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Medical Imaging (medical + imaging)

Distribution by Scientific Domains

Medical Sciences	52%
Physics and Astronomy	11%
Life Sciences	11%
Chemistry	11%

Selected Abstracts

Medical imaging and MRI in nail disorders: report of 119 cases and review of the literature

DERMATOLOGIC THERAPY, Issue 2 2002
Bertrand Richert
Radiographs remain the golden standard for exploration of the bony structures located beneath the nail plate, but they provide no information on the perionychium. Until a few years ago the nail apparatus was deprived of investigative medical imaging. Glomus tumor was the only condition that was explored using invasive techniques such as angiography or scintigraphy. High-frequency ultrasound rapidly came up against technical limits. High-resolution magnetic resonance imaging (MRI) offers a superior alternative in detection of distal lesions as well as their relationship with the adjacent structures. MRI provides an accurate analysis of the nail apparatus with detection of lesions as small as 1 mm. This noninvasive technique will allow us to better understand, diagnose, and treat pathologies of the distal phalanx. [source]

4. Cervical Radicular Pain

PAIN PRACTICE, Issue 1 2010
FIPP, Jan Van Zundert MD
Abstract Cervical radicular pain is defined as pain perceived as arising in the arm caused by irritation of a cervical spinal nerve or its roots. Approximately 1 person in 1,000 suffers from cervical radicular pain. In the absence of a gold standard, the diagnosis is based on a combination of history, clinical examination, and (potentially) complementary examination. Medical imaging may show abnormalities, but those findings may not correlate with the patient's pain. Electrophysiologic testing may be requested when nerve damage is suspected but will not provide quantitative/qualitative information about the pain. The presumed causative level may be confirmed by means of selective diagnostic blocks. Conservative treatment typically consists of medication and physical therapy. There are no studies assessing the effectiveness of different types of medication specifically in patients suffering cervical radicular pain. Cochrane reviews did not find sufficient proof of efficacy for either education or cervical traction. When conservative treatment fails, interventional treatment may be considered. For subacute cervical radicular pain, the available evidence on efficacy and safety supports a recommendation (2B+) of interlaminar cervical epidural corticosteroid administration. A recent negative randomized controlled trial of transforaminal cervical epidural corticosteroid administration, coupled with an increasing number of reports of serious adverse events, warrants a negative recommendation (2B,). Pulsed radiofrequency treatment adjacent to the cervical dorsal root ganglion is a recommended treatment for chronic cervical radicular pain (1B+). When its effect is insufficient or of short duration, conventional radiofrequency treatment is recommended (2B+). In selected patients with cervical radicular pain, refractory to other treatment options, spinal cord stimulation may be considered. This treatment should be performed in specialized centers, preferentially study related. [source]

Medical imaging and MRI in nail disorders: report of 119 cases and review of the literature

Extraction of media and plaque boundaries in intravascular ultrasound images by level sets and min/max flow

EXPERT SYSTEMS, Issue 2 2010
Ali Iskurt
Abstract: Estimation of the plaque area in intravascular ultrasound images after extraction of the media and plaque,lumen interfaces is an important application of computer-aided diagnosis in medical imaging. This paper presents a novel system for fully automatic and fast calculation of plaque quantity by capturing the surrounding ring called media. The system utilizes an algorithm that consists of an enhanced technique for noise removal and a method of detecting different iso levels by sinking the image gradually under zero level. Moreover, an important novelty with this technique is the simultaneous extraction of media and lumen,plaque interfaces at satisfactory levels. There are no higher dimensional surfaces and evolution of contours, stopping at high image gradients. Thus, the system runs really fast with curvature velocity only and has no complexity. Experiments also show that this shape-recovering curvature term not only removes the noisy behaviour of ultrasound images but also strengthens very weak boundaries and even completes the missing walls of the media. In addition, the lumen,plaque interface can be detected simultaneously. For validation, a new and very useful algorithm is developed for labelling of intravascular ultrasound images, taken from video sequences of 15 patients, and a comparison-based verification is done between manual contours by experts and the contours extracted by our system. [source]

Origin of Radiation-Induced Degradation in Polymer Solar Cells

ADVANCED FUNCTIONAL MATERIALS, Issue 16 2010
Ankit Kumar
Abstract Polymer solar cells have been shown to degrade under X-rays. Here, in situ polymer photovoltaic performance and recombination lifetimes are measured and it is found that charge accumulation is the primary reason for degradation of solar cells. This is affected by the mixing ratio of donor and acceptor in the bulk heterojunction. Both a quantitative understanding and the physical model of the degradation mechanism are presented. Understanding of the degradation mechanism is extended in polymer donor,acceptor bulk heterojunction systems to propose a material combination for making radiation hard diodes that can find important application in fields ranging from memory arrays to organic X-ray detectors for medical imaging. [source]

pH-Dependent Assembly of DNA,Gold Nanoparticles Based on the i-Motif: A Switchable Device with the Potential of a Nanomachine

HELVETICA CHIMICA ACTA, Issue 9 2006
Frank Seela
Abstract The pH-dependent self-assembling of gold nanoparticles is described. Oligonucleotides containing four or six consecutive dC residues are immobilized on 15-nm gold nanoparticles. Their assembly is based on the formation of a DNA i-motif as determined by the color change from red to blue between pH,5.5 and 6.5. The process occurs within a narrow pH range and is reversible. The i-motif is formed by the antiparallel intercalation of two parallel duplexes provided by two different gold nanoparticles. This assembly process can be utilized to generate novel systems for colorimetric sensing, applications in medical imaging and therapy, and for the construction of a proton-driven nanomachine. [source]

High-energy X-ray diffraction using the Pixium 4700 flat-panel detector

JOURNAL OF SYNCHROTRON RADIATION, Issue 4 2009
J. E. Daniels
The Pixium 4700 detector represents a significant step forward in detector technology for high-energy X-ray diffraction. The detector design is based on digital flat-panel technology, combining an amorphous Si panel with a CsI scintillator. The detector has a useful pixel array of 1910 × 2480 pixels with a pixel size of 154,µm × 154,µm, and thus it covers an effective area of 294,mm × 379,mm. Designed for medical imaging, the detector has good efficiency at high X-ray energies. Furthermore, it is capable of acquiring sequences of images at 7.5 frames per second in full image mode, and up to 60 frames per second in binned region of interest modes. Here, the basic properties of this detector applied to high-energy X-ray diffraction are presented. Quantitative comparisons with a widespread high-energy detector, the MAR345 image plate scanner, are shown. Other properties of the Pixium 4700 detector, including a narrow point-spread function and distortion-free image, allows for the acquisition of high-quality diffraction data at high X-ray energies. In addition, high frame rates and shutterless operation open new experimental possibilities. Also provided are the necessary data for the correction of images collected using the Pixium 4700 for diffraction purposes. [source]

Case studies in novel narial anatomy: 2.

JOURNAL OF ZOOLOGY, Issue 4 2004
The enigmatic nose of moose (Artiodactyla: Cervidae: Alces alces)
Abstract The facial region of moose Alces alces is highly divergent relative to other cervids and other ruminants. In particular, the narial region forms an expanded muzzle or proboscis that overhangs the mouth. The nose of moose provides a case study in the evolution of narial novelty within a phylogenetically well-resolved group (Cervidae). The function of the nasal apparatus of moose remains enigmatic, and new hypotheses are proposed based on our anatomical findings. Head specimens of moose and outgroup taxa were subjected to medical imaging (CT scanning), vascular injection, gross anatomical dissection, gross sectioning, and skeletonization. Moose noses are characterized by highly enlarged nostrils accompanied by specialized musculature, expanded nasal cartilages, and an increase in the connective-tissue pad serving as the termination of the alar fold. The nostrils are widely separated, and the rhinarium that encircles both nostrils in outgroups is reduced to a tiny central patch in moose. The dorsal lateral nasal cartilage is modified to form a pulley mechanism associated with the levator muscle of the upper lip. The lateral accessory nasal cartilage is enlarged and serves as an attachment site for musculature controlling the aperture of the nostril, particularly the lateralis nasi, the apical dilatators, and the rectus nasi. Bony support for narial structures is reduced. Moose show greatly enlarged nasal cartilages, and the entire osseocartilaginous apparatus is relatively much larger than in outgroups. The nasal vestibule of moose is very large and houses a system of three recesses: one rostral and one caudal to the nostrils, and one associated with the enlarged fibrofatty alar fold. As a result of the expanded nasal vestibule, osseous support for the nasal conchae (i.e. turbinates) has retracted caudally along with the bony nasal aperture. The nasoturbinate and its mucosal counterparts (dorsal nasal concha and rectal fold) are reduced. The upturned maxilloturbinate, however, is associated with an enlarged ventral nasal concha and alar fold. Moose are the only species of cervid with these particular characteristics, indicating that this anatomical configuration is indeed novel. Although functional hypotheses await testing, our anatomical findings and published behavioural observations suggest that the novel narial apparatus of moose probably has less to do with respiratory physiology than with functions pertaining specifically to the nostrils. The widely separated and laterally facing nostrils may enhance stereolfaction (i.e. extracting directional cues from gradients of odorant molecules in the environment), but other attributes of narial architecture (enlarged cartilages, specialized musculature, recesses, fibrofatty pads) suggest that this function may not have been the evolutionary driving force. Rather, these attributes suggest a mechanical function, namely, an elaborated nostril-closing system. [source]

Quantum Well Intermixing Revolutionizes High Power Laser Diodes

LASER TECHNIK JOURNAL, Issue 5 2007
Monolithically integrated systems drive applications
Quantum well intermixing (QWI), an innovative monolithic integration platform, is changing the way diode lasers solve evolving optoelectronic needs , from high density, individually addressable laser arrays to high power laser products. QWI-enabled lasers deliver superior performance in terms of power, brightness, reliability, and yield, and are driving a revolution across market sectors including digital printing, defense, industrial, and medical imaging. [source]

Automatic quality assessment in structural brain magnetic resonance imaging,

MAGNETIC RESONANCE IN MEDICINE, Issue 2 2009
Bénédicte Mortamet
Abstract MRI has evolved into an important diagnostic technique in medical imaging. However, reliability of the derived diagnosis can be degraded by artifacts, which challenge both radiologists and automatic computer-aided diagnosis. This work proposes a fully-automatic method for measuring image quality of three-dimensional (3D) structural MRI. Quality measures are derived by analyzing the air background of magnitude images and are capable of detecting image degradation from several sources, including bulk motion, residual magnetization from incomplete spoiling, blurring, and ghosting. The method has been validated on 749 3D T1 -weighted 1.5T and 3T head scans acquired at 36 Alzheimer's Disease Neuroimaging Initiative (ADNI) study sites operating with various software and hardware combinations. Results are compared against qualitative grades assigned by the ADNI quality control center (taken as the reference standard). The derived quality indices are independent of the MRI system used and agree with the reference standard quality ratings with high sensitivity and specificity (>85%). The proposed procedures for quality assessment could be of great value for both research and routine clinical imaging. It could greatly improve workflow through its ability to rule out the need for a repeat scan while the patient is still in the magnet bore. Magn Reson Med, 2009. © 2009 Wiley-Liss, Inc. [source]

Clinical two-photon microendoscopy

MICROSCOPY RESEARCH AND TECHNIQUE, Issue 5 2007
K. König
Abstract Two-photon medical imaging has found its way into dermatology as an excellent method for noninvasive skin cancer detection without need of contrast agents as well as for in situ drug screening of topically-applied cosmetical and pharmaceutical components. There is an increasing demand to apply the multiphoton technology also for deep-tissue skin imaging as well as for intracorporal imaging. We report on the first clinical use of multiphoton endoscopes, in particular of a miniaturized rigid two-photon GRIN lens endoscope. The microendoscope was attached to the multiphoton tomograph DermaInspect and employed to detect the extracellular matrix proteins collagen and elastin in the human dermis of volunteers and patients with ulcera by in vivo second harmonic generation and in vivo two-photon autofluorescence. Microsc. Res. Tech., 2007. © 2007 Wiley-Liss, Inc. [source]

Craniofacial imaging informatics and technology development

ORTHODONTICS & CRANIOFACIAL RESEARCH, Issue 2003
MW Vannier
Structured Abstract Author, Vannier MW Purpose , ,Craniofacial imaging informatics' refers to image and related scientific data from the dentomaxillofacial complex, and application of ,informatics techniques' (derived from disciplines such as applied mathematics, computer science and statistics) to understand and organize the information associated with the data. Method , Major trends in information technology determine the progress made in craniofacial imaging and informatics. These trends include industry consolidation, disruptive technologies, Moore's law, electronic atlases and on-line databases. Each of these trends is explained and documented, relative to their influence on craniofacial imaging. Results , Craniofacial imaging is influenced by major trends that affect all medical imaging and related informatics applications. The introduction of cone beam craniofacial computed tomography scanners is an example of a disruptive technology entering the field. An important opportunity lies in the integration of biologic knowledge repositories with craniofacial images. Conclusion , The progress of craniofacial imaging will continue subject to limitations imposed by the underlying technologies, especially imaging informatics. Disruptive technologies will play a major role in the evolution of this field. [source]

Physiotherapists' perceptions and use of medical imaging information in practice

PHYSIOTHERAPY RESEARCH INTERNATIONAL, Issue 1 2006
Tamara Little
Abstract Background and Purpose. Physiotherapists must take responsibility for all aspects of patient care. Information from medical imaging studies can influence clinical decisions. The purpose of the present study was to gather information about physiotherapists' perceptions and use of medical imaging information in clinical practice. Method. A survey questionnaire was developed, validated and pilot tested. Subjects were randomly selected from a pool of licensed physiotherapists practising in four California Physical Therapy Association Districts. The survey was sent to 500 physiotherapists. Data gathered from the survey were transcribed to spreadsheets for analysis. Results. One hundred and twenty participants completed and returned the survey. Information from radiographs was most frequently available, followed by MRI and CT scan information, respectively. Respondents reported more use of information from reports than from images. Respondents also indicated that it was important to be able to review medical imaging information (70%), that they use medical imaging information in their practice when it is available (83.4%), that physiotherapists have the necessary knowledge and skills to use this type of information (77.3%), and that medical imaging should be covered in entry-level educational programmes (84.2%). Respondents additionally indicated that medical imaging information could be used to understand a patient's disease process (85%), improve communication about patient care (90%), improve diagnosis, prognosis and interventions for patients (81.6%), and identify contraindications to examination and interventions (87.5%). Conclusions. Physiotherapists have access to some medical imaging information and perceive that this information could be valuable in patient care; however, not all therapists are confident in their ability to interpret this information. Curricula in entry-level physiotherapist educational programmes should include information about medical imaging. Copyright © 2006 John Wiley & Sons, Ltd. [source]

Scaffold Modeling Application in the Repair of Skull Defects

ARTIFICIAL ORGANS, Issue 4 2010
Weibing Wan
Abstract The repair of large segmental bone defects caused by trauma, inflammation, and surgery on tumors pose a major clinical challenge. Tissue-engineered bone is emerging as a good choice for prefabricating cellular scaffold, and computer-aided technologies and medical imaging have created new possibilities in biomedical engineering. An accurate and efficient construction of anatomic models is critical to the application of these computational methods. Such models must be validated prior to application. In this article, we explore the potential of combining these techniques to scaffold and repair a pediatric skull. Working under the hypothesis that the autogenously cultivated osteoblasts can be grown on individualized scaffolds to improve bone regeneration in skull defects, we focus our study on potential problems concerning the segmentation, reconstruction, and mesh simplification for a pediatric skull. We also propose a new framework to improve the accuracy of the model entity from image segmentation to mesh simplification. [source]

Doppler tomography of accretion in binaries

ASTRONOMISCHE NACHRICHTEN, Issue 3 2004
Article first published online: 3 MAR 200, D. Steeghs
Abstract Since its conception, Doppler tomography has matured into a versatile and widely used tool. It exploits the information contained in the highly-structured spectral line-profiles typically observed in mass-transferring binaries. Using inversion techniques akin to medical imaging, it permits the reconstruction of Doppler maps that image the accretion flow on micro-arcsecond scales. I summarise the basic concepts behind the technique and highlight two recent results; the use of donor star emission as a means to system parameter determination, and the real-time movies of the evolving accretion flow in the cataclysmic variable WZ Sge during its 2001 outburst. I conclude with future opportunities in Doppler tomography by exploiting the combination of superior data sets, second generation reconstruction codes and simulated theoretical tomograms to delve deeper into the physics of accretion flows. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Anatomical development of urinary bladder during the fetal period

CLINICAL ANATOMY, Issue 7 2008
O. Sulak
Abstract The aim of this study was to determine the development, location, and size of the urinary bladder during the fetal period. The study was performed on 149 human fetuses between 9 and 40 weeks of gestation. The location of the urinary bladder with respect to transverse plane between the highest point of pubic symphysis and the sacral promontory and median sagittal plane was first determined. The dimensions and the angle of the urinary bladder were measured, and bladder shapes were determined. In addition, the edges of the vesical trigone were measured. There was no significant difference between sexes for any of the parameters (P > 0.05). A significant correlation was observed between all parameters and gestational age (P < 0.001). The urinary bladder was located above the transverse plane in most of the cases (83%) and in the median sagittal plane in every case. It was determined that the angle of bladder did not change and the mean value of the angle was 151° during the fetal period. Bladder was categorized into four different shapes (ellipsoid, round, cuboid, and triangular), and the most common shape found during the fetal period was cuboid. The vesical trigone was an isosceles triangle during the fetal period. The new data provided by this study will enable evaluation of the development of the fetal urinary bladder, and should be useful in several fields such as anatomy, fetopathology, medical imaging, obstetrics, and pediatric urology. Clin. Anat. 21:683,690, 2008. © 2008 Wiley-Liss, Inc. [source]

LARGE-SCALE SIMULATION OF THE HUMAN ARTERIAL TREE

CLINICAL AND EXPERIMENTAL PHARMACOLOGY AND PHYSIOLOGY, Issue 2 2009
L Grinberg
SUMMARY 1Full-scale simulations of the virtual physiological human (VPH) will require significant advances in modelling, multiscale mathematics, scientific computing and further advances in medical imaging. Herein, we review some of the main issues that need to be resolved in order to make three-dimensional (3D) simulations of blood flow in the human arterial tree feasible in the near future. 2A straightforward approach is computationally prohibitive even on the emerging petaflop supercomputers, so a three-level hierarchical approach based on vessel size is required, consisting of: (i) a macrovascular network (MaN); (ii) a mesovascular network (MeN); and (iii) a microvascular network (MiN). We present recent simulations of MaN obtained by solving the 3D Navier,Stokes equations on arterial networks with tens of arteries and bifurcations and accounting for the neglected dynamics through proper boundary conditions. 3A multiscale simulation coupling MaN,MeN,MiN and running on hundreds of thousands of processors on petaflop computers will require no more than a few CPU hours per cardiac cycle within the next 5 years. The rapidly growing capacity of supercomputing centres opens up the possibility of simulation studies of cardiovascular diseases, drug delivery, perfusion in the brain and other pathologies. [source]