaet nach der adjuvanten Strahlentherapie von linksseitigem Brustkrebs. Obwohl moderne strahlentherapeutische

  14. Accuracy of Routine Treatment Planning 4-Dimensional and Deep-Inspiration Breath-Hold Computed Tomography Delineation of the Left Anterior Descending Artery in Radiation Therapy

    Energy Technology Data Exchange (ETDEWEB)

    White, Benjamin M., E-mail: benjamin.white@uphs.upenn.edu [Department of Radiation Oncology, University of Pennsylvania, Philadelphia, PA (United States); Vennarini, Sabina [L' Unità Operativa di Protonterapia, Azienda Provinciale per i Servizi Sanitari, Trento (Italy); Lin, Lilie; Freedman, Gary [Department of Radiation Oncology, University of Pennsylvania, Philadelphia, PA (United States); Santhanam, Anand; Low, Daniel A. [Department of Radiation Oncology, University of California, Los Angeles, California (United States); Both, Stefan [Department of Radiation Oncology, University of Pennsylvania, Philadelphia, PA (United States)

    2015-03-15

    Purpose: To assess the feasibility of radiation therapy treatment planning 4-dimensional computed tomography (4DCT) and deep-inspiration breath-hold (DIBH) CT to accurately contour the left anterior descending artery (LAD), a primary indicator of radiation-induced cardiac toxicity for patients undergoing radiation therapy. Methods and Materials: Ten subjects were prospectively imaged with a cardiac-gated MRI protocol to determine cardiac motion effects, including the displacement of a region of interest comprising the LAD. A series of planar views were obtained and resampled to create a 3-dimensional (3D) volume. A 3D optical flow deformable image registration algorithm determined tissue displacement during the cardiac cycle. The measured motion was then used as a spatial boundary to characterize motion blurring of the radiologist-delineated LAD structure for a cohort of 10 consecutive patients enrolled prospectively on a breast study including 4DCT and DIBH scans. Coronary motion–induced blurring artifacts were quantified by applying an unsharp filter to accentuate the LAD structure despite the presence of motion blurring. The 4DCT maximum inhalation and exhalation respiratory phases were coregistered to determine the LAD displacement during tidal respiration, as visualized in 4DCT. Results: The average 90th percentile heart motion for the region of interest was 0.7 ± 0.1 mm (left–right [LR]), 1.3 ± 0.6 mm (superior–inferior [SI]), and 0.6 ± 0.2 mm (anterior–posterior [AP]) in the cardiac-gated MRI cohort. The average relative increase in the number of voxels comprising the LAD contour was 69.4% ± 4.5% for the DIBH. The LAD volume overestimation had the dosimetric impact of decreasing the reported mean LAD dose by 23% ± 9% on average in the DIBH. During tidal respiration the average relative LAD contour increase was 69.3% ± 5.9% and 67.9% ± 4.6% for inhalation and exhalation respiratory phases, respectively. The average 90th

  15. Optimization of magnetic flux density measurement using multiple RF receiver coils and multi-echo in MREIT.

    Science.gov (United States)

    Jeong, Woo Chul; Chauhan, Munish; Sajib, Saurav Z K; Kim, Hyung Joong; Serša, Igor; Kwon, Oh In; Woo, Eung Je

    2014-09-01

    Magnetic Resonance Electrical Impedance Tomography (MREIT) is an MRI method that enables mapping of internal conductivity and/or current density via measurements of magnetic flux density signals. The MREIT measures only the z-component of the induced magnetic flux density B = (Bx, By, Bz) by external current injection. The measured noise of Bz complicates recovery of magnetic flux density maps, resulting in lower quality conductivity and current-density maps. We present a new method for more accurate measurement of the spatial gradient of the magnetic flux density gradient (∇ Bz). The method relies on the use of multiple radio-frequency receiver coils and an interleaved multi-echo pulse sequence that acquires multiple sampling points within each repetition time. The noise level of the measured magnetic flux density Bz depends on the decay rate of the signal magnitude, the injection current duration, and the coil sensitivity map. The proposed method uses three key steps. The first step is to determine a representative magnetic flux density gradient from multiple receiver coils by using a weighted combination and by denoising the measured noisy data. The second step is to optimize the magnetic flux density gradient by using multi-echo magnetic flux densities at each pixel in order to reduce the noise level of ∇ Bz and the third step is to remove a random noise component from the recovered ∇ Bz by solving an elliptic partial differential equation in a region of interest. Numerical simulation experiments using a cylindrical phantom model with included regions of low MRI signal to noise ('defects') verified the proposed method. Experimental results using a real phantom experiment, that included three different kinds of anomalies, demonstrated that the proposed method reduced the noise level of the measured magnetic flux density. The quality of the recovered conductivity maps using denoised ∇ Bz data showed that the proposed method reduced the conductivity

  16. The impact of spin coupling signal loss on fat content characterization in multi-echo acquisitions with different echo spacing.

    Science.gov (United States)

    Nikiforaki, K; Manikis, G C; Boursianis, T; Marias, K; Karantanas, A; Maris, T G

    2017-05-01

    This study aimed to assess the effect of echo spacing in transverse magnetization (T2) signal decay of gel and fat (oil) samples. Additionally, we assess the feasibility of using spin coupling as a determinant of fat content. Phantoms of known T2 values, as well as vegetable oil phantoms, were scanned at 1.5T scanner with a multi echo FSE sequence of variable echo spacing above and below the empirical threshold of 20ms for echo train signal modulation (6.7, 13.6, 26.8, and 40ms). T2 values were calculated from monoexponential fitting of the data. Relative signal loss between the four acquisitions of different echo spacing was calculated. Agreement in the T2 values of water gel phantom was observed in all acquisitions as opposed to fat phantom (oil) samples. Relative differences in signal intensity between two successive sequences of different echo spacing on composite fat/water regions of interest was found to be linearly correlated to fat fraction of the ROI. The sample specific degree of signal loss that was observed between different fat samples (vegetable oils) can be attributed to the composition of each sample in J coupled fat components. Hence, spin coupling may be used as a determinant of fat content. Copyright © 2016 Elsevier Inc. All rights reserved.

  17. Efeito do broncodilatador no tempo de apneia voluntária máxima em pacientes com distúrbios ventilatórios obstrutivos Bronchodilator effect on maximal breath-hold time in patients with obstructive lung disease

    Directory of Open Access Journals (Sweden)

    Raqueli Biscayno Viecili

    2011-12-01

    Full Text Available OBJETIVO: Identificar o papel do broncodilatador no tempo de apneia voluntária máxima em pacientes com distúrbios ventilatórios obstrutivos (DVOs. MÉTODOS: Estudo caso-controle incluindo pacientes com DVOs e grupo controle. Foram realizadas espirometrias antes e após o uso de broncodilatador, assim como testes de apneia respiratória, utilizando-se um microprocessador eletrônico e um pneumotacógrafo como transdutor de fluxo. As curvas de fluxo respiratório foram exibidas em tempo real em um computador portátil, e os tempos de apneia voluntária inspiratória e expiratória máximos (TAVIM e TAVEM, respectivamente foram determinados a partir do sinal adquirido. RESULTADOS: Um total de 35 pacientes com DVOs e 16 controles foram incluídos no estudo. O TAVIM sem o uso de broncodilatador foi significativamente menor no grupo DVO que no grupo controle (22,27 ± 11,81 s vs. 31,45 ± 15,73; p = 0,025, mas essa diferença não foi significativa após o uso de broncodilatador (24,94 ± 12,89 s vs. 31,67 ± 17,53 s. Os valores de TAVEM foram significativamente menores no grupo DVO que no grupo controle antes (16,88 ± 6,58 s vs. 22,09 ± 7,95 s; p = 0,017 e após o uso de broncodilatador (21,22 ± 9,37 s vs. 28,53 ± 12,46 s; p = 0,024. CONCLUSÕES: Estes resultados fornecem uma evidência adicional da utilidade clínica do teste de apneia na avaliação da função pulmonar e do papel do broncodilatador nesse teste.OBJECTIVE: To identify the role of bronchodilators in the maximal breath-hold time in patients with obstructive lung disease (OLD. METHODS: We conducted a case-control study including patients with OLD and a control group. Spirometric tests were performed prior to and after the use of a bronchodilator, as were breath-hold tests, using an electronic microprocessor and a pneumotachograph as a flow transducer. Respiratory flow curves were displayed in real time on a portable computer. The maximal breath-hold times at end

  18. 早产儿晚期"屏气发作"相关危险因素分析%Study on Risk Factors of Breath Holding Spell in Later Period of Premature Neonatals with Hypocaicemia

    Institute of Scientific and Technical Information of China (English)

    陆丹; 彭巧英; 管婉华; 胡洪波

    2011-01-01

    目的 探讨早产儿晚期"屏气发作"的原因及干预措施.方法 按照对本院新生儿科2006年6月-2009年6月出院后2~4周的早产儿进行了随访,并记录出生时一般情况、随访时日龄、日期(季节)、喂养方式和出院后的疾病征象等;采用雷度ABL800血气分析仪测定微量血Ca2+、K+、Na+.结果 早产儿晚期"屏气发作"的原因与"低离子钙血症"相关,补充钙剂和维生素AD可缓解症状.结论 "屏气发作"有可能是"低钙惊厥"的特殊表现形式,是早产儿晚期常见的疾病征象;目睹其发作过程,可能存有"低氧血症"而加重已有脑损伤的早产儿病情;屏气发作导致睡眠障碍不仅继续影响、干扰其生长发育,且引起儿童时期各系统疾病,导致早产儿不良结局.%Objective To study the undesirable consequences and intervention measures of breath holding spell in later period of the premature neonatals. Methods All the premature neonatals hospitalized in Hubei Maternal and Child Health Hospital from June, 2006 to June, 2009 were followed up 2~4 weeks after hospital discharge. The general state of health, age, date (season), feeding- pattems and clinical symptoms of the premature neonatals were recorded. Clinical analysis of electrolytes change of breath holding spell was also performed. Results The causation of breathholding spell in later period of the premature neonatals was interrelated with hypocalcemia. It was effective to supplement calcium and vitamin AD to relief the symptoms. Conclusions As a particular manifestation of hypocalcemia, breath holding spell is a common symptom in later period of the premature neonatals. So far as what we witness, it is likely that hypoxemia aggravates the illness of the premature neonatal that has a brain injury. As a result of breath holding spell, sleeping disturbance not only affects and interferes with the growth and development of the patients, but also leads to the systematic diseases during

  19. TH-C-12A-11: Target Correlation of a 3D Surface Surrogate for Left Breast Irradiation Using the Respiratory-Gated Deep-Inspiration Breath-Hold Technique

    Energy Technology Data Exchange (ETDEWEB)

    Rong, Y; Walston, S [A Quick, Ohio State University, Columbus, OH (United States)

    2014-06-15

    Purpose: To evaluate the use of 3D optical surface imaging as a new surrogate for respiratory motion gated deep-inspiration breath-hold (DIBH) technique for left breast cancer patients. Methods: Patients with left-sided breast cancer after lumpectomy or mastectomy were selected as candidates for DIBH technique for their external beam radiation therapy. Treatment plans were created on both free breathing (FB) and DIBH CTs to determine whether DIBH was beneficial in reducing heart doses. The Real-time Position Management (RPM) system was used to acquire patient's breathing trace during DIBH CT acquisition and treatment delivery. The reference 3D surface models from FB and DIBH CTs were generated and transferred to the “AlignRT” system for patient positioning and real-time treatment monitoring. MV Cine images were acquired for each beam as quality assurance for intra-fractional position verification. The chest wall excursions measured on these images were used to define the actual target position during treatment, and to investigate the accuracy and reproducibility of RPM and AlignRT. Results: Reduction in heart dose can be achieved for left-sided breast patients using DIBH. Results showed that RPM has poor correlation with target position, as determined by the MV Cine imaging. This indicates that RPM may not be an adequate surrogate in defining the breath-hold level when used alone. Alternatively, the AlignRT surface imaging demonstrated a better correlation with the actual CW excursion during DIBH. Both the vertical and magnitude real-time deltas (RTDs) reported by AlignRT can be used as the gating parameter, with a recommend threshold of ±3 mm and 5 mm, respectively. Conclusion: 3D optical surface imaging serves as a superior target surrogate for the left breast treatment when compared to RPM. Working together with the realtime MV Cine imaging, they ensure accurate patient setup and dose delivery, while minimizing the imaging dose to patients.

  20. A comparison of multi-echo spin-echo and triple-echo steady-state T2 mapping for in vivo evaluation of articular cartilage

    Energy Technology Data Exchange (ETDEWEB)

    Juras, Vladimir; Szomolanyi, Pavol [Medical University of Vienna, High Field MR Centre, Department of Biomedical Imaging and Image-Guided Therapy, Vienna (Austria); Institute of Measurement Science, Department of Imaging Methods, Bratislava (Slovakia); Bohndorf, Klaus; Kronnerwetter, Claudia; Hager, Benedikt; Zbyn, Stefan [Medical University of Vienna, High Field MR Centre, Department of Biomedical Imaging and Image-Guided Therapy, Vienna (Austria); Heule, Rahel; Bieri, Oliver [University of Basel Hospital, Division of Radiological Physics, Department of Radiology, Basel (Switzerland); Trattnig, Siegfried [Medical University of Vienna, High Field MR Centre, Department of Biomedical Imaging and Image-Guided Therapy, Vienna (Austria); Christian Doppler Laboratory for Clinical Molecular MR Imaging, Vienna (Austria); Ludwig Boltzmann Institute for Experimental and Clinical Traumatology, Austrian Cluster for Tissue Regeneration, Vienna (Austria)

    2016-06-15

    To assess the clinical relevance of T{sub 2} relaxation times, measured by 3D triple-echo steady-state (3D-TESS), in knee articular cartilage compared to conventional multi-echo spin-echo T{sub 2}-mapping. Thirteen volunteers and ten patients with focal cartilage lesions were included in this prospective study. All subjects underwent 3-Tesla MRI consisting of a multi-echo multi-slice spin-echo sequence (CPMG) as a reference method for T{sub 2} mapping, and 3D TESS with the same geometry settings, but variable acquisition times: standard (TESSs 4:35min) and quick (TESSq 2:05min). T{sub 2} values were compared in six different regions in the femoral and tibial cartilage using a Wilcoxon signed ranks test and the Pearson correlation coefficient (r). The local ethics committee approved this study, and all participants gave written informed consent. The mean quantitative T{sub 2} values measured by CPMG (mean: 46±9ms) in volunteers were significantly higher compared to those measured with TESS (mean: 31±5ms) in all regions. Both methods performed similarly in patients, but CPMG provided a slightly higher difference between lesions and native cartilage (CPMG: 90ms→61ms [31%],p=0.0125;TESS 32ms→24ms [24%],p=0.0839). 3D-TESS provides results similar to those of a conventional multi-echo spin-echo sequence with many benefits, such as shortening of total acquisition time and insensitivity to B{sub 1} and B{sub 0} changes. (orig.)

  1. In vivo evaluation of multi-echo hybrid PRF/T1 approach for temperature monitoring during breast MR-guided focused ultrasound surgery treatments.

    Science.gov (United States)

    Todd, Nick; Diakite, Mahamadou; Payne, Allison; Parker, Dennis L

    2014-09-01

    To evaluate the precision of in vivo temperature measurements in adipose and glandular breast tissue using a multi-echo hybrid PRF/T1 pulse sequence. A high-bandwidth, multi-echo hybrid PRF/T1 sequence was developed for monitoring temperature changes simultaneously in fat- and water-based tissues. The multiple echoes were combined with the optimal weightings for magnitude and phase images, allowing for precise measurement of both T1 and the proton resonance frequency (PRF) shift. The sequence was tested during in vivo imaging of 10 healthy volunteers in a breast-specific MR-guided focused ultrasound system and also during focused ultrasound heating of excised breast adipose tissue. The in vivo results indicated that the sequence can measure PRF temperatures with 1.25 × 1.25 × 3.5 mm resolution, 1.9 s temporal resolution, and 1.0°C temperature precision, and can measure T1 values with 3.75 × 3.75 × 3.5 mm resolution, 3.8 s temporal resolution, and 2.5%-4.8% precision. The excised tissue heating experiments demonstrate the sequence's ability to monitor temperature changes simultaneously in water- and fat-based tissues. The addition of a high-bandwidth, multi-echo readout to the hybrid PRF/T1 sequence improves the precision of each measurement, providing a sequence that will be beneficial to several MR-guided thermal therapies. Copyright © 2013 Wiley Periodicals, Inc.

  2. Improving intra-fractional target position accuracy using a 3D surface surrogate for left breast irradiation using the respiratory-gated deep-inspiration breath-hold technique.

    Directory of Open Access Journals (Sweden)

    Yi Rong

    Full Text Available PURPOSE: To evaluate the use of 3D optical surface imaging as a surrogate for respiratory gated deep-inspiration breath-hold (DIBH for left breast irradiation. MATERIAL AND METHODS: Patients with left-sided breast cancer treated with lumpectomy or mastectomy were selected as candidates for DIBH treatment for their external beam radiation therapy. Treatment plans were created on both free breathing (FB and DIBH computed tomography (CT simulation scans to determine dosimetric benefits from DIBH. The Real-time Position Management (RPM system was used to acquire patient's breathing trace during DIBH CT acquisition and treatment delivery. The reference 3D surface models from FB and DIBH CT scans were generated and transferred to the "AlignRT" system for patient positioning and real-time treatment monitoring. MV Cine images were acquired during treatment for each beam as quality assurance for intra-fractional position verification. The chest wall excursions measured on these images were used to define the actual target position during treatment, and to investigate the accuracy and reproducibility of RPM and AlignRT. RESULTS: Reduction in heart dose can be achieved using DIBH for left breast/chest wall radiation. RPM was shown to have inferior correlation with the actual target position, as determined by the MV Cine imaging. Therefore, RPM alone may not be an adequate surrogate in defining the breath-hold level. Alternatively, the AlignRT surface imaging demonstrated a superior correlation with the actual target positioning during DIBH. Both the vertical and magnitude real-time deltas (RTDs reported by AlignRT can be used as the gating parameter, with a recommended threshold of ±3 mm and 5 mm, respectively. CONCLUSION: The RPM system alone may not be sufficient for the required level of accuracy in left-sided breast/CW DIBH treatments. The 3D surface imaging can be used to ensure patient setup and monitor inter- and intra- fractional motions

  3. Clinical evaluation of X-ray voxel Monte Carlo versus pencil beam-based dose calculation in stereotactic body radiotherapy of lung cancer under normal and deep inspiration breath hold.

    Science.gov (United States)

    Landoni, V; Borzì, G R; Strolin, S; Bruzzaniti, V; Soriani, A; D'Alessio, D; Ambesi, F; Di Grazia, A M; Strigari, L

    2015-06-01

    The purpose of this study is to evaluate the differences between dose distributions calculated with the pencil beam (PB) and X-ray voxel Monte Carlo (MC) algorithms for patients with lung cancer using intensity-modulated radiotherapy (IMRT) or HybridArc techniques. The 2 algorithms were compared in terms of dose-volume histograms, under normal and deep inspiration breath hold, and in terms of the tumor control probability (TCP). The dependence of the differences in tumor volume and location was investigated. Dosimetric validation was performed using Gafchromic EBT3 (International Specialty Products, ISP, Wayne, NJ). Forty-five Computed Tomography (CT) data sets were used for this study; 40 Gy at 8 Gy/fraction was prescribed with 5 noncoplanar 6-MV IMRT beams or 3 to 4 dynamic conformal arcs with 3 to 5 IMRT beams distributed per arc. The plans were first calculated with PB and then recalculated with MC. The difference between the mean tumor doses was approximately 10% ± 4%; these differences were even larger under deep inspiration breath hold. Differences between the mean tumor dose correlated with tumor volume and path length of the beams. The TCP values changed from 99.87% ± 0.24% to 96.78% ± 4.81% for both PB- and MC-calculated plans (P = .009). When a fraction of hypoxic cells was considered, the mean TCP values changed from 76.01% ± 5.83% to 34.78% ± 18.06% for the differently calculated plans (P < .0001). When the plans were renormalized to the same mean dose at the tumor, the mean TCP for oxic cells was 99.05% ± 1.59% and for hypoxic cells was 60.20% ± 9.53%. This study confirms that the MC algorithm adequately accounts for inhomogeneities. The inclusion of the MC in the process of IMRT optimization could represent a further step in the complex problem of determining the optimal treatment plan.

  4. Breath-hold gadolinium-enhanced three-dimensional MR thoracic aortography. Higher spatial resolution imaging with phased-array coil and three-dimensional surface display

    Energy Technology Data Exchange (ETDEWEB)

    Nakanishi, Tadashi; Hata, Ryoichiro; Tamura, Akihisa; Kohata, Minako; Miyasaka, Kenji; Kajima, Toshio; Fukuoka, Haruhito; Ito, Katsuhide [Hiroshima Univ. (Japan). School of Medicine

    2000-09-01

    The aim of this study was to examine signal intensities of data sets from MR thoracic aortography and to evaluate three-dimensional surface display (3DSD) for postprocessing. Twenty-five patients were imaged with gadolinium-enhanced 3D fast gradient echo sequence. The intensity at the aortic arch was significantly higher than that at the mediastinal fat (p<0.0001). The signal-to-noise ratio was lower at the aortic arch than at the ascending and descending aorta, whereas the contrast-to-noise ratio was fairly high at the aortic arch. Although in one case (4%) the intensity at the arch was smaller than that at the mediastinal fat, 3DSD was successfully performed in all cases. Superiority of 3DSD over maximum intensity projection was obtained in 67% of the cases. 3DSD was evaluated to be superior to maximum intensity projection in all cases of thoracic aortic aneurysm and coarctation of aorta. Higher resolution MR thoracic aortography could be successfully performed with phased-array coil and 3DSD. (author)

  5. Dose evaluation and risk estimation for secondary cancer in contralateral breast and a study of correlation between thorax shape and dose to organs at risk following tangentially breast irradiation during deep inspiration breath-hold and free breathing.

    Science.gov (United States)

    Johansen, Safora; Vikström, Johan; Hjelstuen, Mari Helene Blihovde; Mjaaland, Ingvil; Dybvik, Kjell Ivar; Olsen, Dag Rune

    2011-05-01

    To assess the impact of using breathing adapted radiotherapy on contralateral breast (CB) dose, to relate the thorax shape with the dose to the organs at risk (OARs) and to predict the risk for induced malignancies in CB using linear and non-linear models, following tangential irradiation of breast. Sixteen patients with stage I-II breast cancer treatment planned with tangential fields using deep inspiration breath hold (DIBH) and free breathing (FB) techniques were included in this analysis. The dose results mainly based on DVH analysis were compared. Four parameters were defined to describe thoracic shape. Excess relative risk (ERR) for cancer induction in CB, employing linear and non-linear models was calculated. Average CB volumes exposed to a dose of 1 Gy is 1.3 times higher in DIBH plans than in FB plans. No significant difference in average V3Gy and V5Gy for DIBH and FB plans is observed. The average mean CB dose for DIBH and FB plans is 0.33 and 0.28 Gy, respectively. No correlation between thorax shape parameters and mean OARs dose is observed. The estimated average mean ERR with linear model is lower in FB plans (0.12) than for the DIBH plans (0.14). The estimated ERR with non-linear model is 0.14 for DIBH plans and 0.15 for FB plans. No significant difference in CB dose between DIBH and FB plans is observed. The four thorax shape parameters defined in this study can not be related to the dose at OARs using DIBH and FB radiation techniques. The ERR estimates for secondary CB cancer are nearly the same for FB and DIBH planning when using a linear and non-linear risk prediction models.

  6. Prospective intraindividual comparison between respiratory-triggered balanced steady-state free precession and breath-hold gradient-echo and time-of-flight magnetic resonance imaging for assessment of portal and hepatic veins

    Energy Technology Data Exchange (ETDEWEB)

    Willmann, Juergen K.; Goepfert, Kerstin; Lutz, Amelie M.; Marincek, Borut; Weishaupt, Dominik [University Hospital Zurich, Institute of Diagnostic Radiology, Zurich (Switzerland); Nanz, Daniel [University Hospital Zurich, Department of Medical Radiology, Zurich (Switzerland); McCormack, Lucas; Petrowsky, Henrik [University Hospital Zurich, Department of Visceral and Transplantation Surgery, Zurich (Switzerland); Seifert, Burkhardt [University of Zurich, Department of Biostatistics, Zurich (Switzerland); Hervo, Patrice [GE Healthcare, Buc Cedex (France)

    2007-01-15

    The purpose of this study was to compare respiratory-triggered balanced steady-state free precession (bSSFP) with breath-hold contrast-enhanced dynamic two-dimensional (2D) gradient-echo (GRE) and time-of-flight (TOF) magnetic resonance imaging (MRI) for portal and hepatic vein visualization and assessment of portal and hepatic venous variants. Sixty patients with liver disease underwent nonenhanced bSSFP and contrast-enhanced GRE, bSSFP, and TOF imaging. Contrast-to-noise ratios (CNRs) for portal and hepatic veins were measured. Two readers rated the quality of portal and hepatic vein visualization on a 5-point Likert scale. The diagnostic performance of each MRI series in the detection of portal and hepatic venous variants was assessed in 40/60 patients who also underwent contrast-enhanced multidetector-row computed tomography (MDCT). CNRs for portal and hepatic veins were highest on contrast-enhanced bSSFP images. Image quality of portal and hepatic veins was rated higher for nonenhanced bSSFP than for contrast-enhanced GRE (p<0.03) and TOF (p<0.003) and higher for contrast-enhanced than for nonenhanced bSSFP (p<0.003). Compared with MDCT, portal and hepatic venous variants were identified with an accuracy of 99% on bSSFP images, with an excellent interobserver agreement ({kappa}=0.97). Compared with MDCT, presence of surgically important portal and hepatic venous anatomical variants can be predicted with high accuracy on bSSFP images. (orig.)

  7. Differentiation between focal malignant marrow-replacing lesions and benign red marrow deposition of the spine with T2{sup *}-corrected fat-signal fraction map using a three -echo volume interpolated breath-hold gradient echo dixon sequence

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Yong Pyo; Kim, Sung Jun; Chung, Tae Sub; Yoo, Yeon Hwa; Yoon, Choon Sik [Dept. of Radiology, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul (Korea, Republic of); Kanneengiesser, Stephan [MR Applications Development, Siemens AG, Healthcare Sector, Erlangen (Germany); Paek, Moon Young [Siemens Ltd., Seoul (Korea, Republic of); Song, Ho Taek; Lee, Young Han; Suh, Jin Suck [Dept. of Radiology, Severance Hospital, Yonsei University College of Medicine, Seoul (Korea, Republic of)

    2014-12-15

    To assess the feasibility of T2{sup *}-corrected fat-signal fraction (FF) map by using the three-echo volume interpolated breath-hold gradient echo (VIBE) Dixon sequence to differentiate between malignant marrow-replacing lesions and benign red marrow deposition of vertebrae. We assessed 32 lesions from 32 patients who underwent magnetic resonance imaging after being referred for assessment of a known or possible vertebral marrow abnormality. The lesions were divided into 21 malignant marrow-replacing lesions and 11 benign red marrow depositions. Three sequences for the parameter measurements were obtained by using a 1.5-T MR imaging scanner as follows: three-echo VIBE Dixon sequence for FF; conventional T1-weighted imaging for the lesion-disc ratio (LDR); pre- and post-gadolinium enhanced fat-suppressed T1-weighted images for the contrast-enhancement ratio (CER). A region of interest was drawn for each lesion for parameter measurements. The areas under the curve (AUC) of the parameters and their sensitivities and specificities at the most ideal cutoff values from receiver operating characteristic curve analysis were obtained. AUC, sensitivity, and specificity were respectively compared between FF and CER. The AUCs of FF, LDR, and CER were 0.96, 0.80, and 0.72, respectively. In the comparison of diagnostic performance between the FF and CER, the FF showed a significantly larger AUC as compared to the CER (p = 0.030), although the difference of sensitivity (p = 0.157) and specificity (p = 0.157) were not significant. Fat-signal fraction measurement using T2{sup *}-corrected three-echo VIBE Dixon sequence is feasible and has a more accurate diagnostic performance, than the CER, in distinguishing benign red marrow deposition from malignant bone marrow-replacing lesions.

  8. Radial volumetric imaging breath-hold examination (VIBE) with k-space weighted image contrast (KWIC) for dynamic gadoxetic acid (Gd-EOB-DTPA)-enhanced MRI of the liver: advantages over Cartesian VIBE in the arterial phase

    Energy Technology Data Exchange (ETDEWEB)

    Fujinaga, Yasunari; Ohya, Ayumi; Tokoro, Hirokazu; Yamada, Akira; Ueda, Kazuhiko; Kadoya, Masumi [Shinshu University School of Medicine, Department of Radiology, Matsumoto (Japan); Ueda, Hitoshi; Kitou, Yoshihiro; Adachi, Yasuo; Shiobara, Aya; Tamaru, Naomichi [Radiology Division of Shinshu University Hospital, Matsumoto (Japan); Nickel, Marcel D. [Siemens AG Healthcare Sector, H IM MR PI TIO Oncology, Erlangen (Germany); Maruyama, Katsuya [Siemens Japan. K. K., Imaging and Therapy Systems Division, Shinagawa, Tokyo (Japan)

    2014-06-15

    To compare radial volumetric imaging breath-hold examination with k-space weighted image contrast reconstruction (r-VIBE-KWIC) to Cartesian VIBE (c-VIBE) in arterial phase dynamic gadoxetic acid (Gd-EOB-DTPA)-enhanced magnetic resonance imaging (DCE-MRI) of the liver. We reviewed 53 consecutive DCE-MRI studies performed on a 3-T unit using c-VIBE and 53 consecutive cases performed using r-VIBE-KWIC with full-frame image subset (r-VIBE{sub full}) and sub-frame image subsets (r-VIBE{sub sub}; temporal resolution, 2.5-3 s). All arterial phase images were scored by two readers on: (1) contrast-enhancement ratio (CER) in the abdominal aorta; (2) scan timing; (3) artefacts; (4) visualisation of the common, right, and left hepatic arteries. Mean abdominal aortic CERs for c-VIBE, r-VIBE{sub full}, and r-VIBE{sub sub} were 3.2, 4.3 and 6.5, respectively. There were significant differences between each group (P < 0.0001). The mean score for c-VIBE was significantly lower than that for r-VIBE{sub full} and r-VIBE{sub sub} in all factors except for visualisation of the common hepatic artery (P < 0.05). The mean score of all factors except for scan timing for r-VIBE{sub sub} was not significantly different from that for r-VIBE{sub full}. Radial VIBE-KWIC provides higher image quality than c-VIBE, and r-VIBE{sub sub} features high temporal resolution without image degradation in arterial phase DCE-MRI. circle Radial VIBE-KWIC minimised artefact and produced high-quality and high-temporal-resolution images. circle Maximum abdominal aortic enhancement was observed on sub-frame images of r-VIBE-KWIC. (orig.)

  9. Comparison of Superparamagnetic Iron Oxide Labeling Efficiency between Poly-L-Lysine and Protamine Sulfate for Human Mesenchymal Stem Cells: Quantitative Analysis Using Multi-Echo T2 Magnetic Resonance Imaging

    Energy Technology Data Exchange (ETDEWEB)

    Suh, Ji Yeon; Lee, Jeong Hyun; Lee, Chang Kyung; Shin, Ji Hoon; Choi, Choong Gon; Kim, Jeong Kon [Dept. of Radiology and Research Institute of Radiology, University of Ulsan College of Medicine, Asan Medical Center, Seoul (Korea, Republic of)

    2013-02-15

    To quantify in vitro labeling efficiency of protamine sulfate (PS) and poly-L-lysine (PLL) for labeling of human mesenchymal stem cells (hMSCs) with superparamagnetic iron oxide (SPIO) using multi-echo T2 magnetic resonance (MR) imaging at 4.7 T. The hMSCs were incubated with SPIO-PS or SPIO-PLL complexes. Their effects on the cell metabolism and differentiation capability were evaluated, respectively. The decrease of iron concentrations in the labeled cells were assessed immediately, and at 4 d after labeling using multi-echo T2 MR imaging at 4.7 T. The results were compared with those of Prussian blue colorimetry. The hMSCs were labeled more efficiently by SPIO-PLL than SPIO-PS without any significant effect on cell metabolism and differentiation capabilities. It was feasible to quantify the iron concentrations in SPIO-agarose-phantoms and in agarose mixture with the labeled cells from T2 maps obtained from multi-echo T2 MRI. However, the iron concentration of the labeled cells was significantly higher by T2-maps than the results of Prussian blue colorimetry. The hMSCs can be effectively labeled with SPIO-PLL complexes more than with SPIO-PS without significant change in cell metabolism and differentiation. In vitro quantification of the iron concentrations of the labeled is feasible from multi-echo T2 MRI, but needs further investigation.

  10. SU-D-18A-06: Variation of Controlled Breath Hold From CT Simulation to Treatment and Its Dosimetric Impact for Left-Sided Breast Radiotherapy with a Real-Time Optical Tracking System

    Energy Technology Data Exchange (ETDEWEB)

    Mittauer, K; Deraniyagala, R; Li, J; Lu, B; Liu, C; Lightsey, J; Yan, G [University of Florida, Gainesville, FL (United States)

    2014-06-01

    Purpose: Different breath-hold (BH) maneuvers (abdominal breathing vs. chest breathing) during CT simulation and treatment can lead to chest wall positional variation. The purpose of this study is to quantify the variation of active breathing control (ABC)-assisted BH and estimate its dosimetric impact for left-sided whole-breast radiotherapy with a real-time optical tracking system (OTS). Methods: Seven breast cancer patients were included. An in-house OTS tracked an infrared (IR) marker affixed over the xiphoid process of the patient at CT simulation and throughout the treatment course to measure BH variations. Correlation between the IR marker and the breast was studied for dosimetric purposes. The positional variations of 860 BHs were retrospectively incorporated into treatment plans to assess their dosimetric impact on breast and cardiac organs (heart and left anterior descending artery [LAD]). Results: The mean intrafraction variations were 2.8 mm, 2.7 mm, and 1.6 mm in the anteroposterior (AP), craniocaudal (CC), and mediolateral (ML) directions, respectively. Mean stability in any direction was within 1.5 mm. A general trend of BH undershoot at treatment relative to CT simulation was observed with an average of 4.4 mm, 3.6 mm, and 0.1 mm in the AP, CC, and ML directions, respectively. Undershoot up to 12.6 mm was observed for individual patients. The difference between the planned and delivered dose to breast targets was negligible. The average planned/delivered mean heart doses, mean LAD doses, and max LAD doses were 1.4/2.1, 7.4/15.7, and 18.6/31.0 Gy, respectively. Conclusion: Systematic undershoot was observed in ABC-assisted BHs from CT simulation to treatment. Its dosimetric impact on breast coverage was minimized with image guidance, but the benefits of cardiac organ sparing were degraded. A real-time tracking system can be used in junction with the ABC device to improve BH reproducibility.

  11. Correction of phase errors in quantitative water-fat imaging using a monopolar time-interleaved multi-echo gradient echo sequence.

    Science.gov (United States)

    Ruschke, Stefan; Eggers, Holger; Kooijman, Hendrik; Diefenbach, Maximilian N; Baum, Thomas; Haase, Axel; Rummeny, Ernst J; Hu, Houchun H; Karampinos, Dimitrios C

    2017-09-01

    To propose a phase error correction scheme for monopolar time-interleaved multi-echo gradient echo water-fat imaging that allows accurate and robust complex-based quantification of the proton density fat fraction (PDFF). A three-step phase correction scheme is proposed to address a) a phase term induced by echo misalignments that can be measured with a reference scan using reversed readout polarity, b) a phase term induced by the concomitant gradient field that can be predicted from the gradient waveforms, and c) a phase offset between time-interleaved echo trains. Simulations were carried out to characterize the concomitant gradient field-induced PDFF bias and the performance estimating the phase offset between time-interleaved echo trains. Phantom experiments and in vivo liver and thigh imaging were performed to study the relevance of each of the three phase correction steps on PDFF accuracy and robustness. The simulation, phantom, and in vivo results showed in agreement with the theory an echo time-dependent PDFF bias introduced by the three phase error sources. The proposed phase correction scheme was found to provide accurate PDFF estimation independent of the employed echo time combination. Complex-based time-interleaved water-fat imaging was found to give accurate and robust PDFF measurements after applying the proposed phase error correction scheme. Magn Reson Med 78:984-996, 2017. © 2016 International Society for Magnetic Resonance in Medicine. © 2016 International Society for Magnetic Resonance in Medicine.

  12. T2-weighted MR imaging of liver lesions: a prospective evaluation comparing turbo spin-echo, breath-hold turbo spin-echo and half-Fourier turbo spin-echo (HASTE) sequences; Estudio de lesiones hepaticas con imagenes de resonancia magnetica potenciadas en T2: evaluacion prospectiva comparando secuencias turbo eco del espin, turbo eco del espin con respiracion sostenida y half-Fourier turbo eco del espin (HASTE)

    Energy Technology Data Exchange (ETDEWEB)

    Martin, J.; Villajos, M.; Oses, M. J.; Veintemillas, M.; Rue, M.; Puig, J.; Sentis, M. [Fundacion Parc Tauli. Sabadell (Spain)

    2000-07-01

    To compare turbo spin-echo (TSE), breath-hold TSE and half-Fourier acquisition single-shot turbo spin-echo (HASTE) sequences quantitatively and qualitatively in T2-weighted images of liver lesions. The authors evaluated prospectively 89 liver lesions in 73 patients using a 1.0-T magnetic resonance system to compare TSE, breath-hold TSE and HASTE sequences. The quantitative parameters were: lesion-to-liver contrast and lesion-to-liver contrast-to-noise ratio. The qualitative analysis was performed by two observers in consensus who examined four parameters: respiratory artifacts, lesion edge definition, intrahepatic vessel definition and image quality. Repeated measures analysis of variance was utilized to compare the quantitative variables and Friedman's nonparametric test for the qualitative parameters. In quantitative terms, the lesion-to-liver contrast was similar in TSE and breath-hold TSE sequences (2.45{+-}1.44 versus 2.60{+-}1.66), both of which were significantly better than the HASTE sequence (1.12{+-}0.72; p<0.001). The lesion-to-liver contrast-to-noise ratio was significantly higher in the TSE sequence (62.60{+-}46.40 versus 40.22{+-}25.35 versus 50.90{+-}32.10 for TSE, breath-hold TSE and HASTE sequences, respectively; p<0.001). In the qualitative comparisons, the HASTE sequence was significantly better than the TSE and breath-hold TSE sequences (p<0.001) in terms of artifacts and definition of lesion edge and intrahepatic vessels. Image quality was also significantly greater in the HASTE sequence (p<0.001). In quantitative terms, the TSE sequence is better than the breath-hold TSE and HASTE sequences, but there are no movement artifacts in the HASTE sequence, which is also significantly superior to TSE and breath-hold TSE sequences in qualitative terms and, thus, can be employed for T2-weighted images in liver studies. (Author) 17 refs.

  13. Breath-hold technique in conventional APPA or intensity-modulated radiotherapy for Hodgkin's lymphoma. Comparison of ILROG IS-RT and the GHSG IF-RT

    Energy Technology Data Exchange (ETDEWEB)

    Kriz, Jan; Spickermann, Max; Lehrich, Philipp; Reinartz, Gabriele; Eich, Hans; Haverkamp, Uwe [University of Muenster, Department of Radiation Oncology, Muenster (Germany); Schmidberger, Heinz [University Mainz, Department of Radiation Oncology, Mainz (Germany)

    2015-09-15

    The present study addresses the role of intensity-modulated radiotherapy (IMRT) in contrast to standard RT (APPA) for patients with Hodgkin's lymphoma (HL) with a focus on deep inspiration breath-hold (DIBH) technique and a comparison between the International Lymphoma Radiation Oncology Group (ILROG) Involved Site Radiotherapy (IS-RT) versus the German Hodgkin Study Group (GHSG) Involved Field Radiotherapy (IF-RT). APPA treatment and 2 IMRT plans were compared for 11 patients with HL. Furthermore, treatment with DIBH versus free breathing (FB) and two different treatment volumes, i.e. IF-RT versus IS-RT, were compared. IMRT was planned as a sliding-window technique with 5 and 7 beam angles. For each patient 12 different treatment plans were calculated (132 plans). Following organs at risk (OAR) were analysed: lung, heart, spinal cord, oesophagus, female breast and skin. Comparisons of the different values with regard to dose-volume histograms (DVH), conformity and homogeneity indices were made. IS-RT reduces treatment volumes. With respect to the planning target volume (PTV), IMRT achieves better conformity but the same homogeneity. Regarding the D{sub mean} for the lung, IMRT shows increased doses, while RT in DIBH reduces doses. The IMRT shows improved values for D{sub max} concerning the spinal cord, whereas the APPA shows an improved D{sub mean} of the lung and the female breast. IS-RT reduces treatment volumes. Intensity-modulated radiotherapy shows advantages in the conformity. Treatment in DIBH also reduces the dose applied to the lungs and the heart. (orig.) [German] Ziel dieser Auswertung ist es, die konventionelle APPA-Feldanordnung mit der Intensitaetsmodulierten Radiotherapie (IMRT) bei Patienten mit Hodgkin-Lymphom (HL) zu vergleichen. Ein besonderer Fokus liegt hierbei auf der Bestrahlung in tiefer Inspiration und Atemanhaltetechnik (DIBH). Des Weiteren wurde die ''Involved-site''-Radiotherapie (IS-RT) der International

  14. Is the Deep Inspiration Breath-Hold Technique Superior to the Free Breathing Technique in Cardiac and Lung Sparing while Treating both Left-Sided Post-Mastectomy Chest Wall and Supraclavicular Regions

    Directory of Open Access Journals (Sweden)

    Anupama Darapu

    2017-01-01

    Full Text Available Aims: To evaluate the efficacy of the deep inspirational breath-hold (DIBH technique and its dosimetric advantages over the free breathing (FB technique in cardiac (heart and left anterior descending artery [LAD] and ipsilateral lung sparing in left-sided post-mastectomy field-in-field conformal radiotherapy. DIBH is highly reproducible, and this study aims to find out its dosimetric benefits over FB. Materials and Methods: Nineteen left-sided mastectomy patients were immobilized using breast boards with both arms positioned above the head. All patients had 2 sets of planning CT images (one in FB and another in DIBH with a Biograph TruePoint HD CT scanner in the same setup. DIBH was performed by tracking the respiratory cycles using a Varian Real-Time Position Management system. The target (chest wall and supraclavicular region, organs at risk (OARs; ipsilateral lung, contralateral lung, heart, LAD, and contralateral breast, and other organs of interests were delineated as per the RTOG (Radiation Therapy Oncology Group contouring guidelines. The single-isocenter conformal fields in the field treatment plans were generated with the Eclipse Treatment Planning System (Varian Medical Systems for both FB and DIBH images, and the doses to the target and OARs were compared. The standard fractionation regimen of 50 Gy in 25 fractions over a period of 5 weeks was used for all patients in this study. Results and Discussion: The target coverage parameters (V95, V105, V107, and Dmean were found to be 97.8 ± 0.9, 6.1 ± 3.4, 0.2 ± 0.3, and 101.9 ± 0.5% in the FB plans and 98.1 ± 0.8, 6.1 ± 3.2, 0.2 ± 0.3, and 101.9 ± 0.4% in the DIBH plans, respectively. The plan quality indices (conformity index and homogeneity index also showed 1.3 ± 0.2 and 0.1 for the FB plans and 1.2 ± 0.3 and 0.1 for the DIBH plans, respectively. There was a significant reduction in dose to the heart in the DIBH plans compared to the FB plans, with p values of nearly 0 for the

  15. Quantitative comparison of cortical surface reconstructions from MP2RAGE and multi-echo MPRAGE data at 3 and 7 T.

    Science.gov (United States)

    Fujimoto, Kyoko; Polimeni, Jonathan R; van der Kouwe, André J W; Reuter, Martin; Kober, Tobias; Benner, Thomas; Fischl, Bruce; Wald, Lawrence L

    2014-04-15

    The Magnetization-Prepared 2 Rapid Acquisition Gradient Echo (MP2RAGE) method achieves spatially uniform contrast across the entire brain between gray matter and surrounding white matter tissue and cerebrospinal fluid by rapidly acquiring data at two points during an inversion recovery, and then combining the two volumes so as to cancel out sources of intensity and contrast bias, making it useful for neuroimaging studies at ultrahigh field strengths (≥7T). To quantify the effectiveness of the MP2RAGE method for quantitative morphometric neuroimaging, we performed tissue segmentation and cerebral cortical surface reconstruction of the MP2RAGE data and compared the results with those generated from conventional multi-echo MPRAGE (MEMPRAGE) data across a group of healthy subjects. To do so, we developed a preprocessing scheme for the MP2RAGE image data to allow for automatic cortical segmentation and surface reconstruction using FreeSurfer and analysis methods to compare the positioning of the surface meshes. Using image volumes with 1mm isotropic voxels we found a scan-rescan reproducibility of cortical thickness estimates to be 0.15 mm (or 6%) for the MEMPRAGE data and a slightly lower reproducibility of 0.19 mm (or 8%) for the MP2RAGE data. We also found that the thickness estimates were systematically smaller in the MP2RAGE data, and that both the interior and exterior cortical boundaries estimated from the MP2RAGE data were consistently positioned within the corresponding boundaries estimated from the MEMPRAGE data. Therefore several measureable differences exist in the appearance of cortical gray matter and its effect on automatic segmentation methods that must be considered when choosing an acquisition or segmentation method for studies requiring cortical surface reconstructions. We propose potential extensions to the MP2RAGE method that may help to reduce or eliminate these discrepancies. Copyright © 2013 Elsevier Inc. All rights reserved.

  16. Improving effect size estimation and statistical power with multi-echo fMRI and its impact on understanding the neural systems supporting mentalizing.

    Science.gov (United States)

    Lombardo, Michael V; Auyeung, Bonnie; Holt, Rosemary J; Waldman, Jack; Ruigrok, Amber N V; Mooney, Natasha; Bullmore, Edward T; Baron-Cohen, Simon; Kundu, Prantik

    2016-11-15

    Functional magnetic resonance imaging (fMRI) research is routinely criticized for being statistically underpowered due to characteristically small sample sizes and much larger sample sizes are being increasingly recommended. Additionally, various sources of artifact inherent in fMRI data can have detrimental impact on effect size estimates and statistical power. Here we show how specific removal of non-BOLD artifacts can improve effect size estimation and statistical power in task-fMRI contexts, with particular application to the social-cognitive domain of mentalizing/theory of mind. Non-BOLD variability identification and removal is achieved in a biophysical and statistically principled manner by combining multi-echo fMRI acquisition and independent components analysis (ME-ICA). Without smoothing, group-level effect size estimates on two different mentalizing tasks were enhanced by ME-ICA at a median rate of 24% in regions canonically associated with mentalizing, while much more substantial boosts (40-149%) were observed in non-canonical cerebellar areas. Effect size boosting occurs via reduction of non-BOLD noise at the subject-level and consequent reductions in between-subject variance at the group-level. Smoothing can attenuate ME-ICA-related effect size improvements in certain circumstances. Power simulations demonstrate that ME-ICA-related effect size enhancements enable much higher-powered studies at traditional sample sizes. Cerebellar effects observed after applying ME-ICA may be unobservable with conventional imaging at traditional sample sizes. Thus, ME-ICA allows for principled design-agnostic non-BOLD artifact removal that can substantially improve effect size estimates and statistical power in task-fMRI contexts. ME-ICA could mitigate some issues regarding statistical power in fMRI studies and enable novel discovery of aspects of brain organization that are currently under-appreciated and not well understood.

  17. FAST

    DEFF Research Database (Denmark)

    Zuidmeer-Jongejan, Laurian; Fernandez-Rivas, Montserrat; Poulsen, Lars K.

    2012-01-01

    ABSTRACT: The FAST project (Food Allergy Specific Immunotherapy) aims at the development of safe and effective treatment of food allergies, targeting prevalent, persistent and severe allergy to fish and peach. Classical allergen-specific immunotherapy (SIT), using subcutaneous injections with aqu......ABSTRACT: The FAST project (Food Allergy Specific Immunotherapy) aims at the development of safe and effective treatment of food allergies, targeting prevalent, persistent and severe allergy to fish and peach. Classical allergen-specific immunotherapy (SIT), using subcutaneous injections...... with aqueous food extracts may be effective but has proven to be accompanied by too many anaphylactic side-effects. FAST aims to develop a safe alternative by replacing food extracts with hypoallergenic recombinant major allergens as the active ingredients of SIT. Both severe fish and peach allergy are caused...... in depth serological and cellular immune analyses will be performed, allowing identification of novel biomarkers for monitoring treatment efficacy. FAST aims at improving the quality of life of food allergic patients by providing a safe and effective treatment that will significantly lower their threshold...

  18. 分娩球运动待产结合自主式屏气法在促进自然分娩中的临床应用%Clinical application of childbirth ball movement predelivery combined with autonomous breath holding method in promo-ting natural childbirth

    Institute of Scientific and Technical Information of China (English)

    陈叔容; 刘静梅; 任玉平; 李艳; 邓富秋

    2015-01-01

    目的:探讨分娩球运动待产与自主式屏气法联合对促进自然分娩的效果分析。方法选取200例初产妇作为研究对象,将其随机分为研究组与对照组,每组各100例。研究组产妇第一产程应用分娩球运动待产,第二产程应用自主式屏气法分娩。对照组产妇第一产程应用传统方式分娩,第二产程应用自主式屏气法分娩。结果研究组和对照组的自然分娩率分别为90.0%、72.0%,差异有统计学意义(P<0.05)。研究组和对照组的满意度分别为92.0%、73.0%,两组差异有统计学意义(P<0.05)。研究组第一产程时间、第二产程时间、屏气用力时长、产后2 h 出血量明显低于对照组,研究组先露下降速度明显高于对照组,差异均有统计学意义(P<0.05)。结论应用分娩球运动待产与自主式屏气法联合可以促进自然分娩,提高自然分娩率,缩短产程时间,提高产妇的护理满意度。%Objective To investigate the effect of childbirth ball movement predelivery combined with autono‐mous breath holding method in promoting natural childbirth .Methods 200 primiparae were selected as the research subjects and randomly divided into the study group and the control group ,100 cases in each group .The study group applied the childbirth ball movement for conducting predelivery during the first stage of labor and the autonomous breath holding method for delivery during the second stage of labor .The control group applied the conventional mode for delivery during the first stage of labor and the autonomous breath holding method for delivery during the second stage of labor .Results The natural birth rate was 90 .0% in the study group and 72 .0% in the control group ,the difference was statistically significant(P< 0 .05) .The satisfaction degree was 92 .0% in the study group and 73 .0%in the control group ,the difference was statistically significant

  19. Detection of pulmonary nodules with breath-hold magnetic resonance imaging in comparison with computed tomography; Detektion von Lungenrundherden mit der Magnetresonanztomographie in Atemanhaltetechnik im Vergleich zur Spiral-Computertomographie

    Energy Technology Data Exchange (ETDEWEB)

    Schaefer, J.F.; Vollmar, J.; Seemann, M.D.; Kamm, P.; Erdtmann, B.; Claussen, C.D. [Abt. fuer Radiologische Diagnostik, Universitaetsklinikum Tuebingen (Germany); Schick, F. [Abt. fuer Radiologische Diagnostik, Sektion Experimentelle Radiologie, Universitaetsklinikum Tuebingen (Germany)

    2005-01-01

    Purpose: evaluation of sensitivity and false positive findings of two fast MRI sequences for the detection of pulmonary nodules in comparison with spiral CT by two independent observers. Materials and methods: all 30 enrolled patients had a spiral CT or MSCT as base line study. MRI was performed with a 1.5 T MR scanner (Sonata, Siemens) using a transverse 3D gradient echo sequence (3D-GRE: TR/TE/flip = 2.9 ms/1.1 ms/5 ) and a half-Fourier single-shot fast spin-echo sequence (HASTE: TR/TE/flip = 800/25/150 ) acquired in three planes. A separate analysis for both sequences was carried out prospectively by two independent readers (A and B) with different experience regarding pulmonary MRI. Additionally, a retrospective reading with knowledge of the CT scans was done. Results were calculated for all lesions and for lesions larger than 4 mm. Results: the sensitivities were 73%, 70% and 84% for the 3D-GRE sequence (reader A, reader B, retrospective reading) and 65%, 68% and 81% for the HASTE sequence. For lesions larger than 4 mm, the sensitivities were 93%, 89%, 96% for the 3D-GRE sequence and 85%, 85%, 96% for the HASTE sequence. The rate of false positive findings depended on the reader's experience, but was generally lower for the 3D-GRE sequence with 2 and 16 (reader A and B) false positive nodules compared to 4 and 40 false positive findings for the HASTE sequence. The 3D-GRE sequence was more accurate for both readers (reader A: p = 0.08, reader B: p = 0.00003). Conclusion: the sensitivity of MRI for the detection of lung nodules was only acceptable for lesions larger than 4 mm. The 3D-GRE sequence is superior to the HASTE sequence due to the reduced amount of false positive findings with comparable sensitivity. (orig.)

  20. Time of flight MR angiography using 2DFT-fast spoiled GRASS technique

    Energy Technology Data Exchange (ETDEWEB)

    Igarashi, Hideshi; Matsushita, Masaki (Osaka Teishin Hospital (Japan)); Murakami, Takamichi (and others)

    1994-01-01

    MR angiography using a fast spoiled GRASS (FSPGR) technique was performed in 24 patients with portal hypertension and seven normal subjects on a 1.5-T MR unit (GE Signa). The results were compared to those for conventional 2D time-of-flight MR angiography obtained with a spoiled GRASS (SPGR) technique (40/12/25, TR/TE/flip angle). Twenty five to 30 sections were obtained by FSPGR (8.1/3.1/30 TR/TE/flip angel) within a 25-30 second single breath-hold technique. SPGR images were obtained with repeated breath-holds within 20-30 seconds. The projection MR angiography was reconstructed from these images with maximum intensity projection technique. Signal-to-noise ratios for FSPGR images that were measured on the vessel and the liver were significantly superior to those for SPGR images (P<0.01). Anatomical details such as portal veins or other vessel were better delineated with FSPGR than with SPGR. MR angiography using a FSPGR is useful in evaluating the portal veins and collateral vessels in patients with portal hypertention. (author).

  1. 屏气与呼吸触发氢质子磁共振波谱量化肝脏脂肪含量的比较%Comparison of breath-hold and respiratory-triggered proton MR spectroscopy in quantification of liver fat content

    Institute of Scientific and Technical Information of China (English)

    林楚岚; 江桂华; 刘金武; 李武铭; 颜剑豪; 梁联保; 全显跃

    2015-01-01

    Objective To compare the consistency and correlation of multiple breath-hold (BH) with respiratory-triggered (RT) 1H-MRS for quantification of hepatic lipid content. Methods Sixty subjects were underwent RT 1H-MRS of the liver (Couinaud segment VII) and BH 1H-MRS at 1.5 Tesla Magnetic Resonace Imaging (MRI). The peak areas of water and methylene obtained on RT and BH 1H-MRS were recorded respectively and the liver fat fraction was calculated. Pearson correlation coefficient , Bland-Altman 95% limit of agreement, and concordance correlation coefficient were calculated. Results Mean liver fat fraction measured in RT and BH 1H-MRS were (8.6 ± 8.7)% and (9.4 ± 9.3)% respectively. There was a strong correlation between RT and BH 1H-MRS(r = 0.973, P < 0.000 1, concordance correlation coefficient = 0.95). With the Bland-Altman method, 91.7% data points were within the 95% limits of agreement. Conclusion RT and BH 1H-MRS are alternative tools for intrahepatic lipid quantification. These two methods have a strong correlation and perfect consistency.%目的:比较多次屏气与呼吸触发氢质子磁共振波谱(hydrogen 1 magnetic resonance spectroscopy,1H-MRS)对肝脏脂肪含量量化的一致性和相关性。方法:60例受试者使用1.5 T 磁共振扫描仪在肝脏Ⅶ段分别行多次屏气和呼吸触发1H-MRS采集。分别记录波谱曲线中亚甲基峰和水峰下面积,计算脂肪分数。计算两者的Pearson 相关系数、Bland-Altman 95%一致性界限和一致性相关系数。结果:多次屏气和呼吸触发1H-MRS 得到的平均肝脏脂肪含量分别为(8.6±8.7)%和(9.4±9.3)%,两者高度相关(r =0.973, P <0.0001;一致性相关系数为0.95)。用Bland-Altman方法,91.7%点都在95%一致性界限内。结论:多次屏气与呼吸触发1H-MRS均能用于量化肝脏脂肪含量。这两种方法高度相关且一致性良好。

  2. Effect of physiological heart rate variability on quantitative T2 measurement with ECG-gated Fast Spin Echo (FSE) sequence and its retrospective correction.

    Science.gov (United States)

    de Roquefeuil, Marion; Vuissoz, Pierre-André; Escanyé, Jean-Marie; Felblinger, Jacques

    2013-11-01

    Quantitative T2 measurement is applied in cardiac Magnetic Resonance Imaging (MRI) for the diagnosis and follow-up of myocardial pathologies. Standard Electrocardiogram (ECG)-gated fast spin echo pulse sequences can be used clinically for T2 assessment, with multiple breath-holds. However, heart rate is subject to physiological variability, which causes repetition time variations and affects the recovery of longitudinal magnetization between TR periods. The bias caused by heart rate variability on quantitative T2 measurements is evaluated for fast spin echo pulse sequence. Its retrospective correction based on an effective TR is proposed. Heart rate variations during breath-holds are provided by the ECG recordings from healthy volunteers. T2 measurements were performed on a phantom with known T2 values, by synchronizing the sequence with the recorded ECG. Cardiac T2 measurements were performed twice on six volunteers. The impact of T1 on T2 is also studied. Maximum error in T2 is 26% for phantoms and 18% for myocardial measurement. It is reduced by the proposed compensation method to 20% for phantoms and 10% for in vivo measurements. Only approximate knowledge of T1 is needed for T2 correction. Heart rate variability may cause a bias in T2 measurement with ECG-gated FSE. It needs to be taken into account to avoid a misleading diagnosis from the measurements. © 2013.

  3. Fast MR Imaging of the Paediatric Abdomen with CAIPIRINHA-Accelerated T1w 3D FLASH and with High-Resolution T2w HASTE: A Study on Image Quality

    Directory of Open Access Journals (Sweden)

    Mengxia Li

    2015-01-01

    Full Text Available The aim of this study was to explore the applicability of fast MR techniques to routine paediatric abdominopelvic MRI at 1.5 Tesla. “Controlled Aliasing in Parallel Imaging Results in Higher Acceleration-” (CAIPIRINHA- accelerated contrast-enhanced-T1w 3D FLASH imaging was compared to standard T1w 2D FLASH imaging with breath-holding in 40 paediatric patients and to respiratory-triggered T1w TSE imaging in 10 sedated young children. In 20 nonsedated patients, we compared T2w TIRM to fat-saturated T2w HASTE imaging. Two observers performed an independent and blinded assessment of overall image quality. Acquisition time was reduced by the factor of 15 with CAIPIRINHA-accelerated T1w FLASH and by 7 with T2w HASTE. With CAIPIRINHA and with HASTE, there were significantly less motion artefacts in nonsedated patients. In sedated patients, respiratory-triggered T1w imaging in general showed better image quality. However, satisfactory image quality was achieved with CAIPIRINHA in two sedated patients where respiratory triggering failed. In summary, fast scanning with CAIPIRINHA and HASTE presents a reliable high quality alternative to standard sequences in paediatric abdominal MRI. Paediatric patients, in particular, benefit greatly from fast image acquisition with less breath-hold cycles or shorter sedation.

  4. Lactate flux and gluconeogenesis in fasting, weaned northern elephant seals (Mirounga angustirostris).

    Science.gov (United States)

    Tavoni, Stephen K; Champagne, Cory D; Houser, Dorian S; Crocker, Daniel E

    2013-05-01

    Elephant seals maintain rates of endogenous glucose production (EGP) typical of post-absorptive mammals despite enduring prolonged periods of food deprivation concurrent with low rates of glucose oxidation. These high rates of EGP suggest extensive glucose recycling during fasting. We investigated lactate metabolism in fasting elephant seals to assess its role in glucose recycling. Whole-animal glucose and lactate fluxes were measured as the rates of appearance of glucose and lactate (Ra gluc and Ra lac, respectively) using a primed constant infusion of [U-(14)C] lactate and [6-(3)H] glucose, and we calculated the minimum contribution of lactate to gluconeogenesis (GNG lac). Ra lac was high compared to resting values in other species (3.21 ± 0.71 mmol min(-1)* kg(-1)), did not change between 14 ± 1 and 31 ± 8 days of fasting and varied directly with Ra glu. The minimum GNG lac was 44.6 ± 6.0% of EGP, varied directly with plasma lactate levels, and did not change over the fast. Ra lac and Ra glu both varied directly with plasma insulin concentrations. These data suggest that lactate is the predominant gluconeogenic precursor in fasting elephant seals and that high rates of glucose recycling through Cori cycle activity contribute to the maintenance of EGP during fasting. High levels of Cori cycle activity and EGP may be important components of metabolic adaptations that maintain glucose production while avoiding ketosis during extended fasting or are related to sustained metabolic alterations associated with extended breath-holds in elephant seals.

  5. Ascent exhalations of Antarctic fur seals: a behavioural adaptation for breath-hold diving?

    Science.gov (United States)

    Hooker, Sascha K; Miller, Patrick J O; Johnson, Mark P; Cox, Oliver P; Boyd, Ian L

    2005-02-22

    Novel observations collected from video, acoustic and conductivity sensors showed that Antarctic fur seals consistently exhale during the last 50-85% of ascent from all dives (10-160 m, n > 8000 dives from 50 seals). The depth of initial bubble emission was best predicted by maximum dive depth, suggesting an underlying physical mechanism. Bubble sound intensity recorded from one seal followed predictions of a simple model based on venting expanding lung air with decreasing pressure. Comparison of air release between dives, together with lack of variation in intensity of thrusting movement during initial descent regardless of ultimate dive depth, suggested that inhaled diving lung volume was constant for all dives. The thrusting intensity in the final phase of ascent was greater for dives in which ascent exhalation began at a greater depth, suggesting an energetic cost to this behaviour, probably as a result of loss of buoyancy from reduced lung volume. These results suggest that fur seals descend with full lung air stores, and thus face the physiological consequences of pressure at depth. We suggest that these regular and predictable ascent exhalations could function to reduce the potential for a precipitous drop in blood oxygen that would result in shallow-water blackout.

  6. Dosimetric comparison of free-breathing and deep inspiration breath-hold radiotherapy for lung cancer

    Energy Technology Data Exchange (ETDEWEB)

    Marchand, V.; Desrousseaux, J.; Dauphinot, C. [Institut Curie, Paris (France). Dept. of Radiotherapy; Zefkili, S.; Simon, L. [Institut Curie, Paris (France). Dept. of Radiophysics; Giraud, P. [Institut Curie, Paris (France). Dept. of Radiotherapy; Hopital Europeen Georges Pompidou, Paris Descartes Univ., Paris (France). Dept. of Radiotherapy

    2012-07-15

    Purpose: The goal of this work was to evaluate the feasibility and outcome of intensity-modulated arc therapy {+-} cisplatin (IMAT {+-} C) followed by hysterectomy for locally advanced cervical cancer. Patients and methods: A total of 30 patients were included in the study. The primary tumour and PET-positive lymph node(s) received a simultaneous integrated boost. Four weeks after IMAT {+-} C treatment, response was evaluated. Resection consisted of hysterectomy with or without lymphadenectomy. Tumour response, acute and late radiation toxicity, postoperative morbidity and outcome were evaluated. Results: All hysterectomy specimens were macroscopically tumour-free with negative resection margins; pathological complete response was 40%. In 2 patients, one resected lymph node was positive. There was no excess in postoperative morbidity. Apart from two grade 3 hematologic toxicities, no grade 3 or 4 acute radiation toxicity was observed. No grade 3, 1 grade 4 (4%) intestinal, and 4 grade 3 (14%) urinary late toxicities were observed. The 2-year local and regional control rates were 96% and 100%, respectively. The 2-year distant control rate was 92%. Actuarial 2-year progression free survival rate was 89%. Actuarial 1- and 2-year overall survival rates were 96% and 91%, while 3-year overall survival was 84%. Conclusion: Surgery after IMAT {+-} C is feasible with low postoperative morbidity and radiation toxicity. Local, regional, distant control and survival rates are promising. (orig.)

  7. Fast Vascular Ultrasound Imaging With Enhanced Spatial Resolution and Background Rejection.

    Science.gov (United States)

    Bar-Zion, Avinoam; Tremblay-Darveau, Charles; Solomon, Oren; Adam, Dan; Eldar, Yonina C

    2017-01-01

    Ultrasound super-localization microscopy techniques presented in the last few years enable non-invasive imaging of vascular structures at the capillary level by tracking the flow of ultrasound contrast agents (gas microbubbles). However, these techniques are currently limited by low temporal resolution and long acquisition times. Super-resolution optical fluctuation imaging (SOFI) is a fluorescence microscopy technique enabling sub-diffraction limit imaging with high temporal resolution by calculating high order statistics of the fluctuating optical signal. The aim of this work is to achieve fast acoustic imaging with enhanced resolution by applying the tools used in SOFI to contrast-enhance ultrasound (CEUS) plane-wave scans. The proposed method was tested using numerical simulations and evaluated using two in-vivo rabbit models: scans of healthy kidneys and VX-2 tumor xenografts. Improved spatial resolution was observed with a reduction of up to 50% in the full width half max of the point spread function. In addition, substantial reduction in the background level was achieved compared to standard mean amplitude persistence images, revealing small vascular structures within tumors. The scan duration of the proposed method is less than a second while current super-localization techniques require acquisition duration of several minutes. As a result, the proposed technique may be used to obtain scans with enhanced spatial resolution and high temporal resolution, facilitating flow-dynamics monitoring. Our method can also be applied during a breath-hold, reducing the sensitivity to motion artifacts.

  8. Fast MR arthrography using VIBE sequences to evaluate the rotator cuff

    Energy Technology Data Exchange (ETDEWEB)

    Vandevenne, Jan E. [Ziekenhuizen Oost-Limburg, Department of Radiology, Genk (Belgium); Universitair Ziekenhuis Antwerpen, University of Antwerp, Department of Radiology, Edegem (Belgium); Vanhoenacker, Filip; Parizel, Paul M. [Universitair Ziekenhuis Antwerpen, University of Antwerp, Department of Radiology, Edegem (Belgium); Mahachie John, Jestinah M. [University of Hasselt, Centre for Statistics, Diepenbeek (Belgium); Gelin, Geert [Ziekenhuizen Oost-Limburg, Department of Radiology, Genk (Belgium)

    2009-07-15

    The purpose of this paper was to evaluate if short volumetric interpolated breath-hold examination (VIBE) sequences can be used as a substitute for T1-weighted with fat saturation (T1-FS) sequences when performing magnetic resonance (MR) arthrography to diagnose rotator cuff tears. Eighty-two patients underwent direct MR arthrography of the shoulder joint using VIBE (acquisition time of 13 s) and T1-FS (acquisition time of 5 min) sequences in the axial and paracoronal plane on a 1.0-T MR unit. Two radiologists scored rotator cuff tendons on VIBE and T1-FS images separately as normal, small/large partial thickness and full thickness tears with or without geyser sign. T1-FS sequences were considered the gold standard. Surgical correlation was available in a small sample. Sensitivity, specificity, and positive and negative predictive values of VIBE were greater than 92% for large articular-sided partial thickness and full thickness tears. For detecting fraying and articular-sided small partial thickness tears, these parameters were 55%, 94%, 94%, and 57%, respectively. The simple kappa value was 0.76, and the weighted kappa value was 0.86 for agreement between T1-FS and VIBE scores. All large partial and full thickness tears at surgery were correctly diagnosed using VIBE or T1-FS MR images. Fast MR arthrography of the shoulder joint using VIBE sequences showed good concordance with the classically used T1-FS sequences for the appearance of the rotator cuff, in particular for large articular-sided partial thickness tears and for full thickness tears. Due to its very short acquisition time, VIBE may be especially useful when performing MR arthrography in claustrophobic patients or patients with a painful shoulder. (orig.)

  9. Fast MR arthrography using VIBE sequences to evaluate the rotator cuff.

    Science.gov (United States)

    Vandevenne, Jan E; Vanhoenacker, Filip; Mahachie John, Jestinah M; Gelin, Geert; Parizel, Paul M

    2009-07-01

    The purpose of this paper was to evaluate if short volumetric interpolated breath-hold examination (VIBE) sequences can be used as a substitute for T1-weighted with fat saturation (T1-FS) sequences when performing magnetic resonance (MR) arthrography to diagnose rotator cuff tears. Eighty-two patients underwent direct MR arthrography of the shoulder joint using VIBE (acquisition time of 13 s) and T1-FS (acquisition time of 5 min) sequences in the axial and paracoronal plane on a 1.0-T MR unit. Two radiologists scored rotator cuff tendons on VIBE and T1-FS images separately as normal, small/large partial thickness and full thickness tears with or without geyser sign. T1-FS sequences were considered the gold standard. Surgical correlation was available in a small sample. Sensitivity, specificity, and positive and negative predictive values of VIBE were greater than 92% for large articular-sided partial thickness and full thickness tears. For detecting fraying and articular-sided small partial thickness tears, these parameters were 55%, 94%, 94%, and 57%, respectively. The simple kappa value was 0.76, and the weighted kappa value was 0.86 for agreement between T1-FS and VIBE scores. All large partial and full thickness tears at surgery were correctly diagnosed using VIBE or T1-FS MR images. Fast MR arthrography of the shoulder joint using VIBE sequences showed good concordance with the classically used T1-FS sequences for the appearance of the rotator cuff, in particular for large articular-sided partial thickness tears and for full thickness tears. Due to its very short acquisition time, VIBE may be especially useful when performing MR arthrography in claustrophobic patients or patients with a painful shoulder.

  10. Fast 3D coronary artery contrast-enhanced magnetic resonance angiography with magnetization transfer contrast, fat suppression and parallel imaging as applied on an anthropomorphic moving heart phantom.

    Science.gov (United States)

    Irwan, Roy; Rüssel, Iris K; Sijens, Paul E

    2006-09-01

    A magnetic resonance sequence for high-resolution imaging of coronary arteries in a very short acquisition time is presented. The technique is based on fast low-angle shot and uses fat saturation and magnetization transfer contrast prepulses to improve image contrast. GeneRalized Autocalibrating Partially Parallel Acquisitions (GRAPPA) is implemented to shorten acquisition time. The sequence was tested on a moving anthropomorphic silicone heart phantom where the coronary arteries were filled with a gadolinium contrast agent solution, and imaging was performed at varying heart rates using GRAPPA. The clinical relevance of the phantom was validated by comparing the myocardial relaxation times of the phantom's homogeneous silicone cardiac wall to those of humans. Signal-to-noise ratio and contrast-to-noise ratio were higher when parallel imaging was used, possibly benefiting from the acquisition of one partition per heartbeat. Another advantage of parallel imaging for visualizing the coronary arteries is that the entire heart can be imaged within a few breath-holds.

  11. Evaluation of a motion artifacts removal approach on breath-hold cine-magnetic resonance images of hypertrophic cardiomyopathy subjects

    Science.gov (United States)

    Betancur, Julián.; Simon, Antoine; Schnell, Frédéric; Donal, Erwan; Hernández, Alfredo; Garreau, Mireille

    2013-11-01

    The acquisition of ECG-gated cine magnetic resonance images of the heart is routinely performed in apnea in order to suppress the motion artifacts caused by breathing. However, many factors including the 2D nature of the acquisition and the use of di erent beats to acquire the multiple-view cine images, cause this kind of artifacts to appear. This paper presents the qualitative evaluation of a method aiming to remove motion artifacts in multipleview cine images acquired on patients with hypertrophic cardiomyopathy diagnosis. The approach uses iconic registration to reduce for in-plane artifacts in long-axis-view image stacks and in-plane and out-of-plane motion artifacts in sort-axis-view image stack. Four similarity measures were evaluated: the normalized correlation, the normalized mutual information, the sum of absolute voxel di erences and the Slomka metric proposed by Slomka et al. The qualitative evaluation assessed the misalignment of di erent anatomical structures of the left ventricle as follows: the misalignment of the interventricular septum and the lateral wall for short-axis-view acquisitions and the misalignment between the short-axis-view image and long-axis-view images. Results showed the correction using the normalized correlation as the most appropriated with an 80% of success.

  12. Breathing adapted radiotherapy of breast cancer: reduction of cardiac and pulmonary doses using voluntary inspiration breath-hold

    DEFF Research Database (Denmark)

    Pedersen, Anders N; Korreman, Stine; Nyström, Håkan

    2004-01-01

    BACKGROUND AND PURPOSE: Adjuvant radiotherapy of breast cancer using wide tangential photon fields implies a risk of late cardiac and pulmonary toxicity. This CT-study evaluates the detailed potential dosimetric consequences of applying breathing adapted radiotherapy (BART), and the feasibility......%. CONCLUSIONS: Irradiated cardiac volumes can consistently be reduced for left-sided breast cancers using DIBH for wide tangential treatment fields. Additionally, substantial dose reductions in the lung are observed for both right- and left-sided tumours....

  13. Improved quality of life after treatment of prolonged asystole during breath holding spells with a cardiac pacemaker

    Directory of Open Access Journals (Sweden)

    Bruno Kolterer

    2015-01-01

    Conclusion: Cardiac pacing using appropriate pacemaker settings seems effective in the prevention of LOC and reduction of the frequency of BHS. Our results imply a reduction of subjective stress levels of patients and parents as well as an increased quality of everyday life. After all, randomized controlled trials of the influence of cardiac pacemaker implantation on subjective stress levels in patients with BHS are needed.

  14. Setup error and motion during deep inspiration breath-hold breast radiotherapy measured with continuous portal imaging

    DEFF Research Database (Denmark)

    Lutz, Christina Maria; Poulsen, Per Rugaard; Fledelius, Walther;

    2016-01-01

    differences between the groups were found. In a combined analysis, the group mean inter-fraction setup error was M = - 0.1 mm, with random and systematic errors of σ = 1.7 mm and Σ = 1.4 mm. The group mean inter-field shift was M = 0.0 (σ = 1.3 mm and Σ = 1.1 mm) and the group mean standard deviation......). At every third treatment fraction, continuous portal images were acquired. The time-resolved chest wall position during treatment was compared with the planned position to determine the inter-fraction setup errors and the intra-fraction motion of the chest wall. RESULTS: The DIBH compliance was 95% during...... both recruitment periods. A tendency of smaller inter-fraction setup errors and intra-fraction motion was observed for group 2 (medial marker block position). However, apart from a significantly reduced inter-field random shift (σ = 1.7 mm vs. σ = 0.9 mm, p = 0.005), no statistically significant...

  15. Improved abdominal MRI in non-breath-holding children using a radial k-space sampling technique.

    Science.gov (United States)

    Lee, Jong Hyuk; Choi, Young Hun; Cheon, Jung Eun; Lee, So Mi; Cho, Hyun Hae; Shin, Su Mi; Kim, Woo Sun; Kim, In One

    2015-06-01

    Radial k-space sampling techniques have been shown to reduce motion artifacts in adult abdominal MRI. To compare a T2-weighted radial k-space sampling MRI pulse sequence (BLADE) with standard respiratory-triggered T2-weighted turbo spin echo (TSE) in pediatric abdominal imaging. Axial BLADE and respiratory-triggered turbo spin echo sequences were performed without fat suppression in 32 abdominal MR examinations in children. We retrospectively assessed overall image quality, the presence of respiratory, peristaltic and radial artifact, and lesion conspicuity. We evaluated signal uniformity of each sequence. BLADE showed improved overall image quality (3.35 ± 0.85 vs. 2.59 ± 0.59, P sampling technique improved the quality and reduced respiratory motion artifacts in young children compared with conventional respiratory-triggered turbo spin-echo sequences.

  16. Improved abdominal MRI in non-breath-holding children using a radial k-space sampling technique

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jong Hyuk; Choi, Young Hun; Cheon, Jung Eun; Lee, So Mi; Cho, Hyun Hae; Kim, Woo Sun; Kim, In One [Seoul National University Children' s Hospital, Department of Radiology, Seoul (Korea, Republic of); Shin, Su Mi [SMG-SNU Boramae Medical Center, Department of Radiology, Seoul (Korea, Republic of)

    2015-06-15

    Radial k-space sampling techniques have been shown to reduce motion artifacts in adult abdominal MRI. To compare a T2-weighted radial k-space sampling MRI pulse sequence (BLADE) with standard respiratory-triggered T2-weighted turbo spin echo (TSE) in pediatric abdominal imaging. Axial BLADE and respiratory-triggered turbo spin echo sequences were performed without fat suppression in 32 abdominal MR examinations in children. We retrospectively assessed overall image quality, the presence of respiratory, peristaltic and radial artifact, and lesion conspicuity. We evaluated signal uniformity of each sequence. BLADE showed improved overall image quality (3.35 ± 0.85 vs. 2.59 ± 0.59, P < 0.001), reduced respiratory motion artifact (0.51 ± 0.56 vs. 1.89 ± 0.68, P < 0.001), and improved lesion conspicuity (3.54 ± 0.88 vs. 2.92 ± 0.77, P = 0.006) compared to respiratory triggering turbo spin-echo (TSE) sequences. The bowel motion artifact scores were similar for both sequences (1.65 ± 0.77 vs. 1.79 ± 0.74, P = 0.691). BLADE introduced a radial artifact that was not observed on the respiratory triggering-TSE images (1.10 ± 0.85 vs. 0, P < 0.001). BLADE was associated with diminished signal variation compared with respiratory triggering-TSE in the liver, spleen and air (P < 0.001). The radial k-space sampling technique improved the quality and reduced respiratory motion artifacts in young children compared with conventional respiratory-triggered turbo spin-echo sequences. (orig.)

  17. Breathing adapted radiotherapy for breast cancer: comparison of free breathing gating with the breath-hold technique

    DEFF Research Database (Denmark)

    Korreman, Stine Sofia; Pedersen, Anders N; Nøttrup, Trine Jakobi;

    2005-01-01

    -hold (EBH). The Varian Real-time Position Management system (RPM) was used to monitor respiratory movement and to gate the scanner. For each breathing phase, a population based internal margin (IM) was estimated based on average chest wall excursion, and incorporated into an individually optimised three...

  18. A segmented K-space velocity mapping protocol for quantification of renal artery blood flow during breath-holding

    DEFF Research Database (Denmark)

    Thomsen, C; Cortsen, M; Söndergaard, L

    1995-01-01

    methods showed sufficient robustness toward complex flow in a phantom model. In comparison with the ECG technique, the segmentation technique reduced vessel blurring and pulsatility artifacts caused by respiratory motion, and average flow values obtained in vivo in the left renal artery agreed between...

  19. FAST: FAST Analysis of Sequences Toolbox.

    Science.gov (United States)

    Lawrence, Travis J; Kauffman, Kyle T; Amrine, Katherine C H; Carper, Dana L; Lee, Raymond S; Becich, Peter J; Canales, Claudia J; Ardell, David H

    2015-01-01

    FAST (FAST Analysis of Sequences Toolbox) provides simple, powerful open source command-line tools to filter, transform, annotate and analyze biological sequence data. Modeled after the GNU (GNU's Not Unix) Textutils such as grep, cut, and tr, FAST tools such as fasgrep, fascut, and fastr make it easy to rapidly prototype expressive bioinformatic workflows in a compact and generic command vocabulary. Compact combinatorial encoding of data workflows with FAST commands can simplify the documentation and reproducibility of bioinformatic protocols, supporting better transparency in biological data science. Interface self-consistency and conformity with conventions of GNU, Matlab, Perl, BioPerl, R, and GenBank help make FAST easy and rewarding to learn. FAST automates numerical, taxonomic, and text-based sorting, selection and transformation of sequence records and alignment sites based on content, index ranges, descriptive tags, annotated features, and in-line calculated analytics, including composition and codon usage. Automated content- and feature-based extraction of sites and support for molecular population genetic statistics make FAST useful for molecular evolutionary analysis. FAST is portable, easy to install and secure thanks to the relative maturity of its Perl and BioPerl foundations, with stable releases posted to CPAN. Development as well as a publicly accessible Cookbook and Wiki are available on the FAST GitHub repository at https://github.com/tlawrence3/FAST. The default data exchange format in FAST is Multi-FastA (specifically, a restriction of BioPerl FastA format). Sanger and Illumina 1.8+ FastQ formatted files are also supported. FAST makes it easier for non-programmer biologists to interactively investigate and control biological data at the speed of thought.

  20. FAST: FAST Analysis of Sequences Toolbox

    Directory of Open Access Journals (Sweden)

    Travis J. Lawrence

    2015-05-01

    Full Text Available FAST (FAST Analysis of Sequences Toolbox provides simple, powerful open source command-line tools to filter, transform, annotate and analyze biological sequence data. Modeled after the GNU (GNU’s Not Unix Textutils such as grep, cut, and tr, FAST tools such as fasgrep, fascut, and fastr make it easy to rapidly prototype expressive bioinformatic workflows in a compact and generic command vocabulary. Compact combinatorial encoding of data workflows with FAST commands can simplify the documentation and reproducibility of bioinformatic protocols, supporting better transparency in biological data science. Interface self-consistency and conformity with conventions of GNU, Matlab, Perl, BioPerl, R and GenBank help make FAST easy and rewarding to learn. FAST automates numerical, taxonomic, and text-based sorting, selection and transformation of sequence records and alignment sites based on content, index ranges, descriptive tags, annotated features, and in-line calculated analytics, including composition and codon usage. Automated content- and feature-based extraction of sites and support for molecular population genetic statistics makes FAST useful for molecular evolutionary analysis. FAST is portable, easy to install and secure thanks to the relative maturity of its Perl and BioPerl foundations, with stable releases posted to CPAN. Development as well as a publicly accessible Cookbook and Wiki are available on the FAST GitHub repository at https://github.com/tlawrence3/FAST. The default data exchange format in FAST is Multi-FastA (specifically, a restriction of BioPerl FastA format. Sanger and Illumina 1.8+ FastQ formatted files are also supported. FAST makes it easier for non-programmer biologists to interactively investigate and control biological data at the speed of thought.

  1. Faster pediatric 3-T abdominal magnetic resonance imaging: comparison between conventional and variable refocusing flip-angle single-shot fast spin-echo sequences

    Energy Technology Data Exchange (ETDEWEB)

    Ruangwattanapaisarn, Nichanan [Mahidol University, Department of Diagnostic and Therapeutic Radiology, Ramathibodi Hospital, Bangkok (Thailand); Stanford University, LPCH Department of Radiology, Stanford, CA (United States); Loening, Andreas M.; Saranathan, Manojkumar; Vasanawala, Shreyas S. [Stanford University, LPCH Department of Radiology, Stanford, CA (United States); Litwiller, Daniel V. [GE Healthcare, Rochester, MN (United States)

    2015-06-15

    Single-shot fast spin echo (SSFSE) is particularly appealing in pediatric patients because of its motion robustness. However radiofrequency energy deposition at 3 tesla forces long pauses between slices, leading to longer scans, longer breath-holds and more between-slice motion. We sought to learn whether modulation of the SSFSE refocusing flip-angle train could reduce radiofrequency energy deposition without degrading image quality, thereby reducing inter-slice pauses and overall scan times. We modulated the refocusing flip-angle train for SSFSE to minimize energy deposition while minimizing blurring and motion-related signal loss. In a cohort of 50 consecutive patients (25 boys, mean age 5.5 years, range 1 month to 17 years) referred for abdominal MRI we obtained standard SSFSE and variable refocusing flip-angle (vrfSSFSE) images and recorded sequence scan times. Two readers independently scored the images in blinded, randomized order for noise, tissue contrast, sharpness, artifacts and left lobe hepatic signal uniformity on a four-point scale. The null hypothesis of no difference between SSFSE and vrfSSFSE image-quality was assessed with a Mann-Whitney U test, and the null hypothesis of no scan time difference was assessed with the paired t-test. SSFSE and vrfSSFSE mean acquisition times were 54.3 and 26.2 s, respectively (P-value <0.0001). For each reader, SSFSE and vrfSSFSE noise, tissue contrast, sharpness and artifacts were not significantly different (P-values 0.18-0.86). However, SSFSE had better left lobe hepatic signal uniformity (P < 0.01, both readers). vrfSSFSE is twice as fast as SSFSE, with equivalent image quality with the exception of left hepatic lobe signal heterogeneity. (orig.)

  2. HCUP Fast Stats

    Data.gov (United States)

    U.S. Department of Health & Human Services — HCUP Fast Stats provides easy access to the latest HCUP-based statistics for health information topics. HCUP Fast Stats uses visual statistical displays in...

  3. Fast food (image)

    Science.gov (United States)

    Fast foods are quick, reasonably priced, and readily available alternatives to home cooking. While convenient and economical for a busy lifestyle, fast foods are typically high in calories, fat, saturated ...

  4. Fast food tips (image)

    Science.gov (United States)

    ... challenge to eat healthy when going to a fast food place. In general, avoiding items that are deep ... challenge to eat healthy when going to a fast food place. In general, avoiding items that are deep ...

  5. Is fast food addictive?

    Science.gov (United States)

    Garber, Andrea K; Lustig, Robert H

    2011-09-01

    Studies of food addiction have focused on highly palatable foods. While fast food falls squarely into that category, it has several other attributes that may increase its salience. This review examines whether the nutrients present in fast food, the characteristics of fast food consumers or the presentation and packaging of fast food may encourage substance dependence, as defined by the American Psychiatric Association. The majority of fast food meals are accompanied by a soda, which increases the sugar content 10-fold. Sugar addiction, including tolerance and withdrawal, has been demonstrated in rodents but not humans. Caffeine is a "model" substance of dependence; coffee drinks are driving the recent increase in fast food sales. Limited evidence suggests that the high fat and salt content of fast food may increase addictive potential. Fast food restaurants cluster in poorer neighborhoods and obese adults eat more fast food than those who are normal weight. Obesity is characterized by resistance to insulin, leptin and other hormonal signals that would normally control appetite and limit reward. Neuroimaging studies in obese subjects provide evidence of altered reward and tolerance. Once obese, many individuals meet criteria for psychological dependence. Stress and dieting may sensitize an individual to reward. Finally, fast food advertisements, restaurants and menus all provide environmental cues that may trigger addictive overeating. While the concept of fast food addiction remains to be proven, these findings support the role of fast food as a potentially addictive substance that is most likely to create dependence in vulnerable populations.

  6. Ramadan, fasting and pregnancy

    DEFF Research Database (Denmark)

    Ahmed, Urfan Zahoor; Lykke, Jacob Alexander

    2014-01-01

    In Islam, the month of Ramadan is a period of fasting lasting 29 or 30 days. Epidemiological studies among Muslims in Denmark have not been conducted, but studies show, that fasting among pregnant Muslim women is common. Fasting does not increase the risk of growth restriction or preterm delivery......, but there are reports of decreased foetal movements. Furthermore, the fasting may have long-term health consequences for the offspring, especially when they reach their middle age. According to Islam and the interpretation, pregnant and breast-feeding women are allowed to postpone the fasting of the month of Ramadan...

  7. Integrative Physiology of Fasting.

    Science.gov (United States)

    Secor, Stephen M; Carey, Hannah V

    2016-03-15

    Extended bouts of fasting are ingrained in the ecology of many organisms, characterizing aspects of reproduction, development, hibernation, estivation, migration, and infrequent feeding habits. The challenge of long fasting episodes is the need to maintain physiological homeostasis while relying solely on endogenous resources. To meet that challenge, animals utilize an integrated repertoire of behavioral, physiological, and biochemical responses that reduce metabolic rates, maintain tissue structure and function, and thus enhance survival. We have synthesized in this review the integrative physiological, morphological, and biochemical responses, and their stages, that characterize natural fasting bouts. Underlying the capacity to survive extended fasts are behaviors and mechanisms that reduce metabolic expenditure and shift the dependency to lipid utilization. Hormonal regulation and immune capacity are altered by fasting; hormones that trigger digestion, elevate metabolism, and support immune performance become depressed, whereas hormones that enhance the utilization of endogenous substrates are elevated. The negative energy budget that accompanies fasting leads to the loss of body mass as fat stores are depleted and tissues undergo atrophy (i.e., loss of mass). Absolute rates of body mass loss scale allometrically among vertebrates. Tissues and organs vary in the degree of atrophy and downregulation of function, depending on the degree to which they are used during the fast. Fasting affects the population dynamics and activities of the gut microbiota, an interplay that impacts the host's fasting biology. Fasting-induced gene expression programs underlie the broad spectrum of integrated physiological mechanisms responsible for an animal's ability to survive long episodes of natural fasting.

  8. FAST User Guide

    Science.gov (United States)

    Walatka, Pamela P.; Clucas, Jean; McCabe, R. Kevin; Plessel, Todd; Potter, R.; Cooper, D. M. (Technical Monitor)

    1994-01-01

    The Flow Analysis Software Toolkit, FAST, is a software environment for visualizing data. FAST is a collection of separate programs (modules) that run simultaneously and allow the user to examine the results of numerical and experimental simulations. The user can load data files, perform calculations on the data, visualize the results of these calculations, construct scenes of 3D graphical objects, and plot, animate and record the scenes. Computational Fluid Dynamics (CFD) visualization is the primary intended use of FAST, but FAST can also assist in the analysis of other types of data. FAST combines the capabilities of such programs as PLOT3D, RIP, SURF, and GAS into one environment with modules that share data. Sharing data between modules eliminates the drudgery of transferring data between programs. All the modules in the FAST environment have a consistent, highly interactive graphical user interface. Most commands are entered by pointing and'clicking. The modular construction of FAST makes it flexible and extensible. The environment can be custom configured and new modules can be developed and added as needed. The following modules have been developed for FAST: VIEWER, FILE IO, CALCULATOR, SURFER, TOPOLOGY, PLOTTER, TITLER, TRACER, ARCGRAPH, GQ, SURFERU, SHOTET, and ISOLEVU. A utility is also included to make the inclusion of user defined modules in the FAST environment easy. The VIEWER module is the central control for the FAST environment. From VIEWER, the user can-change object attributes, interactively position objects in three-dimensional space, define and save scenes, create animations, spawn new FAST modules, add additional view windows, and save and execute command scripts. The FAST User Guide uses text and FAST MAPS (graphical representations of the entire user interface) to guide the user through the use of FAST. Chapters include: Maps, Overview, Tips, Getting Started Tutorial, a separate chapter for each module, file formats, and system

  9. An Improved Susceptibility Weighted Imaging Method using Multi-Echo Acquisition

    Science.gov (United States)

    Oh, Sung Suk; Oh, Se-Hong; Nam, Yoonho; Han, Dongyeob; Stafford, Randall B.; Hwang, Jinyoung; Kim, Dong-Hyun; Park, HyunWook; Lee, Jongho

    2013-01-01

    Purpose To introduce novel acquisition and post-processing approaches for susceptibility weighted imaging (SWI) to remove background field inhomogeneity artifacts in both magnitude and phase data. Method The proposed method acquires three echoes in a 3D gradient echo (GRE) sequence, with a field compensation gradient (z-shim gradient) applied to the third echo. The artifacts in the magnitude data are compensated by signal estimation from all three echoes. The artifacts in phase signals are removed by modeling the background phase distortions using Gaussians. The method was applied in vivo and compared with conventional SWI. Results The method successfully compensates for background field inhomogeneity artifacts in magnitude and phase images, and demonstrated improved SWI images. In particular, vessels in frontal lobe, which were not observed in conventional SWI, were identified in the proposed method. Conclusion The new method improves image quality in SWI by restoring signal in the frontal and temporal regions. PMID:24105838

  10. Referenceless PRF thermometry with multi-echo processing to monitor prostate ablation

    Science.gov (United States)

    Rieke, Viola; Kinsey, Adam M.; Nau, William H.; Diederich, Chris J.; Sommer, Graham; Pauly, Kim Butts

    2007-05-01

    Referenceless proton resonance frequency (PRF) shift thermometry provides a means to measure temperature changes during minimally invasive thermotherapy that is inherently robust to motion and tissue displacement. An extension to the referenceless method allows temperature estimation in the presence of phase discontinuities that occur at water/fat interfaces between prostate and periprostatic fat. Three images at different echo times are acquired and binary water and fat maps are generated from a Dixon reconstruction. For the background phase estimation, water and fat regions are treated separately and the phase offset between the two tissue types is determined. Here we present a new pulse sequence to acquire the necessary three images, which allows for temperature monitoring of the prostate with increased temporal resolution, optimal temperature resolution with respect to heating pattern of transurethral US applicators, and provides high resolution anatomical images. The method is demonstrated during in vivo thermal ablation of canine prostate.

  11. Fast growth in control

    NARCIS (Netherlands)

    Z. Rico (Zulay)

    2009-01-01

    textabstractThe focus of this paper is on the influence of the fast growth of organizations on the design process of management control systems. What are the management accounting and control problems that a fast growth organization encounters that can be ascribed to this growth. What are the circum

  12. Fast protein folding kinetics

    Science.gov (United States)

    Gelman, Hannah; Gruebele, Martin

    2014-01-01

    Fast folding proteins have been a major focus of computational and experimental study because they are accessible to both techniques: they are small and fast enough to be reasonably simulated with current computational power, but have dynamics slow enough to be observed with specially developed experimental techniques. This coupled study of fast folding proteins has provided insight into the mechanisms which allow some proteins to find their native conformation well less than 1 ms and has uncovered examples of theoretically predicted phenomena such as downhill folding. The study of fast folders also informs our understanding of even “slow” folding processes: fast folders are small, relatively simple protein domains and the principles that govern their folding also govern the folding of more complex systems. This review summarizes the major theoretical and experimental techniques used to study fast folding proteins and provides an overview of the major findings of fast folding research. Finally, we examine the themes that have emerged from studying fast folders and briefly summarize their application to protein folding in general as well as some work that is left to do. PMID:24641816

  13. Ramadan, faste og graviditet

    DEFF Research Database (Denmark)

    Ahmed, Urfan Zahoor; Lykke, Jacob Alexander

    2014-01-01

    , but there are reports of decreased foetal movements. Furthermore, the fasting may have long-term health consequences for the offspring, especially when they reach their middle age. According to Islam and the interpretation, pregnant and breast-feeding women are allowed to postpone the fasting of the month of Ramadan...

  14. Fast protein folding kinetics.

    Science.gov (United States)

    Gelman, Hannah; Gruebele, Martin

    2014-05-01

    Fast-folding proteins have been a major focus of computational and experimental study because they are accessible to both techniques: they are small and fast enough to be reasonably simulated with current computational power, but have dynamics slow enough to be observed with specially developed experimental techniques. This coupled study of fast-folding proteins has provided insight into the mechanisms, which allow some proteins to find their native conformation well fast folders also informs our understanding of even 'slow' folding processes: fast folders are small; relatively simple protein domains and the principles that govern their folding also govern the folding of more complex systems. This review summarizes the major theoretical and experimental techniques used to study fast-folding proteins and provides an overview of the major findings of fast-folding research. Finally, we examine the themes that have emerged from studying fast folders and briefly summarize their application to protein folding in general, as well as some work that is left to do.

  15. Fast ejendom III

    DEFF Research Database (Denmark)

    Munk-Hansen, Carsten

    Bogen er det tredje bind af tre planlagte bind om fast ejendom: I Overdragelsen, II Bolighandlen og III Ejerbeføjelsen. Fremstillingens giver et grundigt overblik over centrale områder af en omfattende regulering af fast ejendom, med angivelse af litteratur, hvor læseren kan søge yderligere...... oplysning. En ejer af fast ejendom er på særdeles mange områder begrænset i sin råden sammenlignet med ejeren af et formuegode i almindelighed. Fremstillingen tager udgangspunkt i ejerens perspektiv (fremfor samfundets eller myndighedernes). Både den privatretlige og offentligretlige regulering behandles......, eksempelvis ejendomsdannelsen, servitutter, naboretten, hævd, zoneinddelingen, den fysiske planlægning, beskyttelse af natur, beskyttelse af kultur, forurening fra fast ejendom, erstatning for forurening, jordforurening, ekspropriation, byggeri og adgang til fast ejendom....

  16. Islamic Fasting and Diabetes

    Directory of Open Access Journals (Sweden)

    Fereidoun Azizi

    2013-07-01

    Full Text Available The aim of this article is to review health-related aspects of Ramadan fasting in normal individuals and diabetics. During fasting days of Ramadan, glucose homeostasis is maintained by meal taken bepore dawn and by liver glycogen stores. Changes in serum lipids are variable and defend on the quality and quantity of food consumption and changes in weight. Compliant, well controlled type 2 diabetics may observe Ramadan fasting; but fasting is not recommended for type 1, non complaint, poorly controlled and pregnant diabetics. Although Ramadan fasting is safe for all healthy individuals and well controlled diabetics, those with uncontrolled diabetics and diabetics with complications should consult physicians and follow scientific recommendations.

  17. Fast Spectrum Reactors

    CERN Document Server

    Todd, Donald; Tsvetkov, Pavel

    2012-01-01

    Fast Spectrum Reactors presents a detailed overview of world-wide technology contributing to the development of fast spectrum reactors. With a unique focus on the capabilities of fast spectrum reactors to address nuclear waste transmutation issues, in addition to the well-known capabilities of breeding new fuel, this volume describes how fast spectrum reactors contribute to the wide application of nuclear power systems to serve the global nuclear renaissance while minimizing nuclear proliferation concerns. Readers will find an introduction to the sustainable development of nuclear energy and the role of fast reactors, in addition to an economic analysis of nuclear reactors. A section devoted to neutronics offers the current trends in nuclear design, such as performance parameters and the optimization of advanced power systems. The latest findings on fuel management, partitioning and transmutation include the physics, efficiency and strategies of transmutation, homogeneous and heterogeneous recycling, in addit...

  18. FAST Construction Progress

    Science.gov (United States)

    Nan, R. D.; Zhang, H. Y.; Zhang, Y.; Yang, L.; Cai, W. J.; Liu, N.; Xie, J. T.; Zhang, S. X.

    2016-11-01

    The Five-hundred-meter Aperture Spherical radio Telescope (FAST) is a Chinese mega-science project to build the largest single dish radio telescope in the world. A unique karst depression in Guizhou province has been selected as the site to build an active reflector radio telescope with a diameter of 500 m and three outstanding aspects, which enables FAST to have a large sky coverage and the ability of observing astronomical targets with a high precision. Chinese Academy of Sciences and Guizhou province are in charge of FAST construction. The first light of the telescope was expected on September 25, 2016.

  19. Fast Breeder Reactor studies

    Energy Technology Data Exchange (ETDEWEB)

    Till, C.E.; Chang, Y.I.; Kittel, J.H.; Fauske, H.K.; Lineberry, M.J.; Stevenson, M.G.; Amundson, P.I.; Dance, K.D.

    1980-07-01

    This report is a compilation of Fast Breeder Reactor (FBR) resource documents prepared to provide the technical basis for the US contribution to the International Nuclear Fuel Cycle Evaluation. The eight separate parts deal with the alternative fast breeder reactor fuel cycles in terms of energy demand, resource base, technical potential and current status, safety, proliferation resistance, deployment, and nuclear safeguards. An Annex compares the cost of decommissioning light-water and fast breeder reactors. Separate abstracts are included for each of the parts.

  20. Gas cooled fast reactor

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1972-06-01

    Although most of the development work on fast breeder reactors has been devoted to the use of liquid metal cooling, interest has been expressed for a number of years in alternative breeder concepts using other coolants. One of a number of concepts in which interest has been retained is the Gas-Cooled Fast Reactor (GCFR). As presently envisioned, it would operate on the uranium-plutonium mixed oxide fuel cycle, similar to that used in the Liquid Metal Fast Breeder Reactor (LMFBR), and would use helium gas as the coolant.

  1. FAST joins Breakthrough programme

    Science.gov (United States)

    Banks, Michael

    2016-11-01

    The 180m Five-hundred-meter Aperture Spherical radio Telescope (FAST) - the world's largest single-aperture radio receiver - has become part of the Breakthrough Listen programme, which launched in July 2015 to look for intelligent life beyond Earth.

  2. CMS Fast Facts

    Data.gov (United States)

    U.S. Department of Health & Human Services — CMS has developed a new quick reference statistical summary on annual CMS program and financial data. CMS Fast Facts includes summary information on total program...

  3. FAST Maser Surveys

    Indian Academy of Sciences (India)

    J. S. Zhang

    2014-09-01

    FAST, the Five-hundred meter Aperture Spherical radio Telescope, will become the largest operating single-dish telescope in the coming years. It has many advantages: much better sensitivity for its largest collecting area; large sky coverage due to its innovative design of the active primary surface; extremely radio quiet from its unique location, etc. In this work, I will highlight the future capabilities of FAST to discover and observe both galactic and extragalactic masers.

  4. Fasting and Urinary Stones

    Directory of Open Access Journals (Sweden)

    Ali Shamsa

    2013-11-01

    Full Text Available Introduction: Fasting is considered as one of the most important practices of Islam, and according to Prophet Mohammad, fasting is obligatory upon Muslims. The aim of this study is to evaluate the effects of fasting on urinary stones. Materials and Methods: Very few studies have been carried out on urinary stones and the effect of Ramadan fasting. The sources of the present study are Medline and articles presented by local and Muslim researchers. Meanwhile, since we are acquainted with three well-known researchers in the field of urology, we contacted them via email and asked for their professional opinions. Results: The results of studies about the relationship of urinary stones and their incidence in Ramadan are not alike, and are even sometimes contradictory. Some believe that increased incidence of urinary stones in Ramadan is related not to fasting, but to the rise of weather temperature in hot months, and an increase in humidity. Conclusion: Numerous biological and behavioral changes occur in people who fast in Ramadan and some researchers believe that urinary stone increases during this month.

  5. Fasting and urinary stones

    Directory of Open Access Journals (Sweden)

    Ali Shamsa

    2013-12-01

    Full Text Available Introduction: Fasting is considered as one of the most important practices of Islam, and according to Prophet Mohammad, fasting is obligatory upon Muslims. The aim of this study is to evaluate the effects of fasting on urinary stones. Materials and Methods:Very few studies have been carried out on urinary stones and the effect of Ramadan fasting. The sources of the present study are Medline and articles presented by local and Muslim researchers. Meanwhile, since we are acquainted with three well-known researchers in the field  of urology, we contacted them via email and asked for their professional opinions. Results:The results of studies about the relationship of urinary stones and their incidence in Ramadan are not alike, and are even sometimes contradictory. Some believe that increased incidence of urinary stones in Ramadan is related not to fasting, but to the rise of weather temperature in hot months, and an increase in humidity. Conclusion: Numerous biological and behavioral changes occur in people who fast in Ramadan and some researchers believe that urinary stone increases during this month.

  6. Effect of gadoxetic acid on quantification of hepatic steatosis using magnetic resonance spectroscopy: A prospective study

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Ju Won; Kim, Sung Mo; Heo, Sook Hee; Kim, Jin Woong; Jeong, Yong Yeon; Kang, Heoung Keun [Dept. of Radiology, Chonnam National University Hwasun Hospital, Hwasun (Korea, Republic of); Jeong, Gwang Woo; Shin, Sang Soo [Dept. of Radiology, Chonnam National University Hospital, Gwangju (Korea, Republic of)

    2017-04-15

    We prospectively evaluated whether gadoxetic acid (Gd-EOB-DTPA) administration for liver magnetic resonance (MR) imaging affects the quantification of hepatic steatosis using MR spectroscopy (MRS). A total of 155 patients were included, who underwent gadoxetic acid-enhanced liver MR imaging and MRS during a 5-month period. Fast breath-hold high-speed T2-corrected multi-echo MRS was used before, and 20 min after, gadoxetic acid injection. The same location was maintained in the pre-contrast and post-contrast MRS. Changes in the fat fraction (FF) were compared between the pre- and post-contrast MRS using a paired t-test. The change in FF between cirrhotic and non-cirrhotic patients was compared using an independent t-test. In cirrhotic patients, the correlation between FF change and biochemical marker using Pearson's correlation test, was evaluated. The mean FF in the post-contrast MRS (5.05 ± 5.26%) was significantly higher than in the pre-contrast MRS (4.77 ± 0.57%) (p < 0.000). The FF change between pre-contrast and post-contrast MRS was significantly higher in non-cirrhotic patients (0.41 ± 0.77%) than in cirrhotic patients (0.14 ± 0.59) (p = 0.010). Albumin and alkaline phosphatase shows weak correlation with FF change (both p < 0.02). Gadoxetic acid affects the quantification of hepatic steatosis by MRS. Hence, MRS should be performed before gadoxetic acid injection, particularly in non-cirrhotic patients.

  7. CAIPIRINHA-Dixon-TWIST (CDT)-volume-interpolated breath-hold examination (VIBE) for dynamic liver imaging: Comparison of gadoterate meglumine, gadobutrol and gadoxetic acid

    Energy Technology Data Exchange (ETDEWEB)

    Budjan, Johannes, E-mail: Johannes.Budjan@umm.de [Institute of Clinical Radiology and Nuclear Medicine, University Medical Center Mannheim, Medical Faculty Mannheim—Heidelberg University, Mannheim (Germany); Ong, Melissa; Riffel, Philipp [Institute of Clinical Radiology and Nuclear Medicine, University Medical Center Mannheim, Medical Faculty Mannheim—Heidelberg University, Mannheim (Germany); Morelli, John N. [Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD (United States); Michaely, Henrik J.; Schoenberg, Stefan O.; Haneder, Stefan [Institute of Clinical Radiology and Nuclear Medicine, University Medical Center Mannheim, Medical Faculty Mannheim—Heidelberg University, Mannheim (Germany)

    2014-11-15

    Highlights: • We examined the influence of different clinically used contrast agents on the image quality of a new sequence called CDT-VIBE for dynamic MRI of the liver. • CDT-VIBE is a robust sequence for clinical routine as it provides good image quality regardless of the utilized contrast agent. • In average, more than 3 hepatic arterial dominant phases are acquired with the CDT-VIBE sequence regardless of the contrast agent. - Abstract: Purpose: CAIPIRINHA-Dixon-TWIST (CDT)-VIBE is a robust method for abdominal magnetic resonance imaging providing both high spatial and high temporal resolution. The purpose of this study was to examine the influence of different gadolinium based contrast agents (GBCA) on image quality (IQ) with CDT-VIBE. Materials and methods: In this IRB-approved, retrospective, inter-individual comparison study, 86 patients scanned at 3T were included. Within 28 s, 14 high-resolution 3D datasets were acquired using CDT-VIBE. 37 patients received 0.1 mmol/kg gadoterate meglumine, 28 patients 0.1 mmol/kg gadobutrol, and 19 patients 0.1 mL/kg gadoxetic acid. Two blinded, board-certified radiologists assessed the image quality on a 5 point scale, as well as the number of hepatic arterial dominant (HAD) phases. Results: Regardless of the GBCA utilized, CDT-VIBE resulted in good IQ in terms of best IQ achieved among all 14 datasets (gadobutrol 4.3, gadoterate meglumine 3.9, gadoxetic acid 3.7). With respect to worst IQ, the three groups showed statistically significant differences with gadobutrol receiving the highest rating (3.6) and gadoxetic acid the lowest (2.4) (gadoterate meglumine 3.0; 0.0014 < p < 0.0485). No statistically significant differences were found in the mean number of acquired HAD phases (gadobutrol 3.4, gadoterate meglumine 3.9, gadoxetic acid 3.1; 0.18 < p < 0.57). Conclusion: Different gadolinium-based contrast agents can be utilized for dynamic liver imaging with CDT-VIBE resulting in good image quality.

  8. Adaptation requirements due to anatomical changes in free-breathing and deep-inspiration breath-hold for standard and dose-escalated radiotherapy of lung cancer patients

    DEFF Research Database (Denmark)

    Sibolt, Patrik; Ottosson, Wiviann; Sjöström, David

    2015-01-01

    to investigate the need for adaptation due to anatomical changes, for both standard (ST) and DE plans in free-breathing (FB) and DIBH. Material and methods. The effect of tumor shrinkage (TS), pleural effusion (PE) and atelectasis was investigated for patients and for a CIRS thorax phantom. Sixteen patients were...... and had no effect for DIBH. Conclusion. Phantom simulations provided potential adaptation action levels for PE and TS. For the more complex patient geometry, individual assessment of the dosimetric impact is recommended for both ST and DE plans in DIBH as well as in FB. However, DIBH was found...

  9. The fast code

    Energy Technology Data Exchange (ETDEWEB)

    Freeman, L.N.; Wilson, R.E. [Oregon State Univ., Dept. of Mechanical Engineering, Corvallis, OR (United States)

    1996-09-01

    The FAST Code which is capable of determining structural loads on a flexible, teetering, horizontal axis wind turbine is described and comparisons of calculated loads with test data are given at two wind speeds for the ESI-80. The FAST Code models a two-bladed HAWT with degrees of freedom for blade bending, teeter, drive train flexibility, yaw, and windwise and crosswind tower motion. The code allows blade dimensions, stiffnesses, and weights to differ and models tower shadow, wind shear, and turbulence. Additionally, dynamic stall is included as are delta-3 and an underslung rotor. Load comparisons are made with ESI-80 test data in the form of power spectral density, rainflow counting, occurrence histograms, and azimuth averaged bin plots. It is concluded that agreement between the FAST Code and test results is good. (au)

  10. A fast friend

    Institute of Scientific and Technical Information of China (English)

    高怡

    2010-01-01

    我们都知道fast food的意思是“快餐”。那fast friend能解释为“快速或速成的朋友”吗?也许你会说:“什么是速成朋友呀?It doesn’t make sense.”没错,交朋友怎么会有速成的呢?原来;fast还有一个意思是“忠实的、牢固的”,所以a fast friend的真正意思是“可靠、忠实的朋友”。

  11. Fast Distributed Gradient Methods

    CERN Document Server

    Jakovetic, Dusan; Moura, Jose M F

    2011-01-01

    The paper proposes new fast distributed optimization gradient methods and proves convergence to the exact solution at rate O(\\log k/k), much faster than existing distributed optimization (sub)gradient methods with convergence O(1/\\sqrt{k}), while incurring practically no additional communication nor computation cost overhead per iteration. We achieve this for convex (with at least one strongly convex,) coercive, three times differentiable and with Lipschitz continuous first derivative (private) cost functions. Our work recovers for distributed optimization similar convergence rate gains obtained by centralized Nesterov gradient and fast iterative shrinkage-thresholding algorithm (FISTA) methods over ordinary centralized gradient methods. We also present a constant step size distributed fast gradient algorithm for composite non-differentiable costs. A simulation illustrates the effectiveness of our distributed methods.

  12. Fast ejendom II

    DEFF Research Database (Denmark)

    Munk-Hansen, Carsten

    Fremstillingen påviser, at lov om forbrugerbeskyttelse ved erhvervelse af fast ejendom mv. lider af en række svagheder og at ankenævnspraksis bevæger sig væk fra retspraksis på en række områder.......Fremstillingen påviser, at lov om forbrugerbeskyttelse ved erhvervelse af fast ejendom mv. lider af en række svagheder og at ankenævnspraksis bevæger sig væk fra retspraksis på en række områder....

  13. Moms og fast ejendom

    DEFF Research Database (Denmark)

    Edlund, Hans Henrik

    1999-01-01

    I artiklen gives et overblik over, hvorledes fast ejendom behandles momsmæssigt. Derfor findes en kort skitsering af reglerne for moms på byggearbejder, afgrænsningen mellem momspligtig og momsfri udlejning, muligheden for frivillig registrering af udlejning samt opgørelse af reguleringsforpligte......I artiklen gives et overblik over, hvorledes fast ejendom behandles momsmæssigt. Derfor findes en kort skitsering af reglerne for moms på byggearbejder, afgrænsningen mellem momspligtig og momsfri udlejning, muligheden for frivillig registrering af udlejning samt opgørelse af...

  14. Fast Josephson vortex

    Energy Technology Data Exchange (ETDEWEB)

    Malishevskii, A.S.; Silin, V.P.; Uryupin, S.A

    2002-12-30

    For the magnetically coupled waveguide and long Josephson junction we gave the analytic description of two separate velocity domains where the free motion of traveling vortex (2{pi}-kink) exists. The role of the mutual influence of waveguide and long Josephson junction is discussed. It is shown the possibility of the fast vortex motion with the velocity much larger than Swihart velocity of Josephson junction and close to the speed of light in the waveguide. The excitation of motion of such fast Josephson vortex is described.

  15. ATLAS fast physics monitoring

    Indian Academy of Sciences (India)

    Karsten Köneke; on behalf of the ATLAS Collaboration

    2012-11-01

    The ATLAS experiment at the Large Hadron Collider is recording data from proton–proton collisions at a centre-of-mass energy of 7 TeV since the spring of 2010. The integrated luminosity has grown nearly exponentially since then and continues to rise fast. The ATLAS Collaboration has set up a framework to automatically process the rapidly growing dataset and produce performance and physics plots for the most interesting analyses. The system is designed to give fast feedback. The histograms are produced within hours of data reconstruction (2–3 days after data taking). Hints of potentially interesting physics signals obtained this way are followed up by physics groups.

  16. Handel med fast ejendom

    DEFF Research Database (Denmark)

    Edlund, Hans Henrik

    Bogen tilstræber at give et overblik over nogle af de vigtigste generelle problemområder på markedet for ejendomshandel, der jo bliver mere og mere kompliceret. Værket er opdelt i følgende hovedafsnit: Ejendomsbegrebet. Indgåelse af aftale om salg af fast ejendom. Begrænsninger i adgangen til...

  17. Not so fast

    DEFF Research Database (Denmark)

    Marras, Stefano; Noda, Takuji; Steffensen, John Fleng

    2015-01-01

    , it is an open question whether such supposedly very fast swimmers do use high-speed bursts when feeding on evasive prey, in addition to using their bill for slashing prey. Here, we measured the swimming behavior of sailfish by using high-frequency accelerometry and high-speed video observations during predator...

  18. Fast Passenger Tracks Network

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    China’s fast passenger tracks network consists of four parts:express rail- way with speeds between 300km/h and 350 kin/h,passenger rail lines with speeds between 200 km/h and 250 km/h,intercity high-speed railways that run

  19. Integral Fast Reactor concept

    Energy Technology Data Exchange (ETDEWEB)

    Till, C.E.; Chang, Y.I.

    1986-01-01

    The Integral Fast Reactor (IFR) is an innovative LMR concept, being developed at Argonne National Laboratory, that fully exploits the inherent properties of liquid metal cooling and metallic fuel to achieve breakthroughs in economics and inherent safety. This paper describes key features and potential advantages of the IFR concept, technology development status, fuel cycle economics potential, and future development path.

  20. Fast Air Temperature Sensors

    DEFF Research Database (Denmark)

    Hendricks, Elbert

    1998-01-01

    The note documents briefly work done on a newly developed sensor for making fast temperature measurements on the air flow in the intake ports of an SI engine and in the EGR input line. The work reviewed has been carried out in close cooperation with Civ. Ing. Michael Føns, the author (IAU...

  1. Parallel Fast Legendre Transform

    NARCIS (Netherlands)

    Alves de Inda, M.; Bisseling, R.H.; Maslen, D.K.

    2001-01-01

    We discuss a parallel implementation of a fast algorithm for the discrete polynomial Legendre transform We give an introduction to the DriscollHealy algorithm using polynomial arithmetic and present experimental results on the eciency and accuracy of our implementation The algorithms were implemente

  2. Foinaven fast track flowlines

    Energy Technology Data Exchange (ETDEWEB)

    Taylor, L.H.; Mair, J.

    1996-12-31

    The decision by British Petroleum to develop offshore fields west of the Shetlands in water depths exceeding 500 meters within three and a half years of discovery posed a unique submarine pipeline installation challenge. This paper summarizes the salient features of a fast track program to install a diverless subsea pipeline system using rigid reeled pipe technology in an offshore frontier area.

  3. Fast food tips

    Science.gov (United States)

    ... Order smaller servings when you can. Split some fast-food items to reduce calories and fat. Ask for a "doggy bag." You can also leave the extra food on your plate. Your food choices can teach your children how to eat healthy, too. Choosing a variety ...

  4. Fast Fourier Orthogonalization

    NARCIS (Netherlands)

    Ducas, L.; Prest, T.; Abramov, S.A.; Zima, E.V.; Gao, X-S.

    2016-01-01

    The classical fast Fourier transform (FFT) allows to compute in quasi-linear time the product of two polynomials, in the {\\em circular convolution ring} R[x]/(x^d−1) --- a task that naively requires quadratic time. Equivalently, it allows to accelerate matrix-vector products when the matrix is *circ

  5. Tachycardia | Fast Heart Rate

    Science.gov (United States)

    ... SA) node --- the heart's natural pacemaker - sends out electrical signals faster than usual. The heart rate is fast, but the heart beats properly. Causes of sinus tachycardia A rapid heartbeat may be your body's response to common conditions such as: Fever Anxiety ...

  6. Beyond Fast Mapping

    OpenAIRE

    Carey, Susan

    2010-01-01

    Since the seminal 1957 studies of word learning by Roger Brown, most experimental studies of lexical acquisition have concerned fast mapping: the process through which a new lexical entry is established, and through which representations of the linguistic context of a newly heard word interact with representations of its nonlinguistic context to fix an initial partial meaning. Here I focus on the subsequent extended process through which the adult meaning is approximated. Two factors lead to ...

  7. Fast Radio Bursts

    Indian Academy of Sciences (India)

    Akshaya Rane; Duncan Lorimer

    2017-09-01

    We summarize our current state of knowledge of fast radio bursts (FRBs) which were first discovered a decade ago. Following an introduction to radio transients in general, including pulsars and rotating radio transients, we discuss the discovery of FRBs. We then discuss FRB follow-up observations in the context of repeat bursts before moving on to review propagation effects on FRB signals, FRB progenitor models and an outlook on FRBs as potential cosmological tools.

  8. PHENIX Fast TOF

    Energy Technology Data Exchange (ETDEWEB)

    Soha, Aria [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Chiu, Mickey [Brookhaven National Lab. (BNL), Upton, NY (United States); Mannel, Eric [Brookhaven National Lab. (BNL), Upton, NY (United States); Stoll, Sean [Brookhaven National Lab. (BNL), Upton, NY (United States); Lynch, Don [Brookhaven National Lab. (BNL), Upton, NY (United States); Boose, Steve [Brookhaven National Lab. (BNL), Upton, NY (United States); Northacker, Dave [Brookhaven National Lab. (BNL), Upton, NY (United States); Alfred, Marcus [Howard Univ., Washington, DC (United States); Lindesay, James [Howard Univ., Washington, DC (United States); Chujo, Tatsuya [Univ. of Tsukuba (Japan); Inaba, Motoi [Univ. of Tsukuba (Japan); Nonaka, Toshihiro [Univ. of Tsukuba (Japan); Sato, Wataru [Univ. of Tsukuba (Japan); Sakatani, Ikumi [Univ. of Tsukuba (Japan); Hirano, Masahiro [Univ. of Tsukuba (Japan); Choi, Ihnjea [Univ. of Illinois, Urbana-Champaign, IL (United States)

    2014-01-15

    This is a technical scope of work (TSW) between the Fermi National Accelerator Laboratory (Fermilab) and the experimenters of PHENIX Fast TOF group who have committed to participate in beam tests to be carried out during the FY2014 Fermilab Test Beam Facility program. The goals for this test beam experiment are to verify the timing performance of the two types of time-of-flight detector prototypes.

  9. Fast Air Temperature Sensors

    DEFF Research Database (Denmark)

    Hendricks, Elbert

    1998-01-01

    The note documents briefly work done on a newly developed sensor for making fast temperature measurements on the air flow in the intake ports of an SI engine and in the EGR input line. The work reviewed has been carried out in close cooperation with Civ. Ing. Michael Føns, the author (IAU......) and Spencer C. Sorenson (ET). The theory which decribes in detail the overall dynamic chracteristics of the sensor was developed at IAU, DTU....

  10. ADT fast losses MD

    CERN Document Server

    Priebe, A; Dehning, B; Redaelli, S; Salvachua Ferrando, BM; Sapinski, M; Solfaroli Camillocci, M; Valuch, D

    2013-01-01

    The fast beam losses in the order of 1 ms are expected to be a potential major luminosity limitation for higher beam energies after the LHC long shutdown (LS1). Therefore a Quench Test is planned in the winter 2013 to estimate the quench limit in this timescale and revise the current models. This experiment was devoted to determination the LHC Transverse Damper (ADT) as a system for fast losses induction. A non-standard operation of the ADT was used to develop the beam oscillation instead of suppressing them. The sign flip method had allowed us to create the fast losses within several LHC turns at 450 GeV during the previous test (26th March 2012). Thus, the ADT could be potentially used for the studies of the UFO ("Unidentied Falling Object") impact on the cold magnets. Verification of the system capability and investigations of the disturbed beam properties were the main objectives of this MD. During the experiment, the pilot bunches of proton beam were excited independently in the horizontal and vertical ...

  11. Fast Light Optical Gyroscopes

    Science.gov (United States)

    Smith, David D.

    2015-01-01

    Next-generation space missions are currently constrained by existing spacecraft navigation systems which are not fully autonomous. These systems suffer from accumulated dead-reckoning errors and must therefore rely on periodic corrections provided by supplementary technologies that depend on line-of-sight signals from Earth, satellites, or other celestial bodies for absolute attitude and position determination, which can be spoofed, incorrectly identified, occluded, obscured, attenuated, or insufficiently available. These dead-reckoning errors originate in the ring laser gyros themselves, which constitute inertial measurement units. Increasing the time for standalone spacecraft navigation therefore requires fundamental improvements in gyroscope technologies. One promising solution to enhance gyro sensitivity is to place an anomalous dispersion or fast light material inside the gyro cavity. The fast light essentially provides a positive feedback to the gyro response, resulting in a larger measured beat frequency for a given rotation rate as shown in figure 1. Game Changing Development has been investing in this idea through the Fast Light Optical Gyros (FLOG) project, a collaborative effort which began in FY 2013 between NASA Marshall Space Flight Center (MSFC), the U.S. Army Aviation and Missile Research, Development, and Engineering Center (AMRDEC), and Northwestern University. MSFC and AMRDEC are working on the development of a passive FLOG (PFLOG), while Northwestern is developing an active FLOG (AFLOG). The project has demonstrated new benchmarks in the state of the art for scale factor sensitivity enhancement. Recent results show cavity scale factor enhancements of approx.100 for passive cavities.

  12. Metabolic Effects of Intermittent Fasting.

    Science.gov (United States)

    Patterson, Ruth E; Sears, Dorothy D

    2017-08-21

    The objective of this review is to provide an overview of intermittent fasting regimens, summarize the evidence on the health benefits of intermittent fasting, and discuss physiological mechanisms by which intermittent fasting might lead to improved health outcomes. A MEDLINE search was performed using PubMed and the terms "intermittent fasting," "fasting," "time-restricted feeding," and "food timing." Modified fasting regimens appear to promote weight loss and may improve metabolic health. Several lines of evidence also support the hypothesis that eating patterns that reduce or eliminate nighttime eating and prolong nightly fasting intervals may result in sustained improvements in human health. Intermittent fasting regimens are hypothesized to influence metabolic regulation via effects on (a) circadian biology, (b) the gut microbiome, and (c) modifiable lifestyle behaviors, such as sleep. If proven to be efficacious, these eating regimens offer promising nonpharmacological approaches to improving health at the population level, with multiple public health benefits.

  13. Neighborhood fast food availability and fast food consumption.

    Science.gov (United States)

    Oexle, Nathalie; Barnes, Timothy L; Blake, Christine E; Bell, Bethany A; Liese, Angela D

    2015-09-01

    Recent nutritional and public health research has focused on how the availability of various types of food in a person's immediate area or neighborhood influences his or her food choices and eating habits. It has been theorized that people living in areas with a wealth of unhealthy fast-food options may show higher levels of fast-food consumption, a factor that often coincides with being overweight or obese. However, measuring food availability in a particular area is difficult to achieve consistently: there may be differences in the strict physical locations of food options as compared to how individuals perceive their personal food availability, and various studies may use either one or both of these measures. The aim of this study was to evaluate the association between weekly fast-food consumption and both a person's perceived availability of fast-food and an objective measure of fast-food presence - Geographic Information Systems (GIS) - within that person's neighborhood. A randomly selected population-based sample of eight counties in South Carolina was used to conduct a cross-sectional telephone survey assessing self-report fast-food consumption and perceived availability of fast food. GIS was used to determine the actual number of fast-food outlets within each participant's neighborhood. Using multinomial logistic regression analyses, we found that neither perceived availability nor GIS-based presence of fast-food was significantly associated with weekly fast-food consumption. Our findings indicate that availability might not be the dominant factor influencing fast-food consumption. We recommend using subjective availability measures and considering individual characteristics that could influence both perceived availability of fast food and its impact on fast-food consumption. If replicated, our findings suggest that interventions aimed at reducing fast-food consumption by limiting neighborhood fast-food availability might not be completely effective.

  14. Serum Lipid Profile: Fasting or Non-fasting?

    OpenAIRE

    Nigam, P. K.

    2010-01-01

    Serum lipid profile has now become almost a routine test. It is usually done in fasting state due to certain limitations in non-fasting serum sample. In the recent past efforts have been made to simplify blood sampling by replacing fasting lipid profile with non-fasting lipid profile. However, fasting specimen is preferred if cardiovascular risk assessment is based on total cholesterol, LDL cholesterol or non-HDL cholesterol. A lot has yet to be done in this area. Till then we have to believe...

  15. Serum Lipid Profile: Fasting or Non-fasting?

    OpenAIRE

    Nigam, P. K.

    2010-01-01

    Serum lipid profile has now become almost a routine test. It is usually done in fasting state due to certain limitations in non-fasting serum sample. In the recent past efforts have been made to simplify blood sampling by replacing fasting lipid profile with non-fasting lipid profile. However, fasting specimen is preferred if cardiovascular risk assessment is based on total cholesterol, LDL cholesterol or non-HDL cholesterol. A lot has yet to be done in this area. Till then we have to believe...

  16. Role of fast ignitor in fast-shock ignition concept

    Directory of Open Access Journals (Sweden)

    S. A. Ghasemi

    2014-03-01

    Full Text Available This paper deals with the role of fast ignitor in fast-shock ignition (FSI concept. The semi-analytical model indicates that the FSI target gain is a function of fast ignitor laser wavelength. If the energy of fast ignitor driver is and the laser wavelength is less than 0.53 micron, then with a fuel mass about 2 mg the FSI has a considerable advantage over pure shock ignition and the figure of merit is better than 1.2. When the wavelength of fast ignitor becomes shorter, the approaches , and for wavelengths shorter than 0.25 micron no additional is advantage is obtained.

  17. Hispanics in Fast Food Jobs.

    Science.gov (United States)

    Charner, Ivan; Fraser, Bryna Shore

    A study examined the employment of Hispanics in the fast-food industry. Data were obtained from a national survey of employees at 279 fast-food restaurants from seven companies in which 194 (4.2 percent) of the 4,660 respondents reported being Hispanic. Compared with the total sample, Hispanic fast-food employees were slightly less likely to be…

  18. Methods of Fast Exponentiation

    Directory of Open Access Journals (Sweden)

    Mohammed A. Maitah

    2010-01-01

    Full Text Available Problem statement: Modular exponentiation constitutes the basis of many well-known and widely used public key cryptosystems. Approach: A fast portable modular exponentiation algorithm considerably enhanced the speed and applicability of these systems, also an efficient implementation of this algorithm was the key to high performance of such system. Results: In this study, two main approaches for solving this problem were proposed. The proposed approaches involved calculations without usage of extra operational memory for saving constants and calculations with usage of preliminary calculated constants. Conclusion/Recommendations: The estimation of complexity of the speedup and effectiveness of proposed approaches for the data were presented.

  19. FAST NEUTRONIC REACTOR

    Science.gov (United States)

    Snell, A.H.

    1957-12-01

    This patent relates to a reactor and process for carrying out a controlled fast neutron chain reaction. A cubical reactive mass, weighing at least 920 metric tons, of uranium metal containing predominantly U/sup 238/ and having a U/sup 235/ content of at least 7.63% is assembled and the maximum neutron reproduction ratio is limited to not substantially over 1.01 by insertion and removal of a varying amount of boron, the reactive mass being substantially freed of moderator.

  20. Fasting and sport: an introduction.

    Science.gov (United States)

    Maughan, R J

    2010-06-01

    Most humans observe an overnight fast on a daily basis, and the human body copes well with short duration fasting. Periodic fasting is widely practised for cultural, religious or health reasons. Fasting may take many different forms. Prolonged restriction of food and fluid is harmful to health and performance, and it is often automatically assumed that intermittent fasting will lead to decrements in exercise performance. Athletes who choose to fast during training or competitions may therefore be at a disadvantage. The available evidence does not entirely support this view, but there is little or no information on the effects on elite athletes competing in challenging environments. Prolonged periods of training in the fasted state may not allow optimum adaptation of muscles and other tissues. Further research on a wide range of athletes with special nutrition needs is urgently required. In events where performance might be affected, other strategies to eliminate or minimise any effects must be sought.

  1. Fast Fourier transform telescope

    Science.gov (United States)

    Tegmark, Max; Zaldarriaga, Matias

    2009-04-01

    We propose an all-digital telescope for 21 cm tomography, which combines key advantages of both single dishes and interferometers. The electric field is digitized by antennas on a rectangular grid, after which a series of fast Fourier transforms recovers simultaneous multifrequency images of up to half the sky. Thanks to Moore’s law, the bandwidth up to which this is feasible has now reached about 1 GHz, and will likely continue doubling every couple of years. The main advantages over a single dish telescope are cost and orders of magnitude larger field-of-view, translating into dramatically better sensitivity for large-area surveys. The key advantages over traditional interferometers are cost (the correlator computational cost for an N-element array scales as Nlog⁡2N rather than N2) and a compact synthesized beam. We argue that 21 cm tomography could be an ideal first application of a very large fast Fourier transform telescope, which would provide both massive sensitivity improvements per dollar and mitigate the off-beam point source foreground problem with its clean beam. Another potentially interesting application is cosmic microwave background polarization.

  2. Fast SCR Thyratron Driver

    Energy Technology Data Exchange (ETDEWEB)

    Nguyen, M.N.; /SLAC

    2007-06-18

    As part of an improvement project on the linear accelerator at SLAC, it was necessary to replace the original thyratron trigger generator, which consisted of two chassis, two vacuum tubes, and a small thyratron. All solid-state, fast rise, and high voltage thyratron drivers, therefore, have been developed and built for the 244 klystron modulators. The rack mounted, single chassis driver employs a unique way to control and generate pulses through the use of an asymmetric SCR, a PFN, a fast pulse transformer, and a saturable reactor. The resulting output pulse is 2 kV peak into 50 {Omega} load with pulse duration of 1.5 {mu}s FWHM at 180 Hz. The pulse risetime is less than 40 ns with less than 1 ns jitter. Various techniques are used to protect the SCR from being damaged by high voltage and current transients due to thyratron breakdowns. The end-of-line clipper (EOLC) detection circuit is also integrated into this chassis to interrupt the modulator triggering in the event a high percentage of line reflections occurred.

  3. Fast Food Jobs. National Study of Fast Food Employment.

    Science.gov (United States)

    Charner, Ivan; Fraser, Bryna Shore

    A study examined employment in the fast-food industry. The national survey collected data from employees at 279 fast-food restaurants from seven companies. Female employees outnumbered males by two to one. The ages of those fast-food employees in the survey sample ranged from 14 to 71, with fully 70 percent being in the 16- to 20-year-old age…

  4. Islamic fasting and multiple sclerosis

    Science.gov (United States)

    2014-01-01

    Background Month-long daytime Ramadan fasting pose s major challenges to multiple sclerosis (MS) patients in Muslim countries. Physicians should have practical knowledge on the implications of fasting on MS. We present a summary of database searches (Cochrane Database of Systematic Reviews, PubMed) and a mini-symposium on Ramadan fasting and MS. In this symposium, we aimed to review the effect of fasting on MS and suggest practical guidelines on management. Discussion In general, fasting is possible for most stable patients. Appropriate amendment of drug regimens, careful monitoring of symptoms, as well as providing patients with available evidence on fasting and MS are important parts of management. Evidence from experimental studies suggests that calorie restriction before disease induction reduces inflammation and subsequent demyelination and attenuates disease severity. Fasting does not appear to have unfavorable effects on disease course in patients with mild disability (Expanded Disability Status Scale (EDSS) score ≤3). Most experts believed that during fasting (especially in summer), some MS symptoms (fatigue, fatigue perception, dizziness, spasticity, cognitive problems, weakness, vision, balance, gait) might worsen but return to normal levels during feasting. There was a general consensus that fasting is not safe for patients: on high doses of anti-convulsants, anti-spastics, and corticosteroids; with coagulopathy or active disease; during attacks; with EDSS score ≥7. Summary These data suggest that MS patients should have tailored care. Fasting in MS patients is a challenge that is directly associated with the spiritual belief of the patient. PMID:24655543

  5. Ramadan fasting, pregnancy and lactation

    Directory of Open Access Journals (Sweden)

    Mohsen Khoshniat Nikoo

    2014-04-01

    Full Text Available Background: Fasting and malnutrition during pregnancy is associated with deleterious consequences such as hypoglycemia, ketonemia, impaired fetal IQ, low birth weight and even abortion. Comparison of pregnancy length and year duration shows that about 75% of pregnancies coincided with Ramadan. Also, fasting during Ramadan is not equivalent to hunger and malnutrition, however, knowledge of the effects of Ramadan fasting on pregnancy outcome is important. In this review, the results of all studies related to the possible effects of Ramadan fasting in pregnancy and lactation have been collected. Material and Methods: Keywords such as "Ramadan", "Ramadan Fasting", "Islamic Fasting", "Fasting in Ramadan "and Fasting with words Pregnancy, Birth Weight, Lactation, Preterm, Milk Composition, Breast Milk were searched in PubMed Database, SID (Scientific Information Database, and some regional journals and 40 related articles (descriptive cross - sectional, cohort, clinical trial and review articles from 1968 to 2010 were studied. Results: Based on available information, if the maternal nutrition during Ramadan is good, the normal process of pregnancy will be maintained and Ramadan fasting would not have deleterious effects on fetal physical and mental growth. Conclusion: Considering nutritional tips, nursing mothers could also fast during Ramadan.

  6. Beyond Fast Mapping.

    Science.gov (United States)

    Carey, Susan

    2010-07-08

    Since the seminal 1957 studies of word learning by Roger Brown, most experimental studies of lexical acquisition have concerned fast mapping: the process through which a new lexical entry is established, and through which representations of the linguistic context of a newly heard word interact with representations of its nonlinguistic context to fix an initial partial meaning. Here I focus on the subsequent extended process through which the adult meaning is approximated. Two factors lead to an extended learning process; the size of the hypothesis space and the need, sometimes, for the creation of new semantic primitives. Sometimes lexical learning requires conceptual change. I sketch a learning mechanism through which this can be achieved. A case study of learning the meanings of verbal numerals illustrates the argument.

  7. Materials analysis fast ions

    CERN Document Server

    Denker, A; Rauschenberg, J; Röhrich, J; Strub, E

    2006-01-01

    Materials analysis with ion beams exploits the interaction of ions with the electrons and nuclei in the sample. Among the vast variety of possible analytical techniques available with ion beams we will restrain to ion beam analysis with ion beams in the energy range from one to several MeV per mass unit. It is possible to use either the back-scattered projectiles (RBS – Rutherford Back Scattering) or the recoiled atoms itself (ERDA – Elastic Recoil Detection Analysis) from the elastic scattering processes. These techniques allow the simultaneous and absolute determination of stoichiometry and depth profiles of the detected elements. The interaction of the ions with the electrons in the sample produces holes in the inner electronic shells of the sample atoms, which recombine and emit X-rays characteristic for the element in question. Particle Induced X-ray Emission (PIXE) has shown to be a fast technique for the analysis of elements with an atomic number above 11.

  8. Fast reactor programme in India

    Indian Academy of Sciences (India)

    P Chellapandi; P R Vasudeva Rao; Prabhat Kumar

    2015-09-01

    Role of fast breeder reactor (FBR) in the Indian context has been discussed with appropriate justification. The FBR programme since 1985 till 2030 is highlighted focussing on the current status and future direction of fast breeder test reactor (FBTR), prototype fast breeder reactor (PFBR) and FBR-1 and 2. Design and technological challenges of PFBR and design and safety targets with means to achieve the same are the major highlights of this paper.

  9. Fast word reading in pure alexia: "fast, yet serial".

    Science.gov (United States)

    Bormann, Tobias; Wolfer, Sascha; Hachmann, Wibke; Neubauer, Claudia; Konieczny, Lars

    2015-01-01

    Pure alexia is a severe impairment of word reading in which individuals process letters serially with a pronounced length effect. Yet, there is considerable variation in the performance of alexic readers with generally very slow, but also occasionally fast responses, an observation addressed rarely in previous reports. It has been suggested that "fast" responses in pure alexia reflect residual parallel letter processing or that they may even be subserved by an independent reading system. Four experiments assessed fast and slow reading in a participant (DN) with pure alexia. Two behavioral experiments investigated frequency, neighborhood, and length effects in forced fast reading. Two further experiments measured eye movements when DN was forced to read quickly, or could respond faster because words were easier to process. Taken together, there was little support for the proposal that "qualitatively different" mechanisms or reading strategies underlie both types of responses in DN. Instead, fast responses are argued to be generated by the same serial-reading strategy.

  10. Responder fast steering mirror

    Science.gov (United States)

    Bullard, Andrew; Shawki, Islam

    2013-10-01

    Raytheon Space and Airborne Systems (SAS) has designed, built and tested a 3.3-inch diameter fast steering mirror (FSM) for space application. This 2-axis FSM operates over a large angle (over 10 degree range), has a very high servo bandwidth (over 3.3 Khz closed loop bandwidth), has nanoradian-class noise, and is designed to support microradian class line of sight accuracy. The FSM maintains excellent performance over large temperature ranges (which includes wave front error) and has very high reliability with the help of fully redundant angle sensors and actuator circuits. The FSM is capable of achieving all its design requirements while also being reaction-compensated. The reaction compensation is achieved passively and does not need a separate control loop. The FSM has undergone various environmental testing which include exported forces and torques and thermal vacuum testing that support the FSM design claims. This paper presents the mechanical design and test results of the mechanism which satisfies the rigorous vacuum and space application requirements.

  11. Fast dual tomography

    Science.gov (United States)

    Carrion, Philip M.

    1990-09-01

    This paper can be considered as a continuation of the work by Carrion and Carneiro (1989), where a generalized approach to linearized inversion of geophysical data was developed. Their method allows one to incorporate virtually any constraints in the inversion and reformulate the problem in the dual space of Langrangian multipliers (see also Carrion, 1989a). The constrained tomography makes traveltime inversion robust: it automatically rejects “bad data” which correspond to solutions beyond the chosen constraints and allows one to start inversion with an arbitrary chosen initial model.In this paper, I will derive basic formulas for constrained tomographic imaging that can be used in such areas of geophysics as global mapping of the earth interior, exploration geophysics, etc. The method is fast: an example that will be shown in the paper took only 6 min. of VAX CPU time. Had the conventional least-squares matrix inversion been used it would have taken more than 10 hours of the CPU time to solve the same problem.

  12. Fast dual tomography

    Energy Technology Data Exchange (ETDEWEB)

    Carrion, P.M. (PPPG/UFBA - Campus Universitario da Federacao, Salvador-Bahia (Brazil))

    1990-09-01

    This paper can be considered as a continuation of the work by Carrion and Carneiro (1989), where a generalized approach to linearized inversion of geophysical data was developed. Their method allows one to incorporate virtually any constraints in the inversion and reformulate the problem in the dual space of Langrangian multipliers (see also Carrion, 1989a). The constrained tomography makes traveltime inversion robust: it automatically rejects bad data which correspond to solutions beyond the chosen constraints and allows one to start inversion with an arbitrary chosen initial model. In this paper, the author derives basic formulas for constrained tomographic imaging that can be used in such areas of geophysics as global mapping of the earth interior, exploration geophysics, etc. The method is fast: an example that will be shown in the paper took only 6 min. of VAX CPU time. Had the conventional least-squares matrix inversion been used it would have taken more than 10 hours of the CPU time to solve the same problem.

  13. The ATLAS Fast Tracker

    CERN Document Server

    Volpi, Guido; The ATLAS collaboration

    2015-01-01

    The use of tracking information at the trigger level in the LHC Run II period is crucial for the trigger an data acquisition (TDAQ) system. The tracking precision is in fact important to identify specific decay products of the Higgs boson or new phenomena, a well as to distinguish the contributions coming from many contemporary collisions that occur at every bunch crossing. However, the track reconstruction is among the most demanding tasks performed by the TDAQ computing farm; in fact, full reconstruction at full Level-1 trigger accept rate (100 KHz) is not possible. In order to overcome this limitation, the ATLAS experiment is planning the installation of a specific processor: the Fast Tracker (FTK), which is aimed at achieving this goal. The FTK is a pipeline of high performance electronic, based on custom and commercial devices, which is expected to reconstruct, with high resolution, the trajectories of charged tracks with a transverse momentum above 1 GeV, using the ATLAS inner tracker information. Patte...

  14. Fast Flooding over Manhattan

    CERN Document Server

    Clementi, Andrea; Silvestri, Riccardo

    2010-01-01

    We consider a Mobile Ad-hoc NETwork (MANET) formed by n agents that move at speed V according to the Manhattan Random-Way Point model over a square region of side length L. The resulting stationary (agent) spatial probability distribution is far to be uniform: the average density over the "central zone" is asymptotically higher than that over the "suburb". Agents exchange data iff they are at distance at most R within each other. We study the flooding time of this MANET: the number of time steps required to broadcast a message from one source agent to all agents of the network in the stationary phase. We prove the first asymptotical upper bound on the flooding time. This bound holds with high probability, it is a decreasing function of R and V, and it is tight for a wide and relevant range of the network parameters (i.e. L, R and V). A consequence of our result is that flooding over the sparse and highly-disconnected suburb can be as fast as flooding over the dense and connected central zone. Rather surprisin...

  15. Fast Aerial Video Stitching

    Directory of Open Access Journals (Sweden)

    Jing Li

    2014-10-01

    Full Text Available The highly efficient and robust stitching of aerial video captured by unmanned aerial vehicles (UAVs is a challenging problem in the field of robot vision. Existing commercial image stitching systems have seen success with offline stitching tasks, but they cannot guarantee high-speed performance when dealing with online aerial video sequences.In this paper, we present a novel system which has an unique ability to stitch high-frame rate aerial video at a speed of 150 frames per second (FPS. In addition, rather than using a high-speed vision platform such as FPGA or CUDA, our system is running on a normal personal computer. To achieve this, after the careful comparison of the existing invariant features, we choose the FAST corner and binary descriptor for efficient feature extraction and representation, and present a spatial and temporal coherent filter to fuse the UAV motion information into the feature matching. The proposed filter can remove the majority of feature correspondence outliers and significantly increase the speed of robust feature matching by up to 20 times. To achieve a balance between robustness and efficiency, a dynamic key frame-based stitching framework is used to reduce the accumulation errors.Extensive experiments on challenging UAV datasets demonstrate that our approach can break through the speed limitation and generate an accurate stitching image for aerial video stitching tasks.

  16. Fast feedback in classroom practice

    NARCIS (Netherlands)

    Emmett, K.M.; Klaassen, K.; Eijkelhof, H.

    2009-01-01

    In this article we describe one application of the fast feedback method (see Berg 2003 Aust. Sci. Teach. J. 28–34) in secondary mechanics education. Two teachers tried out a particular sequence twice, in consecutive years, once with and once without the use of fast feedback. We found the method to b

  17. Fasting and nonfasting lipid levels

    DEFF Research Database (Denmark)

    Langsted, Anne; Freiberg, Jacob J; Nordestgaard, Børge G

    2008-01-01

    Lipid profiles are usually measured after fasting. We tested the hypotheses that these levels change only minimally in response to normal food intake and that nonfasting levels predict cardiovascular events.......Lipid profiles are usually measured after fasting. We tested the hypotheses that these levels change only minimally in response to normal food intake and that nonfasting levels predict cardiovascular events....

  18. Fasting and nonfasting lipid levels

    DEFF Research Database (Denmark)

    Langsted, Anne; Freiberg, Jacob J; Nordestgaard, Børge G

    2008-01-01

    Lipid profiles are usually measured after fasting. We tested the hypotheses that these levels change only minimally in response to normal food intake and that nonfasting levels predict cardiovascular events.......Lipid profiles are usually measured after fasting. We tested the hypotheses that these levels change only minimally in response to normal food intake and that nonfasting levels predict cardiovascular events....

  19. Glycemic management during Jain fasts

    OpenAIRE

    Sandeep Julka; Alok Sachan; Sarita Bajaj; Rakesh Sahay; Rajeev Chawla; Navneet Agrawal; Banshi Saboo; Unnikrishnan, A. G.; Baruah, Manash P.; Girish Parmar; Sanjay Kalra

    2017-01-01

    This review describes the various fasts observed by adherents of the Jain religion. It attempts to classify them according to their suitability for people with diabetes and suggests appropriate regime and dose modification for those observing these fasts. The review is an endeavor to encourage rational and evidence-based management in this field of diabetology.

  20. Oil Analysis by Fast DSC

    NARCIS (Netherlands)

    Wetten, I.A.; Herwaarden, A.W.; Splinter, R.; Ruth, van S.M.

    2014-01-01

    Thermal analysis of Olive and Sunflower Oil is done by Fast DSC to evaluate its potential to replace DSC for adulteration detection. DSC measurements take hours, Fast DSC minutes. Peak temperatures of the crystallisation peak in cooling for different Olive and Sunflower Oils are both comparable to D

  1. Oil Analysis by Fast DSC

    NARCIS (Netherlands)

    Wetten, I.A.; Herwaarden, A.W.; Splinter, R.; Ruth, van S.M.

    2014-01-01

    Thermal analysis of Olive and Sunflower Oil is done by Fast DSC to evaluate its potential to replace DSC for adulteration detection. DSC measurements take hours, Fast DSC minutes. Peak temperatures of the crystallisation peak in cooling for different Olive and Sunflower Oils are both comparable to

  2. Fast Feedback in Classroom Practice

    Science.gov (United States)

    Emmett, Katrina; Klaassen, Kees; Eijkelhof, Harrie

    2009-01-01

    In this article we describe one application of the fast feedback method (see Berg 2003 "Aust. Sci. Teach. J." 28-34) in secondary mechanics education. Two teachers tried out a particular sequence twice, in consecutive years, once with and once without the use of fast feedback. We found the method to be successful, and the data that we obtained…

  3. Effect of gadolinium on hepatic fat quantification using multi-echo reconstruction technique with T2* correction and estimation

    Energy Technology Data Exchange (ETDEWEB)

    Ge, Mingmei; Wu, Bing; Liu, Zhiqin; Song, Hai; Meng, Xiangfeng; Wu, Xinhuai [The Military General Hospital of Beijing PLA, Department of Radiology, Beijing (China); Zhang, Jing [The 309th Hospital of Chinese People' s Liberation Army, Department of Radiology, Beijing (China)

    2016-06-15

    To determine whether hepatic fat quantification is affected by administration of gadolinium using a multiecho reconstruction technique with T2* correction and estimation. Forty-eight patients underwent the investigational sequence for hepatic fat quantification at 3.0T MRI once before and twice after administration of gadopentetate dimeglumine (0.1 mmol/kg). A one-way repeated-measures analysis of variance with pairwise comparisons was conducted to evaluate the systematic bias of fat fraction (FF) and R2* measurements between three acquisitions. Bland-Altman plots were used to assess the agreements between pre- and post-contrast FF measurements in the liver. A P value <0.05 indicated statistically significant difference. FF measurements of liver, spleen and spine revealed no significant systematic bias between the three measurements (P > 0.05 for all). Good agreements (95 % confidence interval) of FF measurements were demonstrated between pre-contrast and post-contrast1 (-0.49 %, 0.52 %) and post-contrast2 (-0.83 %, 0.77 %). R2* increased in liver and spleen (P = 0.039, P = 0.01) after administration of gadolinium. Although under the impact of an increased R2* in liver and spleen post-contrast, the investigational sequence can still obtain stable fat quantification. Therefore, it could be applied post-contrast to substantially increase the efficiency of MR examination and also provide a backup for the occasional failure of FF measurements pre-contrast. (orig.)

  4. Fast food: unfriendly and unhealthy.

    Science.gov (United States)

    Stender, S; Dyerberg, J; Astrup, A

    2007-06-01

    Although nutrition experts might be able to navigate the menus of fast-food restaurant chains, and based on the nutritional information, compose apparently 'healthy' meals, there are still many reasons why frequent fast-food consumption at most chains is unhealthy and contributes to weight gain, obesity, type 2 diabetes and coronary artery disease. Fast food generally has a high-energy density, which, together with large portion sizes, induces over consumption of calories. In addition, we have found it to be a myth that the typical fast-food meal is the same worldwide. Chemical analyses of 74 samples of fast-food menus consisting of French fries and fried chicken (nuggets/hot wings) bought in McDonalds and KFC outlets in 35 countries in 2005-2006 showed that the total fat content of the same menu varies from 41 to 65 g at McDonalds and from 42 to 74 g at KFC. In addition, fast food from major chains in most countries still contains unacceptably high levels of industrially produced trans-fatty acids (IP-TFA). IP-TFA have powerful biological effects and may contribute to increased weight gain, abdominal obesity, type 2 diabetes and coronary artery disease. The food quality and portion size need to be improved before it is safe to eat frequently at most fast-food chains.

  5. FastID: Extremely Fast Forensic DNA Comparisons

    Science.gov (United States)

    2017-05-19

    FastID: Extremely Fast Forensic DNA Comparisons Darrell O. Ricke, PhD Bioengineering Systems & Technologies Massachusetts Institute of...Technology Lincoln Laboratory Lexington, MA USA Darrell.Ricke@ll.mit.edu Abstract—Rapid analysis of DNA forensic samples can have a critical impact on...time sensitive investigations. Analysis of forensic DNA samples by massively parallel sequencing is creating the next gold standard for DNA

  6. fast,rapid,quick和speedy

    Institute of Scientific and Technical Information of China (English)

    张德兴

    2003-01-01

    fast,rapid,quick和speedy这组词都有“快的”意思,但将它们放在一起略作议论,仍有必要,并不乏词趣。 fast和rapid虽然有时可以互换使用,彼此仍有差异,fast在作形容词的时候,强调物体进行相对运动。如a fast horse,a fast train.除形容词外,fast可做副词。如:

  7. Molecular imaging with fast beams

    Energy Technology Data Exchange (ETDEWEB)

    Heber, O. [Weizmann Inst. of Science, Rehovoth (Israel). Dept. of Particle Physics; Zajfman, D. [Weizmann Inst. of Science, Rehovoth (Israel). Dept. of Particle Physics; Kella, D. [Weizmann Inst. of Science, Rehovoth (Israel). Dept. of Particle Physics; Vager, Z. [Weizmann Inst. of Science, Rehovoth (Israel). Dept. of Particle Physics; Watson, R.L. [Cyclotron Institute, Texas A and M University, College Station, Texas 77843 (United States); Horvat, V. [Cyclotron Institute, Texas A and M University, College Station, Texas 77843 (United States)

    1995-05-01

    Three dimensional imaging of the molecular dissociation process in fast collisions is presented with two different setups. One setup is for a fast molecular beam from an accelerator colliding with a gas target. The second setup is for a molecular target system and the collision process is with highly ionized fast beam. The advantages of each system are discussed. The three dimensional imaging of the molecular fragments is done with special detectors that combine the CCD image with time of flight data. An example of the molecular beam measurement is given for an 11 MeV B{sub 2} beam. (orig.).

  8. Fast discriminative latent Dirichlet allocation

    Data.gov (United States)

    National Aeronautics and Space Administration — This is the code for fast discriminative latent Dirichlet allocation, which is an algorithm for topic modeling and text classification. The related paper is at...

  9. FastStats: Sinus Conditions

    Science.gov (United States)

    ... please visit this page: About CDC.gov . FastStats Homepage Diseases and Conditions Anemia or Iron Deficiency Arthritis ... Statistics Tables for U.S. Adults: National Health Interview Survey, 2014, Table A-2 [PDF - 219 KB] Physician ...

  10. Fast Picometer Mirror Mount Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The proposed innovation is a 6DOF controllable mirror mount with high dynamic range and fast tip/tilt capability for space based applications. It will enable the...

  11. Fast generation of dendritic cells

    DEFF Research Database (Denmark)

    Kvistborg, P; Bøgh, Marie; Claesson, M H

    2009-01-01

    we have developed fast DC protocol by comparing two different fast DC protocols with SDDC. DC were evaluated by FACS analysis, and the optimal profile was considered: CD14(low), CD80(high), CD83(high), CD86(high), CCR7(high), HLA class I and II(high). FACS profiles were used as the selection criteria...... together with yield and morphology. Two fast DC protocols fulfilled these criteria and were selected for functional analysis. Our results demonstrate that DC generated within 5days or 48h are comparable with SDDC both phenotypically and functionally. However, we found that 48h DC were more susceptible than...... SDDC to the IL-10 inducing stimulus of TLR ligands (R848 and LPS). Thus to determine the clinical relevance of fast DC protocols in cancer settings, small phase I trials should be conducted monitoring regulatory T cells carefully....

  12. Still on the Fast Track

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    North China’s Inner Mongolia Autonomous Region’s development is progressing comparatively fast,though there is still a long way to go until it catches up with advances being made in other parts of China, officials said.

  13. vysmaw: Fast visibility stream muncher

    Science.gov (United States)

    Pokorny, Martin; Law, Casey J.

    2017-10-01

    The vysmaw client library facilitates the development of code for processes to tap into the fast visibility stream on the National Radio Astronomy Observatory's Very Large Array correlator back-end InfiniBand network.

  14. Allegheny County Fast Food Establishments

    Data.gov (United States)

    Allegheny County / City of Pittsburgh / Western PA Regional Data Center — The Allegheny County Health Department has generated this list of fast food restaurants by exporting all chain restaurants without an alcohol permit from the...

  15. Fast Calorimeter Simulation in ATLAS

    CERN Document Server

    Schaarschmidt, Jana; The ATLAS collaboration

    2017-01-01

    Producing the very large samples of simulated events required by many physics and performance studies with the ATLAS detector using the full GEANT4 detector simulation is highly CPU intensive. Fast simulation tools are a useful way of reducing CPU requirements when detailed detector simulations are not needed. During the LHC Run-1, a fast calorimeter simulation (FastCaloSim) was successfully used in ATLAS. FastCaloSim provides a simulation of the particle energy response at the calorimeter read-out cell level, taking into account the detailed particle shower shapes and the correlations between the energy depositions in the various calorimeter layers. It is interfaced to the standard ATLAS digitization and reconstruction software, and it can be tuned to data more easily than GEANT4. It is 500 times faster than full simulation in the calorimeter system. Now an improved version of FastCaloSim is in development, incorporating the experience with the version used during Run-1. The new FastCaloSim makes use of mach...

  16. Upgrading ATLAS Fast Calorimeter Simulation

    CERN Document Server

    Heath, Matthew Peter; The ATLAS collaboration

    2017-01-01

    Producing the very large samples of simulated events required by many physics and performance studies with the ATLAS detector using the full GEANT4 detector simulation is highly CPU intensive. Fast simulation tools are a useful way of reducing CPU requirements when detailed detector simulations are not needed. During the LHC Run-1, a fast calorimeter simulation (FastCaloSim) was successfully used in ATLAS. FastCaloSim provides a simulation of the particle energy response at the calorimeter read-out cell level, taking into account the detailed particle shower shapes and the correlations between the energy depositions in the various calorimeter layers. It is interfaced to the standard ATLAS digitization and reconstruction software, and it can be tuned to data more easily than Geant4. Now an improved version of FastCaloSim is in development, incorporating the experience with the version used during Run-1. The new FastCaloSim aims to overcome some limitations of the first version by improving the description of s...

  17. Quantifying Cricket Fast Bowling Skill.

    Science.gov (United States)

    Feros, Simon A; Young, Warren B; O'Brien, Brendan J

    2017-09-27

    To evaluate the current evidence regarding the quantification of cricket fast bowling skill. Studies that assessed fast bowling skill (bowling speed and accuracy) were identified from searches in SPORTDiscus (EBSCO) in June 2017. The reference lists of identified papers were also examined for relevant investigations. Sixteen papers matched the inclusion criteria, and discrepancies in assessment procedures were evident. Differences in: test environment, pitch and cricket ball characteristics, the warm-up prior to test, test familiarisation procedures, permitted run-up lengths, bowling spell length, delivery sequence, test instructions, collection of bowling speed data, collection and reportage of bowling accuracy data were apparent throughout the literature. The reliability and sensitivity of fast bowling skill measures has rarely been reported across the literature. Only one study has attempted to assess the construct validity of their skill measures. There are several discrepancies in how fast bowling skill has been assessed and subsequently quantified in the literature to date. This is a problem, as comparisons between studies are often difficult. Therefore, a strong rationale exists for the creation of match-specific standardised fast bowling assessments that offer greater ecological validity while maintaining acceptable reliability and sensitivity of the skill measures. If prospective research can act on the proposed recommendations from this review, then coaches will be able to make more informed decisions surrounding player selection, talent identification, return to skill following injury, and the efficacy of short- and long-term training interventions for fast bowlers.

  18. Theory of Fast Electron Transport for Fast Ignition

    CERN Document Server

    Robinson, A P L; Davies, J R; Gremillet, L; Honrubia, J J; Johzaki, T; Kingham, R J; Sherlock, M; Solodov, A A

    2013-01-01

    Fast Ignition Inertial Confinement Fusion is a variant of inertial fusion in which DT fuel is first compressed to high density and then ignited by a relativistic electron beam generated by a fast (< 20 ps) ultra-intense laser pulse, which is usually brought in to the dense plasma via the inclusion of a re-entrant cone. The transport of this beam from the cone apex into the dense fuel is a critical part of this scheme, as it can strongly influence the overall energetics. Here we review progress in the theory and numerical simulation of fast electron transport in the context of Fast Ignition. Important aspects of the basic plasma physics, descriptions of the numerical methods used, a review of ignition-scale simulations, and a survey of schemes for controlling the propagation of fast electrons are included. Considerable progress has taken place in this area, but the development of a robust, high-gain FI `point design' is still an ongoing challenge.

  19. A Comparison of Fast Marching, Fast Sweeping and Fast Iterative Methods for the Solution of the Eikonal Equation

    Directory of Open Access Journals (Sweden)

    A. Capozzoli

    2014-11-01

    Full Text Available We compare the computational performance of the Fast Marching Method, the Fast Sweeping Method and the Fast Iterative Method to determine a numerical solution to the eikonal equation. We point out how the Fast Iterative Method outperforms the other two thanks to its parallel processing capabilities.

  20. How fast does a seal swim? Variations in swimming behaviour under differing foraging conditions.

    Science.gov (United States)

    Gallon, Susan L; Sparling, Carol E; Georges, Jean-Yves; Fedak, Michael A; Biuw, Martin; Thompson, Dave

    2007-09-01

    The duration of breath-hold dives and the available time for foraging in submerged prey patches is ultimately constrained by oxygen balance. There is a close relationship between swim speed and oxygen utilisation, so it is likely that breath-holding divers optimise their speeds to and from the feeding patch to maximise time spent feeding at depth. Optimal foraging models suggest that transit swim speed should decrease to minimum cost of transport (MCT) speed in deeper and longer duration dives. Observations also suggest that descent and ascent swimming mode and speed may vary in response to changes in buoyancy. We measured the swimming behaviour during simulated foraging of seven captive female grey seals (two adults and five pups). Seals had to swim horizontally underwater from a breathing box to a submerged automatic feeder. The distance to the feeder and the rate of prey food delivery could be varied to simulate different feeding conditions. Diving durations and distances travelled in dives recorded during these experiments were similar to those recorded in the wild. Mean swim speed decreased significantly with increasing distance to the patch, indicating that seals adjusted their speed in response to travel distance, consistent with optimality model predictions. There was, however, no significant relationship between the transit swim speeds and prey density at the patch. Interestingly, all seals swam 10-20% faster on their way to the prey patch compared to the return to the breathing box, despite the fact that any effect of buoyancy on swimming speed should be the same in both directions. These results suggest that the swimming behaviour exhibited by foraging grey seals might be a combination of having to overcome the forces of buoyancy during vertical swimming and also of behavioural choices made by the seals.

  1. Preoperative fasting time in children.

    LENUS (Irish Health Repository)

    Adeel, S

    2012-02-01

    The aim of preoperative fasting is to prevent regurgitation and pulmonary aspiration while limiting potential problems of thirst, dehydration and hypoglycaemia. The American Society of Anaesthesiologists (ASA) has suggested guidelines for preoperative fasting for children undergoing elective surgery. We did a postal survey to determine the current practice regarding these guidelines amongst all specialist registrars in anaesthesia in Ireland. A questionnaire was sent to all specialist registrars in anaesthesia (90 in total), 60 (67%) were returned and analysed. The question asked was how long children should be kept fasting before elective surgery. The results of our survey suggest that most of the respondents are following the ASA guidelines for clear fluids and solids however there were differing opinion regarding the duration of fasting for formula milk and breast milk. In conclusion, we would recommend greater awareness and collaboration between anaesthetists, nurses and surgeons to ensure that fasting instructions are consistent with the ASA guidelines and that patient and their parents understand these directives as well.

  2. HI intensity mapping with FAST

    CERN Document Server

    Bigot-Sazy, Marie-Anne; Battye, Richard A; Browne, Ian W A; Chen, Tianyue; Dickinson, Clive; Harper, Stuart; Maffei, Bruno; Olivari, Lucas C; Wilkinson, Peter N

    2015-01-01

    We discuss the detectability of large-scale HI intensity fluctuations using the FAST telescope. We present forecasts for the accuracy of measuring the Baryonic Acoustic Oscillations and constraining the properties of dark energy. The FAST $19$-beam L-band receivers ($1.05$--$1.45$ GHz) can provide constraints on the matter power spectrum and dark energy equation of state parameters ($w_{0},w_{a}$) that are comparable to the BINGO and CHIME experiments. For one year of integration time we find that the optimal survey area is $6000\\,{\\rm deg}^2$. However, observing with larger frequency coverage at higher redshift ($0.95$--$1.35$ GHz) improves the projected errorbars on the HI power spectrum by more than $2~\\sigma$ confidence level. The combined constraints from FAST, CHIME, BINGO and Planck CMB observations can provide reliable, stringent constraints on the dark energy equation of state.

  3. Printtimalliston suunnitteluprosessi fast fashion -yritykselle

    OpenAIRE

    Heikkilä, Inna

    2016-01-01

    Opinnäytetyöni käsittelee suunnitteluprosessia fast fashion -yrityksessä. Oman prosessini kautta selvitän, millaisia vaikutuksia fast fashion -ilmiöllä on tekstiilisuunnittelijan työhön ja, mitä suunnittelijalta vaaditaan nopeatempoisessa suunnitteluprosessissa. Opinnäytetyön toimeksiantajana toimii Seppälä. Toiminnallinen osuus koostuu viiden t-paitaprintin suunnittelusta Seppälä Womanin elokuun 2016 mallistoon Seppälän suunnittelijoiden Katja Tuhkasaaren ja Elina Savolaisen ohjauksessa. Teo...

  4. A Fast Fractional Difference Algorithm

    DEFF Research Database (Denmark)

    Jensen, Andreas Noack; Nielsen, Morten Ørregaard

    We provide a fast algorithm for calculating the fractional difference of a time series. In standard implementations, the calculation speed (number of arithmetic operations) is of order T 2, where T is the length of the time series. Our algorithm allows calculation speed of order T logT . For mode......We provide a fast algorithm for calculating the fractional difference of a time series. In standard implementations, the calculation speed (number of arithmetic operations) is of order T 2, where T is the length of the time series. Our algorithm allows calculation speed of order T log...

  5. Fast Setting Cement - Literature Survey

    Science.gov (United States)

    1973-01-01

    materials does produce early set times and high strengths . It is re- ported, also, that the addition of 1.5 percent Ca"l 2 to clinkers contain- Ing more than...produce high strength concrete. They include addition of iron asggregate, physical treatment of clinker , ’ addition of highly reactive SiO2 or Ca0, and...Fast-Fix. The Western Co. has developed materials designated as Fast-Fix with rapid setting and high strength properties. Published data show i .1

  6. Fast Food Problems and Responsibilities

    Institute of Scientific and Technical Information of China (English)

    Zhang; Jing

    2015-01-01

    <正>People are living in a world that acquires almost everyone to chase efficiency and speed.The real inner quality of daily life is not approximately taken into people’s consideration.Fast food is one of the common model reactions of this rapid developing society.Recently,it’s getting popular that people would rather have fast food to save time for other extra work.Problems and public concern are following that kind of life condition and someone or something should be put blame on for this.

  7. Fast data processing with Spark

    CERN Document Server

    Sankar, Krishna

    2015-01-01

    Fast Data Processing with Spark - Second Edition is for software developers who want to learn how to write distributed programs with Spark. It will help developers who have had problems that were too big to be dealt with on a single computer. No previous experience with distributed programming is necessary. This book assumes knowledge of either Java, Scala, or Python.

  8. Fast electromagnetic field strength probes

    NARCIS (Netherlands)

    Leferink, Frank; Serra, Ramiro

    2013-01-01

    Diode detectors and thermocouple detectors are conventionally used to measure electromagnetic field strength. Both detectors have some disadvantages for applications where a fast response and a high dynamic range is required. The diode detector is limited in dynamic range. The dynamic range is impor

  9. Enhanced Model for Fast Ignition

    Energy Technology Data Exchange (ETDEWEB)

    Mason, Rodney J. [Research Applications Corporation, Los Alamos, NM (United States)

    2010-10-12

    Laser Fusion is a prime candidate for alternate energy production, capable of serving a major portion of the nation's energy needs, once fusion fuel can be readily ignited. Fast Ignition may well speed achievement of this goal, by reducing net demands on laser pulse energy and timing precision. However, Fast Ignition has presented a major challenge to modeling. This project has enhanced the computer code ePLAS for the simulation of the many specialized phenomena, which arise with Fast Ignition. The improved code has helped researchers to understand better the consequences of laser absorption, energy transport, and laser target hydrodynamics. ePLAS uses efficient implicit methods to acquire solutions for the electromagnetic fields that govern the accelerations of electrons and ions in targets. In many cases, the code implements fluid modeling for these components. These combined features, "implicitness and fluid modeling," can greatly facilitate calculations, permitting the rapid scoping and evaluation of experiments. ePLAS can be used on PCs, Macs and Linux machines, providing researchers and students with rapid results. This project has improved the treatment of electromagnetics, hydrodynamics, and atomic physics in the code. It has simplified output graphics, and provided new input that avoids the need for source code access by users. The improved code can now aid university, business and national laboratory users in pursuit of an early path to success with Fast Ignition.

  10. Micro mixer with fast diffusion

    NARCIS (Netherlands)

    Miyake, Ryo; Miyake, R.; Lammerink, Theodorus S.J.; Elwenspoek, Michael Curt; Fluitman, J.H.J.

    1993-01-01

    A new concept for micro-mixing of liquid is introduced and feasibility is demonstrated. The mixer allows fast mixing of small amounts of two liquids and it is application to micro-liquid handling systems [1]. The mixer has a channel for the liquid, an inlet port for the reagent, and a 2.2 mm × 2 mm

  11. Fast, Massively Parallel Data Processors

    Science.gov (United States)

    Heaton, Robert A.; Blevins, Donald W.; Davis, ED

    1994-01-01

    Proposed fast, massively parallel data processor contains 8x16 array of processing elements with efficient interconnection scheme and options for flexible local control. Processing elements communicate with each other on "X" interconnection grid with external memory via high-capacity input/output bus. This approach to conditional operation nearly doubles speed of various arithmetic operations.

  12. Fast Timing for Collider Detectors

    CERN Document Server

    CERN. Geneva

    2017-01-01

    Advancements in fast timing particle detectors have opened up new possibilities to design collider detectors that fully reconstruct and separate event vertices and individual particles in the time domain. The applications of these techniques are considered for the physics at HL-LHC.

  13. The Fast-Casual Conundrum: Fast-Casual Restaurant Entrées Are Higher in Calories than Fast Food.

    Science.gov (United States)

    Schoffman, Danielle E; Davidson, Charis R; Hales, Sarah B; Crimarco, Anthony E; Dahl, Alicia A; Turner-McGrievy, Gabrielle M

    2016-10-01

    Frequently eating fast food has been associated with consuming a diet high in calories, and there is a public perception that fast-casual restaurants (eg, Chipotle) are healthier than traditional fast food (eg, McDonald's). However, research has not examined whether fast-food entrées and fast-casual entrées differ in calorie content. The purpose of this study was to determine whether the caloric content of entrées at fast-food restaurants differed from that found at fast-casual restaurants. This study was a cross-sectional analysis of secondary data. Calorie information from 2014 for lunch and dinner entrées for fast-food and fast-casual restaurants was downloaded from the MenuStat database. Mean calories per entrée between fast-food restaurants and fast-casual restaurants and the proportion of restaurant entrées that fell into different calorie ranges were assessed. A t test was conducted to test the hypothesis that there was no difference between the average calories per entrée at fast-food and fast-casual restaurants. To examine the difference in distribution of entrées in different calorie ranges between fast-food and fast-casual restaurants, χ(2) tests were used. There were 34 fast-food and 28 fast-casual restaurants included in the analysis (n=3,193 entrées). Fast-casual entrées had significantly more calories per entrée (760±301 kcal) than fast-food entrées (561±268; Pfast-casual entrées compared with fast-food entrées exceeded the median of 640 kcal per entrée (Pfast-casual entrées contained more calories than fast-food entrées in the study sample, future studies should compare actual purchasing patterns from these restaurants to determine whether the energy content or nutrient density of full meals (ie, entrées with sides and drinks) differs between fast-casual restaurants and fast-food restaurants. Calorie-conscious consumers should consider the calorie content of entrée items before purchase, regardless of restaurant type. Copyright

  14. [Preoperative fasting guidelines: an update].

    Science.gov (United States)

    López Muñoz, A C; Busto Aguirreurreta, N; Tomás Braulio, J

    2015-03-01

    Anesthesiology societies have issued various guidelines on preoperative fasting since 1990, not only to decrease the incidence of lung aspiration and anesthetic morbidity, but also to increase patient comfort prior to anesthesia. Some of these societies have been updating their guidelines, as such that, since 2010, we now have 2 evidence-based preoperative fasting guidelines available. In this article, an attempt is made to review these updated guidelines, as well as the current instructions for more controversial patients such as infants, the obese, and a particular type of ophthalmic surgery. Copyright © 2014 Sociedad Española de Anestesiología, Reanimación y Terapéutica del Dolor. Publicado por Elsevier España, S.L.U. All rights reserved.

  15. A Repeating Fast Radio Burst

    CERN Document Server

    Spitler, L G; Hessels, J W T; Bogdanov, S; Brazier, A; Camilo, F; Chatterjee, S; Cordes, J M; Crawford, F; Deneva, J; Ferdman, R D; Freire, P C C; Kaspi, V M; Lazarus, P; Lynch, R; Madsen, E C; McLaughlin, M A; Patel, C; Ransom, S M; Seymour, A; Stairs, I H; Stappers, B W; van Leeuwen, J; Zhu, W W

    2016-01-01

    Fast Radio Bursts are millisecond-duration astronomical radio pulses of unknown physical origin that appear to come from extragalactic distances. Previous follow-up observations have failed to find additional bursts at the same dispersion measures (i.e. integrated column density of free electrons between source and telescope) and sky position as the original detections. The apparent non-repeating nature of the fast radio bursts has led several authors to hypothesise that they originate in cataclysmic astrophysical events. Here we report the detection of ten additional bursts from the direction of FRB121102, using the 305-m Arecibo telescope. These new bursts have dispersion measures and sky positions consistent with the original burst. This unambiguously identifies FRB121102 as repeating and demonstrates that its source survives the energetic events that cause the bursts. Additionally, the bursts from FRB121102 show a wide range of spectral shapes that appear to be predominantly intrinsic to the source and wh...

  16. Spherical Demons: Fast Surface Registration

    Science.gov (United States)

    Yeo, B.T. Thomas; Sabuncu, Mert; Vercauteren, Tom; Ayache, Nicholas; Fischl, Bruce; Golland, Polina

    2009-01-01

    We present the fast Spherical Demons algorithm for registering two spherical images. By exploiting spherical vector spline interpolation theory, we show that a large class of regularizers for the modified demons objective function can be efficiently implemented on the sphere using convolution. Based on the one parameter subgroups of diffeomorphisms, the resulting registration is diffeomorphic and fast – registration of two cortical mesh models with more than 100k nodes takes less than 5 minutes, comparable to the fastest surface registration algorithms. Moreover, the accuracy of our method compares favorably to the popular FreeSurfer registration algorithm. We validate the technique in two different settings: (1) parcellation in a set of in-vivo cortical surfaces and (2) Brodmann area localization in ex-vivo cortical surfaces. PMID:18979813

  17. ATLAS FTK: The Fast Tracker

    CERN Document Server

    T, Iizawa; The ATLAS collaboration

    2014-01-01

    The Fast TracKer (FTK) will perform global track reconstruction after each Level-1 trigger accept to enable the software-based High Level Trigger to have early access to tracking information. FTK is a dedicated processor based on a mixture of advanced technologies. Modern, powerful Field Programmable Gate Arrays (FPGAs) form an important part of the system architecture, and the large level of computing power required for pattern recognition is provided by incorporating standard-cell ASICs named Associative Memory (AM). FTK provides global track reconstruction in the full inner silicon detector in approximately 100 microseconds with resolution comparable to the offline algorithms. It allows a fast and precise detection of the primary and secondary vertex information. The track and vertex information is then used by the High Level Trigger algorithms, allowing highly improved trigger performance for the important signatures such as b-jets. In this paper, the architecture and the hardware development status of FT...

  18. Ultra-fast silicon detectors

    Energy Technology Data Exchange (ETDEWEB)

    Sadrozinski, H. F.-W., E-mail: hartmut@scipp.ucsc.edu [Santa Cruz Institute for Particle Physics, UC Santa Cruz, Santa Cruz, CA 95064 (United States); Ely, S.; Fadeyev, V.; Galloway, Z.; Ngo, J.; Parker, C.; Petersen, B.; Seiden, A.; Zatserklyaniy, A. [Santa Cruz Institute for Particle Physics, UC Santa Cruz, Santa Cruz, CA 95064 (United States); Cartiglia, N.; Marchetto, F. [INFN Torino, Torino (Italy); Bruzzi, M.; Mori, R.; Scaringella, M.; Vinattieri, A. [University of Florence, Department of Physics and Astronomy, Sesto Fiorentino, Firenze (Italy)

    2013-12-01

    We propose to develop a fast, thin silicon sensor with gain capable to concurrently measure with high precision the space (∼10 μm) and time (∼10 ps) coordinates of a particle. This will open up new application of silicon detector systems in many fields. Our analysis of detector properties indicates that it is possible to improve the timing characteristics of silicon-based tracking sensors, which already have sufficient position resolution, to achieve four-dimensional high-precision measurements. The basic sensor characteristics and the expected performance are listed, the wide field of applications are mentioned and the required R and D topics are discussed. -- Highlights: •We are proposing thin pixel silicon sensors with 10's of picoseconds time resolution. •Fast charge collection is coupled with internal charge multiplication. •The truly 4-D sensors will revolutionize imaging and particle counting in many applications.

  19. Fast Moreau envelope computation I

    Science.gov (United States)

    Lucet, Yves

    2006-11-01

    The present article summarizes the state of the art algorithms to compute the discrete Moreau envelope, and presents a new linear-time algorithm, named NEP for NonExpansive Proximal mapping. Numerical comparisons between the NEP and two existing algorithms: The Linear-time Legendre Transform (LLT) and the Parabolic Envelope (PE) algorithms are performed. Worst-case time complexity, convergence results, and examples are included. The fast Moreau envelope algorithms first factor the Moreau envelope as several one-dimensional transforms and then reduce the brute force quadratic worst-case time complexity to linear time by using either the equivalence with Fast Legendre Transform algorithms, the computation of a lower envelope of parabolas, or, in the convex case, the non expansiveness of the proximal mapping.

  20. A fast meteor detection algorithm

    Science.gov (United States)

    Gural, P.

    2016-01-01

    A low latency meteor detection algorithm for use with fast steering mirrors had been previously developed to track and telescopically follow meteors in real-time (Gural, 2007). It has been rewritten as a generic clustering and tracking software module for meteor detection that meets both the demanding throughput requirements of a Raspberry Pi while also maintaining a high probability of detection. The software interface is generalized to work with various forms of front-end video pre-processing approaches and provides a rich product set of parameterized line detection metrics. Discussion will include the Maximum Temporal Pixel (MTP) compression technique as a fast thresholding option for feeding the detection module, the detection algorithm trade for maximum processing throughput, details on the clustering and tracking methodology, processing products, performance metrics, and a general interface description.

  1. Le logiciel FastCart

    OpenAIRE

    1986-01-01

    FastCart est un logiciel destiné à l'enseignement de la géographie. Il permet aux élèves de créer leurs propres documents d'études: histogrammes, cartes en hachures, cartes de classification de l'espace. Sa rapidité d'exécution et sa facilité d'utilisation en font un outil adapté aux exigences des enseignants.

  2. The FastGas detector

    Energy Technology Data Exchange (ETDEWEB)

    Bateman, J.E.; Dalgliesh, R.M. [Science and Technology Facilities Council, Rutherford Appleton Laboratory, Harwell Science and Innovation Campus, Didcot, Oxfordshire, OX11 0QX (United Kingdom); Duxbury, D.M., E-mail: dom.duxbury@stfc.ac.u [Science and Technology Facilities Council, Rutherford Appleton Laboratory, Harwell Science and Innovation Campus, Didcot, Oxfordshire, OX11 0QX (United Kingdom); Holt, S.A.; McPhail, D.J. [Science and Technology Facilities Council, Rutherford Appleton Laboratory, Harwell Science and Innovation Campus, Didcot, Oxfordshire, OX11 0QX (United Kingdom); Marsh, A.S. [Diamond Light Source LTD, Harwell Science and Innovation Campus, Diamond House, Chilton, Didcot, Oxfordshire, OX11 0DE (United Kingdom); Rhodes, N.J.; Schooneveld, E.M.; Spill, E.J.; Stephenson, R. [Science and Technology Facilities Council, Rutherford Appleton Laboratory, Harwell Science and Innovation Campus, Didcot, Oxfordshire, OX11 0QX (United Kingdom)

    2010-04-21

    The development and testing of the FastGas neutron detector is described. Based on a Gas Microstrip Chamber the aim of the project was to produce a high counting rate detector capable of replacing the existing {sup 3}He tubes for specular reflectometry, currently in use on the ISIS reflectometer instruments. The detector system is described together with results of neutron beam tests carried out at the ISIS spallation neutron source.

  3. Instrumentation of the fast detector

    CERN Document Server

    Barczyk, A.; Malgeri, L.; Casella, C.; Pohl, M.; Deiters, K.; Dick, P.; Berdugo, J.; Casaus, J.; Mana, C.; Marin, J.; Martinez, G.; Sanchez, E.; Willmott, C.

    2008-01-01

    The Fiber Active Scintillator Target (FAST) is an imaging particle detector intended for high precision muon lifetime measurement. This measurement will lead to a determination of the Fermi coupling constant (GF) with an uncertainty of 1 ppm, one order of magnitude better than the current world average. This contribution presents a description of the detector instrumentation and the first results, which have validated the design of the system.

  4. Programmable fast data acquisition system

    Science.gov (United States)

    Montebugnoli, S.; Bianchi, G.; Zoni, L.

    The goal of this work is to investigate the possibility to install on modern radiotelescopes a fast and programmable backend instead of several backends, each dedicated to a single acquisition task. Such an approach could lower the costs and make available a more compact and flexible back end. Exploiting the state-of-the-art of the FPGAs (Field Programmable Gate Arrays) and innovative architectures, a programmable system might be conceived.

  5. Fast regularized image interpolation method

    Institute of Scientific and Technical Information of China (English)

    Hongchen Liu; Yong Feng; Linjing Li

    2007-01-01

    The regularized image interpolation method is widely used based on the vector interpolation model in which down-sampling matrix has very large dimension and needs large storage consumption and higher computation complexity. In this paper, a fast algorithm for image interpolation based on the tensor product of matrices is presented, which transforms the vector interpolation model to matrix form. The proposed algorithm can extremely reduce the storage requirement and time consumption. The simulation results verify their validity.

  6. ATLAS Fast Physics Monitoring: TADA

    CERN Document Server

    Elsing, Markus; The ATLAS collaboration; Sabato, Gabriele; Kamioka, Shusei; Nairz, Armin Michael; Moyse, Edward; Gumpert, Christian

    2016-01-01

    The ATLAS Experiment at the LHC is recording data from proton-proton collisions with 13 TeV center-of-mass energy since spring 2015. The collaboration is using a fast physics monitoring framework (TADA) to automatically perform a broad range of fast searches for early signs of new physics and to monitor the data quality across the year with the full analysis level calibrations applied to the rapidly growing data. TADA is designed to provide fast feedback directly after the collected data has been fully calibrated and processed at the Tier-0. The system can monitor a large range of physics channels, offline data quality and physics performance quantities nearly final analysis level object calibrations. TADA output is available on a website accessible by the whole collaboration that gets updated twice a day with the data from newly processed runs. Hints of potentially interesting physics signals or performance issues identified in this way are reported to be followed up by physics or combined performance groups...

  7. ATLAS Fast Physics Monitoring: TADA

    CERN Document Server

    Sabato, Gabriele; The ATLAS collaboration

    2017-01-01

    The ATLAS experiment at the LHC is recording data from proton-proton collisions with 13 TeV center-of-mass energy since spring 2015. The collaboration is using a fast physics monitoring framework (TADA) to automatically perform a broad range of fast searches for early signs of new physics and to monitor the data quality across the year with the full analysis level calibrations applied to the rapidly growing data.TADA is designed to provide fast feedback directly after the collected data has been fully calibrated and processed at the Tier-0, the CERN Data Center. The system can monitor a large range of physics channels, offline data quality and physics performance quantities nearly final analysis level object calibrations. TADA output is available on a website accessible by the whole collaboration that gets updated twice a day with the data from newly processed runs. Hints of potentially interesting physics signals or performance issues identified in this way are reported to be followed up by physics or combin...

  8. Heterogeneous Transmutation Sodium Fast Reactor

    Energy Technology Data Exchange (ETDEWEB)

    S. E. Bays

    2007-09-01

    The threshold-fission (fertile) nature of Am-241 is used to destroy this minor actinide by capitalizing upon neutron capture instead of fission within a sodium fast reactor. This neutron-capture and its subsequent decay chain leads to the breeding of even neutron number plutonium isotopes. A slightly moderated target design is proposed for breeding plutonium in an axial blanket located above the active “fast reactor” driver fuel region. A parametric study on the core height and fuel pin diameter-to-pitch ratio is used to explore the reactor and fuel cycle aspects of this design. This study resulted in both non-flattened and flattened core geometries. Both of these designs demonstrated a high capacity for removing americium from the fuel cycle. A reactivity coefficient analysis revealed that this heterogeneous design will have comparable safety aspects to a homogeneous reactor of comparable size. A mass balance analysis revealed that the heterogeneous design may reduce the number of fast reactors needed to close the current once-through light water reactor fuel cycle.

  9. High-resolution cine MRI with TGRAPPA for fast assessment of left ventricular function at 3 Tesla

    Energy Technology Data Exchange (ETDEWEB)

    Theisen, Daniel, E-mail: daniel.theisen@med.uni-muenchen.de [Department of Clinical Radiology, University Hospitals of Munich Grosshadern, Munich (Germany); Munich Heart Alliance, Munich (Germany); Sandner, Torleif A., E-mail: torleif.sandner@med.uni-muenchen.de [Department of Clinical Radiology, University Hospitals of Munich Grosshadern, Munich (Germany); Bamberg, Fabian, E-mail: fabian.bamberg@med.uni-muenchen.de [Department of Clinical Radiology, University Hospitals of Munich Grosshadern, Munich (Germany); Munich Heart Alliance, Munich (Germany); Bauner, Kerstin U., E-mail: kerstin.bauner@med.uni-muenchen.de [Department of Clinical Radiology, University Hospitals of Munich Grosshadern, Munich (Germany); Schwab, Felix, E-mail: felix.schwab@med.uni-muenchen.de [Department of Clinical Radiology, University Hospitals of Munich Grosshadern, Munich (Germany); Schwarz, Florian, E-mail: florian.schwarz@med.uni-muenchen.de [Department of Clinical Radiology, University Hospitals of Munich Grosshadern, Munich (Germany); Arnoldi, Elisabeth, E-mail: elisabeth.arnoldi@med.uni-muenchen.de [Department of Clinical Radiology, University Hospitals of Munich Grosshadern, Munich (Germany); Reiser, Maximilian F., E-mail: maximilian.reiser@med.uni-muenchen.de [Department of Clinical Radiology, University Hospitals of Munich Grosshadern, Munich (Germany); Munich Heart Alliance, Munich (Germany); Wintersperger, Bernd J., E-mail: bernd.wintersperger@med.uni-muenchen.de [Department of Clinical Radiology, University Hospitals of Munich Grosshadern, Munich (Germany); Department of Medical Imaging, University of Toronto, Toronto, Ontario (Canada)

    2013-05-15

    Purpose: To implement and evaluate the accuracy of multislice dual-breath hold cine MR for analysis of global systolic and diastolic left ventricular function at 3 T. Materials and methods: 25 patients referred to cardiac MR underwent cine imaging at 3 T (MAGNETOM Verio) using prospective triggered SSFP (TR 3.1 ms; TE 1.4 ms; FA 60°). Analysis of LV function was performed using a standard non-accelerated single-slice approach (STD) with multiple breath-holds and an accelerated multi-slice technique (TGRAPPA; R = 4) encompassing the ventricles with 5 slices/breath-hold. Parameters of spatial and temporal resolution were kept identical (pixel: 1.9 × 2.5 mm{sup 2}; temporal resolution: 47 ms). Data of both acquisition techniques were analyzed by two readers using semiautomatic algorithms (syngoARGUS) with respect to EDV, ESV, EF, myocardial mass (MM), peak filling rate (PFR) and peak ejection rate (PER) including assessment of interobserver agreement. Results: Volumetric results of the TGRAPPA approach did not show significant differences to the STD approach for left ventricular ejection fraction (62.3 ± 10.6 vs. 61.0 ± 8.4, P = 0.2), end-diastolic volume (135.8 ± 47.5 vs. 130.8 ± 46.4, P = 0.07), endsystolic volume (53.0 ± 29.7 vs. 53.1 ± 32.7, P = 0.99) and myocardial mass (114.2 ± 32.5 vs. 114.6 ± 30.6, P = 0.9). Moreover, a comparison of peak ejection rate (601.3 ± 190.2 vs. 590.8 ± 218.2, P = 0.8) and peak filling rate (535.1 ± 191.2 vs. 535.4 ± 210.7, P = 0.99) did not reveal significant differences between the two groups. Limits in interobserver agreement were low for all systolic and diastolic parameters in both groups (P ≥ 0.05). Total acquisition time for STD was 273 ± 124 s and 34 ± 5 s for TGRAPPA (P ≤ 0.001). Evaluation time for standard and multislice approach was equal (10.8 ± 1.4 vs. 9.8 ± 2.1 min; P = 0.08)

  10. Fleet Assistance and Support Team (FAST) Lab

    Data.gov (United States)

    Federal Laboratory Consortium — The FAST team was established by PMA-264 for introduction of multistatic ASW systems into the Fleet.FAST provides Air ASW mission planning, tactics/tactical sensor...

  11. The Fast Simulation Chain for ATLAS

    CERN Document Server

    Basalaev, Artem; The ATLAS collaboration

    2017-01-01

    In order to generate the huge number of Monte Carlo events that will be required by the ATLAS experiment over the next several runs, a very fast simulation is critical. Fast detector simulation alone, however, is insufficient: with very high numbers of simultaneous proton-proton collisions expected in Run 3 and beyond, the digitization (detector response emulation) and event reconstruction time quickly become comparable to the time required for detector simulation. The ATLAS Fast Chain simulation has been developed to solve this problem. Modules are implemented for fast simulation, fast digitization, and fast track reconstruction. The application is sufficiently fast - several orders of magnitude faster than the standard simulation - that the simultaneous proton-proton collisions can be generated during the simulation job, so Pythia8 also runs concurrently with the rest of the algorithms. The Fast Chain has been built to be extremely modular and flexible, so that each sample can be custom-tailored to match th...

  12. Fleet Assistance and Support Team (FAST) Lab

    Data.gov (United States)

    Federal Laboratory Consortium — The FAST team was established by PMA-264 for introduction of multistatic ASW systems into the Fleet.FAST provides Air ASW mission planning, tactics/tactical sensor...

  13. The Fast Simulation Chain for ATLAS

    CERN Document Server

    Basalaev, Artem; The ATLAS collaboration

    2016-01-01

    In order to generate the huge number of Monte Carlo events that will be required by the ATLAS experiment over the next several runs, a very fast simulation is critical. Fast detector simulation alone, however, is insufficient: with very high numbers of simultaneous proton-proton collisions expected in Run 3 and beyond, the digitization (detector response emulation) and event reconstruction time quickly become comparable to the time required for detector simulation. The ATLAS Fast Chain simulation has been developed to solve this problem. Modules are implemented for fast simulation, fast digitization, and fast track reconstruction. The application is sufficiently fast -- several orders of magnitude faster than the standard simulation -- that the simultaneous proton-proton collisions can be generated during the simulation job, so Pythia8 also runs concurrently with the rest of the algorithms. The Fast Chain has been built to be extremely modular and flexible, so that each sample can be custom-tailored to match ...

  14. The digital backend of FAST

    Science.gov (United States)

    Yu, Xinying; Zhang, Xia; Duan, Ran; li, di; Hao, Jie

    2015-08-01

    The receiver system is an important part of FAST (Five-hundred-meter Aperture Spherical Radio Telescope) and plays a key role in determining the performance of the telescope.This research covers three major aspects: establishment of system synchronization and timestamps, field-programmable gate array (FPGA)-based data transmission and analysis, and the rear receiver monitoring system. We intend to combine the use of GPS and a frequency standard instrument with network access to Unix timestamps to form actual timestamps. The data are stored with timestamps that contain integer and fractional seconds to be precise and headers, which are primarily intended to distinguish the data from each other.The data analysis procedures includes converting the timestamp information to real-time information, and merging the 8 channels’ data conversion results into frequency and energy data using corresponding conversion formulae. We must develop tailored monitoring software for the FAST receiver to customize the data format and perform data transmission. Signals on the front-end and back-end of the receiver can be monitored and controlled by adjusting the parameters on the software to increase the flexibility of the receiver.Most operations are performed on FPGA board, which can be shown from the figure, including the analog-to-digital conversion (ADC), fast Fourier transform (FFT), and pulse per second (1PPS) and Unix timestamp access operations.When analog data arrive, we initialize two ADCs at a sampling rate of 3Gsps, following by 8-channel FFT parallel processing.In collaboration with the Institute of Automation, we have developed a custom FPGA board which we call "FDB"("FAST Digital Backend"). The board is integrated with two Virtex-6 and one Virtex-5 high-speed Xilinx chips. The main function of the two Virtex-6 devices is to run the FFT and PFB programs, whereas the main function of Virtex-5 is configuration of the board.This research is indispensable for realizing the

  15. Fast Food Paradox: Freedom and Cultural Imperialism

    OpenAIRE

    Lelia Voinea

    2012-01-01

    Fast food is often regarded as a form of cultural imperialism. Fast-food products, originating in the U.S.A., are considered by the critics of this phenomenon as responsible for eroding the interest in local food traditions and affecting their continuity. Based on the results of some researches realized at international and national level, the paper highlights the main issues underlying young people preference for fast-food. The consumption of fast food is associated with the idea of independ...

  16. Fast neutron imaging device and method

    Science.gov (United States)

    Popov, Vladimir; Degtiarenko, Pavel; Musatov, Igor V.

    2014-02-11

    A fast neutron imaging apparatus and method of constructing fast neutron radiography images, the apparatus including a neutron source and a detector that provides event-by-event acquisition of position and energy deposition, and optionally timing and pulse shape for each individual neutron event detected by the detector. The method for constructing fast neutron radiography images utilizes the apparatus of the invention.

  17. Fast Foods, Organic Foods, Fad Diets

    Science.gov (United States)

    There is no standard definition of fast food. Generally, fast food is eaten without cutlery, and fast-food restaurants have no wait staff. Failure to have a standardized definition makes it difficult to compare studies. Foods available outside the home tend to be high in energy and fat compared w...

  18. Self-Gated Free-Breathing 3D Coronary CINE Imaging with Simultaneous Water and Fat Visualization

    Science.gov (United States)

    Liu, Jing; Nguyen, Thanh D.; Zhu, Yanchun; Spincemaille, Pascal; Prince, Martin R.; Weinsaft, Jonathan W.; Saloner, David; Wang, Yi

    2014-01-01

    The aim of this study was to develop a novel technique for acquiring 3-dimensional (3D) coronary CINE magnetic resonance images with both water and fat visualization during free breathing and without external respiratory or cardiac gating. The implemented multi-echo hybrid 3D radial balanced Steady-State Free Precession (SSFP) sequence has an efficient data acquisition and is robust against motion. The k-space center along the slice encoding direction was repeatedly acquired to derive both respiratory and cardiac self-gating signals without an increase in scan time, enabling a free-breathing acquisition. The multi-echo acquisition allowed image reconstruction with water-fat separation, providing improved visualization of the coronary artery lumen. Ten healthy subjects were imaged successfully at 1.5 T, achieving a spatial resolution of 1.0×1.0×3.0 mm3 and scan time of about 5 minutes. The proposed imaging technique provided coronary vessel depiction comparable to that obtained with conventional breath-hold imaging and navigator gated free-breathing imaging. PMID:24586682

  19. Comparison of Fast-Food and Non-Fast-Food Children's Menu Items

    Science.gov (United States)

    Serrano, Elena L.; Jedda, Virginia B.

    2009-01-01

    Objective: Compare the macronutrient content of children's meals sold by fast-food restaurants (FFR) and non-fast-food restaurants (NFF). Design: All restaurants within the designated city limits were surveyed. Non-fast-food children's meals were purchased, weighed, and analyzed using nutrition software. All fast-food children's meals were…

  20. Isochoric implosions for fast ignition

    Energy Technology Data Exchange (ETDEWEB)

    Clark, D S; Tabak, M

    2006-06-05

    Fast Ignition (FI) exploits the ignition of a dense, uniform fuel assembly by an external energy source to achieve high gain. In conventional ICF implosions, however, the fuel assembles as a dense shell surrounding a low density, high-pressure hotspot. Such configurations are far from optimal for FI. Here, it is shown that a self-similar spherical implosion of the type originally studied by Guderley [Luftfahrtforschung 19, 302 (1942).] may be employed to implode a dense, quasi-uniform fuel assembly with minimal energy wastage in forming a hotspot. A scheme for realizing these specialized implosions in a practical ICF target is also described.

  1. Fast, efficient lossless data compression

    Science.gov (United States)

    Ross, Douglas

    1991-01-01

    This paper presents lossless data compression and decompression algorithms which can be easily implemented in software. The algorithms can be partitioned into their fundamental parts which can be implemented at various stages within a data acquisition system. This allows for efficient integration of these functions into systems at the stage where they are most applicable. The algorithms were coded in Forth to run on a Silicon Composers Single Board Computer (SBC) using the Harris RTX2000 Forth processor. The algorithms require very few system resources and operate very fast. The performance of the algorithms with the RTX enables real time data compression and decompression to be implemented for a wide range of applications.

  2. ATLAS FTK Fast Track Trigger

    CERN Document Server

    Iizawa, T; The ATLAS collaboration

    2014-01-01

    The Fast TracKer (FTK) will perform global track reconstruction after each Level-1 trigger accept signal to enable the software-based higher level trigger to have early access to tracking information. FTK is a dedicated processor based on a mixture of advanced technologies. Modern, powerful Field Programmable Gate Arrays (FPGAs) form an important part of the system architecture, and the large level of computing power required for pattern recognition is provided by incorporating standard-cell ASICs named Associative Memory (AM). Motivation and the architecture of the FTK system will be presented, and the status of hardware and simulation will be following.

  3. Fast-acting valve actuator

    Science.gov (United States)

    Cho, Nakwon

    1980-01-01

    A fast-acting valve actuator utilizes a spring driven pneumatically loaded piston to drive a valve gate. Rapid exhaust of pressurized gas from the pneumatically loaded side of the piston facilitates an extremely rapid piston stroke. A flexible selector diaphragm opens and closes an exhaust port in response to pressure differentials created by energizing and de-energizing a solenoid which controls the pneumatic input to the actuator as well as selectively providing a venting action to one side of the selector diaphragm.

  4. Fast global sequence alignment technique

    KAUST Repository

    Bonny, Mohamed Talal

    2011-11-01

    Bioinformatics database is growing exponentially in size. Processing these large amount of data may take hours of time even if super computers are used. One of the most important processing tool in Bioinformatics is sequence alignment. We introduce fast alignment algorithm, called \\'Alignment By Scanning\\' (ABS), to provide an approximate alignment of two DNA sequences. We compare our algorithm with the wellknown sequence alignment algorithms, the \\'GAP\\' (which is heuristic) and the \\'Needleman-Wunsch\\' (which is optimal). The proposed algorithm achieves up to 51% enhancement in alignment score when it is compared with the GAP Algorithm. The evaluations are conducted using different lengths of DNA sequences. © 2011 IEEE.

  5. Concept and canons of fasting in Ayurveda

    Directory of Open Access Journals (Sweden)

    H Shripathi Adiga

    2013-03-01

    Full Text Available Ayurveda, manoeuvres mankind to head a healthy life in order to pursue four-fold bliss. With a view to combat physical and mental annoyances, classics have explicated two-fold therapeutic modalities; langhana/depletion and brihmana/nourishing. Upavasa /fasting is one among ten depletion therapies explained. It is envisioned at all three levels of Ayurvedic therapies- rational/objectively planned, psychological, and spiritual. Fasting is reckoned to be refraining from all forms of food intake for a given period, under supervision of a qualified physician. Acharya Charaka advocates fasting in diseases of milder intensity, in those due to aama (metabolic toxin, after purificatory procedures. Fasting person should avoid beautifying oneself, day sleep, sexual acts, and feasting prior and ulterior to fasting. Fasting is contraindicated in very young, elderly, emaciated, pregnant lady, and shortly after strenuous exercise. The principle avers that fasting kindles metabolic/digestive fire which, in absence of food, brings about paachana of vitiated doshas, thereby riposting health. Sound fasting ensues proper elimination of excretory wastes, clear belch, sweat, and taste for food. Benefits of fasting include lucidity of sense organs, lightness of body and mind, control of diseases, and enthusiasm. Yoga Shastra describes fasting with respect to three levels of food: physical, impressions, and associations and a means to unite three bodies: astral, physical, and causal. Ayurveda thus advocates fasting depending upon the dosha, agni, vaya, kala, and bala of the individual, as a preventive as well as therapeutic modality.

  6. Body composition changes associated with fasted versus non-fasted aerobic exercise

    OpenAIRE

    Schoenfeld, Brad Jon; Aragon, Alan Albert; Wilborn, Colin D; Krieger, James W.; Sonmez, Gul T

    2014-01-01

    It has been hypothesized that performing aerobic exercise after an overnight fast accelerates the loss of body fat. The purpose of this study was to investigate changes in fat mass and fat-free mass following four weeks of volume-equated fasted versus fed aerobic exercise in young women adhering to a hypocaloric diet. Twenty healthy young female volunteers were randomly assigned to 1 of 2 experimental groups: a fasted training (FASTED) group that performed exercise after an overnight fast (n ...

  7. GRIFFIN's Fast-Timing Array

    Science.gov (United States)

    Olaizola, Bruno; Griffin Collaboration

    2016-09-01

    The Gamma-Ray Infrastructure For Fundamental Investigations of Nuclei (GRIFFIN) is the new β-decay spectrometer facility at TRIUMF-ISAC. Consists of an array of 16 large-volume HPGe clover detectors with an unparalleled efficiency of 19% at 1.33 MeV. Its strongest advantage is the versatility of the ancillary detectors that can be coupled to the main array to tag on β particles, neutrons or precisely measure conversion electron spectra. An ancillary array of 8 LaBr3(Ce) detectors for γ-rays and a fast plastic scintillator for β-particles has been optimized for fast-timing experiments with GRIFFIN. The 51 mm x 51 mm cylindrical LaBr3(Ce) crystals are coupled to Hamamatsu R2083 photomultipliers. Timing resolutions as good as FWHM 200 ps and time-walks below +/- 30 ps have been obtained for individual crystals using analog electronics. There is also an ongoing project to develop an active BGO shield for the LaBr3(Ce) crystals. The LaBr3(Ce) array commissioning experiment to measure the 145,146Cs decay to 145,146Ba will test its capabilities over a wide range of lifetimes. Preliminary results on the lifetimes of some of the low-laying states will be presented.

  8. RCD+: Fast loop modeling server.

    Science.gov (United States)

    López-Blanco, José Ramón; Canosa-Valls, Alejandro Jesús; Li, Yaohang; Chacón, Pablo

    2016-07-08

    Modeling loops is a critical and challenging step in protein modeling and prediction. We have developed a quick online service (http://rcd.chaconlab.org) for ab initio loop modeling combining a coarse-grained conformational search with a full-atom refinement. Our original Random Coordinate Descent (RCD) loop closure algorithm has been greatly improved to enrich the sampling distribution towards near-native conformations. These improvements include a new workflow optimization, MPI-parallelization and fast backbone angle sampling based on neighbor-dependent Ramachandran probability distributions. The server starts by efficiently searching the vast conformational space from only the loop sequence information and the environment atomic coordinates. The generated closed loop models are subsequently ranked using a fast distance-orientation dependent energy filter. Top ranked loops are refined with the Rosetta energy function to obtain accurate all-atom predictions that can be interactively inspected in an user-friendly web interface. Using standard benchmarks, the average root mean squared deviation (RMSD) is 0.8 and 1.4 Å for 8 and 12 residues loops, respectively, in the challenging modeling scenario in where the side chains of the loop environment are fully remodeled. These results are not only very competitive compared to those obtained with public state of the art methods, but also they are obtained ∼10-fold faster. © The Author(s) 2016. Published by Oxford University Press on behalf of Nucleic Acids Research.

  9. ATLAS FTK: Fast Track Trigger

    CERN Document Server

    Volpi, Guido; The ATLAS collaboration

    2015-01-01

    An overview of the ATLAS Fast Tracker processor is presented, reporting the design of the system, its expected performance, and the integration status. The next LHC runs, with a significant increase in instantaneous luminosity, will provide a big challenge to the trigger and data acquisition systems of all the experiments. An intensive use of the tracking information at the trigger level will be important to keep high efficiency in interesting events, despite the increase in multiple p-p collisions per bunch crossing (pile-up). In order to increase the use of tracks within the High Level Trigger (HLT), the ATLAS experiment planned the installation of an hardware processor dedicated to tracking: the Fast TracKer (FTK) processor. The FTK is designed to perform full scan track reconstruction at every Level-1 accept. To achieve this goal, the FTK uses a fully parallel architecture, with algorithms designed to exploit the computing power of custom VLSI chips, the Associative Memory, as well as modern FPGAs. The FT...

  10. Universality in fast quantum quenches

    CERN Document Server

    Das, Sumit R; Myers, Robert C

    2014-01-01

    We expand on the investigation of the universal scaling properties in the early time behaviour of fast but smooth quantum quenches in a general $d$-dimensional conformal field theory deformed by a relevant operator of dimension $\\Delta$ with a time-dependent coupling. The quench consists of changing the coupling from an initial constant value $\\lambda_1$ by an amount of the order of $\\delta \\lambda$ to some other final value $\\lambda_2$, over a time scale $\\delta t$. In the fast quench limit where $\\delta t$ is smaller than all other length scales in the problem, $ \\delta t \\ll \\lambda_1^{1/(\\Delta-d)}, \\lambda_2^{1/(\\Delta-d)}, \\delta \\lambda^{1/(\\Delta-d)}$, the energy (density) injected into the system scales as $\\delta{\\cal E} \\sim (\\delta \\lambda)^2 (\\delta t)^{d-2\\Delta}$. Similarly, the change in the expectation value of the quenched operator at times earlier than the endpoint of the quench scales as $\\langle {\\cal O}_\\Delta\\rangle \\sim \\delta \\lambda\\, (\\delta t)^{d-2\\Delta}$, with further logarithmic...

  11. Respiration phase-locks to fast stimulus presentations: implications for the interpretation of posterior midline “deactivations”

    Science.gov (United States)

    Huijbers, W.; Pennartz, C.M.A.; Beldzik, E.; Domagalik, A.; Vinck, M.; Hofman, W.F.; Cabeza, R.; Daselaar, S.M.

    2015-01-01

    The posterior midline region (PMR) –considered a core of the default mode network- is deactivated during successful performance in different cognitive tasks. The extent of PMR-deactivations is correlated with task-demands and associated with successful performance in various cognitive domains. In the domain of episodic memory, functional MRI (fMRI) studies found that PMR-deactivations reliably predict learning (successful encoding). Yet, it is unclear what explains this relation. One intriguing possibility is that PMR-deactivations are partially-mediated by respiratory artifacts. There is evidence that the fMRI signal in PMR is particularly prone to respiratory artifacts, because of its large surrounding blood vessels. Since respiratory fluctuations has been shown to track changes in attention, it is critical for the general interpretation of fMRI results to clarify the relation between respiratory fluctuations, cognitive performance, and fMRI signal. Here, we investigated this issue by measuring respiration during word encoding, together with a breath-holding condition during fMRI-scanning. Stimulus-locked respiratory analyses showed that respiratory fluctuations predicted successful encoding via a respiratory phase-locking mechanism. At the same time, the fMRI analyses showed that PMR-deactivations associated with learning were reduced during breath-holding and correlated with individual differences in the respiratory phase-locking effect during normal breathing. A left frontal region –used as a control region– did not show these effects. These findings indicate that respiration is a critical factor in explaining the link between PMR-deactivation and successful cognitive performance. Further research is necessary to demonstrate whether our findings are restricted to episodic memory encoding, or also extend to other cognitive domains. PMID:24737724

  12. Fast Steerable Principal Component Analysis.

    Science.gov (United States)

    Zhao, Zhizhen; Shkolnisky, Yoel; Singer, Amit

    2016-03-01

    Cryo-electron microscopy nowadays often requires the analysis of hundreds of thousands of 2-D images as large as a few hundred pixels in each direction. Here, we introduce an algorithm that efficiently and accurately performs principal component analysis (PCA) for a large set of 2-D images, and, for each image, the set of its uniform rotations in the plane and their reflections. For a dataset consisting of n images of size L × L pixels, the computational complexity of our algorithm is O(nL(3) + L(4)), while existing algorithms take O(nL(4)). The new algorithm computes the expansion coefficients of the images in a Fourier-Bessel basis efficiently using the nonuniform fast Fourier transform. We compare the accuracy and efficiency of the new algorithm with traditional PCA and existing algorithms for steerable PCA.

  13. First results on fast baking

    Energy Technology Data Exchange (ETDEWEB)

    Visentin, B. [CEA-Saclay, DSM/DAPNIA/SACM - 91191 Gif/Yvette Cedex (France)]. E-mail: bvisentin@cea.fr; Gasser, Y. [CEA-Saclay, DSM/DAPNIA/SACM - 91191 Gif/Yvette Cedex (France); Charrier, J.P. [CEA-Saclay, DSM/DAPNIA/SACM - 91191 Gif/Yvette Cedex (France)

    2006-07-15

    High gradient performances of bulk niobium cavities go through a low-temperature baking during one or two days, the temperature parameter is adjusted in a narrow tuning range around 110 or 120deg, C. With such treatment, the intrinsic quality factor Q{sub 0} is improved at high fields. Assuming the oxygen diffusion is involved in this phenomenon, we have developed the 'fast baking' (145deg, C/3h) as an alternative method. Similar results have been achieved with this method compared to standard baking. Consequently, for the first time, a link between oxygen diffusion and high field Q-slope has been demonstrated. Furthermore, this method open the way to a simpler and better baking procedure for the large-scale cavity production due to:*time reduction and *possibility to combine baking and drying during cavity preparation.

  14. First results on fast baking

    Science.gov (United States)

    Visentin, B.; Gasser, Y.; Charrier, J. P.

    2006-07-01

    High gradient performances of bulk niobium cavities go through a low-temperature baking during one or two days, the temperature parameter is adjusted in a narrow tuning range around 110 or 120 °C. With such treatment, the intrinsic quality factor Q0 is improved at high fields. Assuming the oxygen diffusion is involved in this phenomenon, we have developed the “fast baking” (145 °C/3 h) as an alternative method. Similar results have been achieved with this method compared to standard baking. Consequently, for the first time, a link between oxygen diffusion and high field Q-slope has been demonstrated. Furthermore, this method open the way to a simpler and better baking procedure for the large-scale cavity production due to: time reduction and possibility to combine baking and drying during cavity preparation.

  15. Fast Reference-Based MRI

    CERN Document Server

    Weizman, Lior; Ben-Basaht, Dafna

    2015-01-01

    In many clinical MRI scenarios, existing imaging information can be used to significantly shorten acquisition time or to improve Signal to Noise Ratio (SNR). In some cases, a previously acquired image can serve as a reference image, that may exhibit similarity to the image being acquired. Examples include similarity between adjacent slices in high resolution MRI, similarity between various contrasts in the same scan and similarity between different scans of the same patient. In this paper we present a general framework for utilizing reference images for fast MRI. We take into account that the reference image may exhibit low similarity with the acquired image and develop an iterative weighted approach for reconstruction, which tunes the weights according to the degree of similarity. Experiments demonstrate the performance of the method in three different clinical MRI scenarios: SNR improvement in high resolution brain MRI, utilizing similarity between T2-weighted and fluid-attenuated inversion recovery (FLAIR)...

  16. Fast-Growing Vestibular Schwannoma

    Science.gov (United States)

    Falcioni, Maurizio; Taibah, Abdelkader; De Donato, Giuseppe; Piccirillo, Enrico; Russo, Alessandra; Sanna, Mario

    2000-01-01

    A case of a Jehovah's witness affected by an intracanalicular vestibular schwannoma with an extremely fast growth rate is presented. Nine months after presentation, the tumor reached 23 mm in the cerebellopontine angle. A partial removal through a retrosigmoid approach was planned. Because of the presence of a dominant high jugular bulb masquering the internal auditory canal, the intracanalicular portion of the tumor was left in place. The residual tumor grew 12 mm in 2 months. Even after a gross total removal through a middle cranial fossa approach, the tumor recurred, reaching the size of 30 mm in 17 months. A modified transcochlear approach was then performed, and the patient was free of disease at the last radiologic follow-up, 8 months after the surgery. We illustrate our strategy in treating this aggressive benign lesion with unusual behavior. ImagesFigure 1Figure 2Figure 3Figure 4Figure 5Figure 6Figure 7Figure 8Figure 9Figure 10 PMID:17171109

  17. Fast breeder reactor protection system

    Science.gov (United States)

    van Erp, J.B.

    1973-10-01

    Reactor protection is provided for a liquid-metal-fast breeder reactor core by measuring the coolant outflow temperature from each of the subassemblies of the core. The outputs of the temperature sensors from a subassembly region of the core containing a plurality of subassemblies are combined in a logic circuit which develops a scram alarm if a predetermined number of the sensors indicate an over temperature condition. The coolant outflow from a single subassembly can be mixed with the coolant outflow from adjacent subassemblies prior to the temperature sensing to increase the sensitivity of the protection system to a single subassembly failure. Coherence between the sensors can be required to discriminate against noise signals. (Official Gazette)

  18. Proof of Concept to Isolate and Culture Primary Muscle Cells from Northern Elephant Seals to Study the Mechanisms that Maintain Aerobic Metabolism Under the Hypoxic Conditions of Breath-Hold Diving

    Science.gov (United States)

    2014-09-30

    be resolvable with the addition both antibiotics and antimycotics to the transfer and culturing medias. With those changes and our anticipated...transfer cells exclusively in F10 (with antibiotics /antimycotics) for the next field trip. February 2013 With newly-weaned pups available to...2012) and plated onto gelatin-coated plates for proliferation. During this stage the cells were allowed to proliferate and frozen in fetal bovine

  19. Evaluation of LV global function of CHD patients with breath-hold cine-MRI%屏气磁共振电影成像对冠心病患者左心室整体功能的评价

    Institute of Scientific and Technical Information of China (English)

    盛复庚; 高元桂; 安宁豫; 程流泉; 蔡幼铨; 孙玮; 李功杰

    2008-01-01

    目的 探讨屏气磁共振电影成像(Cine-MRI)对冠心病患者左心室整体功能的评价.方法 对34例获得冠状动脉导管造影(CCA)结果 的冠心病患者行Cine-MRI获得短轴位和垂直长轴位电影图像,测量左心室整体功能参数.以CCA判断的冠状动脉狭窄程度为金标准,对各项整体功能参数行统计学评价.结果 冠心病患者表现为心肌质量和心室容积增加,前者具有相对较高的灵敏度、特异度、准确度,舒张期的改变较收缩期敏感;EF和SV下降,具有较高的特异度.结论 屏气Cine-MRI能够较好地评价左心室整体功能,客观反映冠心病患者左心室整体功能的收缩、舒张状态.

  20. Heterogeneous Recycling in Fast Reactors

    Energy Technology Data Exchange (ETDEWEB)

    Forget, Benoit; Pope, Michael; Piet, Steven J.; Driscoll, Michael

    2012-07-30

    Current sodium fast reactor (SFR) designs have avoided the use of depleted uranium blankets over concerns of creating weapons grade plutonium. While reducing proliferation risks, this restrains the reactor design space considerably. This project will analyze various blanket and transmutation target configurations that could broaden the design space while still addressing the non-proliferation issues. The blanket designs will be assessed based on the transmutation efficiency of key minor actinide (MA) isotopes and also on mitigation of associated proliferation risks. This study will also evaluate SFR core performance under different scenarios in which depleted uranium blankets are modified to include minor actinides with or without moderators (e.g. BeO, MgO, B4C, and hydrides). This will be done in an effort to increase the sustainability of the reactor and increase its power density while still offering a proliferation resistant design with the capability of burning MA waste produced from light water reactors (LWRs). Researchers will also analyze the use of recycled (as opposed to depleted) uranium in the blankets. The various designs will compare MA transmutation efficiency, plutonium breeding characteristics, proliferation risk, shutdown margins and reactivity coefficients with a current reference sodium fast reactor design employing homogeneous recycling. The team will also evaluate the out-of-core accumulation and/or burn-down rates of MAs and plutonium isotopes on a cycle-by-cycle basis. This cycle-by-cycle information will be produced in a format readily usable by the fuel cycle systems analysis code, VISION, for assessment of the sustainability of the deployment scenarios.

  1. FastBit Reference Manual

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Kesheng

    2007-08-02

    An index in a database system is a data structure that utilizes redundant information about the base data to speed up common searching and retrieval operations. Most commonly used indexes are variants of B-trees, such as B+-tree and B*-tree. FastBit implements a set of alternative indexes call compressed bitmap indexes. Compared with B-tree variants, these indexes provide very efficient searching and retrieval operations by sacrificing the efficiency of updating the indexes after the modification of an individual record. In addition to the well-known strengths of bitmap indexes, FastBit has a special strength stemming from the bitmap compression scheme used. The compression method is called the Word-Aligned Hybrid (WAH) code. It reduces the bitmap indexes to reasonable sizes and at the same time allows very efficient bitwise logical operations directly on the compressed bitmaps. Compared with the well-known compression methods such as LZ77 and Byte-aligned Bitmap code (BBC), WAH sacrifices some space efficiency for a significant improvement in operational efficiency. Since the bitwise logical operations are the most important operations needed to answer queries, using WAH compression has been shown to answer queries significantly faster than using other compression schemes. Theoretical analyses showed that WAH compressed bitmap indexes are optimal for one-dimensional range queries. Only the most efficient indexing schemes such as B+-tree and B*-tree have this optimality property. However, bitmap indexes are superior because they can efficiently answer multi-dimensional range queries by combining the answers to one-dimensional queries.

  2. Studies on the Mechanism of Fasting Hyperbilirubinemia

    Science.gov (United States)

    bilirubin from the plasma (CBr) was reduced by 28 to 54% during fasting , accounting for the increase in Br. The ratio of the plasma bilirubin...turnover during fasting to that in base line state was 0.99 plus or minus 0.16 (mean plus or minus SD) for these five individuals, indicating that increased...plasma bilirubin turnover did not contribute to the rise in Br. In 5 additional subjects the mean change in carbon monoxide production with fasting

  3. Fast Computation on the Modern Battlefield

    Science.gov (United States)

    2015-04-01

    ARL-TR-7276 ● APR 2015 US Army Research Laboratory Fast Computation on the Modern Battlefield by David L Doria, Jamie K...when it is no longer needed. Do not return it to the originator. ARL-TR-7276 ● APR 2015 US Army Research Laboratory Fast ...TO THE ABOVE ADDRESS. 1. REPORT DATE (DD-MM-YYYY) April 2015 2. REPORT TYPE Final 3. DATES COVERED (From - To) NA 4. TITLE AND SUBTITLE Fast

  4. Fast plunges into Kerr black holes

    OpenAIRE

    Hadar, Shahar; Porfyriadis, Achilleas; Strominger, Andrew E.

    2015-01-01

    Most extreme-mass-ratio-inspirals of small compact objects into supermassive black holes end with a fast plunge from an eccentric last stable orbit. For rapidly rotating black holes such fast plunges may be studied in the context of the Kerr/CFT correspondence because they occur in the near-horizon region where dynamics are governed by the infinite dimensional conformal symmetry. In this paper we use conformal transformations to analytically solve for the radiation emitted from fast plunges i...

  5. Fast Generation of Discrete Random Variables

    Directory of Open Access Journals (Sweden)

    George Marsaglia

    2004-07-01

    Full Text Available We describe two methods and provide C programs for generating discrete random variables with functions that are simple and fast, averaging ten times as fast as published methods and more than five times as fast as the fastest of those. We provide general procedures for implementing the two methods, as well as specific procedures for three of the most important discrete distributions: Poisson, binomial and hypergeometric.

  6. Ramadan fasting: Do we need more evidence?

    Directory of Open Access Journals (Sweden)

    Mohsen Nematy

    2015-03-01

    Full Text Available Over a billion of Muslims fast worldwide during Ramadan each year. Through this religious custom, fasting contributes to their health as well as their spiritual growth. However, available evidence regarding the health-benefits of Ramadan fasting is scarce and highly contentious. Although Islam exempts patients from fasting, many fast conceivably, and their clinical condition is prone to deteriorate due to persistent gap between current expert knowledge and conclusive strong evidence regarding the pathophysiologic and metabolic alterations of fasting and the consensus that should be taken into account to implements guided managing of various patient groups during Ramadan fasting among health care professionals. In this article, we summarized the results of initial studies regarding the effects of Ramadan fasting on some clinical conditions including alterations of body composition and clinically important outcomes of patients with a previous history of cardiovascular disease, asthma and renal colic disease. Our studies have shed light on several outcomes in favor of Ramadan fasting, and encourage those with mentioned diseases to consult their physicians and follow medical and scientific recommendations. In this review we aimed to present a piece of relevant evidence, clarify future scope and provide suggestions for future investigations.

  7. The new ATLAS Fast Calorimeter Simulation

    CERN Document Server

    Schaarschmidt, Jana; The ATLAS collaboration

    2017-01-01

    Current and future need for large scale simulated samples motivate the development of reliable fast simulation techniques. The new Fast Calorimeter Simulation is an improved parameterized response of single particles in the ATLAS calorimeter, that aims to accurately emulate the key features of the detailed calorimeter response as simulated with Geant4, yet approximately ten times faster. Principal component analysis and machine learning techniques are used to improve the performance and decrease the memory need compared to the current version of the ATLAS Fast Calorimeter Simulation. A prototype of this new Fast Calorimeter Simulation is in development and its integration into the ATLAS simulation infrastructure is ongoing.

  8. Fasting: Molecular Mechanisms and Clinical Applications

    Science.gov (United States)

    Longo, Valter D.; Mattson, Mark P.

    2014-01-01

    Fasting has been practiced for millennia, but only recently studies have shed light on its role in adaptive cellular responses that reduce oxidative damage and inflammation, optimize energy metabolism and bolster cellular protection. In lower eukaryotes, chronic fasting extends longevity in part by reprogramming metabolic and stress resistance pathways. In rodents intermittent or periodic fasting protects against diabetes, cancers, heart disease and neurodegeneration, while in humans it helps reduce obesity, hypertension, asthma and rheumatoid arthritis. Thus, fasting has the potential to delay aging and help prevent and treat diseases while minimizing the side effects caused by chronic dietary interventions. PMID:24440038

  9. Fast breeder reactors an engineering introduction

    CERN Document Server

    Judd, A M

    1981-01-01

    Fast Breeder Reactors: An Engineering Introduction is an introductory text to fast breeder reactors and covers topics ranging from reactor physics and design to engineering and safety considerations. Reactor fuels, coolant circuits, steam plants, and control systems are also discussed. This book is comprised of five chapters and opens with a brief summary of the history of fast reactors, with emphasis on international and the prospect of making accessible enormous reserves of energy. The next chapter deals with the physics of fast reactors and considers calculation methods, flux distribution,

  10. SPIO-enhanced MR imaging for HCC detection in cirrhotic patient : comparison of various techniques for optimal sequence selection

    Energy Technology Data Exchange (ETDEWEB)

    Kim, In Hwan; Lee, Jeong Min; Kwak, Hyo Sung; Kim, Chong Soo; Yu, Hee Chul [Chonbuk National University Hospital, Chonju (Korea, Republic of); Kim, Tae Kon; Lee Soo Tiek [Medical School, Chonbuk National University, Chonju (Korea, Republic of)

    2000-05-01

    To compare the efficacy of breathhold and non-breathhold sequences in the detection of hepatocellular carcinoma (HCC) in cirrhotic patients using superparamagnetic iron oxide (SPIO)-enhanced MR imaging, and to determine the optimal sequence combination. By means of unenhanced and iron-oxide-enhanced MRI, 29 patients with 49 nodular HCCs were evaluated for the presence of HCC nodules. Twenty-one were male and eight were female, and their ages ranged from 38 to 71 (mean, 56) years. Eight different MR sequences were used, including four non-breath-hold sequences and four breath-hold, and images were obtained before and after the administration of SPIO particles. Non-breath-hold sequences included T2-, proton density-weighted SE, and TSE imaging, while breath-hold sequences comprised T1-weighted fast low-angle shot (T1w FLASH), half-Fourier acquisition single shot turbo spine echo (HASTE), T2-weighted fast imaging with steady-state free precession (T2{sup *}wFISP) and T2-weighted breath-hold TSE (T2wBHTSE). Image analysis involved both quantitative and qualitative analysis. The quantitative parameters calculated were signal-to noise (S/N) ratios for livers and tumors, contrast to noise (C/N) ratios for tumors seen on precontrast and postcontrast images, and percentage of signal intensity loss (PSIL) after SPIO injection. Images were analysed qualitatively in terms of image artifacts and lesion conspicuity, and prior to calculating sensitivity, the number of lesions detected using various pulse sequences were counted. SPIO had a marked effect on liver S/N ratio but a minimal effect on tumor S/N ratio. PSIL was best in T2{sup *}wFISP images, while T2wSE images showed the second-best results (p less than 0.05). Tumor-to-liver C/N values were also highest with T2{sup *}wFISP, while T2wTSE and HASTE images were next. Qualitative study showed that non-breath hold images and FISP were better than breath hold images in terms of lesion conspicuity. The latter, however, were

  11. ATLAS Fast Tracker Simulation Challenges

    CERN Document Server

    Adelman, Jahred; The ATLAS collaboration; Borodin, Mikhail; Chakraborty, Dhiman; García Navarro, José Enrique; Golubkov, Dmitry; Kama, Sami; Panitkin, Sergey; Smirnov, Yuri; Stewart, Graeme; Tompkins, Lauren; Vaniachine, Alexandre; Volpi, Guido

    2015-01-01

    To deal with Big Data flood from the ATLAS detector most events have to be rejected in the trigger system. the trigger rejection is complicated by the presence of a large number of minimum-bias events – the pileup. To limit pileup effects in the high luminosity environment of the LHC Run-2, ATLAS relies on full tracking provided by the Fast TracKer (FTK) implemented with custom electronics. The FTK data processing pipeline has to be simulated in preparation for LHC upgrades to support electronics design and develop trigger strategies at high luminosity. The simulation of the FTK - a highly parallelized system - has inherent performance bottlenecks on general-purpose CPUs. To take advantage of the Grid Computing power, the FTK simulation is integrated with Monte Carlo simulations at the Production System level above the ATLAS workload management system PanDA. We report on ATLAS experience with FTK simulations on the Grid and next steps for accommodating the growing requirements for resources during the LHC R...

  12. Fast and scalable inequality joins

    KAUST Repository

    Khayyat, Zuhair

    2016-09-07

    Inequality joins, which is to join relations with inequality conditions, are used in various applications. Optimizing joins has been the subject of intensive research ranging from efficient join algorithms such as sort-merge join, to the use of efficient indices such as (Formula presented.)-tree, (Formula presented.)-tree and Bitmap. However, inequality joins have received little attention and queries containing such joins are notably very slow. In this paper, we introduce fast inequality join algorithms based on sorted arrays and space-efficient bit-arrays. We further introduce a simple method to estimate the selectivity of inequality joins which is then used to optimize multiple predicate queries and multi-way joins. Moreover, we study an incremental inequality join algorithm to handle scenarios where data keeps changing. We have implemented a centralized version of these algorithms on top of PostgreSQL, a distributed version on top of Spark SQL, and an existing data cleaning system, Nadeef. By comparing our algorithms against well-known optimization techniques for inequality joins, we show our solution is more scalable and several orders of magnitude faster. © 2016 Springer-Verlag Berlin Heidelberg

  13. Isochoric Implosions for Fast Ignition

    Energy Technology Data Exchange (ETDEWEB)

    Clark, D S; Tabak, M

    2007-04-04

    Various gain models have shown the potentially great advantages of Fast Ignition (FI) Inertial Confinement Fusion (ICF) over its conventional hot spot ignition counterpart [e.g., S. Atzeni, Phys. Plasmas 6, 3316 (1999); M. Tabak et al., Fusion Sci. & Technology 49, 254 (2006)]. These gain models, however, all assume nearly uniform-density fuel assemblies. In contrast, conventional ICF implosions yield hollowed fuel assemblies with a high-density shell of fuel surrounding a low-density, high-pressure hot spot. Hence, to realize fully the advantages of FI, an alternative implosion design must be found which yields nearly isochoric fuel assemblies without substantial hot spots. Here, it is shown that a self-similar spherical implosion of the type originally studied by Guderley [Luftfahrtforschung 19, 302 (1942)] may be employed to yield precisely such quasi-isochoric imploded states. The difficulty remains, however, of accessing these self-similarly imploding configurations from initial conditions representing an actual ICF target, namely a uniform, solid-density shell at rest. Furthermore, these specialized implosions must be realized for practicable drive parameters and at the scales and energies of interest in ICF. A direct-drive implosion scheme is presented which meets all of these requirements and reaches a nearly isochoric assembled density of 300 g=cm{sup 3} and areal density of 2.4 g=cm{sup 2} using 485 kJ of laser energy.

  14. [Fast neutron cross section measurements

    Energy Technology Data Exchange (ETDEWEB)

    Knoll, G.F.

    1992-10-26

    From its inception, the Nuclear Data Project at the University of Michigan has concentrated on two major objectives: (1) to carry out carefully controlled nuclear measurements of the highest possible reliability in support of the national nuclear data program, and (2) to provide an educational opportunity for students with interests in experimental nuclear science. The project has undergone a successful transition from a primary dependence on our photoneutron laboratory to one in which our current research is entirely based on a unique pulsed 14 MeV fast neutron facility. The new experimental facility is unique in its ability to provide nanosecond bursts of 14 MeV neutrons under conditions that are clean'' and as scatter-free as possible, and is the only one of its type currently in operation in the United States. It has been designed and put into operation primarily by graduate students, and has met or exceeded all of its important initial performance goals. We have reached the point of its routine operation, and most of the data are now in hand that will serve as the basis for the first two doctoral dissertations to be written by participating graduate students. Our initial results on double differential neutron cross sections will be presented at the May 1993 Fusion Reactor Technology Workshop. We are pleased to report that, after investing several years in equipment assembly and optimization, the project has now entered its data production'' phase.

  15. GROMACS: fast, flexible, and free.

    Science.gov (United States)

    Van Der Spoel, David; Lindahl, Erik; Hess, Berk; Groenhof, Gerrit; Mark, Alan E; Berendsen, Herman J C

    2005-12-01

    This article describes the software suite GROMACS (Groningen MAchine for Chemical Simulation) that was developed at the University of Groningen, The Netherlands, in the early 1990s. The software, written in ANSI C, originates from a parallel hardware project, and is well suited for parallelization on processor clusters. By careful optimization of neighbor searching and of inner loop performance, GROMACS is a very fast program for molecular dynamics simulation. It does not have a force field of its own, but is compatible with GROMOS, OPLS, AMBER, and ENCAD force fields. In addition, it can handle polarizable shell models and flexible constraints. The program is versatile, as force routines can be added by the user, tabulated functions can be specified, and analyses can be easily customized. Nonequilibrium dynamics and free energy determinations are incorporated. Interfaces with popular quantum-chemical packages (MOPAC, GAMES-UK, GAUSSIAN) are provided to perform mixed MM/QM simulations. The package includes about 100 utility and analysis programs. GROMACS is in the public domain and distributed (with source code and documentation) under the GNU General Public License. It is maintained by a group of developers from the Universities of Groningen, Uppsala, and Stockholm, and the Max Planck Institute for Polymer Research in Mainz. Its Web site is http://www.gromacs.org.

  16. Fast Mapping in Late-Talking Toddlers

    Science.gov (United States)

    Weismer, Susan Ellis; Venker, Courtney E.; Evans, Julia L.; Moyle, Maura Jones

    2013-01-01

    This study investigated fast mapping in late-talking (LT) toddlers and toddlers with normal language (NL) development matched on age, nonverbal cognition, and maternal education. The fast-mapping task included novel object labels and familiar words. The LT group scored significantly lower than the NL group on novel word comprehension and…

  17. Fast Mapping by Bilingual Preschool Children

    Science.gov (United States)

    Kana, Pui Fong; Kohnert, Kathryn

    2008-01-01

    Previous studies show that young monolingual children's ability to "fast map" new word forms is closely associated with both their age and existing vocabulary knowledge. In this study we investigate potential relationships between age, fast mapping skills and existing vocabulary knowledge in both languages of developing bilingual preschool…

  18. Can Fast and Slow Intelligence Be Differentiated?

    Science.gov (United States)

    Partchev, Ivailo; De Boeck, Paul

    2012-01-01

    Responses to items from an intelligence test may be fast or slow. The research issue dealt with in this paper is whether the intelligence involved in fast correct responses differs in nature from the intelligence involved in slow correct responses. There are two questions related to this issue: 1. Are the processes involved different? 2. Are the…

  19. Fast Mapping Verb Meaning from Argument Structure

    Science.gov (United States)

    Johnson, Valerie E.

    2010-01-01

    Purpose: To examine lexical knowledge in children through a fast mapping task. Method: This study compared the performance of 60 African American English-speaking and general American English-speaking children between the ages of 4 and 6 years. They were presented with a comprehension task involving the fast mapping of novel verbs in 4 different…

  20. Effect of fasting on renal physiology

    Directory of Open Access Journals (Sweden)

    Achraf Hendawy

    2014-11-01

    Full Text Available Total abstention from food and water from sunrise to sunset during the month of Ramadan, is practiced by hundreds of millions of Muslims throughout the world. This pattern of fasting during Ramadan is different from the usual fasting as people are allowed to eat and drink between sunset and dawn but not after dawn. The amount and type of food (rich in protein, fat and sugar eaten during the night may also be significantly different to that usually consumed during the rest of the year, while in other countries factors such as poverty ensure that the Ramadan fast results in a reduction in energy intake and a loss of body fat. Also, climate and duration of fasting differs from region to another. According to Islam, sick people are exempted from Fasting, but still a significant number of patients with various chronic diseases including chronic kidney diseases (CKD insist on fasting in Ramadan due to their personal beliefs and physicians are facing this problem every year: What to advice their patients as there are no guidelines or protocols about who can and who cannot fast. In general no detrimental effects on health have been directly attributed to fasting during Ramadan. However caution is advised for moderate to severe CKD patients and the physicians should monitor their patients carefully during Ramadan in order to avoid any deleterious effects.

  1. Advanced Safeguards Approaches for New Fast Reactors

    Energy Technology Data Exchange (ETDEWEB)

    Durst, Philip C.; Therios, Ike; Bean, Robert; Dougan, A.; Boyer, Brian; Wallace, Rick L.; Ehinger, Michael H.; Kovacic, Don N.; Tolk, K.

    2007-12-15

    This third report in the series reviews possible safeguards approaches for new fast reactors in general, and the ABR in particular. Fast-neutron spectrum reactors have been used since the early 1960s on an experimental and developmental level, generally with fertile blanket fuels to “breed” nuclear fuel such as plutonium. Whether the reactor is designed to breed plutonium, or transmute and “burn” actinides depends mainly on the design of the reactor neutron reflector and the whether the blanket fuel is “fertile” or suitable for transmutation. However, the safeguards issues are very similar, since they pertain mainly to the receipt, shipment and storage of fresh and spent plutonium and actinide-bearing “TRU”-fuel. For these reasons, the design of existing fast reactors and details concerning how they have been safeguarded were studied in developing advanced safeguards approaches for the new fast reactors. In this regard, the design of the Experimental Breeder Reactor-II “EBR-II” at the Idaho National Laboratory (INL) was of interest, because it was designed as a collocated fast reactor with a pyrometallurgical reprocessing and fuel fabrication line – a design option being considered for the ABR. Similarly, the design of the Fast Flux Facility (FFTF) on the Hanford Site was studied, because it was a successful prototype fast reactor that ran for two decades to evaluate fuels and the design for commercial-scale fast reactors.

  2. Predictors of Ramadan fasting during pregnancy

    NARCIS (Netherlands)

    van Bilsen, Lily A.; Savitri, Ary I.; Amelia, Dwirani; Baharuddin, Mohammad; Grobbee, Diederick E.; Uiterwaal, Cuno S P M

    2016-01-01

    Although the health effects of Ramadan fasting during pregnancy are still unclear, it is important to identify the predictors and motivational factors involved in women's decision to observe the fast. We investigated these factors in a cross sectional study of 187 pregnant Muslim women who attended

  3. Predictors of Ramadan fasting during pregnancy

    NARCIS (Netherlands)

    van Bilsen, Lily A.; Savitri, Ary I.; Amelia, Dwirani; Baharuddin, Mohammad; Grobbee, Diederick E.; Uiterwaal, Cuno S P M

    2016-01-01

    Although the health effects of Ramadan fasting during pregnancy are still unclear, it is important to identify the predictors and motivational factors involved in women's decision to observe the fast. We investigated these factors in a cross sectional study of 187 pregnant Muslim women who attended

  4. Nutrient quality of fast food kids meals

    Science.gov (United States)

    Exposure of children to kids’ meals at fast food restaurants is high; however, the nutrient quality of such meals has not been systematically assessed. We assessed the nutrient quality of fast food meals marketed to young children, i.e., "kids meals". The nutrient quality of kids’ meals was assessed...

  5. Optical imaging of fast, dynamic neurophysiological function.

    Energy Technology Data Exchange (ETDEWEB)

    Rector, D. M. (David M.); Carter, K. M. (Kathleen M.); Yao, X. (Xincheng); George, J. S. (John S.)

    2002-01-01

    Fast evoked responses were imaged from rat dorsal medulla and whisker barrel cortex. To investigate the biophysical mechanisms involved, fast optical responses associated with isolated crustacean nerve stimulation were recorded using birefringence and scattered light. Such studies allow optimization of non-invasive imaging techniques being developed for use in humans.

  6. Fast Food in the U.S.

    Institute of Scientific and Technical Information of China (English)

    朱大龙

    2001-01-01

    The favorite food in the United States is the hamburger, a kind of round sandwich of cooked ground beef. The favorite place to buy a hamburger is a fast food restaurant. At fast food restaurants people order their food, wait a few minutes, and carry it to their tables themselves.

  7. Fast Qualification Methods for Microelectronic Packages

    NARCIS (Netherlands)

    Ma, X.

    2011-01-01

    This research aims at developing a knowledge based fast qualification method for moisture or thermally induced failure in microelectronic packages. Driven by the market competition and the need for shorter time to market, fast qualification tests are becoming more and more important for the industry

  8. PARALLEL IMPLEMENTATIONS OF THE FAST SWEEPING METHOD

    Institute of Scientific and Technical Information of China (English)

    Hongkai Zhao

    2007-01-01

    The fast sweeping method is an efficient iterative method for hyperbolic problems.It combines Gauss-Seidel iterations with alternating sweeping orderings.In this paper several parallel implementations of the fast sweeping method are presented. These parallel algorithms are simple and efficient due to the causality of the underlying partial different equations. Numerical examples are used to verify our algorithms.

  9. Can fast and slow intelligence be differentiated?

    NARCIS (Netherlands)

    Partchev, I.; de Boeck, P.

    2012-01-01

    Responses to items from an intelligence test may be fast or slow. The research issue dealt with in this paper is whether the intelligence involved in fast correct responses differs in nature from the intelligence involved in slow correct responses. There are two questions related to this issue: 1.

  10. FAST TCP: From Theory to Experiments

    Energy Technology Data Exchange (ETDEWEB)

    Jin, C.

    2004-11-23

    We describe a variant of TCP, called FAST, that can sustain high throughput and utilization at multi-Gbps over large distance. We present the motivation, review the background theory, summarize key features of FAST TCP, and report our first experimental results.

  11. Fast-track revision knee arthroplasty

    DEFF Research Database (Denmark)

    Husted, Henrik; Otte, Niels Kristian Stahl; Kristensen, Billy B;

    2011-01-01

    Abstract Background and purpose Fast-track surgery has reduced the length of hospital stay (LOS), morbidity, and convalescence in primary hip and knee arthroplasty (TKA). We assessed whether patients undergoing revision TKA for non-septic indications might also benefit from fast-track surgery...

  12. Fast Implicit Methods for Stiff Moving Interfaces

    Science.gov (United States)

    2011-03-16

    y) of the elliptic system (2): multiplying Eq. (2) by S, integrating over Ω and applying Gauss ’ theorem yields 1 2 µ(γ)− ∫ Γ P (γ)S(γ − σ)An(σ)µ(σ...Fast ADI iteration for first-order elliptic systems. Preprint, UC Berke- ley Mathematics Department, 2011. [15] J. Strain. Geometric nonuniform fast

  13. The effect of fasting on surgical performance

    DEFF Research Database (Denmark)

    Schefte, David Fenger; Rosenstock, Steffen Jais

    2016-01-01

    BACKGROUND: It is unknown whether fasting has any impact on surgical performance. This simulator-based study investigates whether fasting affects surgical performance. METHODS: Twelve healthy medical students [seven women, mean age 26.5 years (range 23-34)] with no prior experience with surgical...... simulators underwent a short course introduction to the LapSim(®) simulator. After having reached a predefined level, the participants performed five simulated salpingectomies on the LapSim(®) simulator 5-30 days after the initial introduction. The procedures took place at 9 a.m. and 2 p.m. after fasting...... in the longitudinal axis with the left hand. CONCLUSION: The simulator-based study suggests that 17 h of fasting does not deteriorate surgical performance. Further studies on the effect of fasting on surgical performance are needed....

  14. Fast computation of distance estimators

    Directory of Open Access Journals (Sweden)

    Lagergren Jens

    2007-03-01

    Full Text Available Abstract Background Some distance methods are among the most commonly used methods for reconstructing phylogenetic trees from sequence data. The input to a distance method is a distance matrix, containing estimated pairwise distances between all pairs of taxa. Distance methods themselves are often fast, e.g., the famous and popular Neighbor Joining (NJ algorithm reconstructs a phylogeny of n taxa in time O(n3. Unfortunately, the fastest practical algorithms known for Computing the distance matrix, from n sequences of length l, takes time proportional to l·n2. Since the sequence length typically is much larger than the number of taxa, the distance estimation is the bottleneck in phylogeny reconstruction. This bottleneck is especially apparent in reconstruction of large phylogenies or in applications where many trees have to be reconstructed, e.g., bootstrapping and genome wide applications. Results We give an advanced algorithm for Computing the number of mutational events between DNA sequences which is significantly faster than both Phylip and Paup. Moreover, we give a new method for estimating pairwise distances between sequences which contain ambiguity Symbols. This new method is shown to be more accurate as well as faster than earlier methods. Conclusion Our novel algorithm for Computing distance estimators provides a valuable tool in phylogeny reconstruction. Since the running time of our distance estimation algorithm is comparable to that of most distance methods, the previous bottleneck is removed. All distance methods, such as NJ, require a distance matrix as input and, hence, our novel algorithm significantly improves the overall running time of all distance methods. In particular, we show for real world biological applications how the running time of phylogeny reconstruction using NJ is improved from a matter of hours to a matter of seconds.

  15. Neighborhood fast food restaurants and fast food consumption: A national study

    Directory of Open Access Journals (Sweden)

    Gordon-Larsen Penny

    2011-07-01

    Full Text Available Abstract Background Recent studies suggest that neighborhood fast food restaurant availability is related to greater obesity, yet few studies have investigated whether neighborhood fast food restaurant availability promotes fast food consumption. Our aim was to estimate the effect of neighborhood fast food availability on frequency of fast food consumption in a national sample of young adults, a population at high risk for obesity. Methods We used national data from U.S. young adults enrolled in wave III (2001-02; ages 18-28 of the National Longitudinal Study of Adolescent Health (n = 13,150. Urbanicity-stratified multivariate negative binomial regression models were used to examine cross-sectional associations between neighborhood fast food availability and individual-level self-reported fast food consumption frequency, controlling for individual and neighborhood characteristics. Results In adjusted analysis, fast food availability was not associated with weekly frequency of fast food consumption in non-urban or low- or high-density urban areas. Conclusions Policies aiming to reduce neighborhood availability as a means to reduce fast food consumption among young adults may be unsuccessful. Consideration of fast food outlets near school or workplace locations, factors specific to more or less urban settings, and the role of individual lifestyle attitudes and preferences are needed in future research.

  16. Fasts, feasts and festivals in diabetes-1: Glycemic management during Hindu fasts

    Directory of Open Access Journals (Sweden)

    Sanjay Kalra

    2015-01-01

    Full Text Available This communication is the first of a series on South Asian fasts, festivals, and diabetes, designed to spread awareness and stimulate research on this aspect of diabetes and metabolic care. It describes the various fasts observed as part of Hindu religion and offers a classification scheme for them, labeling them as infrequent and frequent. The infrequent fasts are further sub-classified as brief and prolonged, to facilitate a scientific approach to glycemic management during these fasts. Pre-fast counseling, non-pharmacological therapy, pharmacological modification, and post-fast debriefing are discussed in detail. All available drug classes and molecules are covered in this article, which provides guidance about necessary changes in dosage and timing of administration. While in no way exhaustive, the brief review offers a basic framework which diabetes care professionals can use to counsel and manage persons in their care who wish to observe various Hindu fasts.

  17. Perioperative Fasting and the Patient Experience.

    Science.gov (United States)

    Chon, Telliane; Ma, Alfred; Mun-Price, Connie

    2017-05-24

    Standard preparation for a surgical procedure requires patients to fast (nulla per os [NPO]) after midnight before their operation. Unfortunately, given the unpredictable nature of operating room scheduling and unavoidable delays, patients may find themselves anxiously waiting and fasting much longer than expected. In recent years, the usefulness of prolonged fasting to prevent pulmonary aspiration has been questioned. According to the American Society of Anesthesiologists (ASA) guidelines, unnecessarily prolonged fasting can be avoided by allowing patients to have clear liquids with the minimal fasting time of only two hours. This study examines a random sampling of elective scheduled surgeries at a 439-bed safety-net teaching hospital in Southern California in October 2016. The study revealed significantly prolonged NPO times caused by delays in the scheduling of operation times. An analysis of delays revealed that prior surgical procedures running longer than scheduled were the most common reason for a delay in starting an operation and, subsequently, prolonging patient fasting time. Significantly prolonged fasting times warrant the need for institutional management strategy changes and a revamping of clinical education curriculums.

  18. Fast track clinical pathway implications in esophagogastrectomy

    Institute of Scientific and Technical Information of China (English)

    Ke Jiang; Lin Cheng; Jian-Jun Wang; Jin-Song Li; Jun Nie

    2009-01-01

    AIM: To investigate the feasibility of fast track clinical pathway for esophageal tumor resections.METHODS: One hundred and fourteen patients with esophageal carcinoma who underwent esophagogastrectomy from January 2006 to October 2007 in our department were studied. Fast track clinical pathway included analgesia control, fluid infusion volume control, early ambulation and enteral nutrition.Nasogastric tube was removed 3 d after operation and chest tube was removed 4 d after operation as a routine, and full liquid diet 5 d after operation.RESULTS: Among 114 patients (84 men and 30 women), 26 patients underwent fast track surgery,including 17 patients over 65 years old and 9 under 65 ( P = 0.014); 18 patients who had preoperative complications could not bear fast track surgery ( P <0.001). No significant differences in tolerance of fast track surgery were attributed to differences in gender,differentiated degree or stage of tumor, pathological type of tumor, or operative incision. The median length of hospital stay was 7 d (5-28 d), 4% patients werereadmitted to hospital within 30 d of discharge. Three patients died and postoperative mortality was 2.6%.All 3 patients had no determinacy to fast track surgery approach.CONCLUSION: The major I ty of pat ients with esophageal carcinoma can tolerate fast track surgery.Patients younger than 65 or who have no preoperative diseases have the best results. Median length of hospital stay has been reduced to 7 d.

  19. Integration of fastNLO into MCPLOTS

    CERN Document Server

    Tyros, Stefanos

    1993-01-01

    RIVET is a very popular tool that allows precise comparisons between measurements and Monte Carlo (MC) event generators. The MCPLOTS project at CERN uses its functionality to provide a browsable repository of such comparison plots. Higher order predictions, however, are usually too time consuming to be included in these comparisons. fastNLO provides precalculated interpolation tables that can deliver histograms of differential cross sections quickly and efficiently. In this project the capabilities of fastNLO with RIVET were combined to enable the fast histogram production for inclusion into the MCPLOTS collection on request of visitors of the corresponding web page.

  20. Fast Computation of Wigner-Ville Distribution

    Institute of Scientific and Technical Information of China (English)

    曹家麟; 陈光化

    2003-01-01

    The paper proposes a new method for computation of the Wigner-Ville distribution(WVD) taking account of the conjugate symmetry of the WVD kernel function and the periodicity and symmetry of the trigonometric function. The method transfers the computation of WVD into real field from complex field to remove the redundancies in the fast Fourier transform(FFT) computation. The realization of fast cosine operation and fast sine operation considerably reduces the computation cost. Theoretical analysis shows that the algorithm provided in the paper is much more advantageous than the existed ones.

  1. Weizmann Fast Astronomical Survey Telescope (WFAST)

    Science.gov (United States)

    Nir, Guy; Ofek, Eran Oded; Ben-Ami, Sagi; Manulis, Ilan; Gal-Yam, Avishay; Diner, Oz; Rappaport, Michael

    2017-01-01

    The Weizmann Fast Astronomical Survey Telescope (W-FAST) is an experiment designed to explore variability on sub-second time scales. When completed it will consist of two robotic 55-cm f/2 Schmidt telescopes. The optics is capable of providing $\\sim0.5$" image quality over 23 deg$^2$. The focal plane will be equipped with fast readout, low read-noise sCMOS detectors. The first generation focal plane is expected to have 6.2 deg$^2$ field of view. WFAST is designed to study occultations by solar system objects (KBOs and Oort cloud objects), short time scale stellar variability, and high resolution imaging via proper coaddition.

  2. A Fast Fractal Image Compression Coding Method

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Fast algorithms for reducing encoding complexity of fractal image coding have recently been an important research topic. Search of the best matched domain block is the most computation intensive part of the fractal encoding process. In this paper, a fast fractal approximation coding scheme implemented on a personal computer based on matching in range block's neighbours is presented. Experimental results show that the proposed algorithm is very simple in implementation, fast in encoding time and high in compression ratio while PSNR is almost the same as compared with Barnsley's fractal block coding .

  3. Western Fast Food Comes to China

    Institute of Scientific and Technical Information of China (English)

    1995-01-01

    IT’S common knowledge that the Chinese have opened many restaurants outside their own country. Now fast food from the West can be had in the big cities of China. Western fast-food restaurants dot the streets of Beijing. And the food is not the only thing that attracts people. "They are clean and well-lighted and decorated in bright colors," said one scholar in Beijing. "They are not like Chinese restaurants that are often decorated in heavy and solemn colors or use old furnishings." The American fast food giant McDonald’s is one of the most visible

  4. Fast plunges into Kerr black holes

    Energy Technology Data Exchange (ETDEWEB)

    Hadar, Shahar [Racah Institute of Physics, Hebrew University,Jerusalem 91904 (Israel); Porfyriadis, Achilleas P.; Strominger, Andrew [Center for the Fundamental Laws of Nature, Harvard University,Cambridge, MA 02138 (United States)

    2015-07-15

    Most extreme-mass-ratio-inspirals of small compact objects into supermassive black holes end with a fast plunge from an eccentric last stable orbit. For rapidly rotating black holes such fast plunges may be studied in the context of the Kerr/CFT correspondence because they occur in the near-horizon region where dynamics are governed by the infinite dimensional conformal symmetry. In this paper we use conformal transformations to analytically solve for the radiation emitted from fast plunges into near-extreme Kerr black holes. We find perfect agreement between the gravity and CFT computations.

  5. Fast Backprojection Techniques for High Resolution Tomography

    CERN Document Server

    Koshev, Nikolay; Miqueles, Eduardo X

    2016-01-01

    Fast image reconstruction techniques are becoming important with the increasing number of scientific cases in high resolution micro and nano tomography. The processing of the large scale three-dimensional data demands new mathematical tools for the tomographic reconstruction task because of the big computational complexity of most current algorithms as the sizes of tomographic data grow with the development of more powerful acquisition hardware and more refined scientific needs. In the present paper we propose a new fast back-projection operator for the processing of tomographic data and compare it against other fast reconstruction techniques.

  6. The fast debris evolution model

    Science.gov (United States)

    Lewis, H. G.; Swinerd, G. G.; Newland, R. J.; Saunders, A.

    2009-09-01

    The 'particles-in-a-box' (PIB) model introduced by Talent [Talent, D.L. Analytic model for orbital debris environmental management. J. Spacecraft Rocket, 29 (4), 508-513, 1992.] removed the need for computer-intensive Monte Carlo simulation to predict the gross characteristics of an evolving debris environment. The PIB model was described using a differential equation that allows the stability of the low Earth orbit (LEO) environment to be tested by a straightforward analysis of the equation's coefficients. As part of an ongoing research effort to investigate more efficient approaches to evolutionary modelling and to develop a suite of educational tools, a new PIB model has been developed. The model, entitled Fast Debris Evolution (FADE), employs a first-order differential equation to describe the rate at which new objects ⩾10 cm are added and removed from the environment. Whilst Talent [Talent, D.L. Analytic model for orbital debris environmental management. J. Spacecraft Rocket, 29 (4), 508-513, 1992.] based the collision theory for the PIB approach on collisions between gas particles and adopted specific values for the parameters of the model from a number of references, the form and coefficients of the FADE model equations can be inferred from the outputs of future projections produced by high-fidelity models, such as the DAMAGE model. The FADE model has been implemented as a client-side, web-based service using JavaScript embedded within a HTML document. Due to the simple nature of the algorithm, FADE can deliver the results of future projections immediately in a graphical format, with complete user-control over key simulation parameters. Historical and future projections for the ⩾10 cm LEO debris environment under a variety of different scenarios are possible, including business as usual, no future launches, post-mission disposal and remediation. A selection of results is presented with comparisons with predictions made using the DAMAGE environment model

  7. Fast-Food Environments and Family Fast-Food Intake in Nonmetropolitan Areas

    Science.gov (United States)

    Longacre, Meghan R.; Drake, Keith M.; MacKenzie, Todd A.; Gibson, Lucinda; Owens, Peter; Titus, Linda J.; Beach, Michael L.; Dalton, Madeline A.

    2012-01-01

    Background Little is known about the influence of in-town fast-food availability on family-level fast-food intake in nonmetropolitan areas. Purpose The purpose of the current study was to determine whether the presence of chain fast-food outlets was associated with fast-food intake among adolescents and parents, and to assess whether this relationship was moderated by family access to motor vehicles. Methods Telephone surveys were conducted with 1547 adolescent–parent dyads in 32 New Hampshire and Vermont communities between 2007 and 2008. Fast-food intake in the past week was measured through self-report. In-town fast-food outlets were located and enumerated using an onsite audit. Family motor vehicle access was categorized based on the number of vehicles per licensed drivers in the household. Poisson regression was used to determine unadjusted and adjusted risk ratios (RRs). Analyses were conducted in 2011. Results About half (52.1%) of adolescents and 34.7% of parents consumed fast food at least once in the past week. Adolescents and parents who lived in towns with five or more fast-food outlets were about 30% more likely to eat fast food compared to those in towns with no fast-food outlets, even after adjusting for individual, family, and town characteristics (RR=1.29, 95% CI= 1.10, 1.51; RR=1.32, 95% CI=1.07,1.62, respectively). Interaction models demonstrated that the influence of in-town fast-food outlets on fast-food intake was strongest among families with low motor vehicle access. Conclusions In nonmetropolitan areas, household transportation should be considered as an important moderator of the relationship between in-town fast-food outlets and family intake. PMID:22608373

  8. Fast internal dynamics in alcohol dehydrogenase

    Energy Technology Data Exchange (ETDEWEB)

    Monkenbusch, M.; Stadler, A., E-mail: a.stadler@fz-juelich.de; Biehl, R.; Richter, D. [Jülich Centre for Neutron Science JCNS and Institute for Complex Systems ICS, Forschungszentrum Jülich GmbH, 52425 Jülich (Germany); Ollivier, J. [Institut Laue-Langevin, CS 20156, 38042 Grenoble (France); Zamponi, M. [Jülich Centre for Neutron Science JCNS, Forschungszentrum Jülich GmbH, Outstation at MLZ, Lichtenbergstraße 1, 85747 Garching (Germany)

    2015-08-21

    Large-scale domain motions in alcohol dehydrogenase (ADH) have been observed previously by neutron spin-echo spectroscopy (NSE). We have extended the investigation on the dynamics of ADH in solution by using high-resolution neutron time-of-flight (TOF) and neutron backscattering (BS) spectroscopy in the incoherent scattering range. The observed hydrogen dynamics were interpreted in terms of three mobility classes, which allowed a simultaneous description of the measured TOF and BS spectra. In addition to the slow global protein diffusion and domain motions observed by NSE, a fast internal process could be identified. Around one third of the protons in ADH participate in the fast localized diffusive motion. The diffusion coefficient of the fast internal motions is around two third of the value of the surrounding D{sub 2}O solvent. It is tempting to associate the fast internal process with solvent exposed amino acid residues with dangling side chains.

  9. Fast internal dynamics in alcohol dehydrogenase

    Science.gov (United States)

    Monkenbusch, M.; Stadler, A.; Biehl, R.; Ollivier, J.; Zamponi, M.; Richter, D.

    2015-08-01

    Large-scale domain motions in alcohol dehydrogenase (ADH) have been observed previously by neutron spin-echo spectroscopy (NSE). We have extended the investigation on the dynamics of ADH in solution by using high-resolution neutron time-of-flight (TOF) and neutron backscattering (BS) spectroscopy in the incoherent scattering range. The observed hydrogen dynamics were interpreted in terms of three mobility classes, which allowed a simultaneous description of the measured TOF and BS spectra. In addition to the slow global protein diffusion and domain motions observed by NSE, a fast internal process could be identified. Around one third of the protons in ADH participate in the fast localized diffusive motion. The diffusion coefficient of the fast internal motions is around two third of the value of the surrounding D2O solvent. It is tempting to associate the fast internal process with solvent exposed amino acid residues with dangling side chains.

  10. Fast Exact Euclidean Distance (FEED) Transformation

    NARCIS (Netherlands)

    Schouten, Theo; Broek, van den Egon; Kittler, J.; Petrou, M.; Nixon, M.

    2004-01-01

    Fast Exact Euclidean Distance (FEED) transformation is introduced, starting from the inverse of the distance transformation. The prohibitive computational cost of a naive implementation of traditional Euclidean Distance Transformation, is tackled by three operations: restriction of both the number o

  11. A Fast Neutron Spectrometer for Underground Science

    Science.gov (United States)

    Langford, Thomas; Beise, Elizabeth; Breuer, Herbert; Erwin, Dylan; Bass, Christopher; Heimbach, Craig; Nico, Jeff

    2010-02-01

    The characterization of the fast neutron fluence has become a critical issue for experiments that require extreme low-background environments, such as neutrino-less double-beta decay, dark matter searches, and solar neutrino experiments. In such experiments, fast neutrons may be the dominant and a potentially irreducible background, thus necessitating precise information about the fast neutron fluence and energy spectrum. The most reasonable approach to addressing the problem is through the complete characterization of the neutrons through both site-specific measurement and benchmarking of simulation codes. We will discuss the progress toward the development of a large-volume, segmented detector consisting of plastic scintillator and ^3He proportional counters. The detector will be placed in an underground environment to measure the fast neutron flux and energy spectrum. A prototype detector has been constructed and testing is in progress. We will discuss the status of the project and present data from the prototype detector. )

  12. 400 Area/Fast Flux Test Facility

    Data.gov (United States)

    Federal Laboratory Consortium — The 400 Area at Hanford is home primarily to the Fast Flux Test Facility (FFTF), a DOE-owned, formerly operating, 400-megawatt (thermal) liquid-metal (sodium)-cooled...

  13. Spalling Resistance Fast-drying Refractory Castables

    Institute of Scientific and Technical Information of China (English)

    Wang Jing; Peng Xigao

    2010-01-01

    @@ 1 Scope This standard specifies the term and definition,classification, technical requirements, test methods,quality appraisal procedures, packing, marking, transportation, storage, and quality certificate of spalling resistance fast-drying refractory castables.

  14. FastStats: Accidents or Unintentional Injuries

    Science.gov (United States)

    ... please visit this page: About CDC.gov . FastStats Homepage Diseases and Conditions Anemia or Iron Deficiency Arthritis ... 0 million Source: National Hospital Ambulatory Medical Care Survey: 2011 Emergency Department Summary Tables. Table 17 [PDF - ...

  15. FastBit: Interactively Searching Massive Data

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Kesheng; Ahern, Sean; Bethel, E. Wes; Chen, Jacqueline; Childs, Hank; Cormier-Michel, Estelle; Geddes, Cameron; Gu, Junmin; Hagen, Hans; Hamann, Bernd; Koegler, Wendy; Lauret, Jerome; Meredith, Jeremy; Messmer, Peter; Otoo, Ekow; Perevoztchikov, Victor; Poskanzer, Arthur; Prabhat,; Rubel, Oliver; Shoshani, Arie; Sim, Alexander; Stockinger, Kurt; Weber, Gunther; Zhang, Wei-Ming

    2009-06-23

    As scientific instruments and computer simulations produce more and more data, the task of locating the essential information to gain insight becomes increasingly difficult. FastBit is an efficient software tool to address this challenge. In this article, we present a summary of the key underlying technologies, namely bitmap compression, encoding, and binning. Together these techniques enable FastBit to answer structured (SQL) queries orders of magnitude faster than popular database systems. To illustrate how FastBit is used in applications, we present three examples involving a high-energy physics experiment, a combustion simulation, and an accelerator simulation. In each case, FastBit significantly reduces the response time and enables interactive exploration on terabytes of data.

  16. Upgrading the ATLAS fast calorimeter simulation

    Science.gov (United States)

    Hubacek, Z.; ATLAS Collaboration

    2016-10-01

    Many physics and performance studies with the ATLAS detector at the Large Hadron Collider require very large samples of simulated events, and producing these using the full Geant4 detector simulation is highly CPU intensive. Often, a very detailed detector simulation is not needed, and in these cases fast simulation tools can be used to reduce the calorimeter simulation time. In ATLAS, a fast simulation of the calorimeter systems was developed, called Fast Calorimeter Simulation (FastCaloSim). It provides a parametrized simulation of the particle energy response at the calorimeter read-out cell level. It is interfaced to the standard ATLAS digitization and reconstruction software and can be tuned to data more easily than Geant4. An improved parametrization is being developed, to eventually address shortcomings of the original version. It makes use of statistical techniques such as principal component analysis and a neural network parametrization to optimise the amount of information to store in the ATLAS simulation infrastructure.

  17. Fast pyrolysis of biomass at high temperatures

    DEFF Research Database (Denmark)

    Trubetskaya, Anna

    This Ph.D. thesis describes experimental and modeling investigations of fast high temperature pyrolysis of biomass. Suspension firing of biomass is widely used for power generation and has been considered as an important step in reduction of greenhouse gas emissions by using less fossil fuels. Fast...... pyrolysis at high temperatures plays a significant role in the overall combustion process since the biomass type, the reaction kinetics and heat transfer rates during pyrolysis influence the volatile gas release. The solid residue yield and its properties in suspension firing, including particle size...... and shape, composition, reactivity and burnout depend significantly on the operating conditions of the fast pyrolysis. Biomass fast pyrolysis experiments were performed in a laboratory-scale wire mesh reactor and bench scale atmospheric pressure drop tube / entrained flow reactors with the aim...

  18. Nonfasting Versus Initial Fasting Ketogenic Diet

    Directory of Open Access Journals (Sweden)

    J Gordon Millichap

    2005-02-01

    Full Text Available A retrospective evaluation of the ketogenic diet (KD was conducted comparing efficacy and tolerability of the diet with or without initial fasting and fluid restriction and involving university centers in Seoul, Korea.

  19. Upgrading the ATLAS fast calorimeter simulation

    CERN Document Server

    AUTHOR|(INSPIRE)INSPIRE-00032940; The ATLAS collaboration

    2016-01-01

    Many physics and performance studies with the ATLAS detector at the Large Hadron Collider require very large samples of simulated events, and producing these using the full GEANT4 detector simulation is highly CPU intensive. Often, a very detailed detector simulation is not needed, and in these cases fast simulation tools can be used to reduce the calorimeter simulation time. In ATLAS, a fast simulation of the calorimeter systems was developed, called Fast Calorimeter Simulation (FastCaloSim). It provides a parametrized simulation of the particle energy response at the calorimeter read-out cell level. It is interfaced to the standard ATLAS digitization and reconstruction software, and can be tuned to data more easily than with GEANT4. An improved parametrization is being developed, to eventually address shortcomings of the original version. It makes use of statistical techniques such as principal component analysis, and a neural network parametrization to optimise the amount of information to store in the ATL...

  20. Islamic fasting and oral health and diseases

    Directory of Open Access Journals (Sweden)

    A Javadzadeh Blouri

    2014-12-01

    Full Text Available Fasting is a religious obligation, which can be challenging for individuals with oral conditions due to its stringent code of conduct. Moreover, food abstinence during fasting can restrict oral feeding even further in patients whose nutrition has been already compromised. Previous research has mainly concentrated on oral hygiene and gum health, disregarding orodental conditions and diseases. This highlights the importance of further research in this regard. In this paper, we intended to clarify the correlation between fasting and oral injections, bleeding following tooth extraction, and brushing to overcome common misconceptions which indicate the breach of religious disciplines under such circumstances. We also aimed to determine the grave effects of fasting on health in case of severe immunological deficiencies, chronic oral ulcers and certain drug administration protocols for those with rigid religious beliefs.

  1. A mechanism for fast radio bursts

    CERN Document Server

    Romero, Gustavo E; Vieyro, Florencia L

    2015-01-01

    Fast radio bursts are mysterious transient sources likely located at cosmological distances. The derived brightness temperatures exceed by many orders of magnitude the self-absorption limit of incoherent synchrotron radiation, implying the operation of a coherent emission process. We propose a radiation mechanism for fast radio bursts where the emission arises from collisionless Bremsstrahlung in strong plasma turbulence excited by relativistic electron beams. We discuss possible astrophysical scenarios in which this process might operate. The emitting region is a turbulent plasma hit by a relativistic jet, where Langmuir plasma waves produce a concentration of intense electrostatic soliton-like regions (cavitons). The resulting radiation is coherent and, under some physical conditions, can be polarised and have a power-law distribution in energy. We obtain radio luminosities in agreement with the inferred values for fast radio bursts. The timescale of the radio flare in some cases can be extremely fast, of t...

  2. Fast Food Combos Make Type A Lunches

    Science.gov (United States)

    Stashower, Gloria

    1974-01-01

    Clark County school district in Las Vegas, Nevada, has combination lunches available for high school students that meet Type A nutrition requirements but which resemble the commercial fast food menus teenagers prefer. (MLF)

  3. Waves from Propulsion Systems of Fast Ferries

    DEFF Research Database (Denmark)

    Taatø, Søren Haugsted; Aage, Christian; Arnskov, Michael M.

    1998-01-01

    Waves from fast ferries have become an environmental problem of growing concern to the public. Fast ferries produce not only higher waves than conventional ships but also fundamentally different wave systems when they sail at supercritical speeds. Hitherto, ship waves have been considered as being...... generated by the ship hulls alone. Whereas this assumption may be reasonable for conventional ships with large hulls and limited propulsive power, the situation is different for fast ferries with their smaller hulls and very large installed power. A simple theoretical model and a series of model tests...... on a monohull fast ferry seem to indicate that a substantial part of the wave-making can be directly attributed to the propulsion system itself. Thus, two wave systems are created with different phases, but with similar frequency contents, which means that they merge into one system behind the ship, very...

  4. Fast Cure Repair Kit for Composites Project

    Data.gov (United States)

    National Aeronautics and Space Administration — NASA has a need for technologies that will enable them to repair damage to composite structures. Fiber-reinforced polymer composite materials are fast gaining ground...

  5. Sociodemographic differences in fast food price sensitivity

    Science.gov (United States)

    Meyer, Katie A.; Guilkey, David K.; Ng, Shu Wen; Duffey, Kiyah J.; Popkin, Barry M.; Kiefe, Catarina I.; Steffen, Lyn M.; Shikany, James M.; Gordon-Larsen, Penny

    2014-01-01

    Importance Fiscal food policies (e.g., taxation) are increasingly proposed to improve population-level health, but their impact on health disparities is unknown. Objective We estimated subgroup-specific effects of fast food price changes on fast food consumption and cardio-metabolic outcomes, hypothesizing inverse associations between fast food price with fast food consumption, BMI, and insulin resistance and stronger associations among blacks (vs. whites) and participants with relatively lower education or income. Design 20-year follow-up (5 exams) in a biracial U.S. prospective cohort: Coronary Artery Risk Development in Young Adults (CARDIA) (1985/86–2005/06, baseline n=5,115). Participants Aged 18–30 at baseline; designed for equal recruitment by race (black/white), educational attainment, age, and gender. Exposures Community-level price data from the Council for Community and Economic Research (C2ER) temporally- and geographically-linked to study participants’ home address at each exam. Main outcome and measures Participant-reported number of fast food eating occasions per week; BMI (kg/m2) from clinical assessment of weight and height; homeostatic model assessment insulin resistance (HOMA-IR) from fasting glucose and insulin. Covariates included individual- and community-level social and demographic factors. Results In repeated measures regression, multivariable-adjusted associations between fast food price and consumption were non-linear (quadratic, p<0.001), with significant inverse estimated effects on consumption at higher prices; estimates varied according to race (interaction term p=0.04), income (p=0.07), and education (p=0.03). For example, at the 10th percentile of price ($1.25/serving), blacks and whites had mean fast food consumption (times/week) of 2.2 (95% CI: 2.1–2.3) and 1.6 (1.5–1.7), respectively, while at the 90th percentile of price ($1.53/serving), respective mean consumption estimates were 1.9 (1.8–2.0) and 1.5 (1.4–1.6). We

  6. Characteristics and factors influencing fast food intake of young ...

    African Journals Online (AJOL)

    Characteristics and factors influencing fast food intake of young adult consumers in Johannesburg, South Africa. ... their reasons for and frequency of fast food consumption, their specific fast food choices, and their attitudes towards health.

  7. COUPLED FAST-THERMAL POWER BREEDER REACTOR

    Science.gov (United States)

    Avery, R.

    1961-07-18

    A nuclear reactor having a region operating predominantly on fast neutrons and another region operating predominantly on slow neutrons is described. The fast region is a plutonium core and the slow region is a natural uranium blanket around the core. Both of these regions are free of moderator. A moderating reflector surrounds the uranium blanket. The moderating material and thickness of the reflector are selected so that fissions in the uranium blanket make a substantial contribution to the reactivity of the reactor.

  8. Surgery simulation using fast finite elements

    DEFF Research Database (Denmark)

    Bro-Nielsen, Morten

    1996-01-01

    This paper describes our recent work on real-time surgery simulation using fast finite element models of linear elasticity. In addition, we discuss various improvements in terms of speed and realism......This paper describes our recent work on real-time surgery simulation using fast finite element models of linear elasticity. In addition, we discuss various improvements in terms of speed and realism...

  9. Fast Algorithms for Convolutional Neural Networks

    OpenAIRE

    Lavin, Andrew; Gray, Scott

    2015-01-01

    Deep convolutional neural networks take GPU days of compute time to train on large data sets. Pedestrian detection for self driving cars requires very low latency. Image recognition for mobile phones is constrained by limited processing resources. The success of convolutional neural networks in these situations is limited by how fast we can compute them. Conventional FFT based convolution is fast for large filters, but state of the art convolutional neural networks use small, 3x3 filters. We ...

  10. Fast SAR Imaging Algorithm for FLGPR

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    A fast SAR imaging algorithm for near- field subsurface forward-looking ground penetrating radar (FLGPR) is presented. By using nonstationary convolution filter, the refocused image spectrum can be reconstructed directly from the backscattered signal spectrum of target area. The experimental results show the proposed method can fast achieve image refocusing. Also it has higher computational efficiency than the phase-shift migration approach and the delay-and-sum (DAS) approach.

  11. The New ATLAS Fast Calorimeter Simulation

    CERN Document Server

    Heath, Matthew Peter; The ATLAS collaboration

    2017-01-01

    Producing the large samples of simulated events required by many physics and performance studies with the ATLAS detector using the full GEANT4 detector simulation is highly CPU intensive. Fast simulation tools are a useful way of reducing the CPU requirements when detailed detector simulations are not needed. During Run-1 of the LHC, a fast calorimeter simulation (FastCaloSim) was successfully used in ATLAS. FastCaloSim provides a simulation of the particle energy response at the calorimeter read-out cell level, taking into account the detailed particle shower shapes and the correlations between the energy depositions in the various calorimeter layers. It is interfaced to the standard ATLAS digitisation and reconstruction software, and it can be tuned to data more easily than Geant4. Now an improved version of FastCaloSim is in development, incorporating the experience with the version used during Run-1. The new FastCaloSim aims to overcome some limitations of the first version by improving the description of...

  12. Fasting guidelines for diabetic children and adolescents

    Directory of Open Access Journals (Sweden)

    Kiswhar Azad

    2012-01-01

    Full Text Available Fasting during the month of Ramadan, the ninth month of Islamic lunar calendar, is obligatory for all healthy adult and adolescent Muslims from the age of 12 years. Fasting starts from early dawn (Sohur/Sehri till sunset (Iftar. During this period one has to abstain from eating and drinking. Islam has allowed many categories of people to be exempted from fasting, for example, young children, travelers, the sick, the elderly, pregnant, and lactating women. According to expert opinion, patients with type 1 diabetes (type 1 DM who fast during Ramadan are at a very high risk to develop adverse events. However, some experienced physicians are of the opinion that fasting during Ramadan is safe for type 1 DM patients, including adolescents and older children, with good glycemic control who do regular self-monitoring and are under close professional supervision. The strategies to ensure safety of type 1 diabetic adolescents who are planning to fast include the following: Ramadan-focused medical education, pre-Ramadan medical assessment, following a healthy diet and physical activity pattern, modification in insulin regimen, and blood glucose monitoring as advised by the physician.

  13. ITER prototype fast plant system controller

    Energy Technology Data Exchange (ETDEWEB)

    Goncalves, B., E-mail: bruno@ipfn.ist.utl.pt [Instituto de Plasmas e Fusao Nuclear - Laboratorio Associado, Instituto Superior Tecnico, P-1049-001 Lisboa (Portugal); Sousa, J.; Carvalho, B.B.; Rodrigues, A.P.; Correia, M.; Batista, A. [Instituto de Plasmas e Fusao Nuclear - Laboratorio Associado, Instituto Superior Tecnico, P-1049-001 Lisboa (Portugal); Vega, J. [Centro de Investigaciones Energeticas, Medioambientales y Tecnologicas, CIEMAT, Av. Complutense, Madrid (Spain); Ruiz, M.; Lopez, J.M. [Grupo de Investigacion en Instrumentacion y Acustica Aplicada, Universidad Politecnica de Madrid (Spain); Castro, R. [Centro de Investigaciones Energeticas, Medioambientales y Tecnologicas, CIEMAT, Av. Complutense, Madrid (Spain); Wallander, A.; Utzel, N.; Makijarvi, P.; Simrock, S. [ITER Organization, CS 90 046, 13067 St. Paul lez Durance Cedex (France); Neto, A.; Alves, D.; Valcarcel, D.F. [Instituto de Plasmas e Fusao Nuclear - Laboratorio Associado, Instituto Superior Tecnico, P-1049-001 Lisboa (Portugal); Lousa, P.; Piedade, F.; Fernandes, L. [INOV, Lisbon (Portugal)

    2011-10-15

    ITER CODAC Design identified the need for slow and fast control plant systems, based respectively on industrial automation technology with maximum sampling rates below 100 Hz, and on embedded technology with higher sampling rates and more stringent real-time requirements. The fast system is applicable to diagnostics and plant systems in closed-control loops whose cycle times are below 1 ms. Fast controllers will be dedicated industrial controllers with the ability to supervise other fast and/or slow controllers, interface to actuators and sensors and high performance networks (HPN). This contribution presents the engineering design of two prototypes of a fast plant system controller (FPSC), specialized for data acquisition, constrained by ITER technological choices. This prototyping activity contributes to the Plant Control Design Handbook (PCDH) effort of standardization, specifically regarding fast controller characteristics. The prototypes will be built using two different form factors, PXIe and ATCA, with the aim of comparing the implementations. The presented solution took into consideration channel density, synchronization, resolution, sampling rates and the needs for signal conditioning such as filtering and galvanic isolation. The integration of the two controllers in the standard CODAC environment is also presented and discussed. Both controllers contain an EPICS IOC providing the interface to the mini-CODAC which will be used for all testing activities. The alpha version of the FPSC is also presented.

  14. The new ATLAS Fast Calorimeter Simulation

    CERN Document Server

    Hasib, Ahmed; The ATLAS collaboration

    2017-01-01

    Producing the very large samples of simulated events required by many physics and performance studies with the ATLAS detector using the full GEANT4 detector simulation is highly CPU intensive. Fast simulation tools are a useful way of reducing CPU requirements when detailed detector simulations are not needed. During the LHC Run-1, a fast calorimeter simulation (FastCaloSim) was successfully used in ATLAS. FastCaloSim provides a simulation of the particle energy response at the calorimeter read-out cell level, taking into account the detailed particle shower shapes and the correlations between the energy depositions in the various calorimeter layers. It is interfaced to the standard ATLAS digitization and reconstruction software, and it can be tuned to data more easily than GEANT4. Now an improved version of FastCaloSim is in development, incorporating the experience with the version used during Run-1. The new FastCaloSim makes use of statistical techniques such as principal component analysis, and a neural n...

  15. Fasting in pregnancy: A survey of beliefs and manners of Muslim women about Ramadan fasting

    Directory of Open Access Journals (Sweden)

    Mozhgan Firouzbakht

    2013-01-01

    Full Text Available Background: Fasting during Ramadan is compulsory in the Muslim faith. Although pregnant women may be exempted, many still choose to fast because of a confluence of social, religious and cultural factors. Objective: Little is known about the physiological effects of fasting during Ramadan on the mother or unborn baby, and thus nurses and other health-care providers are faced with the difficult task of providing appropriate medical advice to Muslim women regarding the safety and impact of their fasting. In this study, we examined the practice of fasting among pregnant Muslim women in Amol/Iran, and examined their beliefs on fasting during the holy month of Ramadan 2011. Materials and Methods: This is a retrospective study of all Muslim women in Amol who were pregnant and received antenatal care in healthcare center during the month of Ramadan. Exclusion criteria were all women with any problem in pregnancy. A questionnaire was tool of study. Data were analyzed with Statistical Package for the Social Sciences software (SPSS (P < 0.05. Results: From 250 questionnaires, 215 were responded and collected. 31.8% pregnant women fasted during Ramadan. The average time of fasting was 9.88 days. There was a significant relationship between parity (0.035 and gestational age (0.049 and fasting. 85% of women believed that fasting during pregnancy is a ritual. 71.7% women did not change their prenatal care. 73.5% of pregnant women consulted the obstetrician about fasting. The most common complication in mother was fatigue and weakness. The average size of the head circumference and length of newborn was normal. Conclusion: Midwifes and other health workers need to learn as much as possible about the multicultural best practices and research-driven information about fasting in order to help Muslim women make informed decision.

  16. A fast and flexible reactor physics model for simulating neutron spectra and depletion in fast reactors

    Science.gov (United States)

    Recktenwald, Geoff; Deinert, Mark

    2010-03-01

    Determining the time dependent concentration of isotopes within a nuclear reactor core is central to the analysis of nuclear fuel cycles. We present a fast, flexible tool for determining the time dependent neutron spectrum within fast reactors. The code (VBUDS: visualization, burnup, depletion and spectra) uses a two region, multigroup collision probability model to simulate the energy dependent neutron flux and tracks the buildup and burnout of 24 actinides, as well as fission products. While originally developed for LWR simulations, the model is shown to produce fast reactor spectra that show high degree of fidelity to available fast reactor benchmarks.

  17. Ketone-glucose interaction in fed, fasted, and fasted-infected sheep.

    Science.gov (United States)

    Radcliffe, A G; Wolfe, R R; Colpoys, M F; Muhlbacher, F; Wilmore, D W

    1983-05-01

    Ketosis following starvation was suppressed by hindlimb infection in seven fasted sheep. Glucose production determined following the primed constant infusion of [6-3H(N)]glucose was elevated in the fasted-infected animals (9.50 +/- 1.11 mmol X kg-1 X min-1 (mean +/- SE) versus fasted controls (5.56 +/- 2.2). To determine if the ketonemia following sepsis contributed to the increased glucogenesis associated with catabolic disorder, glucose production and arterial substrates were measured before and after infusion of sodium-DL-beta-hydroxybutyrate (beta-OHB, 20 mumol X kg-1 X min-1) in fed, fasted, and fasted-infected animals. Following 3 h of beta-OHB infusion in the awake conditioned animals, beta-OHB and acetoacetate blood concentrations more than doubled. With infusion, blood glucose and alanine concentrations decreased in the fed and fasted sheep but not in the fasted-infected group. Glucose production fell significantly from 10.11 +/- 1.33 to 8.44 +/- 1.05 in the fed animals and from 5.05 +/- 0.28 to 4.11 +/- 0.33 in the fasted group. Glucose production was unaffected by beta-OHB infusion in the fasted-infected animals (9.50 +/- 1.83 vs. 9.11 +/- 1.44). The accelerated rate of glucose production in sheep following infection is not a consequence of the hypoketonemic state associated with sepsis.

  18. Stationary Liquid Fuel Fast Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Won Sik [Purdue Univ., West Lafayette, IN (United States); Grandy, Andrew [Argonne National Lab. (ANL), Argonne, IL (United States); Boroski, Andrew [Argonne National Lab. (ANL), Argonne, IL (United States); Krajtl, Lubomir [Argonne National Lab. (ANL), Argonne, IL (United States); Johnson, Terry [Argonne National Lab. (ANL), Argonne, IL (United States)

    2015-09-30

    For effective burning of hazardous transuranic (TRU) elements of used nuclear fuel, a transformational advanced reactor concept named SLFFR (Stationary Liquid Fuel Fast Reactor) was proposed based on stationary molten metallic fuel. The fuel enters the reactor vessel in a solid form, and then it is heated to molten temperature in a small melting heater. The fuel is contained within a closed, thick container with penetrating coolant channels, and thus it is not mixed with coolant nor flow through the primary heat transfer circuit. The makeup fuel is semi- continuously added to the system, and thus a very small excess reactivity is required. Gaseous fission products are also removed continuously, and a fraction of the fuel is periodically drawn off from the fuel container to a processing facility where non-gaseous mixed fission products and other impurities are removed and then the cleaned fuel is recycled into the fuel container. A reference core design and a preliminary plant system design of a 1000 MWt TRU- burning SLFFR concept were developed using TRU-Ce-Co fuel, Ta-10W fuel container, and sodium coolant. Conservative design approaches were adopted to stay within the current material performance database. Detailed neutronics and thermal-fluidic analyses were performed to develop a reference core design. Region-dependent 33-group cross sections were generated based on the ENDF/B-VII.0 data using the MC2-3 code. Core and fuel cycle analyses were performed in theta-r-z geometries using the DIF3D and REBUS-3 codes. Reactivity coefficients and kinetics parameters were calculated using the VARI3D perturbation theory code. Thermo-fluidic analyses were performed using the ANSYS FLUENT computational fluid dynamics (CFD) code. Figure 0.1 shows a schematic radial layout of the reference 1000 MWt SLFFR core, and Table 0.1 summarizes the main design parameters of SLFFR-1000 loop plant. The fuel container is a 2.5 cm thick cylinder with an inner radius of 87.5 cm. The fuel

  19. Catalytic fast pyrolysis of lignocellulosic biomass

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Changjun; Wang, Huamin; Karim, Ayman M.; Sun, Junming; Wang, Yong

    2014-11-21

    Increasing energy demand, especially in the transportation sector, and soaring CO2 emissions necessitate the exploitation of renewable sources of energy. Despite the large variety of new energy Q3 carriers, liquid hydrocarbon still appears to be the most attractive and feasible form of transportation fuel taking into account the energy density, stability and existing infrastructure. Biomass is an abundant, renewable source of energy; however, utilizing it in a cost-effective way is still a substantial challenge. Lignocellulose is composed of three major biopolymers, namely cellulose, hemicellulose and lignin. Fast pyrolysis of biomass is recognized as an efficient and feasible process to selectively convert lignocellulose into a liquid fuel—bio-oil. However bio-oil from fast pyrolysis contains a large amount of oxygen, distributed in hundreds of oxygenates. These oxygenates are the cause of many negative properties, such as low heating values, high corrosiveness, high viscosity, and instability; they also greatly Q4 limit the application of bio-oil particularly as transportation fuel. Hydrocarbons derived from biomass are most attractive because of their high energy density and compatibility with the existing infrastructure. Thus, converting lignocellulose into transportation fuels via catalytic fast pyrolysis has attracted much attention. Many studies related to catalytic fast pyrolysis of biomass have been published. The main challenge of this process is the development of active and stable catalysts that can deal with a large variety of decomposition intermediates from lignocellulose. This review starts with the current understanding of the chemistry in fast pyrolysis of lignocellulose and focuses on the development of catalysts in catalytic fast pyrolysis. Recent progress in the experimental studies on catalytic fast pyrolysis of biomass is also summarized with the emphasis on bio-oil yields and quality.

  20. On the R2* Relaxometry in Complex Multi-Peak Multi-Echo Chemical Shift-Based Water-Fat Quantification: Applications to the Neuromuscular Diseases

    CERN Document Server

    Siracusano, G; Milazzo, C; Anastasi, G P; Finocchio, G; Gaeta, M

    2016-01-01

    Purpose: Investigation of the feasibility of the R2* mapping techniques by using latest theoretical models corrected for confounding factors and optimized for signal to noise ratio. Theory and Methods: The improvement of the performance of state of the art MRI relaxometry algorithms is challenging because of a non-negligible bias and still unresolved numerical instabilities. Here, R2* mapping reconstructions, including complex-fitting with multi-spectral fat-correction by using single-decay (1D) and double-decay (2D) formulation, are studied in order to identify optimal configuration parameters and minimize numerical artifacts. The effects of echo number, echo spacing, and fat/water relaxation model are evaluated through simulated and in-vivo data. We also explore the stability of such models by analyzing the impact of high percentage of fat infiltrations and local transverse relaxation differences among biological species. Results: The main limits of the MRI relaxometry are the presence of bias and the occur...

  1. FAST - FREEDOM ASSEMBLY SEQUENCING TOOL PROTOTYPE

    Science.gov (United States)

    Borden, C. S.

    1994-01-01

    FAST is a project management tool designed to optimize the assembly sequence of Space Station Freedom. An appropriate assembly sequence coordinates engineering, design, utilization, transportation availability, and operations requirements. Since complex designs tend to change frequently, FAST assesses the system level effects of detailed changes and produces output metrics that identify preferred assembly sequences. FAST incorporates Space Shuttle integration, Space Station hardware, on-orbit operations, and programmatic drivers as either precedence relations or numerical data. Hardware sequencing information can either be input directly and evaluated via the "specified" mode of operation or evaluated from the input precedence relations in the "flexible" mode. In the specified mode, FAST takes as its input a list of the cargo elements assigned to each flight. The program determines positions for the cargo elements that maximize the center of gravity (c.g.) margin. These positions are restricted by the geometry of the cargo elements and the location of attachment fittings both in the orbiter and on the cargo elements. FAST calculates every permutation of cargo element location according to its height, trunnion fitting locations, and required intercargo element spacing. Each cargo element is tested in both its normal and reversed orientation (rotated 180 degrees). The best solution is that which maximizes the c.g. margin for each flight. In the flexible mode, FAST begins with the first flight and determines all feasible combinations of cargo elements according to mass, volume, EVA, and precedence relation constraints. The program generates an assembly sequence that meets mass, volume, position, EVA, and precedence constraints while minimizing the total number of Shuttle flights required. Issues associated with ground operations, spacecraft performance, logistics requirements and user requirements will be addressed in future versions of the model. FAST is written in C

  2. The Physics of Fast Z Pinches

    Energy Technology Data Exchange (ETDEWEB)

    RYUTOV,D.D.; DERZON,MARK S.; MATZEN,M. KEITH

    1999-10-25

    The spectacular progress made during the last few years in reaching high energy densities in fast implosions of annular current sheaths (fast Z pinches) opens new possibilities for a broad spectrum of experiments, from x-ray generation to controlled thermonuclear fusion and astrophysics. Presently Z pinches are the most intense laboratory X ray sources (1.8 MJ in 5 ns from a volume 2 mm in diameter and 2 cm tall). Powers in excess of 200 TW have been obtained. This warrants summarizing the present knowledge of physics that governs the behavior of radiating current-carrying plasma in fast Z pinches. This survey covers essentially all aspects of the physics of fast Z pinches: initiation, instabilities of the early stage, magnetic Rayleigh-Taylor instability in the implosion phase, formation of a transient quasi-equilibrium near the stagnation point, and rebound. Considerable attention is paid to the analysis of hydrodynamic instabilities governing the implosion symmetry. Possible ways of mitigating these instabilities are discussed. Non-magnetohydrodynamic effects (anomalous resistivity, generation of particle beams, etc.) are summarized. Various applications of fast Z pinches are briefly described. Scaling laws governing development of more powerful Z pinches are presented. The survey contains 36 figures and more than 300 references.

  3. Upgrading the ATLAS Fast Calorimeter Simulation

    CERN Document Server

    Hubacek, Zdenek; The ATLAS collaboration

    2016-01-01

    Many physics and performance studies with the ATLAS detector at the Large Hadron Collider require very large samples of simulated events, and producing these using the full GEANT4 detector simulation is highly CPU intensive. Often, a very detailed detector simulation is not needed, and in these cases fast simulation tools can be used to reduce the calorimeter simulation time by a few orders of magnitude. In ATLAS, a fast simulation of the calorimeter systems was developed, called Fast Calorimeter Simulation (FastCaloSim). It provides a parametrized simulation of the particle energy response at the calorimeter read-out cell level. It is interfaced to the standard ATLAS digitization and reconstruction software, and can be tuned to data more easily than with GEANT4. The original version of FastCaloSim has been very important in the LHC Run-1, with several billion events simulated. An improved parametrisation is being developed, to eventually address shortcomings of the original version. It incorporates developme...

  4. The physics of fast Z pinches

    Energy Technology Data Exchange (ETDEWEB)

    Ryutov, D.D. [Lawrence Livermore National Lab., CA (United States); Derzon, M.S.; Matzen, M.K. [Sandia National Labs., Albuquerque, NM (United States)

    1998-07-01

    The spectacular progress made during the last few years in reaching high energy densities in fast implosions of annular current sheaths (fast Z pinches) opens new possibilities for a broad spectrum of experiments, from x-ray generation to controlled thermonuclear fusion and astrophysics. Presently Z pinches are the most intense laboratory X ray sources (1.8 MJ in 5 ns from a volume 2 mm in diameter and 2 cm tall). Powers in excess of 200 TW have been obtained. This warrants summarizes the present knowledge of physics that governs the behavior of radiating current-carrying plasma in fast Z-pinches. This survey covers essentially all aspects of the physics of fast Z pinches: initiation, instabilities of the early stage, magnetic Rayleigh-Taylor instability in the implosion phase, formation of a transient quasi-equilibrium near the stagnation point, and rebound. Considerable attention is paid to the analysis of hydrodynamic instabilities governing the implosion symmetry. Possible ways of mitigating these instabilities are discussed. Non-magnetohydrodynamic effects (anomalous resistivity, generation of particle beams, etc.) are summarized. Various applications of fast Z pinches are briefly described. Scaling laws governing development of more powerful Z pinches are presented. The survey contains 52 figures and nearly 300 references.

  5. Fast Harmonic Splines and Parameter Choice Methods

    Science.gov (United States)

    Gutting, Martin

    2017-04-01

    Solutions to boundary value problems in geoscience where the boundary is the Earth's surface are constructed in terms of harmonic splines. These are localizing trial functions that allow regional modeling or the improvement of a global model in a part of the Earth's surface. Some cases of the occurring kernels can be equipped with a fast matrix-vector multiplication using the fast multipole method (FMM). The main idea of the fast multipole algorithm consists of a hierarchical decomposition of the computational domain into cubes and a kernel approximation for the more distant points. The numerical effort of the matrix-vector multiplication becomes linear in reference to the number of points for a prescribed accuracy of the kernel approximation. This fast spline approximation which also allows the treatment of noisy data requires the choice of a smoothing parameter. We investigate several methods to (ideally automatically) choose this parameter with and without prior knowledge of the noise level. However, in order to keep a fast solution algorithm we do no longer have access to the whole matrix or e.g. its singular values whose computation requires a much larger numerical effort. This must be reflected by the parameter choice methods. Therefore, in some cases a further approximation is necessary. The performance of these methods is considered for different types of noise in a large simulation study with applications to gravitational field modeling as well as to boundary value problems.

  6. Fasting and differential chemotherapy protection in patients.

    Science.gov (United States)

    Raffaghello, Lizzia; Safdie, Fernando; Bianchi, Giovanna; Dorff, Tanya; Fontana, Luigi; Longo, Valter D

    2010-11-15

    Chronic calorie restriction has been known for decades to prevent or retard cancer growth, but its weight-loss effect and the potential problems associated with combining it with chemotherapy have prevented its clinical application. Based on the discovery in model organisms that short term starvation (STS or fasting) causes a rapid switch of cells to a protected mode, we described a fasting-based intervention that causes remarkable changes in the levels of glucose, IGF-I and many other proteins and molecules and is capable of protecting mammalian cells and mice from various toxins, including chemotherapy. Because oncogenes prevent the cellular switch to this stress resistance mode, starvation for 48 hours or longer protects normal yeast and mammalian cells and mice but not cancer cells from chemotherapy, an effect we termed Differential Stress Resistance (DSR). In a recent article, 10 patients who fasted in combination with chemotherapy, reported that fasting was not only feasible and safe but caused a reduction in a wide range of side effects accompanied by an apparently normal and possibly augmented chemotherapy efficacy. Together with the remarkable results observed in animals, these data provide preliminary evidence in support of the human application of this fundamental biogerontology finding, particularly for terminal patients receiving chemotherapy. Here we briefly discuss the basic, pre-clinical, and clinical studies on fasting and cancer therapy.

  7. The new ATLAS Fast Calorimeter Simulation

    CERN Document Server

    Dias, Flavia; The ATLAS collaboration

    2016-01-01

    A very large number of simulated events is required for physics and performance studies with the ATLAS detector at the Large Hadron Collider. Producing these with the full GEANT4 detector simulation is highly CPU intensive. As a very detailed detector simulation is not always required, fast simulation tools have been developed to reduce the calorimeter simulation time by a few orders of magnitude. The fast simulation of ATLAS for the calorimeter systems used in Run 1, called Fast Calorimeter Simulation (FastCaloSim), provides a parameterized simulation of the particle energy response at the calorimeter read-out cell level. It is then interfaced to the ATLAS digitization and reconstruction software. In Run 1, about 13 billion events were simulated in ATLAS, out of which 50% were produced using fast simulation. For Run 2, a new parameterisation is being developed to improve the original version: It incorporates developments in geometry and physics lists of the last five years and benefits from knowledge acquire...

  8. When fast atom diffraction turns 3D

    Energy Technology Data Exchange (ETDEWEB)

    Zugarramurdi, Asier; Borisov, Andrei G., E-mail: andrei.borissov@u-psud.fr

    2013-12-15

    Fast atom diffraction at surfaces (FAD) in grazing incidence geometry is characterized by the slow motion in the direction perpendicular to the surface and fast motion parallel to the surface plane along a low index direction. It is established experimentally that for the typical surfaces the FAD reveals the 2D diffraction patterns associated with exchange of the reciprocal lattice vector perpendicular to the direction of fast motion. The reciprocal lattice vector exchange along the direction of fast motion is negligible. The usual approximation made in the description of the experimental data is then to assume that the effective potential leading to the diffraction results from the averaging of the 3D surface potential along the atomic strings forming the axial channel. In this work we use full quantum wave packet propagation calculations to study theoretically the possibility to observe the 3D diffraction in FAD experiments. We show that for the surfaces with large unit cell, such as can be the case for reconstructed or vicinal surfaces, the 3D diffraction can be observed. The reciprocal lattice vector exchange along the direction of fast motion leads to several Laue circles in the diffraction pattern.

  9. Fast neutron detection with a segmented spectrometer

    Science.gov (United States)

    Langford, T. J.; Bass, C. D.; Beise, E. J.; Breuer, H.; Erwin, D. K.; Heimbach, C. R.; Nico, J. S.

    2015-01-01

    A fast neutron spectrometer consisting of segmented plastic scintillator and 3He proportional counters was constructed for the measurement of neutrons in the energy range 1-200 MeV. We discuss its design, principles of operation, and the method of analysis. The detector is capable of observing very low neutron fluxes in the presence of ambient gamma background and does not require scintillator pulse-shape discrimination. The spectrometer was characterized for its energy response in fast neutron fields of 2.5 MeV and 14 MeV, and the results are compared with Monte Carlo simulations. Measurements of the fast neutron flux and energy response at 120 m above sea-level (39.130°N, 77.218°W) and at a depth of 560 m in a limestone mine are presented. Finally, the design of a spectrometer with improved sensitivity and energy resolution is discussed.

  10. Fast Hugs with Intensive Care Unit

    Directory of Open Access Journals (Sweden)

    Nimet Şenoğlu

    2014-12-01

    Full Text Available Mnemonics are commonly used in medical procedures as cognitive aids to guide clinicians all over the world. The mnemonic ‘FAST HUG’ (Feeding, Analgesia, Sedation, Thromboembolic prophylaxis, Head-of-bed elevation, stress Ulcer prevention, and Glycemic control was proposed almost ten years ago for patient care in intensive care units and have been commonly used worldwide. Beside this, new mnemonics were also determined for improving routine care of the critically ill patients. But none of this was accepted as much as “FAST HUGS”. In our clinical practice we delivered an another mnemonic as FAST HUGS with ICU (Feeding, Analgesia, Sedation, Thromboembolic prophylaxis, Head-of-bed elevation, Stress ulcer prevention, and Glucose control, Water balance, Investigation and Results, Therapy, Hypo-hyper delirium, Invasive devices, Check the daily infection parameters, Use a checklist for checking some of the key aspects in the general care of intensive care patients. In this review we summarized these mnemonics.

  11. Fast Neutron Detection with a Segmented Spectrometer

    CERN Document Server

    Langford, T J; Beise, E J; Breuer, H; Erwin, D K; Heimbach, C R; Nico, J S

    2014-01-01

    A fast neutron spectrometer consisting of segmented plastic scintillator and He-3 proportional counters was constructed for the measurement of neutrons in the energy range 1 MeV to 200 MeV. We discuss its design, principles of operation, and the method of analysis. The detector is capable of observing very low neutron fluxes in the presence of ambient gamma background and does not require scintillator pulse-shape discrimination The spectrometer was characterized for energy resolution and efficiency in fast neutron fields of 2.5 MeV, 14 MeV, and fission spectrum neutrons, and the results are compared with Monte Carlo simulations. Measurements of the fast neutron flux and energy response at 120 m above sea-level (39.130 deg. N, 77.218 deg. W) and at a depth of 560 m in a limestone mine are presented. Finally, the design of a spectrometer with improved sensitivity and energy resolution is discussed.

  12. Fast charging of lead/acid batteries

    Energy Technology Data Exchange (ETDEWEB)

    Calasanzio, D. (FIAMM SpA, Montecchio Maggiore (Italy)); Maja, M. (Polytechnical Univ., Turin (Italy). Dept. of Materials Science and Chemical Engineering); Spinelli, P. (Polytechnical Univ., Turin (Italy). Dept. of Materials Science and Chemical Engineering)

    1993-10-15

    A key point in the development of storage batteries for electric vehicles (EVs) is the possibility for fast recharging. It is widely recognized that the lead/acid system represents an excellent candidate for EVs because of the low cost, durability, and expectance of improvements in the near future. The viability of the lead/acid battery for EV applications would be greatly enhanced if fast recharging could be applied to the system without shortening its life. The present paper reports the results obtained by simulating the charging behaviour with a mathematical model that is capable of predicting the behaviour of nonconventional lead/acid cells both on discharge and recharge. The effects of important parameters such as plate dimensions, acid distribution, and porosity of the active mass are taken into account. The data obtained with the simulation are compared with results got from fast-recharge testing of commercial batteries. (orig.)

  13. Fast neutron detection with a segmented spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Langford, T.J., E-mail: thomas.langford@yale.edu [Department of Physics, University of Maryland, College Park, MD 20742 (United States); Institute for Research in Electronics and Applied Physics, University of Maryland, College Park, MD 20742 (United States); Bass, C.D. [National Institute of Standards and Technology, Gaithersburg, MD 20899 (United States); Beise, E.J.; Breuer, H.; Erwin, D.K. [Department of Physics, University of Maryland, College Park, MD 20742 (United States); Heimbach, C.R.; Nico, J.S. [National Institute of Standards and Technology, Gaithersburg, MD 20899 (United States)

    2015-01-21

    A fast neutron spectrometer consisting of segmented plastic scintillator and {sup 3}He proportional counters was constructed for the measurement of neutrons in the energy range 1–200 MeV. We discuss its design, principles of operation, and the method of analysis. The detector is capable of observing very low neutron fluxes in the presence of ambient gamma background and does not require scintillator pulse-shape discrimination. The spectrometer was characterized for its energy response in fast neutron fields of 2.5 MeV and 14 MeV, and the results are compared with Monte Carlo simulations. Measurements of the fast neutron flux and energy response at 120 m above sea-level (39.130°N, 77.218°W) and at a depth of 560 m in a limestone mine are presented. Finally, the design of a spectrometer with improved sensitivity and energy resolution is discussed.

  14. FastUniq: a fast de novo duplicates removal tool for paired short reads.

    Directory of Open Access Journals (Sweden)

    Haibin Xu

    Full Text Available The presence of duplicates introduced by PCR amplification is a major issue in paired short reads from next-generation sequencing platforms. These duplicates might have a serious impact on research applications, such as scaffolding in whole-genome sequencing and discovering large-scale genome variations, and are usually removed. We present FastUniq as a fast de novo tool for removal of duplicates in paired short reads. FastUniq identifies duplicates by comparing sequences between read pairs and does not require complete genome sequences as prerequisites. FastUniq is capable of simultaneously handling reads with different lengths and results in highly efficient running time, which increases linearly at an average speed of 87 million reads per 10 minutes. FastUniq is freely available at http://sourceforge.net/projects/fastuniq/.

  15. Usefulness of non-fasting lipid parameters in children.

    Science.gov (United States)

    Kubo, Toshihide; Takahashi, Kyohei; Furujo, Mahoko; Hyodo, Yuki; Tsuchiya, Hiroki; Hattori, Mariko; Fujinaga, Shoko; Urayama, Kenji

    2017-01-01

    This study assessed whether non-fasting lipid markers could be substituted for fasting markers in screening for dyslipidemia, whether direct measurement of non-fasting low-density lipoprotein cholesterol [LDL-C (D)] could be substituted for the calculation of fasting LDL-C [LDL-C (F)], and the utility of measuring non-high-density lipoprotein cholesterol (non-HDL-C). In 33 children, the lipid profile was measured in the non-fasting and fasting states within 24 h. Correlations were examined between non-fasting LDL-C (D) or non-HDL-C levels and fasting LDL-C (F) levels. Non-fasting triglyceride (TG), total cholesterol (TC), HDL-C, LDL-C (D), and non-HDL-C levels were all significantly higher than the fasting levels, but the mean difference was within 10% (except for TG). Non-fasting LDL-C (D) and non-HDL-C levels were strongly correlated with the fasting LDL-C (F) levels. In conclusion, except for TG, non-fasting lipid parameters are useful when screening children for dyslipidemia. Direct measurement of non-fasting LDL-C and calculation of non-fasting non-HDL-C could replace the calculation of fasting LDL-C because of convenience.

  16. Conceptual Design of the FAST-D Formation Flying Spacecraft

    NARCIS (Netherlands)

    Maessen, D.C.; Guo, J.; Gill, E.; Gunter, B.; Chu, Q.P.; Bakker, G.; Laan, E.; Moon, S.; Kruijff, M.; Zheng, G.T.

    2009-01-01

    The paper presents the latest results in the design of FAST-D, the Dutch micro-satellite for the Dutch–Chinese FAST (Formation for Atmospheric Science and Technology demonstration) formation flying mission. Over the course of the 2.5 year mission, the two satellites, FAST-D and FAST-T, will demonstr

  17. Does Ramadan Fasting Increase duodenal ulcer perforation?

    Directory of Open Access Journals (Sweden)

    Abdoulhossein Davoodabadi

    2016-03-01

    Full Text Available Introduction: In Ramadan, healthy adult Muslims are obliged to fast. Prolonged fasting increase gastric acid and pepsin levels, which promote the risk of duodenal ulcer perforation (DUP. Effects of Ramadan fasting on DUP have not been thoroughly studied yet, and the limited number of studies investigating the impact of Ramadan fasting on DUP yielded discrepant results. This study aimed to evaluate DUP frequency during Ramadan 2011-2015 and compare it with other months. Methods: This cross-sectional study was performed in 82 patients undergoing surgery due to DUP during July 2011-September 2015. The demographics, history of addiction, use of nonsteroidal and antiinflammatory drugs, previous history of acid peptic disease, as well as complications and outcomes of treatment were recorded and analyzed, and the obtained results were compared between Ramadan and other lunar months. Results: The majority of patients were male (86.6%, 71 patients, with a mean age of 43.9±16.5 years (age range: 20-75 years. Male to female ratio was 6:1. Cases with less than 30 years of age were less frequent (22%, 18 patients. DUP was more frequent during Rajab with nine cases (11%, while during Ramadan, six cases were reported, the difference between Ramadan and other months regarding the incidence of DUP was not significant (P=0.7. Risk factors such as smoking (60% and addiction (44%; especially to crystal and crack were noted. Consumption of nonsteroidal antiinflammatory drugs in 20 (24% patients, and use of antacids in 17 (25% patients. Distribution of DUP in different blood types was as follows: O+=41%, A+=28%, B+=23%, AB=5%, and O-=3%; moreover, post-operative Helicobacter pylori antibody was present in 67% of the patients. Conclusion: Ramadan fasting did not escalate DUP incidence, and those with DUP risk factors can fast with the use of antacids.

  18. Waves from Propulsion Systems of Fast Ferries

    DEFF Research Database (Denmark)

    Taatø, Søren Haugsted; Aage, Christian; Arnskov, Michael M.

    1998-01-01

    Waves from fast ferries have become an environmental problem of growing concern to the public. Fast ferries produce not only higher waves than conventional ships but also fundamentally different wave systems when they sail at supercritical speeds. Hitherto, ship waves have been considered as bein...... similar to that of the hull alone, but with higher wave amplitudes. Conventional propellers will cause increased wave heights of about 10%, whereas water jets will cause increased wave heights of 20-40% as compared to those of the naked monohull....

  19. Fast micrographia: An unusual but distinctive sign

    Directory of Open Access Journals (Sweden)

    Umaiorubahan Meenakshisundaram

    2013-01-01

    Full Text Available Fast micrographia is a rare clinical sign, which is reported in patients with pallidal pathology. A 68-year-old male presented with hypophonia and short shuffling gait with decreased arm swing. About 3 weeks before, he had an acute myocardial infarction and a period of hemodynamic and respiratory distress during which he required mechanical ventilatory support. He was found to have a fast handwriting with micrographia from the outset. His rapid alternating hand and finger movements were normal. Magnetic resonance imaging (MRI of the brain showed features of hypoxic ischemic encephalopathy including hyperintensities on T1 and T2 weighted images in the globus pallidus, and putamen bilaterally.

  20. Intense Terahertz Fields for Fast Energy Release

    Science.gov (United States)

    2016-11-01

    6201 Fort Belvoir, VA 22060-6201 T E C H N IC A L R E P O R T DTRA-TR-17-10 Intense Terahertz Fields for Fast Energy Release...N) Energy /Work/Power electron volt (eV) 1.602 177 × 10 –19 joule (J) erg 1 × 10 –7 joule (J) kiloton (kt) (TNT equivalent) 4.184 × 10 12...customary unit. Grant #  HDTRA 1-12-1-0044 Intense Terahertz Fields for Fast Energy Release Final Report PI: Keith A. Nelson 617-253-1423 kanelson

  1. Fast photon detection for COMPASS RICH-1

    CERN Document Server

    Abbon, P; Angerer, H; Apollonio, M; Birsa, R; Bordalo, P; Bradamante, Franco; Bressan, A; Busso, L; Chiosso, M; Ciliberti, P; Colantoni, M L; Costa, S; Dibiase, N; Dafni, T; Dalla Torre, S; Díaz, V; Duic, V; Delagnes, E; Deschamps, H; Eyrich, W; Faso, D; Ferrero, A; Finger, M; Finger, J M; Fischer, H; Gerassimov, S; Giorgi, M; Gobbo, B; Von Harrach, D; Heinsius, F H; Joosten, R; Ketzer, B; Königsmann, K C; Kolosov, V N; Konorov, I; Kramer, Daniel; Kunne, Fabienne; Levorato, S; Maggiora, A; Magnon, A; Mann, A; Martin, A; Menon, G; Mutter, A; Nähle, O; Neyret, D; Nerling, F; Pagano, P; Paul, S; Panebianco, S; Panzieri, D; Pesaro, G; Pizzolotto, C; Polak, J; Rebourgeard, P; Rocco, E; Robinet, F; Schiavon, Paolo; Schill, C; Schoenmeier, P; Silva, L; Slunecka, M; Steiger, L; Sozzi, F; Sulc, M; Svec, M; Tessarotto, F; Teufel, A; Wollny, H

    2007-01-01

    A fast photon detection system has been built and assembled for the upgrade of COMPASS RICH-1. The system is based on multianode photomultipliers coupled to fused silica lenses to collect the light from a larger surface and to guide it to the photocathode, preserving the position information. The emphasis is on the fast response and high rate capability of the detectors and the associated electronics. The photon detection system is now ready and it will be employed in the 2006 COMPASS data taking. We report about the system design and construction.

  2. Omsætning af fast ejendom

    DEFF Research Database (Denmark)

    Edlund, Hans Henrik

    Bogen er en systematisk gennemgang af lov om omsætning af fast ejendom, der regulerer ejendomsmægleres virke. Følgende emner er bl.a. behandlet: Hvem kan drive ejendomsmæglervirksomhed og ejendomsmæglernes pligter og ansvar.......Bogen er en systematisk gennemgang af lov om omsætning af fast ejendom, der regulerer ejendomsmægleres virke. Følgende emner er bl.a. behandlet: Hvem kan drive ejendomsmæglervirksomhed og ejendomsmæglernes pligter og ansvar....

  3. A pragmatic overview of fast multipole methods

    Energy Technology Data Exchange (ETDEWEB)

    Strickland, J.H.; Baty, R.S.

    1995-12-01

    A number of physics problems can be modeled by a set of N elements which have pair-wise interactions with one another. A direct solution technique requires computational effort which is O(N{sup 2}). Fast multipole methods (FMM) have been widely used in recent years to obtain solutions to these problems requiring a computational effort of only 0 (N lnN) or O (N). In this paper we present an overview of several variations of the fast multipole method along with examples of its use in solving a variety of physical problems.

  4. Fast food and the semiotics of gastronomy

    Directory of Open Access Journals (Sweden)

    Elena FELL

    2015-12-01

    Full Text Available Nourishment stands apart from other physiological events: whilst we normally exercise discretion in relation to bodily functions, food consumption takes place in public. We dine, snack and nibble in front of others, and the imagery associated with food takes on the manifold of meanings—religious, cultural, historic and so forth. Gastronomic practices unite or divide people, and as such are a powerful communication tool. As the twenty-first century confrontational stance between fast food and family meal traditions intensifies, we investigate fast food’s visual imagery and its ability to attract consumers.

  5. Fast Link Adaptation for MIMO-OFDM

    DEFF Research Database (Denmark)

    Jensen, Tobias Lindstrøm; Kant, Shashi; Wehinger, Joachim;

    2010-01-01

    We investigate link-quality metrics (LQMs) based on raw bit-error-rate, effective signal-to-interference-plus-noise ratio, and mutual information (MI) for the purpose of fast link adaptation (LA) in communication systems employing orthogonal frequency-division multiplexing and multiple-input–mult......We investigate link-quality metrics (LQMs) based on raw bit-error-rate, effective signal-to-interference-plus-noise ratio, and mutual information (MI) for the purpose of fast link adaptation (LA) in communication systems employing orthogonal frequency-division multiplexing and multiple...

  6. A fast chopper for medium energy beams

    Energy Technology Data Exchange (ETDEWEB)

    Madrak, R. [Fermilab; Wildman, D. [Fermilab

    2014-10-30

    The key elements have been constructed for a fast chopper system capable of removing single 2.5 MeV proton bunches spaced at 325 MHz. The average chopping rate is ~ 1 MHz. The components include a pulse delaying microstrip structure for deflecting the beam, high voltage (1.2 kV) fast (ns rise time) pulsers, and an associated wideband combiner. Various designs for the deflecting structures have been studied. Measurements of the microstrip structures' coverage factors and pulse shapes are presented.

  7. BEAM COUPLING PHENOMENA IN FAST KICKER SYSTEMS.

    Energy Technology Data Exchange (ETDEWEB)

    ZHANG,W.; AHRENS,L.A.; GLENN,J.; SANDBERG,J.; TSOUPAS,N.

    2001-06-18

    Beam coupling phenomena have been observed in most fast kicker systems through out Brookhaven Collider-Accelerator complex. With ever-higher beam intensity, the signature of the beam becomes increasingly recognizable. The beam coupling at high intensity produced additional heat dissipation in high voltage modulator, thyratron grids, thyratron driver circuit sufficient to damage some components, and causes trigger instability. In this paper, we will present our observations, basic coupling mode analysis, relevance to the magnet structures, issues related to the existing high voltage modulators, and considerations of the future design of the fast kicker systems.

  8. Slow clean-up for fast reactor

    Science.gov (United States)

    Banks, Michael

    2008-05-01

    The year 2300 is so distant that one may be forgiven for thinking of it only in terms of science fiction. But this is the year that workers at the Dounreay power station in Northern Scotland - the UK's only centre for research into "fast" nuclear reactors - term as the "end point" by which time the site will be completely clear of radioactive material. More than 180 facilities - including the iconic dome that housed the Dounreay Fast Reactor (DFR) - were built at at the site since it opened in 1959, with almost 50 having been used to handle radioactive material.

  9. Pre-operative fasting guidelines: an update

    DEFF Research Database (Denmark)

    Søreide, E; Eriksson, L I; Hirlekar, G

    2005-01-01

    Liberal pre-operative fasting routines have been implemented in most countries. In general, clear fluids are allowed up to 2 h before anaesthesia, and light meals up to 6 h. The same recommendations apply for children and pregnant women not in labour. In children......Liberal pre-operative fasting routines have been implemented in most countries. In general, clear fluids are allowed up to 2 h before anaesthesia, and light meals up to 6 h. The same recommendations apply for children and pregnant women not in labour. In children...

  10. NEW ALGORITHM FOR FAST INTEGER AMBIGUITY RESOLUTION

    Institute of Scientific and Technical Information of China (English)

    HEXiao-feng; HUXiao-ping

    2005-01-01

    Fast integer ambiguity resolution is referred as a key part in precision relative positioning of the GPS carrier phase. A new algorithm for fast integer ambiguity resolution based on LAMBDA and FASF methods is proposed. This algorithm integrates the LAMBDA method and the FASF method, thus improving the efficiency of the ambiguity resolution. Firstly, the ambiguity search space transformation in the LAMBDA method is used,and then the FASF method is used to search ambiguities. Experiments in the relative positioning of about 1 km static baseline demonstrate that the error is less than 1 cm.

  11. Sodium fast reactors with closed fuel cycle

    CERN Document Server

    Raj, Baldev; Vasudeva Rao, PR 0

    2015-01-01

    Sodium Fast Reactors with Closed Fuel Cycle delivers a detailed discussion of an important technology that is being harnessed for commercial energy production in many parts of the world. Presenting the state of the art of sodium-cooled fast reactors with closed fuel cycles, this book:Offers in-depth coverage of reactor physics, materials, design, safety analysis, validations, engineering, construction, and commissioning aspectsFeatures a special chapter on allied sciences to highlight advanced reactor core materials, specialized manufacturing technologies, chemical sensors, in-service inspecti

  12. Fast Fourier Transform algorithm design and tradeoffs

    Science.gov (United States)

    Kamin, Ray A., III; Adams, George B., III

    1988-01-01

    The Fast Fourier Transform (FFT) is a mainstay of certain numerical techniques for solving fluid dynamics problems. The Connection Machine CM-2 is the target for an investigation into the design of multidimensional Single Instruction Stream/Multiple Data (SIMD) parallel FFT algorithms for high performance. Critical algorithm design issues are discussed, necessary machine performance measurements are identified and made, and the performance of the developed FFT programs are measured. Fast Fourier Transform programs are compared to the currently best Cray-2 FFT program.

  13. History of fast reactor fuel development

    Energy Technology Data Exchange (ETDEWEB)

    Kittel, J.H.; Frost, B.R.T. (Argonne National Lab., IL (United States)); Mustelier, J.P. (COGEMA, Velizy-Villacoublay (France))

    1992-01-01

    Most of the first generation of fast reactors that were operated at significant power levels employed solid metal fuels. They were constructed in the United States and United Kingdom in the 1950s and included Experimental Breeder Reactor (EBR)-I and -II operated by Argonne National Laboratory, United States, the Enrico Fermi Reactor operated by the Atomic Power Development Associates, United States and DFR operated by the U.K. Atomic Energy Authority (UKAEA). Their paper tracer pre-development of fast reactor fuel from these early days through the 1980s including ceramic fuels.

  14. FAST BUS Test Box (LAIKA) (Engineering Materials)

    Energy Technology Data Exchange (ETDEWEB)

    1983-01-01

    The assembly drawing AD 135-518-00-RO, and the drawings referenced thereon, provide the data and specifications for constructing the LAIKA Test Box. Some drawings are not available, although they are listed on the material lists included. The assembly is a manual tester for FAST BUS modules, both masters and slaves. FAST BUS signals are generated by means of switches or push buttons and provide the state of the bus lines by lighting LED's. The box acts as either a master or slave - depending upon the module under test. It also acts as an ATC to test the arbitration logic of a master or ATC device.

  15. Fast food purchasing and access to fast food restaurants: a multilevel analysis of VicLANES.

    Science.gov (United States)

    Thornton, Lukar E; Bentley, Rebecca J; Kavanagh, Anne M

    2009-05-27

    While previous research on fast food access and purchasing has not found evidence of an association, these studies have had methodological problems including aggregation error, lack of specificity between the exposures and outcomes, and lack of adjustment for potential confounding. In this paper we attempt to address these methodological problems using data from the Victorian Lifestyle and Neighbourhood Environments Study (VicLANES) - a cross-sectional multilevel study conducted within metropolitan Melbourne, Australia in 2003. The VicLANES data used in this analysis included 2547 participants from 49 census collector districts in metropolitan Melbourne, Australia. The outcome of interest was the total frequency of fast food purchased for consumption at home within the previous month (never, monthly and weekly) from five major fast food chains (Red Rooster, McDonalds, Kentucky Fried Chicken, Hungry Jacks and Pizza Hut). Three measures of fast food access were created: density and variety, defined as the number of fast food restaurants and the number of different fast food chains within 3 kilometres of road network distance respectively, and proximity defined as the road network distance to the closest fast food restaurant.Multilevel multinomial models were used to estimate the associations between fast food restaurant access and purchasing with never purchased as the reference category. Models were adjusted for confounders including determinants of demand (attitudes and tastes that influence food purchasing decisions) as well as individual and area socio-economic characteristics. Purchasing fast food on a monthly basis was related to the variety of fast food restaurants (odds ratio 1.13; 95% confidence interval 1.02 - 1.25) after adjusting for individual and area characteristics. Density and proximity were not found to be significant predictors of fast food purchasing after adjustment for individual socio-economic predictors. Although we found an independent

  16. Fast food purchasing and access to fast food restaurants: a multilevel analysis of VicLANES

    Directory of Open Access Journals (Sweden)

    Kavanagh Anne M

    2009-05-01

    Full Text Available Abstract Background While previous research on fast food access and purchasing has not found evidence of an association, these studies have had methodological problems including aggregation error, lack of specificity between the exposures and outcomes, and lack of adjustment for potential confounding. In this paper we attempt to address these methodological problems using data from the Victorian Lifestyle and Neighbourhood Environments Study (VicLANES – a cross-sectional multilevel study conducted within metropolitan Melbourne, Australia in 2003. Methods The VicLANES data used in this analysis included 2547 participants from 49 census collector districts in metropolitan Melbourne, Australia. The outcome of interest was the total frequency of fast food purchased for consumption at home within the previous month (never, monthly and weekly from five major fast food chains (Red Rooster, McDonalds, Kentucky Fried Chicken, Hungry Jacks and Pizza Hut. Three measures of fast food access were created: density and variety, defined as the number of fast food restaurants and the number of different fast food chains within 3 kilometres of road network distance respectively, and proximity defined as the road network distance to the closest fast food restaurant. Multilevel multinomial models were used to estimate the associations between fast food restaurant access and purchasing with never purchased as the reference category. Models were adjusted for confounders including determinants of demand (attitudes and tastes that influence food purchasing decisions as well as individual and area socio-economic characteristics. Results Purchasing fast food on a monthly basis was related to the variety of fast food restaurants (odds ratio 1.13; 95% confidence interval 1.02 – 1.25 after adjusting for individual and area characteristics. Density and proximity were not found to be significant predictors of fast food purchasing after adjustment for individual socio

  17. Association between proximity to and coverage of traditional fast-food restaurants and non-traditional fast-food outlets and fast-food consumption among rural adults

    OpenAIRE

    Horel Scott A; Dean Wesley R; Johnson Cassandra M; Sharkey Joseph R

    2011-01-01

    Abstract Objective The objective of this study is to examine the relationship between residential exposure to fast-food entrées, using two measures of potential spatial access: proximity (distance to the nearest location) and coverage (number of different locations), and weekly consumption of fast-food meals. Methods Traditional fast-food restaurants and non-traditional fast-food outlets, such as convenience stores, supermarkets, and grocery stores, from the 2006 Brazos Valley Food Environmen...

  18. Association between proximity to and coverage of traditional fast-food restaurants and non-traditional fast-food outlets and fast-food consumption among rural adults.

    Science.gov (United States)

    Sharkey, Joseph R; Johnson, Cassandra M; Dean, Wesley R; Horel, Scott A

    2011-05-20

    The objective of this study is to examine the relationship between residential exposure to fast-food entrées, using two measures of potential spatial access: proximity (distance to the nearest location) and coverage (number of different locations), and weekly consumption of fast-food meals. Traditional fast-food restaurants and non-traditional fast-food outlets, such as convenience stores, supermarkets, and grocery stores, from the 2006 Brazos Valley Food Environment Project were linked with individual participants (n = 1409) who completed the nutrition module in the 2006 Brazos Valley Community Health Assessment. Increased age, poverty, increased distance to the nearest fast food, and increased number of different traditional fast-food restaurants, non-traditional fast-food outlets, or fast-food opportunities were associated with less frequent weekly consumption of fast-food meals. The interaction of gender and proximity (distance) or coverage (number) indicated that the association of proximity to or coverage of fast-food locations on fast-food consumption was greater among women and opposite of independent effects. Results provide impetus for identifying and understanding the complex relationship between access to all fast-food opportunities, rather than to traditional fast-food restaurants alone, and fast-food consumption. The results indicate the importance of further examining the complex interaction of gender and distance in rural areas and particularly in fast-food consumption. Furthermore, this study emphasizes the need for health promotion and policy efforts to consider all sources of fast-food as part of promoting healthful food choices.

  19. Association between proximity to and coverage of traditional fast-food restaurants and non-traditional fast-food outlets and fast-food consumption among rural adults

    Science.gov (United States)

    2011-01-01

    Objective The objective of this study is to examine the relationship between residential exposure to fast-food entrées, using two measures of potential spatial access: proximity (distance to the nearest location) and coverage (number of different locations), and weekly consumption of fast-food meals. Methods Traditional fast-food restaurants and non-traditional fast-food outlets, such as convenience stores, supermarkets, and grocery stores, from the 2006 Brazos Valley Food Environment Project were linked with individual participants (n = 1409) who completed the nutrition module in the 2006 Brazos Valley Community Health Assessment. Results Increased age, poverty, increased distance to the nearest fast food, and increased number of different traditional fast-food restaurants, non-traditional fast-food outlets, or fast-food opportunities were associated with less frequent weekly consumption of fast-food meals. The interaction of gender and proximity (distance) or coverage (number) indicated that the association of proximity to or coverage of fast-food locations on fast-food consumption was greater among women and opposite of independent effects. Conclusions Results provide impetus for identifying and understanding the complex relationship between access to all fast-food opportunities, rather than to traditional fast-food restaurants alone, and fast-food consumption. The results indicate the importance of further examining the complex interaction of gender and distance in rural areas and particularly in fast-food consumption. Furthermore, this study emphasizes the need for health promotion and policy efforts to consider all sources of fast-food as part of promoting healthful food choices. PMID:21599955

  20. Association between proximity to and coverage of traditional fast-food restaurants and non-traditional fast-food outlets and fast-food consumption among rural adults

    Directory of Open Access Journals (Sweden)

    Horel Scott A

    2011-05-01

    Full Text Available Abstract Objective The objective of this study is to examine the relationship between residential exposure to fast-food entrées, using two measures of potential spatial access: proximity (distance to the nearest location and coverage (number of different locations, and weekly consumption of fast-food meals. Methods Traditional fast-food restaurants and non-traditional fast-food outlets, such as convenience stores, supermarkets, and grocery stores, from the 2006 Brazos Valley Food Environment Project were linked with individual participants (n = 1409 who completed the nutrition module in the 2006 Brazos Valley Community Health Assessment. Results Increased age, poverty, increased distance to the nearest fast food, and increased number of different traditional fast-food restaurants, non-traditional fast-food outlets, or fast-food opportunities were associated with less frequent weekly consumption of fast-food meals. The interaction of gender and proximity (distance or coverage (number indicated that the association of proximity to or coverage of fast-food locations on fast-food consumption was greater among women and opposite of independent effects. Conclusions Results provide impetus for identifying and understanding the complex relationship between access to all fast-food opportunities, rather than to traditional fast-food restaurants alone, and fast-food consumption. The results indicate the importance of further examining the complex interaction of gender and distance in rural areas and particularly in fast-food consumption. Furthermore, this study emphasizes the need for health promotion and policy efforts to consider all sources of fast-food as part of promoting healthful food choices.