Miracle-dz/UniFAR-FTUs huggingface dataset:
Imaging near metal with a MAVRIC‐SEMAC hybrid

The recently developed multi‐acquisition with variable resonance image combination (MAVRIC) and slice‐encoding metal artifact correction (SEMAC) techniques can significantly reduce image artifacts commonly encountered near embedded metal hardware. These artifact reductions are enabled by applying alternative spectral and spatial‐encoding schemes to conventional spin‐echo imaging techniques. Here, the MAVRIC and SEMAC concepts are connected and discussed. The development of a hybrid technique that utilizes strengths of both methods is then introduced. The presented technique is shown capable of producing minimal artifact, high‐resolution images near total joint replacements in a clinical setting. Magn Reson Med, 2010. © 2010 Wiley‐Liss, Inc.
Cellular self-organizing systems: A field-based behavior regulation approach

Abstract Multiagent systems have been considered as a potential solution for developing adaptive systems. In this research, a cellular self-organizing (CSO) approach is proposed for developing such multiagent adaptive systems. The design of CSO systems however is difficult because the global effect emerges from local actions and interactions that are often hard to specify and control. In order to achieve high-level flexible and robustness of CSO systems and retain the capability of specifying desired global effects, we propose a field-based regulative control mechanism, called field-based behavior regulation (FBR). FBR is a real-time, dynamical, distributed mechanism that regulates the emergence process for CSO systems to self-organize and self-reconfigure in complex operation environments. FBR characterizes the task environment in terms of “fields” and extends the system flexibility and robustness without imposing global control over local cells or agents. This paper describes the model of CSO systems and FBR, and demonstrates their effectiveness through simulation-based case studies.
Microfabricated high‐moment micrometer‐sized MRI contrast agents

While chemically synthesized superparamagnetic microparticles have enabled much new research based on MRI tracking of magnetically labeled cells, signal‐to‐noise levels still limit the potential range of applications. Here it is shown how, through top‐down microfabrication, contrast agent relaxivity can be increased several‐fold, which should extend the sensitivity of such cell‐tracking studies. Microfabricated agents can benefit from both higher magnetic moments and higher uniformity than their chemically synthesized counterparts, implying increased label visibility and more quantitative image analyses. To assess the performance of microfabricated micrometer‐sized contrast agent particles, analytic models and numerical simulations are developed and tested against new microfabricated agents described in this article, as well as against results of previous imaging studies of traditional chemically synthesized microparticle agents. Experimental data showing signal effects of 500‐nm thick, 2‐μm diameter, gold‐coated iron and gold‐coated nickel disks verify the simulations. Additionally, it is suggested that measures of location better than the pixel resolution can be obtained and that these are aided using well‐defined contrast agent particles achievable through microfabrication techniques. Magn Reson Med, 2011. © 2010 Wiley‐Liss, Inc.
Optically detunable, inductively coupled coil for self‐gating in small animal magnetic resonance imaging

An inductively coupled coil concept is presented, which improves the compensation of physiological motion by the self‐gating (SG) technique. The animal is positioned in a conventional volume coil encompassing the whole animal. A small, resonant surface coil (SG‐coil) is placed on the thorax so that its sensitive region includes the heart. Via inductive coupling the SG‐coil amplifies selectively the MR signal of the beating heart. With an optical detuning mechanism, this coupling can be switched off during acquisition of the MR image information, whereas it is active during SG data sampling to provide the physiological information. In vivo experiments on a mouse show an amplification of the SG signal by at least 40%. Magn Reson Med, 2011. © 2010 Wiley‐Liss, Inc.
Validation of VASO cerebral blood volume measurement with positron emission tomography

Cerebral blood volume (CBV) has been shown to be an important biomarker in a number of neurological disorders and in the quantitative interpretation of functional MRI. One approach to determine CBV in humans is vascular‐space‐occupancy MRI, and this technique has been applied to the studies of brain glioma, Schizophrenia, and Alzheimer's disease. However, validation of this technique with a gold standard method has not been reported. In this study, we compared vascular‐space‐occupancy MRI with a radiotracer‐based positron emission tomography technique in a group of healthy subjects. It was found that regional CBV measured with vascular‐space‐occupancy MRI was highly correlated with that of the positron emission tomography data (R = 0.79 ± 0.10, N = 8). Furthermore, absolute CBV values quantified by vascular‐space‐occupancy were also in excellent agreement with those by positron emission tomography (slope = 1.00 ± 0.15). Because of the differences in the labeling principles between the two modalities, systematic CBV differences were observed in large vessel and ventricle regions. Magn Reson Med, 2011. © 2010 Wiley‐Liss, Inc.
Psychometric evaluation of a new instrument in Spanish to measure self-care requisites in patients with schizophrenia.

PURPOSE The purpose of this study was to develop and validate a new instrument in Spanish designed to measure self-care requisites in patients with schizophrenia treated in the community. DESIGN AND METHODS The first phase was conducted to develop the questionnaire through a panel of experts and evaluate for content validity. Psychometric evaluation was then conducted with a consecutive sample of 341 patients. FINDINGS The scale demonstrated good internal consistency and stability over time. The discriminant and convergent validity was satisfactory. The confirmatory factor analysis showed that the theoretical model fits the self-care requisites proposed by Orem's nursing theory from which it originated. PRACTICE IMPLICATIONS This scale is a valid and reliable instrument for use in clinical practice, guiding the nurse in developing the most appropriate care plan for each patient.
Three‐dimensional phase contrast angiography of the mouse aortic arch using spiral MRI

Atherosclerosis is a complex disease whose spatial distribution is hypothesized to be influenced by the local hemodynamic environment. The use of transgenic mice provides a mechanism to study the relationship between hemodynamic forces, most notably wall shear stress (WSS), and the molecular factors that influence the disease process. Phase contrast MRI using rectilinear trajectories has been used to measure boundary conditions for use in computational fluid dynamic models. However, the unique flow environment of the mouse precludes use of standard imaging techniques in complex, curved flow regions such as the aortic arch. In this article, two‐dimensional and three‐dimensional spiral cine phase contrast sequences are presented that enable measurement of velocity profiles in curved regions of the mouse vasculature. WSS is calculated directly from the spatial velocity gradient, enabling WSS calculation with a minimal set of assumptions. In contrast to the outer radius of the aortic arch, the inner radius has a lower time‐averaged longitudinal WSS (7.06 ± 0.76 dyne/cm2 vs. 18.86 ± 1.27 dyne/cm2; P < 0.01) and higher oscillatory shear index (0.14 ± 0.01 vs. 0.08 ± 0.01; P < 0.01). This finding is in agreement with humans, where WSS is lower and more oscillatory along the inner radius, an atheroprone region, than the outer radius, an atheroprotective region. Magn Reson Med, 2011. © 2011 Wiley Periodicals, Inc.
Fast three‐dimensional proton spectroscopic imaging of the human brain at 3 T by combining spectroscopic missing pulse steady‐state free precession and echo planar spectroscopic imaging

The combination of the principles of two fast spectroscopic imaging (SI) methods, spectroscopic missing pulse steady‐state free precession and echo planar SI (EPSI) is described as an approach toward fast 3D SI. This method, termed missing pulse steady‐state free precession echo planar SI, exhibits a considerably reduced minimum total measurement time Tmin, allowing a higher temporal resolution, a larger spatial matrix size, and the use of k‐space weighted averaging and phase cycling, while maintaining all advantages of the original spectroscopic missing pulse steady‐state free precession sequence. The minor signal‐to‐noise ratio loss caused by using oscillating read gradients can be compensated by applying k‐space weighted averaging. The missing pulse steady‐state free precession echo planar SI sequence was implemented on a 3 T head scanner, tested on phantoms and applied to healthy volunteers. Magn Reson Med, 2011. © 2011 Wiley Periodicals, Inc.
CEREBRAL CIRCULATION: XII. THE EFFECT ON PIAL VESSELS OF VARIATIONS IN THE OXYGEN AND CARBON DIOXIDE CONTENT OF THE BLOOD

There is increasing evidence that chemical alterations of the blood, and especially changes of the acid-base equilibrium, have an important regulatory influence both on cerebral circulation and on respiratory movements. In this paper, we shall present observations which are intended to clarify these relationships. Numerous observers have reported that a dilatation of vessels of the brain occurs during asphyxia. 1 Observations by most of these authors have been by indirect methods, such as measurements of brain volume, of resistance to blood flow, or of the pressure in cerebral vessels. Florey 2 made use of direct observation but did not employ a window. In the experiments conducted in this laboratory, vessels of the pia were observed directly through a window in the skull, which procedure preserved the normal closed box arrangement. In confirmation of the observations of the previously mentioned authors, it has been our experience that a period of apnea
Influence of noise correlation in multiple‐coil statistical models with sum of squares reconstruction

Noise in the composite magnitude signal from multiple‐coil systems is usually assumed to follow a noncentral χ distribution when sum of squares is used to combine images sensed at different coils. However, this is true only if the variance of noise is the same for all coils, and no correlation exists between them. We show how correlations may be obviated from this model if effective values are considered. This implies a reduced effective number of coils and an increased effective variance of noise. In addition, the effective variance of noise becomes signal‐dependent. Magn Reson Med, 2012. © 2011 Wiley Periodicals, Inc.
QUIPSS II with window‐sliding saturation sequence (Q2WISE)

A series of periodic saturation pulses used to minimize the error caused by varying transit delays in assessing perfusion using quantitative imaging of perfusion using a single subtraction II with thin‐slice TI1 periodic saturation (Q2TIPS) increases the specific absorption rate. Quantitative imaging of perfusion using a single subtraction II with window‐sliding saturation sequence (Q2WISE) has been developed, in which numerous thin saturation pulses are replaced by two thin pulses and one thick saturation pulse arranged in a window‐sliding manner within the labeling region to maintain a sharp slice profile while reducing specific absorption rate. Q2WISE essentially is a hybrid between Q2TIPS and quantitative imaging of perfusion using a single subtraction II for use in specific absorption rate intensive applications. Q2WISE was implemented on a 3 T MRI scanner to measure perfusion rates in the brain and kidneys of eight healthy volunteers and results were compared with those from Q2TIPS. Mean perfusion values of both methods for the brain (75 ± 17 [Q2WISE] and 74 ± 13 mL/100 g/min [Q2TIPS]) and kidney (308 ± 48 [Q2WISE] and 299 ± 43 mL/100 g/min [Q2TIPS]) were in very good agreement. Magn Reson Med, 2011. © 2011 Wiley‐Liss, Inc.
Generalized spatiotemporal myocardial strain analysis for DENSE and SPAMM imaging

Displacement encoding using stimulated echoes (DENSE) and spatial modulation of magnetization (SPAMM) are MRI techniques for quantifying myocardial displacement and strain. However, DENSE has not been compared against SPAMM in phantoms exhibiting nonhomogeneous strain, and interobserver variability has not been compared between DENSE and SPAMM. To perform these comparisons, there is a need for a generalized analysis framework for the evaluation of myocardial strain. A spatiotemporal mathematical model was used to represent myocardial geometry and motion. The model was warped to each frame using tissue displacement maps calculated from either automated phase unwrapping (DENSE) or nonrigid registration (SPAMM). Strain and motion were then calculated from the model using standard methods. DENSE and SPAMM results were compared in a deformable gel phantom exhibiting known nonhomogeneous strain, and interobserver errors were determined in 19 healthy human volunteers. Nonhomogeneous strain in the phantom was accurately quantified using both DENSE and SPAMM. In the healthy volunteers, DENSE produced better interobserver errors than SPAMM for radial strain (−0.009 ± 0.069 vs. 0.029 ± 0.152, respectively, bias ±95% confidence interval). In conclusion, generalized spatiotemporal modeling enables robust myocardial strain analysis for DENSE or SPAMM. Magn Reson Med, 2011. © 2011 Wiley‐Liss, Inc.
Evaluation of the acute effects of distal coronary microembolization using multidetector computed tomography and magnetic resonance imaging

The purpose of this study was to test the potential of clinical imaging modalities, 64‐slice multidetector computed tomography (MDCT) and 1.5T magnetic resonance imaging (MRI) for qualitative and quantitative evaluation of acute microinfarcts and to determine the effects of <120 μm microemboli on left ventricular function, perfusion, cardiac injury biomarkers, arrhythmia, and cellular and vascular structures. Under X‐ray fluoroscopy, 40–120 μm (16 mm3) microemboli were delivered to embolize the left anterior descending (LAD) coronary artery of nine pigs. MDCT/MRI were performed at 72 h in a single session. Microinfarcts were visible in six of nine animals on delayed contrast‐enhanced MDCT/MR images but measurable in all animals using semiautomated threshold methods. Other MDCT and MRI sequences demonstrated decline in left ventricular ejection fraction, regional strain and perfusion in visible and invisible microinfarcted regions. Microemboli caused significant elevation in cardiac injury enzymes and arrhythmias. Various sizes of microinfarcts appeared microscopically as distinct aggregates of macrophages replacing myocardium. Semiautomated threshold methods are necessary to measure and confirm/deny the presence of myocardial microinfarcts. This study offers support for alternative applications of MDCT/MRI in assessing clinical cases in which microemboli <120 μm escape protective devices during percutaneous coronary interventions. Although microembolization resulted in no mortality, it caused left ventricular dysfunction, perfusion deficit, cellular damage increase in cardiac injury enzymes, and arrhythmias. Magn Reson Med, 2011. © 2011 Wiley Periodicals, Inc.
Carriage of methicillin-resistant Staphylococcus aureus in veterinary personnel

SUMMARY A survey of 280 attendees at a veterinary meeting in the Czech Republic in 2008 revealed a carriage rate of 0·7% for methicillin-resistant Staphylococcus aureus (MRSA). The two strains isolated were of distinct genetic lineages, carried type IV SCCmec determinants and were negative for Panton–Valentine leukocidin genes. The MRSA positivity rates for veterinarians in the Czech Republic is considerably lower than reported elsewhere.
A prolonged outbreak of Salmonella Typhimurium infection related to an uncommon vehicle: hard cheese made from raw milk

SUMMARY In 2006, in The Netherlands, an outbreak of Salmonella Typhimurium phage type 561 (STM DT7, corresponding to the rare DT7 in the international typing scheme) was detected, accumulating to over 200 cases. By telephone interviews, data were collected from all laboratory-confirmed cases. In addition, in August 2006, a case-control study was performed in a subset of cases. Environmental and microbiological investigation was performed on a suspected dairy farm. In the case-control study (51 cases, 105 matched controls), hard cheese purchased from a farm, specifically farm X, and from a market stall were found to be associated with infection. The dairy production room of farm X tested STM DT7-positive in August. However, it was only in November, after earlier unsuccessful attempts, that a low-level contamination was confirmed in the hard farmhouse cheese, triggering control measures. A timely and adequate response was hampered during this outbreak for several reasons. Measures for improvement in handling future similar incidents are discussed.
A parallel imaging approach to wide‐field MR microscopy

Magnetic resonance microscopy, suggested in the earliest papers on MRI, has always been limited by the low signal‐to‐noise ratio resulting from the small voxel size. Magnetic resonance microscopy has largely been enabled by the use of microcoils that provide the signal‐to‐noise ratio improvement required to overcome this limitation. Concomitant with the small coils is a small field‐of‐view, which limits the use of magnetic resonance microscopy as a histological tool or for imaging large regions in general. This article describes initial results in wide field‐of‐view magnetic resonance microscopy using a large array of narrow, parallel coils, which provides a signal‐to‐noise ratio enhancement as well as the ability to use parallel imaging techniques. Comparison images made between a volume coil and the proposed technique demonstrate reductions in imaging time of more than 100 with no loss in signal‐to‐noise ratio or resolution. Magn Reson Med, 2012. © 2011 Wiley Periodicals, Inc.
Anatomy and Tractography of the Language Tracts The Arcuate Fasciculus and Other Language Tracts

http://dx.doi. or 0887-2171/& 2 ment of Radio , Rotterdam, th ment of Neuro , Rotterdam, th reprint reques mus MC—Un Rotterdam, th Diffusion tensor imaging (DTI) has been used to investigate the white matter (WM) tracts underlying the perisylvian cortical regions known to be associatedwith language function. The arcuate fasciculus is composed of 3 segments (1 long and 2 short) whose separate functions correlate with traditional models of conductive and transcortical motor or sensory aphasia, respectively. DTI mapping of language fibers is useful in presurgical planning for patients with dominant hemisphere tumors, particularly when combined with functional magnetic resonance imaging. DTI has found damage to language networks in stroke patients and has the potential to influence poststroke rehabilitation and treatment. Assessment of the WM tracts involved in the default mode network has been found to correlate with mild cognitive impairment, potentially explaining language deficits in patients with apparently mild small vessel ischemic disease. Different patterns of involvement of language-relatedWMstructures appear to correlate with different clinical subtypes of primary progressive aphasias. Semin Ultrasound CT MRI 35:504-516 C 2014 Elsevier Inc. All rights reserved.
Re-conceptualising prenatal life stressors in predicting post-partum depression: cumulative-, specific-, and domain-specific approaches to calculating risk.

BACKGROUND Prenatal life stress predicts post-partum depression (PPD); however, studies generally examine individual stressors (a specific approach) or the summation of such exposure (a cumulative approach) and their associations with PPD. Such approaches may oversimplify prenatal life stress as a risk factor for PPD. We evaluated approaches in assessing prenatal life stress as a predictor of PPD diagnosis, including a domain-specific approach that captures cumulative life stress while accounting for stress across different life stress domains: financial, relational, and physical health. METHODS The Pregnancy Risk Assessment Monitoring System, a population-based survey, was used to analyse the association of prenatal life stressors with PPD diagnoses among 3566 New York City post-partum women. RESULTS Specific stressors were not associated with PPD diagnosis after controlling for sociodemographic variables. Exposure to a greater number of stressors was associated with PPD diagnosis, even after adjusting for both sociodemographic variables and specific stressors [odds ratio (OR) = 3.1, 95% confidence interval (CI) = 1.5, 6.7]. Individuals reporting a moderate-to-high number of financial problems along with a moderate-to-high number of physical problems were at greater odds of PPD (OR = 4.2, 95% CI = 1.2, 15.3); those with a moderate-to-high number of problems in all three domains were at over fivefold increased odds of PPD (OR = 5.5, CI = 1.1, 28.5). CONCLUSIONS In assessing prenatal stress, clinicians should consider the extent to which stressors occur across different life domains; this association appears stronger with PPD diagnosis than simple assessments of individual stressors, which typically overestimate risk or cumulative exposures.
Retrospective image correction in the presence of nonlinear temporal magnetic field changes using multichannel navigator echoes

Spatio‐temporal magnetic field changes in the brain caused by breathing or body movements can lead to image artifacts. This is especially a problem in T2*‐weighted sequences. With the acquisition of an extra echo (navigator), it is possible to measure the magnetic field change induced frequency offset for a given slice during image acquisition. However, substantial local variation across a slice can occur. This work describes an extension of the conventional navigator technique that improves the estimation of the magnetic field distribution in the brain during strong field fluctuations. This is done using the combination of signals from multiple coil elements, the coil sensitivity profiles, and frequency encoding: termed sensitivity‐encoded navigator echoes. In vivo validation was performed in subjects who performed normal breathing, nose touching, and deep breathing during scanning. The sensitivity‐encoded navigator technique leads to an error reduction in estimating the field distribution in the brain of 73% ± 16% compared with 56% ± 14% for conventional estimation. Image quality can be improved via incorporating this navigator information appropriately into the image reconstruction. When the sensitivity‐encoded navigator technique was applied to a T2*‐weighted sequence at 7 T, a ghosting reduction of 47% ± 13% was measured during nose touching experiments compared with no correction. Magn Reson Med, 2012. © 2012 Wiley Periodicals, Inc.