Recent Stanford Publications in PubMed
- Was Cheselden's One-Century-Long Otological Writings Concordant with His Time?Corrales CE, Mudry AOtol Neurotol
- Anterolateral approach to the upper cervical spine: Case report and operative technique.Song Y, Tharin S, Divi V, Prolo LM, Sirjani DBHead Neck
- Large-scale automated analysis of news media: A novel computational method for obesity policy research.Hamad R, Pomeranz JL, Siddiqi A, Basu SObesity (Silver Spring)
- Psychological Well-Being During the Great Recession: Changes in Mental Health Care Utilization in an Occupational Cohort.Modrek S, Hamad R, Cullen MRAm J Public Health
- Controlling radiofrequency-induced currents in guidewires using parallel transmit.Etezadi-Amoli M, Stang P, Kerr A, Pauly J, Scott GMagn Reson Med
- Outcomes of extremely preterm infants after delivery room cardiopulmonary resuscitation in a population-based cohort.Handley SC, Sun Y, Wyckoff MH, Lee HCJ Perinatol
- Combined outer volume suppression and T2 preparation sequence for coronary angiography.Luo J, Addy NO, Ingle RR, Hargreaves BA, Hu BS, Nishimura DG, Shin TMagn Reson Med
- Development of the International Thymic Malignancy Interest Group International Database: An Unprecedented Resource for the Study of a Rare Group of Tumors.Huang J, Ahmad U, Antonicelli A, Catlin AC, Fang W, Gomez D, Loehrer P, Lucchi M, Marom E, Nicholson A, Ruffini E, Travis W, Van Schil P, Wakelee H, Yao X, Detterbeck F, on behalf of the International Thymic Malignancy Interest Group International Database Committee and ContributorsJ Thorac Oncol
- Fmr1 KO and Fenobam Treatment Differentially Impact Distinct Synapse Populations of Mouse Neocortex.Wang GX, Smith SJ, Mourrain PNeuron
- Looks Can Be Deceiving: Reconsidering the Evidence for Gliotransmission.Sloan SA, Barres BANeuron
- MicroRNA Regulation of Vascular Smooth Muscle Function and Phenotype: Early Career Committee Contribution.Maegdefessel L, Rayner KJ, Leeper NJArterioscler Thromb Vasc Biol
- Learning and Generalization in an Isometric Visuomotor Task.Rotella MF, Nisky I, Koehler M, Rinderknecht MD, Bastian AJ, Okamura AMJ Neurophysiol
- A Wnt-TGFβ2 axis induces a fibrogenic program in muscle stem cells from dystrophic mice.Biressi S, Miyabara EH, Gopinath SD, M Carlig PM, Rando TASci Transl Med
- Correct Wilderness Medicine Definitions and Their Impact on Care.Lipman GSSports Med
- Tackling the problem of error in diagnostic radiology.Larson DBPediatr Radiol
- How I use fibrinogen replacement therapy in acquired bleeding.Levy JH, Goodnough LTBlood
- Teachers' Perceptions of Full- and Part-Time Nurses at School.Biag M, Srivastava A, Landau M, Rodriguez EJ Sch Nurs
- Book Review: Review of Rhinology and Endoscopic Skull Base Surgery (Otorhinolaryngology-Head and Neck Surgery Series).Abuzeid WMAnn Otol Rhinol Laryngol
- Joint analysis of sequence data and single-nucleotide polymorphism data using pedigree information for imputation and recombination inference.Song S, Shields R, Li X, Li JBMC Proc
- Mitochondrial protein sorting as a therapeutic target for ATP synthase disorders.Aiyar RS, Bohnert M, Duvezin-Caubet S, Voisset C, Gagneur J, Fritsch ES, Couplan E, von der Malsburg K, Funaya C, Soubigou F, Courtin F, Suresh S, Kucharczyk R, Evrard J, Antony C, St Onge RP, Blondel M, di Rago JP, van der Laan M, Steinmetz LMNat Commun
- How Do Maternal Views of Delivery Outcomes Vary by Demographics and Preferred Mode of Delivery?Sparks TN, Yeaton-Massey A, Granados JM, Handler SJ, Meyer M, Caughey ABAm J Perinatol
- Amplitude-Integrated Electroencephalography: A Survey of Practices in the United States.Shah NA, Van Meurs KP, Davis ASAm J Perinatol
- Early-Onset Severe Preeclampsia by First Trimester Pregnancy-Associated Plasma Protein A and Total Human Chorionic Gonadotropin.Jelliffe-Pawlowski LL, Baer RJ, Currier RJ, Lyell DJ, Blumenfeld YJ, El-Sayed YY, Shaw GM, Druzin MLAm J Perinatol
- Martin L. Perl (1927-2014).Halyo VNature
- Calcineurin regulates the yeast synaptojanin Inp53/Sjl3 during membrane stress.Guiney EL, Goldman AR, Elias JE, Cyert MSMol Biol Cell
- Brain Tumor Epidemiology - A Hub within Multidisciplinary Neuro-oncology. Report on the 15th Brain Tumor Epidemiology Consortium (BTEC) Annual Meeting, Vienna, 2014.Woehrer A, Lau CC, Prayer D, Bauchet L, Rosenfeld M, Capper D, Fisher PG, Kool M, Müller M, Kros JM, Kruchko C, Wiemels J, Wrensch M, Danysh HE, Zouaoui S, Heck JE, Johnson KJ, Qi X, O'Neill BP, Afzal S, Scheurer ME, Bainbridge MN, Nousome D, Bahassi EM, Hainfellner JA, Barnholtz-Sloan JSClin Neuropathol
- The Relationship Between Autistic Symptomatology and Independent Living Skills in Adolescents and Young Adults with Fragile X Syndrome.Hustyi KM, Hall SS, Quintin EM, Chromik LC, Lightbody AA, Reiss ALJ Autism Dev Disord
- Advances in skin grafting and treatment of cutaneous wounds.Sun BK, Siprashvili Z, Khavari PAScience
- Causes of mortality with ticagrelor compared with clopidogrel in acute coronary syndromes.Varenhorst C, Alström U, Braun OÖ, Storey RF, Mahaffey KW, Bertilsson M, Cannon CP, Scirica BM, Himmelmann A, James SK, Wallentin L, Held CHeart
- Long noncoding RNA: significance and potential in skin biology.Wan DC, Wang KCCold Spring Harb Perspect Med
- Productivity in the barents sea--response to recent climate variability.Dalpadado P, Arrigo KR, Hjøllo SS, Rey F, Ingvaldsen RB, Sperfeld E, van Dijken GL, Stige LC, Olsen A, Ottersen GPLoS One
- Dicer regulates differentiation and viability during mouse pancreatic cancer initiation.Morris JP, Greer R, Russ HA, von Figura G, Kim GE, Busch A, Lee J, Hertel KJ, Kim S, McManus M, Hebrok MPLoS One
- Analyzing personalized policies for online biometric verification.Sadhwani A, Yang Y, Wein LMPLoS One
- Disease risk factors identified through shared genetic architecture and electronic medical records.Li L, Ruau DJ, Patel CJ, Weber SC, Chen R, Tatonetti NP, Dudley JT, Butte AJSci Transl Med
- Application of echogenic technology for catheters used in ultrasound-guided continuous peripheral nerve blocks.Mariano ER, Yun RD, Kim TE, Carvalho BJ Ultrasound Med
- Refinements and secondary surgery after flap reconstruction of the traumatized hand.Chiou GJ, Chang JHand Clin
- Predictors of an academic career on radiology residency applications.Grimm LJ, Shapiro LM, Singhapricha T, Mazurowski MA, Desser TS, Maxfield CMAcad Radiol
- Parametric trial-by-trial prediction of pain by easily available physiological measures.Geuter S, Gamer M, Onat S, Büchel CPain
- Response to letter to the editor.Dworkin RH, O'Connor AB, Kent J, Mackey SC, Raja SN, Stacey BR, Levy RM, Backonja M, Baron R, Harke H, Loeser JD, Treede RD, Turk DC, Wells CDPain
- The evolution of a disparity decision in human visual cortex.Cottereau BR, Ales JM, Norcia AMNeuroimage
- A tale of two "forests": random forest machine learning AIDS tropical forest carbon mapping.Mascaro J, Asner GP, Knapp DE, Kennedy-Bowdoin T, Martin RE, Anderson C, Higgins M, Chadwick KDPLoS One
- Perforated appendicitis: an underappreciated mimic of intussusception on ultrasound.Newman B, Schmitz M, Gawande R, Vasanawala S, Barth RPediatr Radiol
- Diagnosis and management of pediatric brugada syndrome: a survey of pediatric electrophysiologists.Harris BU, Miyake CY, Motonaga KS, Dubin AMPacing Clin Electrophysiol
- Heterotaxy syndromes and abnormal bowel rotation.Newman B, Koppolu R, Murphy D, Sylvester KPediatr Radiol
- Ethnic disparities in the association of body mass index with the risk of hypertension and diabetes.Wong RJ, Chou C, Sinha SR, Kamal A, Ahmed AJ Community Health
- Glycemic control in young children with diabetes: the role of parental health literacy.Pulgarón ER, Sanders LM, Patiño-Fernandez AM, Wile D, Sanchez J, Rothman RL, Delamater AMPatient Educ Couns
- The mid-fusiform sulcus: a landmark identifying both cytoarchitectonic and functional divisions of human ventral temporal cortex.Weiner KS, Golarai G, Caspers J, Chuapoco MR, Mohlberg H, Zilles K, Amunts K, Grill-Spector KNeuroimage
- Visualization of intra-thalamic nuclei with optimized white-matter-nulled MPRAGE at 7T.Tourdias T, Saranathan M, Levesque IR, Su J, Rutt BKNeuroimage
- Affective traits link to reliable neural markers of incentive anticipation.Wu CC, Samanez-Larkin GR, Katovich K, Knutson BNeuroimage
- Shock-induced ventricular tachycardia: what is the mechanism?Santangeli P, Hsia HH, Wang PJ, Al-Ahmad APacing Clin Electrophysiol
- Ferumoxytol enhanced resting state fMRI and relative cerebral blood volume mapping in normal human brain.D'Arceuil H, Coimbra A, Triano P, Dougherty M, Mello J, Moseley M, Glover G, Lansberg M, Blankenberg FNeuroimage
- Three-dimensional magnetization-prepared imaging using a concentric cylinders trajectory.Kwon KT, Wu HH, Shin T, Cukur T, Lustig M, Nishimura DGMagn Reson Med
Was Cheselden's One-Century-Long Otological Writings Concordant with His Time?
Otol Neurotol. 2014 Dec 17;
Authors: Corrales CE, Mudry A
William Cheselden's famous anatomical treatise spanned the entire 18th century period with its 15 editions. The aim of this study is to analyze the otological knowledge described in all these editions, to identify key 18th century otological advancements, and to study their concordance. In the first edition (1713), Cheselden notably mentioned four middle ear ossicles: malleus, incus, fourth ossicle, and stapes; four auditory muscles: "external tympani," "external oblique," tensor tympani, and stapedial; and a small opening in the tympanic membrane. In subsequent editions, minimal changes appeared, except for nomenclature changes and the proposal of an artificial opening of the tympanic membrane. Virtually no changes were performed up to the last edition (1806). All Cheselden's Editions confirm the uncertain presence of a fourth ossicle, the disputable presence of a tympanic membrane opening and the "usual" accepted presence of three muscles to the malleus. Key otologic advancements, not found in any of Cheselden's writings, were catherization of the Eustachian tube, presence of fluid in the inner ear, and the surgical opening of the mastoid. This study demonstrates that Cheselden, and his subsequent editors, were unaware of some important otologic developments that revolutionized the field of otology. Description of key advancements lacking in his treatise includes catherization of the Eustachian tube, the presence of fluid in the inner ear, and the surgical opening of the mastoid. Nevertheless, Cheselden is first in proposing to artificially open the tympanic membrane in humans.
PMID: 25522200 [PubMed - as supplied by publisher]
Anterolateral approach to the upper cervical spine: Case report and operative technique.
Head Neck. 2014 Dec 18;
Authors: Song Y, Tharin S, Divi V, Prolo LM, Sirjani DB
Background: Transcervical approaches to the upper cervical spine are challenging because several upper anterior neurovascular structures need to be displaced to provide access. Although various techniques have been described, the anterolateral approach is one of the safest and most effective methods available to access the anterior C2-C3 disc space. Despite the approach's efficacy, however, it can cause postoperative complications due at least partly to inter-surgeon differences in the methods by which the larynx and hypopharynx are displaced medially. Methods/Results: We present a case report of a patient treated with an modified anterolateral approach to C2-C3. The approach provided excellent visualization while protecting vital structures. The patient recovered without any postoperative dysphagia or other surgical complications. Conclusions: The anterolateral approach to C2-C3 described herein safely protects the contents of the submandibular triangle while providing a wide exposure for direct access to the C2-C3 disc space. This article is protected by copyright. All rights reserved.
PMID: 25522016 [PubMed - as supplied by publisher]
Large-scale automated analysis of news media: A novel computational method for obesity policy research.
Obesity (Silver Spring). 2014 Dec 17;
Authors: Hamad R, Pomeranz JL, Siddiqi A, Basu S
OBJECTIVE: Analyzing news media allows obesity policy researchers to understand popular conceptions about obesity, which is important for targeting health education and policies. A persistent dilemma is that investigators have to read and manually classify thousands of individual news articles to identify how obesity and obesity-related policy proposals may be described to the public in the media. A machine learning method called "automated content analysis" that permits researchers to train computers to "read" and classify massive volumes of documents was demonstrated.
METHODS: 14,302 newspaper articles that mentioned the word "obesity" during 2011-2012 were identified. Four states that vary in obesity prevalence and policy (Alabama, California, New Jersey, and North Carolina) were examined. The reliability of an automated program to categorize the media's framing of obesity as an individual-level problem (e.g., diet) and/or an environmental-level problem (e.g., obesogenic environment) was tested.
RESULTS: The automated program performed similarly to human coders. The proportion of articles with individual-level framing (27.7-31.0%) was higher than the proportion with neutral (18.0-22.1%) or environmental-level framing (16.0-16.4%) across all states and over the entire study period (P < 0.05).
CONCLUSIONS: A novel approach to the study of how obesity concepts are communicated and propagated in news media was demonstrated.
PMID: 25522013 [PubMed - as supplied by publisher]
Psychological Well-Being During the Great Recession: Changes in Mental Health Care Utilization in an Occupational Cohort.
Am J Public Health. 2014 Dec 18;:e1-e7
Authors: Modrek S, Hamad R, Cullen MR
Objectives. We examined the mental health effects of the Great Recession of 2008 to 2009 on workers who remained continuously employed and insured. Methods. We examined utilization trends for mental health services and medications during 2007 to 2012 among a panel of workers in the 25 largest plants, located in 15 states, of a US manufacturing firm. We used piecewise regression to compare trends from 2007 to 2010 in service and medication use before and after 2009, the year of mass layoffs at the firm and the peak of the recession. Our models accounted for changes in county-level unemployment rates and individual-level fixed effects. Results. Mental health inpatient and outpatient visits and the yearly supply of mental health-related medications increased among all workers after 2009. The magnitude of the increase in medication usage was higher for workers at plants with more layoffs. Conclusions. The negative effects of the recession on mental health extend to employed individuals, a group considered at lower risk of psychological distress. (Am J Public Health. Published online ahead of print December 18, 2014: e1-e7. doi:10.2105/AJPH.2014.302219).
PMID: 25521885 [PubMed - as supplied by publisher]
Controlling radiofrequency-induced currents in guidewires using parallel transmit.
Magn Reson Med. 2014 Dec 17;
Authors: Etezadi-Amoli M, Stang P, Kerr A, Pauly J, Scott G
PURPOSE: Elongated conductors, such as pacemaker leads, neurostimulator leads, and conductive guidewires used for interventional procedures can couple to the MRI radiofrequency (RF) transmit field, potentially causing dangerous tissue heating. The purpose of this study was to demonstrate the feasibility of using parallel transmit to control induced RF currents in elongated conductors, thereby reducing the RF heating hazard.
METHODS: Phantom experiments were performed on a four-channel parallel transmit system at 1.5T. Parallel transmit "null mode" excitations that induce minimal wire current were designed using coupling measurements derived from axial B1 (+) maps. The resulting current reduction performance was evaluated with B1 (+) maps, current sensor measurements, and fluoroptic temperature probe measurements.
RESULTS: Null mode excitations reduced the maximum coupling mode current by factors ranging from 2 to 80. For the straight wire experiment, a current null imposed at a single wire location was sufficient to reduce tip heating below detectable levels. For longer insertion lengths and a curved geometry, imposing current nulls at two wire locations resulted in more distributed current reduction along the wire length.
CONCLUSION: Parallel transmit can be used to create excitations that induce minimal RF current in elongated conductors, thereby decreasing the RF heating risk, while still allowing visualization of the surrounding volume. Magn Reson Med, 2014. © 2014 Wiley Periodicals, Inc.
PMID: 25521751 [PubMed - as supplied by publisher]
Outcomes of extremely preterm infants after delivery room cardiopulmonary resuscitation in a population-based cohort.
J Perinatol. 2014 Dec 18;
Authors: Handley SC, Sun Y, Wyckoff MH, Lee HC
Objective:To describe the relationship of delivery room cardiopulmonary resuscitation (DR-CPR) to short-term outcomes of extremely preterm infants.Study design:This was a cohort study of 22 to 27+6/7 weeks gestational age (GA) infants during 2005 to 2011. DR-CPR was defined as chest compressions and/or epinephrine administration. Multivariable logistic regression was used to estimate odds ratios (ORs) with 95% confidence intervals (CIs) associated with DR-CPR; analysis was stratified by GA.Result:Of the 13 758 infants, 856 (6.2%) received DR-CPR. Infants 22 to 23+6/7 weeks receiving DR-CPR had similar outcomes to non-recipients. Infants 24 to 25+6/7 weeks receiving DR-CPR had more severe intraventricular hemorrhage (OR 1.36, 95% CI 1.07, 1.72). Infants 26 to 27+6/7 weeks receiving DR-CPR were more likely to die (OR 1.81, 95% CI 1.30, 2.51) and have intraventricular hemorrhage (OR 2.10, 95% CI 1.56, 2.82). Adjusted hospital DR-CPR rates varied widely (median 5.7%).Conclusion:Premature infants receiving DR-CPR had worse outcomes. Mortality and morbidity varied by GA.Journal of Perinatology advance online publication, 18 December 2014; doi:10.1038/jp.2014.222.
PMID: 25521563 [PubMed - as supplied by publisher]
Combined outer volume suppression and T2 preparation sequence for coronary angiography.
Magn Reson Med. 2014 Dec 17;
Authors: Luo J, Addy NO, Ingle RR, Hargreaves BA, Hu BS, Nishimura DG, Shin T
PURPOSE: To develop a magnetization preparation sequence for simultaneous outer volume suppression (OVS) and T2 weighting in whole-heart coronary magnetic resonance angiography.
METHODS: A combined OVS and T2 preparation sequence (OVS-T2 Prep) was designed with a nonselective adiabatic 90° tipdown pulse, two adiabatic 180° refocusing pulses, and a 2D spiral -90° tipup pulse. The OVS-T2 Prep preserves the magnetization inside an elliptic cylinder with T2 weighting, while saturating the magnetization outside the cylinder. Its performance was tested on phantoms and on 13 normal subjects with coronary magnetic resonance angiography using 3D cones trajectories.
RESULTS: Phantom studies showed expected T2 -dependent signal amplitude in the spatial passband and suppressed signal in the spatial stopband. In vivo studies with full-field-of-view cones yielded a passband-to-stopband signal ratio of 3.18 ± 0.77 and blood-myocardium contrast-to-noise ratio enhancement by a factor of 1.43 ± 0.20 (P < 0.001). In vivo studies with reduced-field-of-view cones showed that OVS-T2 Prep well suppressed the aliasing artifacts, as supported by significantly reduced signal in the regions with no tissues compared to the images acquired without preparation (P < 0.0001).
CONCLUSION: OVS-T2 Prep is a compact sequence that can accelerate coronary magnetic resonance angiography by suppressing signals from tissues surrounding the heart while simultaneously enhancing the blood-myocardium contrast. Magn Reson Med, 2014. © 2014 Wiley Periodicals, Inc.
PMID: 25521477 [PubMed - as supplied by publisher]
Development of the International Thymic Malignancy Interest Group International Database: An Unprecedented Resource for the Study of a Rare Group of Tumors.
J Thorac Oncol. 2014 Oct;9(10):1573-1578
Authors: Huang J, Ahmad U, Antonicelli A, Catlin AC, Fang W, Gomez D, Loehrer P, Lucchi M, Marom E, Nicholson A, Ruffini E, Travis W, Van Schil P, Wakelee H, Yao X, Detterbeck F, on behalf of the International Thymic Malignancy Interest Group International Database Committee and Contributors
BACKGROUND:: Our knowledge of thymic malignancies has largely been derived from small, single-institution series. Recognition of the need for broad collaboration led to the creation of the International Thymic Malignancy Interest Group (ITMIG) and the development of a large, centralized database to advance knowledge of these rare tumors.
METHODS:: A multidisciplinary Database Committee was convened to define a common set of data elements a priori. Retrospective data were solicited from ITMIG members and collated using standardized fields. Patients with thymoma, thymic carcinoma, or thymic carcinoid were included.
RESULTS:: Over a 6-month period, 47 institutions spanning 15 countries contributed a total of 6097 cases (mean, 129 [range, 10-1209]). The sex distribution was equal for thymomas, but there was a greater proportion of men with thymic carcinoma and thymic carcinoid (p < 0.0001). Nearly all cases (99%) were treated surgically. WHO type B2 was the most frequent histologic classification among thymomas, whereas squamous was the most common among thymic carcinomas. In total, 38% of patients with thymoma had myasthenia gravis compared with less than or equal to 5% for thymic carcinoma and thymic carcinoid. Median overall survival was 18.9 years (95% confidence interval [CI], 17.4-20.3) for thymoma, 6.8 years (95% CI, 5.5-7.9) for thymic carcinoma, and 7.5 years (95% CI, 6.5-8.5) for thymic carcinoid.
CONCLUSIONS:: The rapid creation of the ITMIG database demonstrates the feasibility of international collaboration for this rare set of malignancies and attests to the engagement of its membership. This database represents the largest collective data set ever assembled and provides an unprecedented resource for research of these tumors.
PMID: 25521402 [PubMed - as supplied by publisher]
Fmr1 KO and Fenobam Treatment Differentially Impact Distinct Synapse Populations of Mouse Neocortex.
Neuron. 2014 Dec 17;84(6):1273-1286
Authors: Wang GX, Smith SJ, Mourrain P
Cognitive deficits in fragile X syndrome (FXS) are attributed to molecular abnormalities of the brain's vast and heterogeneous synapse populations. Unfortunately, the density of synapses coupled with their molecular heterogeneity presents formidable challenges in understanding the specific contribution of synapse changes in FXS. We demonstrate powerful new methods for the large-scale molecular analysis of individual synapses that allow quantification of numerous specific changes in synapse populations present in the cortex of a mouse model of FXS. Analysis of nearly a million individual synapses reveals distinct, quantitative changes in synaptic proteins distributed across over 6,000 pairwise metrics. Some, but not all, of these synaptic alterations are reversed by treatment with the candidate therapeutic fenobam, an mGluR5 antagonist. These patterns of widespread, but diverse synaptic protein changes in response to global perturbation suggest that FXS and its treatment must be understood as a networked system at the synapse level.
PMID: 25521380 [PubMed - as supplied by publisher]
Looks Can Be Deceiving: Reconsidering the Evidence for Gliotransmission.
Neuron. 2014 Dec 17;84(6):1112-1115
Authors: Sloan SA, Barres BA
Gliotransmission, a process involving active vesicular release of glutamate and other neurotransmitters by astrocytes, is thought to play a critical role in many brain functions. A new paper by Nedergaard et al. (2014) identifies an experimental flaw in these previous studies suggesting that astrocytes may not perform active vesicular release after all.
PMID: 25521372 [PubMed - as supplied by publisher]
MicroRNA Regulation of Vascular Smooth Muscle Function and Phenotype: Early Career Committee Contribution.
Arterioscler Thromb Vasc Biol. 2015 Jan;35(1):2-6
Authors: Maegdefessel L, Rayner KJ, Leeper NJ
PMID: 25520518 [PubMed - in process]
Learning and Generalization in an Isometric Visuomotor Task.
J Neurophysiol. 2014 Dec 17;:jn.00255.2014
Authors: Rotella MF, Nisky I, Koehler M, Rinderknecht MD, Bastian AJ, Okamura AM
Adaptation is a prominent feature of the human motor system, and has been studied extensively in reaching movements. This study characterizes adaptation and generalization during isometric reaching, in which the arm remains stationary and the participant controls a virtual cursor via force applied by the hand. We measured how learning of a visual cursor rotation generalizes across workspace to (1) determine the coordinate system that predominates visual rotation learning, and (2) ascertain whether mapping type, namely position or velocity control, influences transfer. Participants performed virtual reaches to one of two orthogonal training targets with the applied rotation. In a new workspace, participants reached to a single target, similar to the training target in either hand or joint space. Further, a control experiment measured within-workspace generalization to an orthogonal target. Across position and velocity mappings, learning transferred predominantly in intrinsic (joint) space, though the transfer was incomplete. The velocity mapping resulted in significantly larger aftereffects and broader within-workspace generalization than the position mapping, potentially due to slower peak speeds, longer trial times, greater target overshoot, or other factors. While we cannot rule out a mixed reference frame in our task, the predominance of intrinsic coding of cursor kinematics in the isometric environment opposes the extrinsic coding of arm kinematics in real reaching, but matches the intrinsic coding of dynamics found in prior work. These findings have implications for the design of isometric control systems in human-machine interaction or in rehabilitation, when coordinated multi-degree-of-freedom movement is difficult to achieve.
PMID: 25520430 [PubMed - as supplied by publisher]
A Wnt-TGFβ2 axis induces a fibrogenic program in muscle stem cells from dystrophic mice.
Sci Transl Med. 2014 Dec 17;6(267):267ra176
Authors: Biressi S, Miyabara EH, Gopinath SD, M Carlig PM, Rando TA
We have previously observed that Wnt signaling activates a fibrogenic program in adult muscle stem cells, called satellite cells, during aging. We genetically labeled satellite cells in a mouse model of Duchenne muscular dystrophy to follow their fate during the progression of the disease. We observed that a fraction of satellite cells had a reduced myogenic potential and showed enhanced expression of profibrotic genes compared to age-matched controls. By combining in vitro and in vivo results, we found that expression of transforming growth factor-β2 (TGFβ2) was induced in response to elevated canonical Wnt signaling in dystrophic muscles and that the resulting increase in TGFβ activity affected the behavior of satellite cells in an autocrine or paracrine fashion. Indeed, pharmacological inhibition of the TGFβ pathway in vivo reduced the fibrogenic characteristics of satellite cells. These studies shed new light on the cellular and molecular mechanisms responsible for stem cell dysfunction in dystrophic muscle and may contribute to the development of more effective and specific therapeutic approaches for the prevention of muscle fibrosis.
PMID: 25520397 [PubMed - in process]
Correct Wilderness Medicine Definitions and Their Impact on Care.
Sports Med. 2014 Dec 18;
Authors: Lipman GS
PMID: 25520160 [PubMed - as supplied by publisher]
Tackling the problem of error in diagnostic radiology.
Pediatr Radiol. 2014 Dec 18;
Authors: Larson DB
PMID: 25520015 [PubMed - as supplied by publisher]
How I use fibrinogen replacement therapy in acquired bleeding.
Blood. 2014 Dec 17;
Authors: Levy JH, Goodnough LT
Fibrinogen is a critical protein for hemostasis and clot formation. However, transfusion guidelines have variable recommendations for maintaining fibrinogen levels in bleeding patients. An increasing number of studies support the practice of fibrinogen replacement therapy for acquired coagulopathies, and additional studies are underway. Fibrinogen therapy can be administered with cryoprecipitate or fibrinogen concentrates, and clinical practice varies according to their availability and licensing status. Fibrinogen concentrate therapy has been studied in animal models and clinical trials, and support the critical role of fibrinogen repletion in bleeding patients. Point-of-care testing will have an important role in guiding fibrinogen replacement for hemostatic therapy in clinical settings such as cardiovascular surgery, postpartum hemorrhage, and trauma. Fibrinogen therapy is an important component of a multimodal strategy for the treatment of coagulopathic bleeding.
PMID: 25519751 [PubMed - as supplied by publisher]
Teachers' Perceptions of Full- and Part-Time Nurses at School.
J Sch Nurs. 2014 Dec 17;
Authors: Biag M, Srivastava A, Landau M, Rodriguez E
Teachers and school nurses partner together to help ensure students stay healthy and engaged in school. The purpose of this study is to generate a deeper understanding of teachers' perceptions on the benefits and challenges of working with full- or part-time school nurses. We conducted a qualitative analysis of open-ended survey responses from 129 teachers in nine low-income, ethnically diverse urban schools. These schools were part of a multiyear project that placed full-time nurses in four schools, while five schools with part-time nurses were used as a comparison group. Findings indicate that teachers had strong appreciation for the wide range of responsibilities undertaken by the school nurse. Teachers' level of satisfaction was linked to the number of hours the nurse is on-site, where teachers reported greater satisfaction with nurses who worked on campus full time. Results point to factors that may improve working relations between teachers and nurses.
PMID: 25519714 [PubMed - as supplied by publisher]
Book Review: Review of Rhinology and Endoscopic Skull Base Surgery (Otorhinolaryngology-Head and Neck Surgery Series).
Ann Otol Rhinol Laryngol. 2015 Jan;124(1):83
Authors: Abuzeid WM
PMID: 25519696 [PubMed - as supplied by publisher]
Joint analysis of sequence data and single-nucleotide polymorphism data using pedigree information for imputation and recombination inference.
BMC Proc. 2014;8(Suppl 1 Genetic Analysis Workshop 18Vanessa Olmo):S20
Authors: Song S, Shields R, Li X, Li J
We developed a general framework for family-based imputation using single-nucleotide polymorphism data and sequence data distributed by Genetic Analysis Workshop 18. By using PedIBD, we first inferred haplotypes and inheritance patterns of each family from SNP data. Then new variants in unsequenced family members can be obtained from sequenced relatives through their shared haplotypes. We then compared the results of our method against the imputation results provided by Genetic Analysis Workshop organizers. The results showed that our strategy uncovered more variants for more unsequenced relatives. We also showed that recombination breakpoints inferred by PedIBD have much higher resolution than those inferred from previous studies.
PMID: 25519372 [PubMed]
Mitochondrial protein sorting as a therapeutic target for ATP synthase disorders.
Nat Commun. 2014;5:5585
Authors: Aiyar RS, Bohnert M, Duvezin-Caubet S, Voisset C, Gagneur J, Fritsch ES, Couplan E, von der Malsburg K, Funaya C, Soubigou F, Courtin F, Suresh S, Kucharczyk R, Evrard J, Antony C, St Onge RP, Blondel M, di Rago JP, van der Laan M, Steinmetz LM
Mitochondrial diseases are systemic, prevalent and often fatal; yet treatments remain scarce. Identifying molecular intervention points that can be therapeutically targeted remains a major challenge, which we confronted via a screening assay we developed. Using yeast models of mitochondrial ATP synthase disorders, we screened a drug repurposing library, and applied genomic and biochemical techniques to identify pathways of interest. Here we demonstrate that modulating the sorting of nuclear-encoded proteins into mitochondria, mediated by the TIM23 complex, proves therapeutic in both yeast and patient-derived cells exhibiting ATP synthase deficiency. Targeting TIM23-dependent protein sorting improves an array of phenotypes associated with ATP synthase disorders, including biogenesis and activity of the oxidative phosphorylation machinery. Our study establishes mitochondrial protein sorting as an intervention point for ATP synthase disorders, and because of the central role of this pathway in mitochondrial biogenesis, it holds broad value for the treatment of mitochondrial diseases.
PMID: 25519239 [PubMed - as supplied by publisher]
How Do Maternal Views of Delivery Outcomes Vary by Demographics and Preferred Mode of Delivery?
Am J Perinatol. 2014 Dec 17;
Authors: Sparks TN, Yeaton-Massey A, Granados JM, Handler SJ, Meyer M, Caughey AB
Objective To investigate how maternal views of delivery outcomes vary by demographic characteristics and preference toward mode of delivery (MOD). Study Design Survey of 719 pregnant women in outpatient clinics at an academic institution during their third trimester. Women ranked outcomes such as vaginal delivery (VD), cesarean delivery (CD), urinary incontinence, perineal lacerations, and induction of labor (IOL) on a visual analog scale (VAS) in order of worst imaginable (0) to best possible (100) outcomes. Results Women of all ages ranked VD as more desirable than CD. However, women ≥ 35 years of age had greater valuations of both MOD compared with women <35 years, with mean VAS scores of 88.4 versus 86.4 for VD (p < 0.001) and 61.5 versus 51.9 for CD (p < 0.001). Women with a college education or higher also rated both MOD as more desirable than women with less than a college education. Additionally, women who preferred VD rather than CD had greater valuations of perineal laceration (43.3 vs. 31.5, p = 0.001) and urinary incontinence (40.7 vs. 30.1, p = 0.002). Conclusion Significant differences exist in women's views toward MOD and peripartum outcomes, by demographics and preferred MOD. Understanding delivery preferences better enables clinicians to counsel women about labor and management options.
PMID: 25519201 [PubMed - as supplied by publisher]
Amplitude-Integrated Electroencephalography: A Survey of Practices in the United States.
Am J Perinatol. 2014 Dec 17;
Authors: Shah NA, Van Meurs KP, Davis AS
Objective Amplitude-integrated electroencephalography (aEEG) is a simplified method for continuous monitoring of brain activity in the neonatal intensive care unit (NICU). Our objective was to describe current aEEG use in the United States. Study Design An online survey was distributed to the American Academy of Pediatrics Section on Perinatal Pediatrics' list serve. Result A total of 654 surveys were received; 55% of respondents reported using aEEG. aEEG was utilized more often in academic and levels III and IV NICUs; hypoxic-ischemic encephalopathy and suspected seizures were the most common indications for use. aEEG was primarily interpreted by neonatologists (87%), with approximately half reporting either self-teaching or hospital-based training for interpretation. For those not using aEEG, uncertain clinical benefit (40%) and cost (17%) were reported as barriers to use. Conclusion More than half of neonatologists utilize aEEG, with practice variation by NICU setting. Barriers to wider adoption include education regarding potential benefit, training, and cost.
PMID: 25519200 [PubMed - as supplied by publisher]
Early-Onset Severe Preeclampsia by First Trimester Pregnancy-Associated Plasma Protein A and Total Human Chorionic Gonadotropin.
Am J Perinatol. 2014 Dec 17;
Authors: Jelliffe-Pawlowski LL, Baer RJ, Currier RJ, Lyell DJ, Blumenfeld YJ, El-Sayed YY, Shaw GM, Druzin ML
Objective This study aims to evaluate the relationship between early-onset severe preeclampsia and first trimester serum levels of pregnancy-associated plasma protein A (PAPP-A) and total human chorionic gonadotropin (hCG). Study Design The association between early-onset severe preeclampsia and abnormal levels of first trimester PAPP-A and total hCG in maternal serum were measured in a sample of singleton pregnancies without chromosomal defects that had integrated prenatal serum screening in 2009 and 2010 (n = 129,488). Logistic binomial regression was used to estimate the relative risk (RR) of early-onset severe preeclampsia in pregnancies with abnormal levels of first trimester PAPP-A or total hCG as compared with controls. Results Regardless of parity, women with low first trimester PAPP-A or high total hCG were at increased risk for early-onset severe preeclampsia. Women with low PAPP-A (multiple of the median [MoM] ≤ the 10th percentile in nulliparous or ≤ the 5th percentile in multiparous) or high total hCG (MoM ≥ the 90th percentile in nulliparous or ≥ the 95th percentile in multiparous) were at more than a threefold increased risk for early-onset severe preeclampsia (RR, 4.2; 95% confidence interval [CI], 3.0-5.9 and RR, 3.3; 95% CI, 2.1-5.2, respectively). Conclusion Routinely collected first trimester measurements of PAPP-A and total hCG provide unique risk information for early-onset severe preeclampsia.
PMID: 25519199 [PubMed - as supplied by publisher]
Martin L. Perl (1927-2014).
Nature. 2014 Dec 17;516(7531):330
Authors: Halyo V
PMID: 25519123 [PubMed - in process]
Calcineurin regulates the yeast synaptojanin Inp53/Sjl3 during membrane stress.
Mol Biol Cell. 2014 Dec 17;
Authors: Guiney EL, Goldman AR, Elias JE, Cyert MS
During hyperosmotic shock, Saccharomyces cerevisiae adjusts to physiological challenges, including large plasma membrane invaginations generated by rapid cell shrinkage. Calcineurin, the Ca(2+)/calmodulin-dependent phosphatase, is normally cytosolic, but concentrates in puncta and at sites of polarized growth during intense osmotic stress; inhibition of calcineurin-activated gene expression, suggests that restricting its access to substrates tunes calcineurin signaling specificity. Hyperosmotic shock promotes calcineurin binding to and dephosphorylation of the PI(4,5)P2 phosphatase, synaptojanin/Inp53/Sjl3 and causes dramatic calcineurin-dependent reorganization of PI(4,5)P2-enriched membrane domains. Inp53 normally promotes sorting at the trans-Golgi network, but localizes to cortical actin patches in osmotically-stressed cells. By activating Inp53, calcineurin repolarizes the actin cytoskeleton, and maintains normal plasma membrane morphology in synaptojanin-limited cells. In response to hyperosmotic shock and calcineurin-dependent regulation, Inp53 shifts from associating predominantly with clathrin to interacting with endocytic proteins, Sla1, Bzz1, and Bsp1, suggesting that Inp53 mediates stress-specific endocytic events. This response has physiological and molecular similarities to calcineurin-regulated activity-dependent bulk endocytosis in neurons, which retrieves a bolus of plasma membrane deposited by synaptic vesicle fusion. We propose that activation of Ca(2+)/calcineurin and PI(4,5)P2 signaling to regulate endocytosis is a fundamental and conserved response to excess membrane in eukaryotic cells.
PMID: 25518934 [PubMed - as supplied by publisher]
Brain Tumor Epidemiology - A Hub within Multidisciplinary Neuro-oncology. Report on the 15th Brain Tumor Epidemiology Consortium (BTEC) Annual Meeting, Vienna, 2014.
Clin Neuropathol. 2015 Jan;34(1):40-46
Authors: Woehrer A, Lau CC, Prayer D, Bauchet L, Rosenfeld M, Capper D, Fisher PG, Kool M, Müller M, Kros JM, Kruchko C, Wiemels J, Wrensch M, Danysh HE, Zouaoui S, Heck JE, Johnson KJ, Qi X, O'Neill BP, Afzal S, Scheurer ME, Bainbridge MN, Nousome D, Bahassi EM, Hainfellner JA, Barnholtz-Sloan JS
The Brain Tumor Epidemiology Consortium (BTEC) is an open scientific forum, which fosters the development of multi-center, international and inter-disciplinary collaborations. BTEC aims to develop a better understanding of the etiology, outcomes, and prevention of brain tumors (http://epi.grants.cancer.gov/btec/). The 15th annual Brain Tumor Epidemiology Consortium Meeting, hosted by the Austrian Societies of Neuropathology and Neuro-oncology, was held on September 9 - 11, 2014 in Vienna, Austria. The meeting focused on the central role of brain tumor epidemiology within multidisciplinary neuro-oncology. Knowledge of disease incidence, outcomes, as well as risk factors is fundamental to all fields involved in research and treatment of patients with brain tumors; thus, epidemiology constitutes an important link between disciplines, indeed the very hub. This was reflected by the scientific program, which included various sessions linking brain tumor epidemiology with clinical neuro-oncology, tissue-based research, and cancer registration. Renowned experts from Europe and the United States contributed their personal perspectives stimulating further group discussions. Several concrete action plans evolved for the group to move forward until next year's meeting, which will be held at the Mayo Clinic at Rochester, MN, USA.
PMID: 25518914 [PubMed - as supplied by publisher]
The Relationship Between Autistic Symptomatology and Independent Living Skills in Adolescents and Young Adults with Fragile X Syndrome.
J Autism Dev Disord. 2014 Dec 18;
Authors: Hustyi KM, Hall SS, Quintin EM, Chromik LC, Lightbody AA, Reiss AL
Few studies have examined the relationship between autistic symptomatology and competence in independent living skills in adolescents and young adults with fragile X syndrome (FXS). In this study, 70 individuals with FXS, aged 15-25 years, and 35 matched controls were administered direct measures of independent living skills and autistic symptomatology. Results showed that higher levels of autistic symptomatology were associated with lower levels of competence in independent living skills in individuals with FXS, but not in controls. These data indicated that the relationship between autistic symptomatology and independent living skills was syndrome-specific. Early intervention strategies that address autistic symptomatology are sorely needed to improve functional outcomes in this population.
PMID: 25518824 [PubMed - as supplied by publisher]
Advances in skin grafting and treatment of cutaneous wounds.
Science. 2014 Nov 21;346(6212):941-5
Authors: Sun BK, Siprashvili Z, Khavari PA
The ability of the skin to repair itself after injury is vital to human survival and is disrupted in a spectrum of disorders. The process of cutaneous wound healing is complex, requiring a coordinated response by immune cells, hematopoietic cells, and resident cells of the skin. We review the classic paradigms of wound healing and evaluate how recent discoveries have enriched our understanding of this process. We evaluate current and experimental approaches to treating cutaneous wounds, with an emphasis on cell-based therapies and skin transplantation.
PMID: 25414301 [PubMed - indexed for MEDLINE]
Causes of mortality with ticagrelor compared with clopidogrel in acute coronary syndromes.
Heart. 2014 Nov;100(22):1762-9
Authors: Varenhorst C, Alström U, Braun OÖ, Storey RF, Mahaffey KW, Bertilsson M, Cannon CP, Scirica BM, Himmelmann A, James SK, Wallentin L, Held C
OBJECTIVE: To describe specific causes of death and evaluate whether bleeding events and infection contributed to mortality in all ticagrelor-treated and clopidogrel-treated patients with acute coronary syndromes.
METHODS: In the PLATelet inhibition and patient Outcomes (PLATO) trial, ticagrelor significantly reduced rates of vascular and total death compared with clopidogrel. In the 905 patients who died postenrolment in the PLATO trial (n=18 624), reviewers, blinded to study treatment, subclassified direct causes of death and evaluated whether infection or bleeding events contributed to fatal events.
RESULTS: Among vascular deaths, there were significantly fewer sudden deaths (63 (0.7%) vs 98 (1.1%), p<0.01) but no significant difference in deaths caused by acute myocardial infarction (179 (1.9%) vs 194 (2.1%), p=0.43) or heart failure (31 (0.3%) vs 42 (0.5%), p=0.20) with ticagrelor compared with clopidogrel. For non-vascular deaths, there was no difference between treatments in deaths directly caused by infection. Although, patients treated with ticagrelor were at lower risk for death where infection was either a direct cause or contributed to death (51 (0.5%) vs 76 (0.8%), HR 0.67 (0.47 to 0.95), p<0.05) but not for bleeding (42 (0.5%) vs 42 (0.5%), HR 0.99 (0.65 to 1.53), p=0.98).
CONCLUSIONS: In this post hoc analysis, ticagrelor compared with clopidogrel reduced total and cardiovascular mortality, which appeared to be mainly mediated by a reduction in sudden death. Importantly, bleeding causing or contributing to death did not differ between treatments.
CLINICAL TRIAL REGISTRATION NUMBER: NCT00391872 (http://www.clinicaltrial.gov).
PMID: 24957530 [PubMed - indexed for MEDLINE]
Long noncoding RNA: significance and potential in skin biology.
Cold Spring Harb Perspect Med. 2014 May;4(5)
Authors: Wan DC, Wang KC
Over the past few years, advances in genome analyses have identified an emerging class of noncoding RNAs that play critical roles in the regulation of gene expression and epigenetic reprogramming. Given their transcriptional pervasiveness, the potential for these intriguing macromolecules to integrate a myriad of external cellular cues with nuclear responses has become increasingly apparent. Recent studies have implicated noncoding RNAs in epidermal development and keratinocyte differentiation, but the complexity of multilevel regulation of transcriptional programs involved in these processes remains ill defined. In this review, we discuss the relevance of noncoding RNA in normal skin development, their involvement in cutaneous malignancies, and their role in the regulation of adult stem-cell maintenance in stratified epithelial tissues. Furthermore, we provide additional examples highlighting the ubiquity of noncoding RNAs in diverse human diseases.
PMID: 24789873 [PubMed - indexed for MEDLINE]
Productivity in the barents sea--response to recent climate variability.
PLoS One. 2014;9(5):e95273
Authors: Dalpadado P, Arrigo KR, Hjøllo SS, Rey F, Ingvaldsen RB, Sperfeld E, van Dijken GL, Stige LC, Olsen A, Ottersen G
The temporal and spatial dynamics of primary and secondary biomass/production in the Barents Sea since the late 1990s are examined using remote sensing data, observations and a coupled physical-biological model. Field observations of mesozooplankton biomass, and chlorophyll a data from transects (different seasons) and large-scale surveys (autumn) were used for validation of the remote sensing products and modeling results. The validation showed that satellite data are well suited to study temporal and spatial dynamics of chlorophyll a in the Barents Sea and that the model is an essential tool for secondary production estimates. Temperature, open water area, chlorophyll a, and zooplankton biomass show large interannual variations in the Barents Sea. The climatic variability is strongest in the northern and eastern parts. The moderate increase in net primary production evident in this study is likely an ecosystem response to changes in climate during the same period. Increased open water area and duration of open water season, which are related to elevated temperatures, appear to be the key drivers of the changes in annual net primary production that has occurred in the northern and eastern areas of this ecosystem. The temporal and spatial variability in zooplankton biomass appears to be controlled largely by predation pressure. In the southeastern Barents Sea, statistically significant linkages were observed between chlorophyll a and zooplankton biomass, as well as between net primary production and fish biomass, indicating bottom-up trophic interactions in this region.
PMID: 24788513 [PubMed - indexed for MEDLINE]
Dicer regulates differentiation and viability during mouse pancreatic cancer initiation.
PLoS One. 2014;9(5):e95486
Authors: Morris JP, Greer R, Russ HA, von Figura G, Kim GE, Busch A, Lee J, Hertel KJ, Kim S, McManus M, Hebrok M
miRNA levels are altered in pancreatic ductal adenocarcinoma (PDA), the most common and lethal pancreatic malignancy, and intact miRNA processing is essential for lineage specification during pancreatic development. However, the role of miRNA processing in PDA has not been explored. Here we study the role of miRNA biogenesis in PDA development by deleting the miRNA processing enzyme Dicer in a PDA mouse model driven by oncogenic Kras. We find that loss of Dicer accelerates Kras driven acinar dedifferentiation and acinar to ductal metaplasia (ADM), a process that has been shown to precede and promote the specification of PDA precursors. However, unconstrained ADM also displays high levels of apoptosis. Dicer loss does not accelerate development of Kras driven PDA precursors or PDA, but surprisingly, we observe that mouse PDA can develop without Dicer, although at the expense of proliferative capacity. Our data suggest that intact miRNA processing is involved in both constraining pro-tumorigenic changes in pancreatic differentiation as well as maintaining viability during PDA initiation.
PMID: 24788257 [PubMed - indexed for MEDLINE]
Analyzing personalized policies for online biometric verification.
PLoS One. 2014;9(5):e94087
Authors: Sadhwani A, Yang Y, Wein LM
Motivated by India's nationwide biometric program for social inclusion, we analyze verification (i.e., one-to-one matching) in the case where we possess similarity scores for 10 fingerprints and two irises between a resident's biometric images at enrollment and his biometric images during his first verification. At subsequent verifications, we allow individualized strategies based on these 12 scores: we acquire a subset of the 12 images, get new scores for this subset that quantify the similarity to the corresponding enrollment images, and use the likelihood ratio (i.e., the likelihood of observing these scores if the resident is genuine divided by the corresponding likelihood if the resident is an imposter) to decide whether a resident is genuine or an imposter. We also consider two-stage policies, where additional images are acquired in a second stage if the first-stage results are inconclusive. Using performance data from India's program, we develop a new probabilistic model for the joint distribution of the 12 similarity scores and find near-optimal individualized strategies that minimize the false reject rate (FRR) subject to constraints on the false accept rate (FAR) and mean verification delay for each resident. Our individualized policies achieve the same FRR as a policy that acquires (and optimally fuses) 12 biometrics for each resident, which represents a five (four, respectively) log reduction in FRR relative to fingerprint (iris, respectively) policies previously proposed for India's biometric program. The mean delay is [Formula: see text] sec for our proposed policy, compared to 30 sec for a policy that acquires one fingerprint and 107 sec for a policy that acquires all 12 biometrics. This policy acquires iris scans from 32-41% of residents (depending on the FAR) and acquires an average of 1.3 fingerprints per resident.
PMID: 24787752 [PubMed - indexed for MEDLINE]
Disease risk factors identified through shared genetic architecture and electronic medical records.
Sci Transl Med. 2014 Apr 30;6(234):234ra57
Authors: Li L, Ruau DJ, Patel CJ, Weber SC, Chen R, Tatonetti NP, Dudley JT, Butte AJ
Genome-wide association studies have identified genetic variants for thousands of diseases and traits. We evaluated the relationships between specific risk factors (for example, blood cholesterol level) and diseases on the basis of their shared genetic architecture in a comprehensive human disease-single-nucleotide polymorphism association database (VARIMED), analyzing the findings from 8962 published association studies. Similarity between traits and diseases was statistically evaluated on the basis of their association with shared gene variants. We identified 120 disease-trait pairs that were statistically similar, and of these, we tested and validated five previously unknown disease-trait associations by searching electronic medical records (EMRs) from three independent medical centers for evidence of the trait appearing in patients within 1 year of first diagnosis of the disease. We validated that the mean corpuscular volume is elevated before diagnosis of acute lymphoblastic leukemia; both have associated variants in the gene IKZF1. Platelet count is decreased before diagnosis of alcohol dependence; both are associated with variants in the gene C12orf51. Alkaline phosphatase level is elevated in patients with venous thromboembolism; both share variants in ABO. Similarly, we found that prostate-specific antigen and serum magnesium levels were altered before the diagnosis of lung cancer and gastric cancer, respectively. Disease-trait associations identify traits that could serve as future prognostics, if validated through EMR and subsequent prospective trials.
PMID: 24786325 [PubMed - indexed for MEDLINE]
Application of echogenic technology for catheters used in ultrasound-guided continuous peripheral nerve blocks.
J Ultrasound Med. 2014 May;33(5):905-11
Authors: Mariano ER, Yun RD, Kim TE, Carvalho B
Limited data exist regarding the echogenicity of perineural catheters, but visualization is crucial to ensure accurate placement and efficacy of the subsequent local anesthetic infusion. The objective of this study was to determine the comparative echogenicity of various regional anesthesia catheters. In an in vitro porcine-bovine model, we compared the echogenic qualities of 3 commercially available regional anesthesia catheters and 1 catheter under development to optimize echogenicity. Outcomes included visual echogenicity ranking, image quality, and scanning time, as assessed by 2 blinded investigators. The experimental catheter was found to be more echogenic than 2 of the 3 comparators.
PMID: 24764346 [PubMed - indexed for MEDLINE]
Refinements and secondary surgery after flap reconstruction of the traumatized hand.
Hand Clin. 2014 May;30(2):211-23, vi
Authors: Chiou GJ, Chang J
The traumatized hand often has soft tissue loss requiring flap reconstruction. Before proceeding with flap selection, the need for future refinement and secondary surgery should be taken into consideration. Although muscle flaps may offer better contour, fasciocutaneous flaps allow easier secondary flap elevation. After the initial flap reconstruction, indications for secondary procedures may be managed according to tissue type: bone, joint, tendon, nerve, and soft tissue.
PMID: 24731611 [PubMed - indexed for MEDLINE]
Predictors of an academic career on radiology residency applications.
Acad Radiol. 2014 May;21(5):685-90
Authors: Grimm LJ, Shapiro LM, Singhapricha T, Mazurowski MA, Desser TS, Maxfield CM
RATIONALE AND OBJECTIVES: To evaluate radiology residency applications to determine if any variables are predictive of a future academic radiology career.
MATERIALS AND METHODS: Application materials from 336 radiology residency graduates between 1993 and 2010 from the Department of Radiology, Duke University and between 1990 and 2010 from the Department of Radiology, Stanford University were retrospectively reviewed. The institutional review boards approved this Health Insurance Portability and Accountability Act-compliant study with a waiver of informed consent. Biographical (gender, age at application, advanced degrees, prior career), undergraduate school (school, degree, research experience, publications), and medical school (school, research experience, manuscript publications, Alpha Omega Alpha membership, clerkship grades, United States Medical Licensing Examination Step 1 and 2 scores, personal statement and letter of recommendation reference to academics, couples match status) data were recorded. Listing in the Association of American Medical Colleges Faculty Online Directory and postgraduation publications were used to determine academic status.
RESULTS: There were 72 (21%) radiologists in an academic career and 264 (79%) in a nonacademic career. Variables associated with an academic career were elite undergraduate school (P = .003), undergraduate school publications (P = .018), additional advanced degrees (P = .027), elite medical school (P = .006), a research year in medical school (P < .001), and medical school publications (P < .001). A multivariate cross-validation analysis showed that these variables are jointly predictive of an academic career (P < .001).
CONCLUSIONS: Undergraduate and medical school rankings and publications, as well as a medical school research year and an additional advanced degree, are associated with an academic career. Radiology residency selection committees should consider these factors in the context of the residency application if they wish to recruit future academic radiologists.
PMID: 24629444 [PubMed - indexed for MEDLINE]
Parametric trial-by-trial prediction of pain by easily available physiological measures.
Pain. 2014 May;155(5):994-1001
Authors: Geuter S, Gamer M, Onat S, Büchel C
Pain is commonly assessed by subjective reports on rating scales. However, in many experimental and clinical settings, an additional, objective indicator of pain is desirable. In order to identify an objective, parametric signature of pain intensity that is predictive at the individual stimulus level across subjects, we recorded skin conductance and pupil diameter responses to heat pain stimuli of different durations and temperatures in 34 healthy subjects. The temporal profiles of trial-wise physiological responses were characterized by component scores obtained from principal component analysis. These component scores were then used as predictors in a linear regression analysis, resulting in accurate pain predictions for individual trials. Using the temporal information encoded in the principal component scores explained the data better than prediction by a single summary statistic (i.e., maximum amplitude). These results indicate that perceived pain is best reflected by the temporal dynamics of autonomic responses. Application of the regression model to an independent data set of 20 subjects resulted in a very good prediction of the pain ratings demonstrating the generalizability of the identified temporal pattern. Utilizing the readily available temporal information from skin conductance and pupil diameter responses thus allows parametric prediction of pain in human subjects.
PMID: 24525275 [PubMed - indexed for MEDLINE]
Response to letter to the editor.
Pain. 2014 May;155(5):1045-6
Authors: Dworkin RH, O'Connor AB, Kent J, Mackey SC, Raja SN, Stacey BR, Levy RM, Backonja M, Baron R, Harke H, Loeser JD, Treede RD, Turk DC, Wells CD
PMID: 24513276 [PubMed - indexed for MEDLINE]
The evolution of a disparity decision in human visual cortex.
Neuroimage. 2014 May 15;92:193-206
Authors: Cottereau BR, Ales JM, Norcia AM
We used fMRI-informed EEG source-imaging in humans to characterize the dynamics of cortical responses during a disparity-discrimination task. After the onset of a disparity-defined target, decision-related activity was found within an extended cortical network that included several occipital regions of interest (ROIs): V4, V3A, hMT+ and the Lateral Occipital Complex (LOC). By using a response-locked analysis, we were able to determine the timing relationships in this network of ROIs relative to the subject's behavioral response. Choice-related activity appeared first in the V4 ROI almost 200 ms before the button press and then subsequently in the V3A ROI. Modeling of the responses in the V4 ROI suggests that this area provides an early contribution to disparity discrimination. Choice-related responses were also found after the button-press in ROIs V4, V3A, LOC and hMT+. Outside the visual cortex, choice-related activity was found in the frontal and temporal poles before the button-press. By combining the spatial resolution of fMRI-informed EEG source imaging with the ability to sort out neural activity occurring before, during and after the behavioral manifestation of the decision, our study is the first to assign distinct functional roles to the extra-striate ROIs involved in perceptual decisions based on disparity, the primary cue for depth.
PMID: 24513152 [PubMed - indexed for MEDLINE]
A tale of two "forests": random forest machine learning AIDS tropical forest carbon mapping.
PLoS One. 2014;9(1):e85993
Authors: Mascaro J, Asner GP, Knapp DE, Kennedy-Bowdoin T, Martin RE, Anderson C, Higgins M, Chadwick KD
Accurate and spatially-explicit maps of tropical forest carbon stocks are needed to implement carbon offset mechanisms such as REDD+ (Reduced Deforestation and Degradation Plus). The Random Forest machine learning algorithm may aid carbon mapping applications using remotely-sensed data. However, Random Forest has never been compared to traditional and potentially more reliable techniques such as regionally stratified sampling and upscaling, and it has rarely been employed with spatial data. Here, we evaluated the performance of Random Forest in upscaling airborne LiDAR (Light Detection and Ranging)-based carbon estimates compared to the stratification approach over a 16-million hectare focal area of the Western Amazon. We considered two runs of Random Forest, both with and without spatial contextual modeling by including--in the latter case--x, and y position directly in the model. In each case, we set aside 8 million hectares (i.e., half of the focal area) for validation; this rigorous test of Random Forest went above and beyond the internal validation normally compiled by the algorithm (i.e., called "out-of-bag"), which proved insufficient for this spatial application. In this heterogeneous region of Northern Peru, the model with spatial context was the best preforming run of Random Forest, and explained 59% of LiDAR-based carbon estimates within the validation area, compared to 37% for stratification or 43% by Random Forest without spatial context. With the 60% improvement in explained variation, RMSE against validation LiDAR samples improved from 33 to 26 Mg C ha(-1) when using Random Forest with spatial context. Our results suggest that spatial context should be considered when using Random Forest, and that doing so may result in substantially improved carbon stock modeling for purposes of climate change mitigation.
PMID: 24489686 [PubMed - indexed for MEDLINE]
Perforated appendicitis: an underappreciated mimic of intussusception on ultrasound.
Pediatr Radiol. 2014 May;44(5):535-41
Authors: Newman B, Schmitz M, Gawande R, Vasanawala S, Barth R
BACKGROUND: We encountered multiple cases in which the US appearance of ruptured appendicitis mimicked intussusception, resulting in diagnostic and therapeutic delay and multiple additional imaging studies.
OBJECTIVE: To explore the clinical and imaging discriminatory features between the conditions.
MATERIALS AND METHODS: Initial US images in six children (age 16 months to 8 years; 4 boys, 2 girls) were reviewed independently and by consensus by three pediatric radiologists. These findings were compared and correlated with the original reports and subsequent US, fluoroscopic, and CT images and reports.
RESULTS: All initial US studies demonstrated a multiple-ring-like appearance (target sign, most apparent on transverse views) with diagnostic consensus supportive of intussusception. In three cases, US findings were somewhat discrepant with clinical concerns. Subsequently, four of the six children had contrast enemas; two were thought to have partial or complete intussusception reduction. Three had a repeat US examination, with recognition of the correct diagnosis. None of the US examinations demonstrated definite intralesional lymph nodes or mesenteric fat, but central echogenicity caused by debris/appendicolith was misinterpreted as fat. All showed perilesional hyperechogenicity that, in retrospect, represented inflamed fat "walling off" of the perforated appendix. There were four CTs, all of which demonstrated a double-ring appearance that correlated with the US target appearance, with inner and outer rings representing the dilated appendix and walled-off appendiceal rupture, respectively. All six children had surgical confirmation of perforated appendicitis.
CONCLUSION: Contained perforated appendicitis can produce US findings closely mimicking intussusception. Clinical correlation and careful multiplanar evaluation should allow for sonographic suspicion of perforated appendicitis, which can be confirmed on CT if necessary.
PMID: 24463638 [PubMed - indexed for MEDLINE]
Diagnosis and management of pediatric brugada syndrome: a survey of pediatric electrophysiologists.
Pacing Clin Electrophysiol. 2014 May;37(5):638-42
Authors: Harris BU, Miyake CY, Motonaga KS, Dubin AM
BACKGROUND: Brugada syndrome (BrS) can be difficult to diagnose and treat, especially in the young patient. As there is currently no consensus on the evaluation and treatment of BrS in the pediatric population, we sought to describe the current practice for the diagnosis and treatment of BrS among pediatric electrophysiologists.
METHODS: A web-based survey was distributed to 204 physician members (MDs) of The Pediatric and Adult Congenital Electrophysiology Society (PACES). Practice characteristics, BrS patient attributes, and diagnostic and therapeutic preferences were collected.
RESULTS: Responses were obtained from 83 pediatric electrophysiologists. The most common initial presentation was family history. There is a large variation in testing, particularly in the use of electrophysiology (EP) studies, drug challenge testing, and genetic testing. Despite limited treatment options, there is only consensus in the therapeutic approach to the pediatric patient with symptomatic BrS with 97% of physicians recommending an implantable cardioverter defibrillator (ICD). In the asymptomatic patient, a wide variation in therapy was seen with only 27% of physicians recommending an ICD CONCLUSIONS: Significant practice variation exists among pediatric electrophysiologists with deviation from accepted diagnostic and therapeutic practices for adult BrS patients. Further studies are necessary to establish best practice guidelines for BrS in the pediatric EP community.
PMID: 24456371 [PubMed - indexed for MEDLINE]
Heterotaxy syndromes and abnormal bowel rotation.
Pediatr Radiol. 2014 May;44(5):542-51
Authors: Newman B, Koppolu R, Murphy D, Sylvester K
BACKGROUND: Bowel rotation abnormalities in heterotaxy are common. As more children survive cardiac surgery, the management of gastrointestinal abnormalities has become controversial.
OBJECTIVE: To evaluate imaging of malrotation in heterotaxy with surgical correlation and provide an algorithm for management.
MATERIALS AND METHODS: Imaging reports of heterotaxic children with upper gastrointestinal (UGI) and/or small bowel follow-through (SBFT) were reviewed. Subsequently, fluoroscopic images were re-reviewed in conjunction with CT/MR studies. The original reports and re-reviewed images were compared and correlated with surgical findings.
RESULTS: Nineteen of 34 children with heterotaxy underwent UGI, 13/19 also had SBFT. In 15/19 reports, bowel rotation was called abnormal: 11 malrotation, 4 non-rotation, no cases of volvulus. Re-review, including CT (10/19) and MR (2/19), designated 17/19 (90%) as abnormal, 10 malrotation (abnormal bowel arrangement, narrow or uncertain length of mesentery) and 7 non-rotation (small bowel and colon on opposite sides plus low cecum with probable broad mesentery). The most useful CT/MR findings were absence of retroperitoneal duodenum in most abnormal cases and location of bowel, especially cecum. Abnormal orientation of mesenteric vessels suggested malrotation but was not universal. Nine children had elective bowel surgery; non-rotation was found in 4/9 and malrotation was found in 5/9, with discrepancies (non-rotation at surgery, malrotation on imaging) with 4 original interpretations and 1 re-review.
CONCLUSION: We recommend routine, early UGI and SBFT studies once other, urgent clinical concerns have been stabilized, with elective laparoscopic surgery in abnormal or equivocal cases. Cross-sectional imaging, usually obtained for other reasons, can contribute diagnostically. Attempting to assess mesenteric width is important in differentiating non-rotation from malrotation and more accurately identifies appropriate surgical candidates.
PMID: 24419494 [PubMed - indexed for MEDLINE]
Ethnic disparities in the association of body mass index with the risk of hypertension and diabetes.
J Community Health. 2014 Jun;39(3):437-45
Authors: Wong RJ, Chou C, Sinha SR, Kamal A, Ahmed A
Despite having lower body mass index (BMI) compared to other ethnic groups, Asians continue to develop significant metabolic diseases such as hypertension and diabetes. To evaluate the disparate association of BMI and risk of hypertension and diabetes in Asians. We retrospectively studied 150,753 adults from the 1985-2011 California Behavioral Risk Factor Survey. Trends in prevalence of obesity, hypertension, and diabetes were stratified by ethnicity. Multivariate logistic regression models evaluated the incremental effect of one unit BMI increase on risk of hypertension and diabetes and the disparate risks of hypertension and diabetes at different BMI thresholds. Asians had the lowest BMI among all groups. However, the impact of increasing BMI on risk of hypertension and diabetes was significantly greater in Asians. For each one unit increase in BMI, Asians were significantly more likely to have hypertension (OR 1.15; 95% CI 1.13-1.18) compared to non-Hispanic whites, blacks, and Hispanics. Similar trends were seen for diabetes (Asians: OR 1.15; 95% CI 1.13-1.18). The risk of hypertension in Asians with BMI ≥ 22 was similar to non-Hispanic whites with BMI ≥ 27 and blacks with BMI ≥ 28. The risk of diabetes in Asians with BMI ≥ 28 was similar to non-Hispanic whites with BMI ≥ 30. Despite lower overall BMI compared to other groups, weight gain in Asians is associated with significantly higher risks of hypertension and diabetes. Compared to other ethnic groups, similar risks of hypertension and diabetes are seen in Asians at much lower BMI.
PMID: 24276618 [PubMed - indexed for MEDLINE]
Glycemic control in young children with diabetes: the role of parental health literacy.
Patient Educ Couns. 2014 Jan;94(1):67-70
Authors: Pulgarón ER, Sanders LM, Patiño-Fernandez AM, Wile D, Sanchez J, Rothman RL, Delamater AM
OBJECTIVE: This cross sectional study examined the relationship between parental health literacy (HL), diabetes related numeracy, and parental perceived diabetes self-efficacy on glycemic control in a sample of young children with Type 1 DM.
METHODS: Seventy primary caregivers of children (age 3-9 years) with Type 1 DM were recruited and surveyed at diabetes outpatient clinic visits. Patients' medical histories were obtained by medical chart review.
RESULTS: Parental diabetes related numeracy (r=-.52, p<01), but not reading skills (r=-.25, p=NS) were inversely correlated with the child's glycemic control (HbA1c). Parental perceived diabetes self-efficacy was also negatively correlated to their child's HbA1c (r=-.47, p<01). When numeracy and parental perceived diabetes self-efficacy were included as predictors of HbA1c, the model was significant (F=12.93, p<.01) with both numeracy (β=-.46, p<.01) and parental perceived diabetes self-efficacy (β=-.36, p=.01) as significant predictors of HbA1c.
CONCLUSIONS: Data from this study highlight the importance of considering the role of parental numeracy, in health outcomes for children with Type 1 DM.
PRACTICE IMPLICATIONS: Practitioners should assess parental health literacy and consider intervention when needed.
PMID: 24091252 [PubMed - indexed for MEDLINE]
The mid-fusiform sulcus: a landmark identifying both cytoarchitectonic and functional divisions of human ventral temporal cortex.
Neuroimage. 2014 Jan 1;84:453-65
Authors: Weiner KS, Golarai G, Caspers J, Chuapoco MR, Mohlberg H, Zilles K, Amunts K, Grill-Spector K
Human ventral temporal cortex (VTC) plays a pivotal role in high-level vision. An under-studied macroanatomical feature of VTC is the mid-fusiform sulcus (MFS), a shallow longitudinal sulcus separating the lateral and medial fusiform gyrus (FG). Here, we quantified the morphological features of the MFS in 69 subjects (ages 7-40), and investigated its relationship to both cytoarchitectonic and functional divisions of VTC with four main findings. First, despite being a minor sulcus, we found that the MFS is a stable macroanatomical structure present in all 138 hemispheres with morphological characteristics developed by age 7. Second, the MFS is the locus of a lateral-medial cytoarchitectonic transition within the posterior FG serving as the boundary between cytoarchitectonic regions FG1 and FG2. Third, the MFS predicts a lateral-medial functional transition in eccentricity bias representations in children, adolescents, and adults. Fourth, the anterior tip of the MFS predicts the location of a face-selective region, mFus-faces/FFA-2. These findings are the first to illustrate that a macroanatomical landmark identifies both cytoarchitectonic and functional divisions of high-level sensory cortex in humans and have important implications for understanding functional and structural organization in the human brain.
PMID: 24021838 [PubMed - indexed for MEDLINE]
Visualization of intra-thalamic nuclei with optimized white-matter-nulled MPRAGE at 7T.
Neuroimage. 2014 Jan 1;84:534-45
Authors: Tourdias T, Saranathan M, Levesque IR, Su J, Rutt BK
Novel MR image acquisition strategies have been investigated to elicit contrast within the thalamus, but direct visualization of individual thalamic nuclei remains a challenge because of their small size and the low intrinsic contrast between adjacent nuclei. We present a step-by-step specific optimization of the 3D MPRAGE pulse sequence at 7T to visualize the intra-thalamic nuclei. We first measured T1 values within different sub-regions of the thalamus at 7T in 5 individuals. We used these to perform simulations and sequential experimental measurements (n=17) to tune the parameters of the MPRAGE sequence. The optimal set of parameters was used to collect high-quality data in 6 additional volunteers. Delineation of thalamic nuclei was performed twice by one rater and MR-defined nuclei were compared to the classic Morel histological atlas. T1 values within the thalamus ranged from 1400ms to 1800ms for adjacent nuclei. Using these values for theoretical evaluations combined with in vivo measurements, we showed that a short inversion time (TI) close to the white matter null regime (TI=670ms) enhanced the contrast between the thalamus and the surrounding tissues, and best revealed intra-thalamic contrast. At this particular nulling regime, lengthening the time between successive inversion pulses (TS=6000ms) increased the thalamic signal and contrast and lengthening the α pulse train time (N*TR) further increased the thalamic signal. Finally, a low flip angle during the gradient echo acquisition (α=4°) was observed to mitigate the blur induced by the evolution of the magnetization along the α pulse train. This optimized set of parameters enabled the 3D delineation of 15 substructures in all 6 individuals; these substructures corresponded well with the known anatomical structures of the thalamus based on the classic Morel atlas. The mean Euclidean distance between the centers of mass of MR- and Morel atlas-defined nuclei was 2.67mm (±1.02mm). The reproducibility of the MR-defined nuclei was excellent with intraclass correlation coefficient measured at 0.997 and a mean Euclidean distance between corresponding centers of mass found at first versus second readings of 0.69mm (±0.38mm). This 7T strategy paves the way to better identification of thalamic nuclei for neurosurgical planning and investigation of regional changes in neurological disorders.
PMID: 24018302 [PubMed - indexed for MEDLINE]
Affective traits link to reliable neural markers of incentive anticipation.
Neuroimage. 2014 Jan 1;84:279-89
Authors: Wu CC, Samanez-Larkin GR, Katovich K, Knutson B
While theorists have speculated that different affective traits are linked to reliable brain activity during anticipation of gains and losses, few have directly tested this prediction. We examined these associations in a community sample of healthy human adults (n=52) as they played a Monetary Incentive Delay task while undergoing functional magnetic resonance imaging (FMRI). Factor analysis of personality measures revealed that subjects independently varied in trait Positive Arousal and trait Negative Arousal. In a subsample (n=14) retested over 2.5years later, left nucleus accumbens (NAcc) activity during anticipation of large gains (+$5.00) and right anterior insula activity during anticipation of large losses (-$5.00) showed significant test-retest reliability (intraclass correlations>0.50, p's<0.01). In the full sample (n=52), trait Positive Arousal correlated with individual differences in left NAcc activity during anticipation of large gains, while trait Negative Arousal correlated with individual differences in right anterior insula activity during anticipation of large losses. Associations of affective traits with neural activity were not attributable to the influence of other potential confounds (including sex, age, wealth, and motion). Together, these results demonstrate selective links between distinct affective traits and reliably-elicited activity in neural circuits associated with anticipation of gain versus loss. The findings thus reveal neural markers for affective dimensions of healthy personality, and potentially for related psychiatric symptoms.
PMID: 24001457 [PubMed - indexed for MEDLINE]
Shock-induced ventricular tachycardia: what is the mechanism?
Pacing Clin Electrophysiol. 2014 Apr;37(4):516-9
Authors: Santangeli P, Hsia HH, Wang PJ, Al-Ahmad A
PMID: 23980924 [PubMed - indexed for MEDLINE]
Ferumoxytol enhanced resting state fMRI and relative cerebral blood volume mapping in normal human brain.
Neuroimage. 2013 Dec;83:200-9
Authors: D'Arceuil H, Coimbra A, Triano P, Dougherty M, Mello J, Moseley M, Glover G, Lansberg M, Blankenberg F
The brain demonstrates spontaneous low-frequency (<0.1 Hz) cerebral blood flow (CBF) fluctuations, measurable by resting state functional MRI (rs-fMRI). Ultra small superparamagnetic iron oxide particles have been shown to enhance task-based fMRI signals (cerebral blood volume fMRI or CBV-fMRI), compared to the BOLD effect, by a factor of ≈2.5 at 3 T in primates and humans. We evaluated the use of ferumoxytol for steady state, resting state FMRI (CBV-rs-fMRI) and relative cerebral blood volume (rCBV) mapping, at 3T, in healthy volunteers. All standard resting state networks (RSNs) were identified in all subjects. On average the RSN Z statistics (MELODIC independent components) and volumes of the visual and default mode (DMN) networks were comparable. rCBV values were averaged for the visual (Vis) and DMN networks and correlated with the corresponding DMN and visual network Z statistics. There was a negative correlation between the rCBV and the Z statistics for the DMN, for both BOLD and CBV-rs-fMRI contrast (R2=0.63, 0.76). A similar correlation was not found for the visual network. Short repetition time rs-fMRI data were Fourier transformed to evaluate the effect of ferumoxytol on cardiac and respiratory fluctuations in the brain rs-BOLD, CBV signals. Cardiac and respiratory fluctuations decreased to baseline within large vessels post ferumoxytol. Robust rs-fMRI and CBV mapping is possible in normal human brain.
PMID: 23831413 [PubMed - indexed for MEDLINE]
Three-dimensional magnetization-prepared imaging using a concentric cylinders trajectory.
Magn Reson Med. 2014 May;71(5):1700-10
Authors: Kwon KT, Wu HH, Shin T, Cukur T, Lustig M, Nishimura DG
PURPOSE: To develop new magnetization-prepared imaging schemes based on a three-dimensional (3D) concentric cylinders trajectory.
METHODS: The 3D concentric cylinders trajectory, which is robust to off-resonance effects and timing delays while requiring fewer excitations than a comparable 3D Cartesian (3DFT) sequence, is used as the readout for magnetization-prepared sequences exploiting its inherently centric-ordered structure. Two applications: (i) T1 -weighted brain imaging with an inversion-recovery-prepared radiofrequency-spoiled gradient-echo (IR-SPGR) sequence, (ii) non-contrast-enhanced (NCE) peripheral angiography with a magnetization-prepared balanced steady-state free precession (bSSFP) sequence are presented to demonstrate the effectiveness of the proposed method. For peripheral angiography, the scan efficiency is further improved by interleaving different preparations at different rates and by carefully designing the sampling geometry for an efficient parallel imaging method.
RESULTS: In vivo brain scans with an IR-SPGR sequence and lower extremity scans with a magnetization-prepared bSSFP sequence for NCE peripheral angiography both demonstrate that the proposed sequences with concentric cylinders effectively capture the transient magnetization-prepared contrast with faster scan times than a corresponding 3DFT sequence. The application of peripheral angiography also shows the feasibility of the proposed interleaving schemes and parallel imaging method.
CONCLUSION: The 3D concentric cylinders trajectory is a robust and efficient readout that is well-suited for magnetization-prepared imaging.
PMID: 23818212 [PubMed - indexed for MEDLINE]
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