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    [Hypophosphatemia is associated with poor prognosis of critically ill patients: a meta-analysis of 1 555 patients].
    Zhonghua Wei Zhong Bing Ji Jiu Yi Xue 2018 Jan;30(1):34-40
    Department of Intensive Care Unit, Affiliated Hospital of Guizhou Medical University, Guiyang 550004, Guizhou, China (Liu B, Cheng YM, Shen F, Wang YH, Wu YQ); Department of Intensive Care Unit, Second Affiliated Hospital of Guizhou Medical University, Kaili 556000, Guizhou, China (Yao L); Department of Intensive Care Unit, Fourth People's Hospital of Zhenjiang City, Zhenjiang 212000, Jiangsu, China (Liu YQ); Department of Oncology, Mineral Hospital of Liupanshui City, Liupanshui 553000, Guizhou, China (Gou XB). Corresponding author: Shen Feng, Email:
    Objective: To evaluate the relationship between hypophosphatemia and prognosis in critically ill patients.

    Methods: Some hypophosphatemia-associated prospective or retrospective clinical cohort studies were searched through CNKI, Wanfang Data, PubMed, Embase, Cochrane library, and Google Scholar English database respectively, with the guidance of these key words such as hypophosphatemia, intensive care, prognosis and fatality rate. The articles were concerned about the correlation between hypophosphatemia and the prognosis of patients in intensive care unit (ICU). Read More

    Mechanically Ventilating the Severe Asthmatic.
    J Intensive Care Med 2017 Jan 1:885066617740079. Epub 2017 Jan 1.
    2 Department of Critical Care, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa.
    The management of the critically ill patients with asthma can be rather challenging. Potentially devastating complications relating to this presentation include hypoxemia, worsening bronchospasm, pulmonary aspiration, tension pneumothorax, dynamic hyperinflation, hypotension, dysrhythmias, and seizures. In contrast to various other pathologies requiring mechanical ventilation, acute asthma is generally associated with better outcomes. Read More

    Clinical management of pressure control ventilation: An algorithmic method of patient ventilatory management to address "forgotten but important variables".
    J Crit Care 2018 Feb 6;43:169-182. Epub 2017 Sep 6.
    Department of Pulmonary and Critical Care Medicine, Tokyo Bay Urayasu Ichikawa Medical Center, 3-4-32 Todaijima, Urayasu City, Chiba 2790001, Japan.
    Pressure controlled ventilation is a common mode of ventilation used to manage both adult and pediatric populations. However, there is very little evidence that distinguishes the efficacy of pressure controlled ventilation over that of volume controlled ventilation in the adult population. This gap in the literature may be due to the absence of a consistent and systematic algorithm for managing pressure controlled ventilation. Read More

    Fast Numerical Simulation of Focused Ultrasound Treatments During Respiratory Motion With Discontinuous Motion Boundaries.
    IEEE Trans Biomed Eng 2017 Jul 23;64(7):1455-1468. Epub 2017 May 23.
    Fraunhofer Institute for Medical Image Computing MEVIS.
    Objective: Focused ultrasound (FUS) is rapidly gaining clinical acceptance for several target tissues in the human body. Yet, treating liver targets is not clinically applied due to a high complexity of the procedure (noninvasiveness, target motion, complex anatomy, blood cooling effects, shielding by ribs, and limited image-based monitoring). To reduce the complexity, numerical FUS simulations can be utilized for both treatment planning and execution. Read More

    Impact of physician education and availability of parameters regarding esophageal pressure and transpulmonary pressure on clinical decisions involving ventilator management.
    J Crit Care 2017 Oct 18;41:112-118. Epub 2017 Apr 18.
    Department of Emergency and Critical Care Medicine, St. Marianna University Hospital, Kanagawa, Japan.
    Purpose: This study investigated the effects of physician education and the availability of Peso and PL data on physicians' decisions regarding ventilator management during specific simulated clinical conditions.

    Materials And Methods: The study was a prospective, before-after study using a case scenario-based questionnaire and a case simulator device comprising an Avea ventilator and an artificial lung and esophagus, which was connected to a Series 1101 Electronic Breathing Simulator. The 99 physicians participating in the study were provided with five simulated cases with on-time ventilator graphics without Peso and PL and completed a questionnaire on decisions they would make regarding ventilator management of the cases. Read More

    Placenta Maps: In Utero Placental Health Assessment of the Human Fetus.
    IEEE Trans Vis Comput Graph 2017 Jun 24;23(6):1612-1623. Epub 2017 Feb 24.
    Institute of Computer Graphics and Algorithms, TU Wien, Vienna, Austria.
    The human placenta is essential for the supply of the fetus. To monitor the fetal development, imaging data is acquired using (US). Although it is currently the gold-standard in fetal imaging, it might not capture certain abnormalities of the placenta. Read More

    Thoracic CT-MRI coregistration for regional pulmonary structure-function measurements of obstructive lung disease.
    Med Phys 2017 May 11;44(5):1718-1733. Epub 2017 Apr 11.
    Robarts Research Institute, The University of Western Ontario, London, Canada.
    Purpose: Recent pulmonary imaging research has revealed that in patients with chronic obstructive pulmonary disease (COPD) and asthma, structural and functional abnormalities are spatially heterogeneous. This novel information may help optimize treatment in individual patients, monitor interventional efficacy, and develop new treatments. Moreover, by automating the measurement of regional biomarkers for the 19 different anatomical lung segments, there is an opportunity to embed imaging biomarkers into clinically acceptable clinical workflows and improve lung disease clinical care. Read More

    Ability of ICU Health-Care Professionals to Identify Patient-Ventilator Asynchrony Using Waveform Analysis.
    Respir Care 2017 Feb 25;62(2):144-149. Epub 2016 Oct 25.
    Department of Respiratory Care, University of Texas Health Sciences Center at San Antonio, San Antonio, Texas.
    Background: Waveform analysis by visual inspection can be a reliable, noninvasive, and useful tool for detecting patient-ventilator asynchrony. However, it is a skill that requires a properly trained professional.

    Methods: This observational study was conducted in 17 urban ICUs. Read More

    Patient-Ventilator Interactions.
    Clin Chest Med 2016 Dec 14;37(4):669-681. Epub 2016 Oct 14.
    Respiratory Care Services, Duke University Hospital, Box 3911 Duke North, Erwin Road, Durham, NC 27710, USA.
    Ventilatory muscle fatigue is a reversible loss of the ability to generate force or velocity of contraction in response to increased elastic and resistive loads. Mechanical ventilation should provide support without imposing additional loads from the ventilator (dys-synchrony). Interactive breaths optimize this relationship but require that patient effort and the ventilator response be synchronous during breath initiation, flow delivery, and termination. Read More

    Assessing Respiratory System Mechanical Function.
    Clin Chest Med 2016 Dec;37(4):615-632
    Universidad Catolica de Chile, 328 Avenida Libertador Bernardo O' Higgins, Santiago de Chile, Chile.
    The main goals of assessing respiratory system mechanical function are to evaluate the lung function through a variety of methods and to detect early signs of abnormalities that could affect the patient's outcomes. In ventilated patients, it has become increasingly important to recognize whether respiratory function has improved or deteriorated, whether the ventilator settings match the patient's demand, and whether the selection of ventilator parameters follows a lung-protective strategy. Ventilator graphics, esophageal pressure, intra-abdominal pressure, and electric impedance tomography are some of the best-known monitoring tools to obtain measurements and adequately evaluate the respiratory system mechanical function. Read More

    Trending autoregulatory indices during treatment for traumatic brain injury.
    J Clin Monit Comput 2016 Dec 7;30(6):821-831. Epub 2015 Oct 7.
    Department of Biomedical Engineering, Rutgers, The State University of New Jersey, Piscataway, NJ, 08854, USA.
    Our goal is to use automatic data monitoring for reliable prediction of episodes of intracranial hypertension in patients with traumatic brain injury. Here we test the validity of our method on retrospective patient data. We developed the Continuous Hemodynamic Autoregulatory Monitor (CHARM), that siphons and stores signals from existing monitors in the surgical intensive care unit (SICU), efficiently compresses them, and standardizes the search for statistical relationships between any proposed index and adverse events. Read More

    Ventilator graphics.
    Minerva Pediatr 2016 Dec 8;68(6):456-469. Epub 2016 Jul 8.
    Section of Critical Care, Department of Pediatrics, University of Alabama, Birmingham, AL, USA -
    Providing optimal mechanical ventilation to critically-ill children remains a challenge. Patient-ventilator dyssynchrony results frequently with numerous deleterious consequences on patient outcome including increased requirement for sedation, prolonged duration of ventilation, and greater imposed work of breathing. Most currently used ventilators have real-time, continuously-displayed graphics of pressure, volume, and flow versus time (scalars) as well as pressure, and flow versus volume (loops). Read More

    Rapid breath-hold assessment of myocardial velocities using spiral UNFOLD-ed SENSE tissue phase mapping.
    J Magn Reson Imaging 2016 Oct 29;44(4):1003-9. Epub 2016 Feb 29.
    UCL Centre for Cardiovascular Imaging, University College London, London, UK.
    Purpose: To develop and validate a rapid breath-hold tissue phase mapping (TPM) sequence.

    Materials And Methods: The sequence was based on an efficient uniform density spiral acquisition, combined with data acceleration. A novel acquisition and reconstruction strategy enabled combination of UNFOLD (2×) and SENSE (3×): UNFOLD-ed SENSE. Read More

    Hypoxic events and concomitant factors in preterm infants on non-invasive ventilation.
    J Clin Monit Comput 2017 Apr 20;31(2):427-433. Epub 2016 Feb 20.
    Department of Paediatrics, Royal Hobart Hospital, Hobart, TAS, Australia.
    Automated control of inspired oxygen for newborn infants is an emerging technology, currently limited by reliance on a single input signal (oxygen saturation, SpO2). This is while other signals that may herald the onset of hypoxic events or identify spurious hypoxia are not usually utilised. We wished to assess the frequency of apnoea, loss of circuit pressure and/or motion artefact in proximity to hypoxic events in preterm infants on non-invasive ventilation. Read More

    Reducing Dose Uncertainty for Spot-Scanning Proton Beam Therapy of Moving Tumors by Optimizing the Spot Delivery Sequence.
    Int J Radiat Oncol Biol Phys 2015 Nov 18;93(3):547-56. Epub 2015 Jun 18.
    Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas.
    Purpose: To develop and validate a novel delivery strategy for reducing the respiratory motion-induced dose uncertainty of spot-scanning proton therapy.

    Methods And Materials: The spot delivery sequence was optimized to reduce dose uncertainty. The effectiveness of the delivery sequence optimization was evaluated using measurements and patient simulation. Read More

    Single breath-hold 3D measurement of left atrial volume using compressed sensing cardiovascular magnetic resonance and a non-model-based reconstruction approach.
    J Cardiovasc Magn Reson 2015 Jun 11;17:47. Epub 2015 Jun 11.
    Division of Cardiology and Cardiac MR Center, University Hospital of Lausanne (CHUV), Lausanne, Switzerland.
    Background: 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.

    Aim: To develop a time-efficient single breath-hold 3D CMR acquisition and reconstruction method to precisely measure LA volumes and function. Read More

    Globally optimal co-segmentation of three-dimensional pulmonary ¹H and hyperpolarized ³He MRI with spatial consistence prior.
    Med Image Anal 2015 Jul 17;23(1):43-55. Epub 2015 Apr 17.
    Robarts Research Institute, The University of Western Ontario, London, ON, Canada; Graduate Program in Biomedical Engineering, The University of Western Ontario, London, ON, Canada; Department of Medical Biophysics, The University of Western Ontario, London, ON, Canada. Electronic address:
    Pulmonary imaging using hyperpolarized (3)He/(129)Xe gas is emerging as a new way to understand the regional nature of pulmonary ventilation abnormalities in obstructive lung diseases. However, the quantitative information derived is completely dependent on robust methods to segment both functional and structural/anatomical data. Here, we propose an approach to jointly segment the lung cavity from (1)H and (3)He pulmonary magnetic resonance images (MRI) by constraining the spatial consistency of the two segmentation regions, which simultaneously employs the image features from both modalities. Read More

    plethy: management of whole body plethysmography data in R.
    BMC Bioinformatics 2015 Apr 29;16:134. Epub 2015 Apr 29.
    Oregon Clinical and Translational Research Institute, Oregon Health and Science University, 3181 SW Sam Jackson Park Rd97239, Portland, Oregon, US.
    Background: Characterization of respiratory phenotypes can enhance complex trait and genomic studies involving allergic/autoimmune and infectious diseases. Many aspects of respiration can be measured using devices known as plethysmographs that can measure thoracic movement. One such approach (the Buxco platform) performs unrestrained whole body plethysmography on mice which infers thoracic movements from pressure differences from the act of inhalation and exhalation. Read More

    Real-time pulmonary graphics.
    Semin Fetal Neonatal Med 2015 Jun 7;20(3):181-91. Epub 2015 Feb 7.
    Department of Pediatrics, Division of Neonatal-Perinatal Medicine, C.S. Mott Children's Hospital, University of Michigan Health System, Ann Arbor, MI, USA.
    Real-time pulmonary graphics now enable clinicians to view lung mechanics and patient-ventilator interactions on a breath-to-breath basis. Displays of pressure, volume, and flow waveforms, pressure-volume and flow-volume loops, and trend screens enable clinicians to customize ventilator settings based on the underlying pathophysiology and responses of the individual patient. This article reviews the basic concepts of pulmonary graphics and demonstrates how they contribute to our understanding of respiratory physiology and the management of neonatal respiratory failure. Read More

    Computational fluid dynamic modelling of the effect of ventilation mode and tracheal tube position on air flow in the large airways.
    Anaesthesia 2015 May 8;70(5):577-84. Epub 2015 Jan 8.
    School of Medicine, University of Leeds, Leeds, UK.
    We have used computational fluid dynamic modelling to study the effects of tracheal tube size and position on regional gas flow in the large airways. Using a three-dimensional mathematical model, we simulated flow with and without a tracheal tube, replicating both physiological and artificial breathing. Ventilation through a tracheal tube increased proportional flow to the left lung from 39. Read More

    An augmented reality framework for soft tissue surgery.
    Med Image Comput Comput Assist Interv 2014 ;17(Pt 1):423-31
    Augmented reality for soft tissue laparoscopic surgery is a growing topic of interest in the medical community and has potential application in intra-operative planning and image guidance. Delivery of such systems to the operating room remains complex with theoretical challenges related to tissue deformation and the practical limitations of imaging equipment. Current research in this area generally only solves part of the registration pipeline or relies on fiducials, manual model alignment or assumes that tissue is static. Read More

    See-saw pattern in ventilator graphic: Is there any story behind?
    Niger Med J 2014 Jul;55(4):359-61
    Department of Neuroanesthesia and Neurocritical Care, All India Institute of Medical Sciences, New Delhi, India.
    The importance of ventilator graphics cannot be over emphasized that provide the useful information about airway, ventilation, compliance and lung mechanics. Some bizarre forms of graphics are usually overlooked in view of artifacts, but sometimes these tracings may in fact predict some relevant information. Read More

    High performance MRI simulations of motion on multi-GPU systems.
    J Cardiovasc Magn Reson 2014 Jul 4;16:48. Epub 2014 Jul 4.
    Department of Computer Science and Biomedical Informatics, University of Thessaly, Lamia, Greece.
    Background: MRI physics simulators have been developed in the past for optimizing imaging protocols and for training purposes. However, these simulators have only addressed motion within a limited scope. The purpose of this study was the incorporation of realistic motion, such as cardiac motion, respiratory motion and flow, within MRI simulations in a high performance multi-GPU environment. Read More

    Monitoring of intratidal lung mechanics: a Graphical User Interface for a model-based decision support system for PEEP-titration in mechanical ventilation.
    J Clin Monit Comput 2014 Dec 19;28(6):613-23. Epub 2014 Feb 19.
    Division for Experimental Anesthesiology, Department of Anesthesiology, University Medical Center Freiburg, Hugstetter Str. 55, 79106, Freiburg, Germany,
    In mechanical ventilation, a careful setting of the ventilation parameters in accordance with the current individual state of the lung is crucial to minimize ventilator induced lung injury. Positive end-expiratory pressure (PEEP) has to be set to prevent collapse of the alveoli, however at the same time overdistension should be avoided. Classic approaches of analyzing static respiratory system mechanics fail in particular if lung injury already prevails. Read More

    Ventilator waveforms.
    Top Companion Anim Med 2013 Aug;28(3):112-23
    Small Animal Emergency and Critical Care Service, Department of Veterinary Surgical and Radiological Sciences, School of Veterinary Medicine, University of California, Davis, CA, USA. Electronic address:
    Ventilator waveforms are graphic representations of changes in pressure, flow, and volume within a ventilator circuit. The changes in these parameters over time may be displayed individually (scalars) or plotted one against another (pressure-volume and flow-volume loops). There are 6 basic shapes of scalar waveforms, but only 3 are functionally distinct (square, ramp, and sine). Read More

    A simple gas exchange model predicting arterial oxygen content for various FiO2 levels.
    Conf Proc IEEE Eng Med Biol Soc 2013 ;2013:465-8
    The application of mechanical ventilation is a life-saving routine therapy that allows the patient to overcome the physiological impact of surgeries, trauma or critical illness by ensuring vital oxygenation and carbon dioxide removal. Above a certain level of minute ventilation (usually set to ensure acceptable carbon dioxide removal and oxygenation) oxygenation is only marginally affected by a further increase in minute ventilation. Thus, oxygenation is predominantly influenced by inspiratory oxygen fraction (FiO2) Usually, finding the appropriate setting is a trial-and-error procedure, as the clinician is unaware of the exact value that needs to be set in order to reach the desired arterial oxygen partial pressures (PaO2) in the patient. Read More

    Patient-ventilator interactions. Implications for clinical management.
    Am J Respir Crit Care Med 2013 Nov;188(9):1058-68
    1 Department of Medicine, Duke University, Durham, North Carolina.
    Assisted/supported modes of mechanical ventilation offer significant advantages over controlled modes in terms of ventilator muscle function/recovery and patient comfort (and sedation needs). However, assisted/supported breaths must interact with patient demands during all three phases of breath delivery: trigger, target, and cycle. Synchronous interactions match ventilator support with patient demands; dyssynchronous interactions do not. Read More

    A technical description of a novel pharmacological anesthesia robot.
    J Clin Monit Comput 2014 Feb 15;28(1):27-34. Epub 2013 Jun 15.
    Department of Experimental Surgery, McGill University, Montreal, QC, Canada,
    To control the three components of general anesthesia (hypnosis, analgesia, and neuromuscular blockade), an automated closed-loop, anesthesia-drug delivery system (McSleepy) was developed. Bispectral index was used as the control variable for hypnosis, the analgoscore for analgesia, and phonomyography for neuromuscular blockade. McSleepy can be used to control the induction, maintenance and emergence from general anesthesia. Read More

    A bond graph approach to modeling the anuran vocal production system.
    J Acoust Soc Am 2013 Jun;133(6):4133-44
    Department of Biological Sciences, Edgewood College, 1000 Edgewood College Drive, Madison, Wisconsin 53711, USA.
    Air-driven vocal production systems such as those found in mammals, birds, and anurans (frogs and toads) combine pneumatic and mechanical elements in species-specific ways to produce a diversity of communication signals. This study uses bond graphs to model a generalized anuran vocal production system. Bond graphs allow an incremental approach to modeling dynamic physical systems involving different domains. Read More

    Relationship between locations of rib defects and loss of respiratory function - a biomechanical study.
    Thorac Cardiovasc Surg 2014 Jun 5;62(4):357-62. Epub 2013 Apr 5.
    Department of Reconstructive Surgery, Keio University Hospital, Tokyo, Japan.
    Objective: The present study elucidates the relationship between the locations of rib defects and loss of respiratory function.

    Methods: Ten sets of three-dimensional finite element models were produced from computed tomography data of 10 persons and categorized as normal type models. These models were modified by removing part of the ribs, and the resultant models were categorized as defect type models. Read More

    Closed loop mechanical ventilation.
    J Clin Monit Comput 2014 Feb 7;28(1):49-56. Epub 2013 Apr 7.
    Research Center, CHU Sainte-Justine Hospital, 3175 Chemin de la Côte-Sainte-Catherine, Montreal, QC, H3T 1C5, Canada,
    Mechanical ventilation is a sophisticated technique with very narrow therapeutic ranges i.e. highly efficient and able to keep alive the most severe patients, but with considerable side effects and unwanted complications if not properly and timely used. Read More

    "Il flauto magico" still works: Mozart's secret of ventilation.
    Multidiscip Respir Med 2013 Mar 19;8(1):23. Epub 2013 Mar 19.
    Medical University of Vienna, Department of Internal Medicine 1, Division of Palliative Care, Waehringer Guertel 18-20, Vienna 1090, Austria.
    Background: Synchronisation/coupling between respiratory patterns and musical structure.

    Methods: Healthy professional musicians and members of the audience were studied during a performance of W.A. Read More

    Dynamic change in respiratory resistance during inspiratory and expiratory phases of tidal breathing in patients with chronic obstructive pulmonary disease.
    Int J Chron Obstruct Pulmon Dis 2012 11;7:259-69. Epub 2012 Apr 11.
    Division of Health Promotion Center, University of Tokyo, Tokyo, Japan.
    Background And Objective: Chronic obstructive pulmonary disease (COPD) is characterized by persistent airflow limitation consisting of airway obstruction and parenchymal emphysema, with loss of elastic recoil. The forced oscillation technique can detect impairment of lung function by measuring lung impedance during normal tidal breathing. Respiratory resistance (Rrs) in COPD has been well-studied, but the differences in Rrs in the inspiratory and expiratory phases between mild and moderate COPD remain poorly understood. Read More

    Visualization and curve-parameter estimation strategies for efficient exploration of phenotype microarray kinetics.
    PLoS One 2012 20;7(4):e34846. Epub 2012 Apr 20.
    DSMZ-German Collection for Microorganisms and Cell Cultures, Braunschweig, Germany.
    Background: The Phenotype MicroArray (OmniLog® PM) system is able to simultaneously capture a large number of phenotypes by recording an organism's respiration over time on distinct substrates. This technique targets the object of natural selection itself, the phenotype, whereas previously addressed '-omics' techniques merely study components that finally contribute to it. The recording of respiration over time, however, adds a longitudinal dimension to the data. Read More

    Electrical impedance tomography system based on active electrodes.
    Physiol Meas 2012 May 24;33(5):831-47. Epub 2012 Apr 24.
    Centre Suisse d'Electronique et de Microtechnique S.A. (CSEM), Landquart, Switzerland.
    Electrical impedance tomography (EIT) can image the distribution of ventilated lung tissue, and is thus a promising technology to help monitor patient breathing to help selection of mechanical ventilation parameters. Two key difficulties in EIT instrumentation make such monitoring difficult: (1) EIT data quality depends on good electrode contact and is sensitive to changes in contact quality, and (2) EIT electrodes are difficult and time consuming to place on patients. This paper presents the design and initial tests of an active electrode-based system to address these difficulties. Read More

    Ventilator waveform interpretation in mechanically ventilated small animals.
    J Vet Emerg Crit Care (San Antonio) 2011 Oct;21(5):496-514
    Critical Care Department at Florida Veterinary Specialists, Busch Lake Blvd, Tampa, FL 33614, USA.
    Objective: To review the topic of ventilator waveforms analysis with emphasis on interpretation of ventilator waveforms and their use in the management and monitoring of mechanically ventilated small animal patients.

    Data Sources: Human clinical studies, scientific reviews, and textbooks, as well as veterinary textbooks and clinical examples of ventilator waveforms in mechanically ventilated dogs.

    Summary: Ventilator waveforms are graphic representations of data collected from the ventilator and reflect patient-ventilator interactions. Read More

    Automated quantification of the synchrogram by recurrence plot analysis.
    IEEE Trans Biomed Eng 2012 Apr 15;59(4):946-55. Epub 2011 Dec 15.
    School of Information Technology and Electrical Engineering, The University of Queensland, Brisbane, Queensland, Australia.
    Recently, the concept of phase synchronization of two weakly coupled oscillators has raised a great research interest and has been applied to characterize synchronization phenomenon in physiological data. Phase synchronization of cardiorespiratory coupling is often studied by a synchrogram analysis, a graphical tool investigating the relationship between instantaneous phases of two signals. Although several techniques have been proposed to automatically quantify the synchrogram, most of them require a preselection of a phase-locking ratio by trial and error. Read More

    Generation of 4D access corridors from real-time multislice MRI for guiding transapical aortic valvuloplasties.
    Med Image Comput Comput Assist Interv 2011 ;14(Pt 1):251-8
    Computer Graphics and Interactive Media Lab, University of Houston, Houston, TX 77004, USA.
    Real-time image-guided cardiac procedures (manual or robot-assisted) are emerging due to potential improvement in patient management and reduction in the overall cost. These minimally invasive procedures require both real-time visualization and guidance for maneuvering an interventional tool safely inside the dynamic environment of a heart. In this work, we propose an approach to generate dynamic 4D access corridors from the apex to the aortic annulus for performing real-time MRI guided transapical valvuloplasties. Read More

    Four-dimensional volume-of-interest reconstruction for cone-beam computed tomography-guided radiation therapy.
    Med Phys 2011 Oct;38(10):5646-56
    Department of Imaging Physics, The University of Texas, MD Anderson Cancer Center, Houston, TX 77030, USA.
    Purpose: Data sufficiency are a major problem in four-dimensional cone-beam computed tomography (4D-CBCT) on linear accelerator-integrated scanners for image-guided radiotherapy. Scan times must be in the range of 4-6 min to avoid undersampling artifacts. Various image reconstruction algorithms have been proposed to accommodate undersampled data acquisitions, but these algorithms are computationally expensive, may require long reconstruction times, and may require algorithm parameters to be optimized. Read More

    Patient-specific modelling of pulmonary airflow using GPU cluster for the application in medical practice.
    Comput Methods Biomech Biomed Engin 2012 2;15(7):771-8. Epub 2011 Aug 2.
    Department of Biomedical Engineering, Tohoku University, Aoba 6-6-01, Sendai, 980-8579, Japan.
    In this paper, we propose a novel patient-specific method of modelling pulmonary airflow using graphics processing unit (GPU) computation that can be applied in medical practice. To overcome the barriers imposed by computation speed, installation price and footprint to the application of computational fluid dynamics, we focused on GPU computation and the lattice Boltzmann method (LBM). The GPU computation and LBM are compatible due to the characteristics of the GPU. Read More

    Visual servoing for a US-guided therapeutic HIFU system by coagulated lesion tracking: a phantom study.
    Int J Med Robot 2011 Jun 28;7(2):237-47. Epub 2011 Apr 28.
    School of Engineering, University of Tokyo, Hongo, Tokyo, Japan.
    Background: Applying ultrasound (US)-guided high-intensity focused ultrasound (HIFU) therapy for kidney tumours is currently very difficult, due to the unclearly observed tumour area and renal motion induced by human respiration. In this research, we propose new methods by which to track the indistinct tumour area and to compensate the respiratory tumour motion for US-guided HIFU treatment.

    Methods: For tracking indistinct tumour areas, we detect the US speckle change created by HIFU irradiation. Read More

    Impact of nonrigid motion correction technique on pixel-wise pharmacokinetic analysis of free-breathing pulmonary dynamic contrast-enhanced MR imaging.
    J Magn Reson Imaging 2011 Apr;33(4):968-73
    Harvard Medical School, Boston, MA, USA.
    Purpose: To investigates the impact of nonrigid motion correction on pixel-wise pharmacokinetic analysis of free-breathing DCE-MRI in patients with solitary pulmonary nodules (SPNs). Misalignment of focal lesions due to respiratory motion in free-breathing dynamic contrast-enhanced MRI (DCE-MRI) precludes obtaining reliable time-intensity curves, which are crucial for pharmacokinetic analysis for tissue characterization.

    Materials And Methods: Single-slice 2D DCE-MRI was obtained in 15 patients. Read More

    Patient-ventilator interaction.
    Respir Care 2011 Feb;56(2):214-28
    Department of Respiratory Care, University of Washington, Seattle, WA, USA.
    Patient-ventilator interaction has been the focus of increasing attention from both manufacturers and researchers during the last 25 years. There is now compelling evidence that passive (controlled) mechanical ventilation leads to respiratory muscle dysfunction and atrophy, prolonging the need for ventilatory support and predisposing to a number of adverse patient outcomes. Although there is consensus that the respiratory muscles should retain some activity during acute respiratory failure, patient-ventilator asynchrony is now recognized as a cause of ineffective ventilation, impaired gas exchange, lung overdistention, increased work of breathing, and patient discomfort. Read More

    Experience with a new device for clearing mucus from the endotracheal tube.
    Respir Care 2011 Apr 21;56(4):520-2. Epub 2011 Jan 21.
    Department of Respiratory Care, St Francis Medical Center, Cape Girardeau, Missouri, USA.
    Partial or total obstruction of an endotracheal tube (ETT) by mucus can cause severe respiratory distress, hypoxemia, or death. Signs of an obstructed ETT include increased ventilation pressure, changes in the ventilator graphics, S(pO(2)) decrease, and cardiovascular changes. We present 3 patients whose ETTs were partially obstructed by mucus. Read More

    Phase-selective image reconstruction of the lungs in small animals using Micro-CT.
    Proc SPIE Int Soc Opt Eng 2010 Feb;7622:76223G.1-76223G.9
    Center for In Vivo Microscopy, Dept. of Radiology, Duke University Medical Center, Durham, NC 27710.
    Gating in small animal imaging can compensate for artifacts due to physiological motion. This paper presents a strategy for sampling and image reconstruction in the rodent lung using micro-CT. The approach involves rapid sampling of free-breathing mice without any additional hardware to detect respiratory motion. Read More

    Patient-ventilator interactions: optimizing conventional ventilation modes.
    Respir Care 2011 Jan;56(1):73-84
    Division of Pulmonary and Critical Care Medicine, Duke University Medical Center, Durham, North Carolina 27710, USA.
    Assisted (interactive) breathing is generally preferred to controlled breaths in patients on mechanical ventilators. Assisted breaths allow the patient's respiratory muscles to be used, and ventilatory muscle atrophy can be prevented. Moreover, the respiratory drive of the patient does not have to be aggressively blunted. Read More

    Cycling of the mechanical ventilator breath.
    Respir Care 2011 Jan;56(1):52-60
    Division of Pulmonary and Critical Care Medicine, Box 3046, Duke University Medical Center, Durham NC 27710, USA.
    Patient-ventilator interaction is a key element in optimizing mechanical ventilation. The change from inspiration to expiration is a crucial point in the mechanically ventilated breath, and is termed "cycling." Patient-ventilator asynchrony may occur if the flow at which the ventilator cycles to exhalation does not coincide with the termination of neural inspiration. Read More

    Level-set segmentation of pulmonary nodules in megavolt electronic portal images using a CT prior.
    Med Phys 2010 Nov;37(11):5703-10
    Carestream Health Inc., Rochester, New York 14615, USA.
    Purpose: Pulmonary nodules present unique problems during radiation treatment due to nodule position uncertainty that is caused by respiration. The radiation field has to be enlarged to account for nodule motion during treatment. The purpose of this work is to provide a method of locating a pulmonary nodule in a megavolt portal image that can be used to reduce the internal target volume (ITV) during radiation therapy. Read More

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