Abstract:
:Repetitive and alternating lower limb movements are a specific component of human gait. Due to technical challenges, the neural mechanisms underlying such movements have not been previously studied with functional magnetic resonance imaging. In this study, we present a novel treadmill device employed to investigate the kinematics and the brain activation patterns involved in alternating and repetitive movements of the lower limbs. Once inside the scanner, 19 healthy subjects were guided by two visual cues and instructed to perform a motor task which involved repetitive and alternating movements of both lower limbs while selecting their individual comfortable amplitude on the treadmill. The device facilitated the performance of coordinated stepping while registering the concurrent lower-limb displacements, which allowed us to quantify some movement primary kinematic features such as amplitude and frequency. During stepping, significant blood oxygen level dependent signal increases were observed bilaterally in primary and secondary sensorimotor cortex, the supplementary motor area, premotor cortex, prefrontal cortex, superior and inferior parietal lobules, putamen and cerebellum, regions that are known to be involved in lower limb motor control. Brain activations related to individual adjustments during motor performance were identified in a right lateralized network including striatal, extrastriatal, and fronto-parietal areas.
journal_name
IEEE Trans Med Imagingjournal_title
IEEE transactions on medical imagingauthors
Martinez M,Villagra F,Loayza F,Vidorreta M,Arrondo G,Luis E,Diaz J,Echeverria M,Fernandez-Seara MA,Pastor MAdoi
10.1109/TMI.2014.2301493subject
Has Abstractpub_date
2014-05-01 00:00:00pages
1044-53issue
5eissn
0278-0062issn
1558-254Xjournal_volume
33pub_type
杂志文章abstract::The polymeric implant material poly(lactide-co-glycolide) (PLGA) degrades by a process of bulk degradation, which allows it to be used for the controlled release of therapeutic molecules from implants and microspheres. The temporal characterization of PLGA microsphere degradation has been limited by the need to destru...
journal_title:IEEE transactions on medical imaging
pub_type: 杂志文章
doi:10.1109/TMI.2008.927356
更新日期:2009-01-01 00:00:00
abstract::While magnetic particle imaging (MPI) constitutes a novel biomedical imaging technique for tracking superparamagnetic nanoparticles in vivo, unlike magnetic resonance imaging (MRI), it cannot provide anatomical background information. Until now these two modalities have been performed in separate scanners and image co...
journal_title:IEEE transactions on medical imaging
pub_type: 杂志文章
doi:10.1109/TMI.2014.2327515
更新日期:2014-10-01 00:00:00
abstract::We describe a new approach to the problem of collimator optimization in nuclear medicine; our methodology is illustrated for the challenging case of gallium-67 imaging. Collimator-design methods based on empirical rules, such as specification of an allowable level of single-septal penetration (SSP) at a fixed energy, ...
journal_title:IEEE transactions on medical imaging
pub_type: 杂志文章
doi:10.1109/TMI.2005.857211
更新日期:2005-10-01 00:00:00
abstract::In Soares et al. (2000), the ensemble statistical properties of the rescaled block-iterative expectation-maximization (RBI-EM) reconstruction algorithm and rescaled block-iterative simultaneous multiplicative algebraic reconstruction technique (RBI-SMART) were derived. Included in this analysis were the special cases ...
journal_title:IEEE transactions on medical imaging
pub_type: 杂志文章
doi:10.1109/tmi.2004.836876
更新日期:2005-01-01 00:00:00
abstract::This paper presents a new variational method for the segmentation of a moving object against a still background, over a sequence of [two-dimensional or three-dimensional (3-D)] image frames. The method is illustrated in application to myocardial gated single photon emission computed tomography (SPECT) data, and incorp...
journal_title:IEEE transactions on medical imaging
pub_type: 杂志文章
doi:10.1109/42.932748
更新日期:2001-07-01 00:00:00
abstract::Fetal brain magnetic resonance imaging (MRI) offers exquisite images of the developing brain but is not suitable for second-trimester anomaly screening, for which ultrasound (US) is employed. Although expert sonographers are adept at reading US images, MR images which closely resemble anatomical images are much easier...
journal_title:IEEE transactions on medical imaging
pub_type: 杂志文章
doi:10.1109/TMI.2020.3018560
更新日期:2020-12-01 00:00:00
abstract::A novel splat feature classification method is presented with application to retinal hemorrhage detection in fundus images. Reliable detection of retinal hemorrhages is important in the development of automated screening systems which can be translated into practice. Under our supervised approach, retinal color images...
journal_title:IEEE transactions on medical imaging
pub_type: 杂志文章
doi:10.1109/TMI.2012.2227119
更新日期:2013-02-01 00:00:00
abstract::The authors present a new algorithmic procedure for the analysis of brain images. This procedure is specifically designed to image the activity and functional organization of the brain. The authors' results are tested on data collected and previously analyzed with the technique known as in vivo optical imaging of intr...
journal_title:IEEE transactions on medical imaging
pub_type: 杂志文章
doi:10.1109/42.414621
更新日期:1995-01-01 00:00:00
abstract::A common challenge when performing surface-based registration of images is ensuring that the surfaces accurately represent consistent anatomical boundaries. Image segmentation may be difficult in some regions due to either poor contrast, low slice resolution, or tissue ambiguities. To address this, we present a novel ...
journal_title:IEEE transactions on medical imaging
pub_type: 杂志文章
doi:10.1109/TMI.2015.2443978
更新日期:2015-12-01 00:00:00
abstract::Cerebral ischemic stroke causes injury to brain tissue characterized by a complex cascade of neuronal and vascular events. Imaging during the early stages of its development allows prediction of tissue infarction and penumbra so that optimal intervention can be determined in order to salvage brain function impairment....
journal_title:IEEE transactions on medical imaging
pub_type: 杂志文章
doi:10.1109/TMI.2019.2895779
更新日期:2019-06-01 00:00:00
abstract::The National Library of Medicine (NLM) is developing a digital chest X-ray (CXR) screening system for deployment in resource constrained communities and developing countries worldwide with a focus on early detection of tuberculosis. A critical component in the computer-aided diagnosis of digital CXRs is the automatic ...
journal_title:IEEE transactions on medical imaging
pub_type: 杂志文章
doi:10.1109/TMI.2013.2290491
更新日期:2014-02-01 00:00:00
abstract::Pharmacokinetic analysis of dynamic positron emission tomography (PET) imaging data maps the measured time activity curves to a set of model-specific pharmacokinetic parameters. Voxel-based parameter estimation via curve fitting is conventionally performed indirectly on a sequence of independently reconstructed PET im...
journal_title:IEEE transactions on medical imaging
pub_type: 杂志文章
doi:10.1109/TMI.2015.2427777
更新日期:2015-11-01 00:00:00
abstract::The most frequent extracranial solid tumors of childhood, named peripheral neuroblastic tumors (pNTs), are very challenging to diagnose due to their diversified categories and varying forms. Auxiliary diagnosis methods of such pediatric malignant cancers are highly needed to provide pathologists assistance and reduce ...
journal_title:IEEE transactions on medical imaging
pub_type: 杂志文章
doi:10.1109/TMI.2020.3027547
更新日期:2021-01-01 00:00:00
abstract::Plane-wave-based ultrafast imaging has become the prevalent technique for non-conventional ultrasound imaging. The image quality, especially in terms of the suppression of artifacts, is generally compromised by reducing the number of transmissions for a higher frame rate. We hereby propose a new ultrafast imaging fram...
journal_title:IEEE transactions on medical imaging
pub_type: 杂志文章
doi:10.1109/TMI.2017.2736423
更新日期:2018-02-01 00:00:00
abstract::Regularization is desirable for image reconstruction in emission tomography. A powerful regularization method is the penalized-likelihood (PL) reconstruction algorithm (or equivalently, maximum a posteriori reconstruction), where the sum of the likelihood and a noise suppressing penalty term (or Bayesian prior) is opt...
journal_title:IEEE transactions on medical imaging
pub_type: 杂志文章
doi:10.1109/TMI.2003.816960
更新日期:2003-09-01 00:00:00
abstract::Generalized matrix inverses are used to estimate source activity distributions from single photon emission computed tomography (SPECT) projection measurements. Image reconstructions for a numerical simulation and a clinical brain study are examined. The photon flux from the source region and photon detection by the ga...
journal_title:IEEE transactions on medical imaging
pub_type: 杂志文章
doi:10.1109/42.141640
更新日期:1992-01-01 00:00:00
abstract::Deep learning is becoming an indispensable tool for various tasks in science and engineering. A critical step in constructing a reliable deep learning model is the selection of a loss function, which measures the discrepancy between the network prediction and the ground truth. While a variety of loss functions have be...
journal_title:IEEE transactions on medical imaging
pub_type: 杂志文章
doi:10.1109/TMI.2020.3031913
更新日期:2020-10-19 00:00:00
abstract::In magnetic resonance imaging, spatial localization is usually achieved using Fourier encoding which is realized by applying a magnetic field gradient along the dimension of interest to create a linear correspondence between the resonance frequency and spatial location following the Larmor equation. In the presence of...
journal_title:IEEE transactions on medical imaging
pub_type: 杂志文章
doi:10.1109/42.712126
更新日期:1998-06-01 00:00:00
abstract::An automatic method has been developed for segmentation of abdominal computed tomography (CT) images for virtual colonoscopy obtained after a bowel preparation of a low-residue diet with ingested contrast solutions to enhance the image intensities of residual colonic materials. Removal of the enhanced materials was pe...
journal_title:IEEE transactions on medical imaging
pub_type: 杂志文章
doi:10.1109/42.897814
更新日期:2000-12-01 00:00:00
abstract::Statistical image reconstruction methods for X-ray computed tomography (CT) provide improved spatial resolution and noise properties over conventional filtered back-projection (FBP) reconstruction, along with other potential advantages such as reduced patient dose and artifacts. Conventional regularized image reconstr...
journal_title:IEEE transactions on medical imaging
pub_type: 杂志文章
doi:10.1109/TMI.2014.2365179
更新日期:2015-02-01 00:00:00
abstract::We aim to compute the movement of permanent stranded implant brachytherapy radioactive sources (seeds) in the prostate from the planned seed distribution to the intraoperative fluoroscopic distribution, and then to the postimplant computed tomography (CT) distribution. We present a novel approach to matching the seeds...
journal_title:IEEE transactions on medical imaging
pub_type: 杂志文章
doi:10.1109/TMI.2011.2178254
更新日期:2012-03-01 00:00:00
abstract::The response characteristics of two tomographic systems were compared for imaging of positron emitters: a) a SPECT system with a 3/8 in crystal and 511 keV detector shielding, equipped with a specially designed 511 keV collimator, and b) a PET V system using coincidence detection. SPECT transverse plane resolution was...
journal_title:IEEE transactions on medical imaging
pub_type: 杂志文章
doi:10.1109/TMI.1986.4307776
更新日期:1986-01-01 00:00:00
abstract::The identification of bronchi on Computed Tomography (CT) images of the lungs provides valuable clinical information in patients with suspected airways diseases including bronchiectasis, emphysema, or constrictive obliterative bronchiolitis. The automated recognition of the airways is, therefore, an important part of ...
journal_title:IEEE transactions on medical imaging
pub_type: 杂志文章
doi:10.1109/42.952731
更新日期:2001-09-01 00:00:00
abstract::We propose an optimization algorithm to solve the brachytherapy seed localization problem in prostate brachytherapy. Our algorithm is based on novel geometric approaches to exploit the special structure of the problem and relies on a number of key observations which help us formulate the optimization problem as a mini...
journal_title:IEEE transactions on medical imaging
pub_type: 杂志文章
doi:10.1109/TMI.2007.900740
更新日期:2007-09-01 00:00:00
abstract::We designed a dedicated multi-detector multi-pinhole brain SPECT scanner to generate images of higher quality compared to general-purpose systems. The system, AdaptiSPECT-C, is intended to adapt its sensitivity-resolution trade-off by varying its aperture configurations allowing both high-sensitivity dynamic and high-...
journal_title:IEEE transactions on medical imaging
pub_type: 杂志文章
doi:10.1109/TMI.2020.3015079
更新日期:2020-12-01 00:00:00
abstract::Cardiac myofibre deformation is an important determinant of the mechanical function of the heart. Quantification of myofibre strain relies on 3D measurements of ventricular wall motion interpreted with respect to the tissue microstructure. In this study, we estimated in vivo myofibre strain using 3D structural and fun...
journal_title:IEEE transactions on medical imaging
pub_type: 杂志文章
doi:10.1109/TMI.2016.2580573
更新日期:2016-11-01 00:00:00
abstract::Image acquisition techniques often suffer from low signal-to-noise ratio (SNR) and/or contrast-to-noise ratio (CNR). Although many acquisition techniques are available to minimize these, post acquisition filtering is a major off-line image processing technique commonly used to improve the SNR and CNR. A major drawback...
journal_title:IEEE transactions on medical imaging
pub_type: 杂志文章
doi:10.1109/42.963817
更新日期:2001-11-01 00:00:00
abstract::We present a method (DMESH) for nonrigid cyclic motion analysis using a series of velocity images covering the cycle acquired, for example, from phase-contrast magnetic resonance imaging. The method is based on fitting a dynamic finite-element mesh model to velocity samples of an extended region, at all time frames. T...
journal_title:IEEE transactions on medical imaging
pub_type: 杂志文章
doi:10.1109/42.790456
更新日期:1999-07-01 00:00:00
abstract::In positron emission tomography (PET) image reconstruction, the Bayesian framework with various regularization terms has been implemented to constrain the radio tracer distribution. Varying the regularizing weight of a maximum a posteriori (MAP) algorithm specifies a lower bound of the tradeoff between variance and sp...
journal_title:IEEE transactions on medical imaging
pub_type: 杂志文章
doi:10.1109/TMI.2018.2803681
更新日期:2018-06-01 00:00:00
abstract::A novel image reconstruction algorithm has been developed and demonstrated for fluorescence-enhanced frequency-domain photon migration (FDPM) tomography from measurements of area illumination with modulated excitation light and area collection of emitted fluorescence light using a gain modulated image-intensified char...
journal_title:IEEE transactions on medical imaging
pub_type: 杂志文章
doi:10.1109/tmi.2004.839359
更新日期:2005-02-01 00:00:00