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PubMed2005

Computer aided surgical reconstruction after complex facial burn injuries -- opportunities and limitations.

In severe facial burn injuries with extensive destruction of anatomical structures, cosmetic and functional outcome of treatment are frequently not satisfactory. Although operative therapy is being continuously refined, the variety and proximity of structures in the facial region is considered a major challenge in reconstructive surgery. We present the case of a 16-year-old patient with a severe facial burn injury. In planning the reconstructive procedures, we used a multimodal approach employing data from computerized tomography imaging, as well as from surface laser scanning, which provided three-dimensional visualization of facial soft tissues. Amount and pattern of structural loss could thus be determined more precisely and studied more vividly than by inspection of two-dimensional imaging alone. Anatomical features to be reconstructed could be projected onto the skin area of the prelaminated vertical rectus abdominis muscle (VRAM) flap that has been chosen to cover the defect. Prior to surgery, correction of the defects was simulated and the results of the virtual procedure superimposed on a three-dimensional head model of the patient. Tissue elasticity and thickness of the flap, however, could not be ascertained in advance, indicating the limitations of the method.

Adolescent↗
PubMed2005

The neurophysiological time pattern of illusionary visual perceptual transitions: a simultaneous EEG and fMRI study.

Several divergent cortical mechanisms generating multistability in visual perception have been suggested. Here, we investigated the neurophysiologic time pattern of multistable perceptual changes by means of a simultaneous recording with electroencephalography (EEG) and functional magnetic resonance imaging (fMRI). Volunteers responded to the subjective perception of a sudden change between stable patterns of illusionary motion (multistable transition) during a stroboscopic paradigm. We found a global deceleration of the EEG frequency prior to a transition and an occipital-accentuated acceleration after a transition, as obtained by low-resolution electromagnetic tomography analysis (LORETA) analysis. A decrease in BOLD response was found in the prefrontal cortex before, and an increase after the transitions was observed in the right anterior insula, the MT/V5 regions and the SMA. The thalamus and left superior temporal gyrus showed a pattern of decrease before and increase after transitions. No such temporal course was found in the control condition. The multimodal approach of data acquisition allows us to argue that the top-down control of illusionary visual perception depends on selective attention, and that a diminution of vigilance reduces selective attention. These are necessary conditions to allow for the occurrence of a perception discontinuity in absence of a physical change of the stimulus.

Adolescent↗
PubMed2001

Evaluation of voxel-based registration of 3-D power Doppler ultrasound and 3-D magnetic resonance angiographic images of carotid arteries.

Spatial registration and fusion of ultrasound (US) images with other modalities may aid clinical interpretation. We implemented and evaluated on patient data an automated retrospective registration of magnetic resonance angiography (MRA) carotid bifurcation images with 3-D power Doppler ultrasound (PD US) and indirectly with 3-D B-mode US. Volumes were initially thresholded to reduce the uncorrelated noise signals. The registration algorithm subsequently maximized the mutual information measure between the PD US and 3-D MRA via iterative simplex search to find best "rigid body" transformation. We rated the performance of the algorithm visually on (n = 5) clinical MRA and 3-D PD US datasets. We also evaluated quantitatively the effect of thresholding, initial misalignment of the paired volumes and the reproducibility registration. We investigated the effect of image artefacts by simulation experiments. Preregistration misalignments of up to 5 mm in the transaxial plane, up to 10 mm along the axis of the carotids and up to 40 degrees resulted in 107 of 110 successful registrations, with translational and rotational errors of 0.32 mm +/- 0.3 mm and 1.6 +/- 2.1 degrees. The algorithm was not affected by missing arterial segments of up to 8 mm in length. The average registration time was 4 min. We conclude that the algorithm could be applied to 3-D US PD and MRA data for automated multimodality registration of carotid vessels without the use of fiducials.

Algorithms↗
PubMed1992

[Evoked potentials in HIV infection].

The study of the literature data on the multimodal evoked potentials in HIV infected patients shows many abnormalities as well in asymptomatic subjects without AIDS as in AIDS subjects with or without neurological signs. Visual evoked potentials (VEPs) reveal prolonged P100 wave latency in 22% of HIV asymptomatic subjects and in 26% of HIV symptomatic subjects; brainstem auditory evoked potentials (BAEPs) reveal an increase of the interpeak latency I-V in 16% of asymptomatic subjects and in 32% of symptomatic subjects; somatosensory evoked potentials (SEPs) by median nerve stimulation reveal prolonged central conduction time in 6% of asymptomatic subjects and in 11% of symptomatic subjects; somatosensory evoked potentials (SEPs) by tibial nerve stimulation reveal prolonged central conduction time in 4% of asymptomatic subjects and in 45% of symptomatic subjects; motor evoked potentials (MEPs) by magnetic stimulation reveal prolonged central motor conduction time in 46% of asymptomatic subjects.

Adult↗
PubMedDate not supplied

Post-war Kosovo: Part 2. Assessment of emergency medicine leadership development strategy.

Since the return of the refugee population to Kosovo, attempts at development of an emergency medical system in Kosovo have met with varied success, and have been hampered by unforeseen barriers. These barriers have been exacerbated by the lack of detailed health system assessments. A multimodal approach of data collection and analysis was used to identify potential barriers, and determine the appropriate level of intervention for emergency medicine (EM) development in Kosovo. The four step, multi-modal, data collection tool utilized: 1) demographic and health systems data; 2) focus group discussions with health-care workers; 3) individual interviews with key individuals in EM development; and 4) Q-Analysis of the attitudes and opinions of EM leaders. Results indicated that Emergency Medicine in Kosovo is under-developed. This method of combined quantitative and qualitative analysis identified a number of developmental needs in the Kosovar health system. There has been little formal training, the EMS system lacks organization, equipment, and a reliable communication system, and centralized emergency centers, other than the center at Prishtina Hospital, are inadequate. Group discussions and interviews support the desire by Kosovar health-care workers to establish EM, and highlight a number of concerns. A Q-methodology analysis of the attitudes of potential leaders in the field, supported these concerns and identified two attitudinal groups with deeper insights into their opinions on the development of such a system. This study suggests that a multi-modal assessment of health systems can provide important information about the need for emergency health system improvements in Kosovo. This methodology may serve as a model for future, system-wide assessments in post-conflict health system reconstruction.

Data Collection↗
PubMed2004

Lipofundin-induced intracranial pressure rise after severe traumatic brain injury--a case report.

Early nutrition is a recognized component of neurosurgical intensive care treatment. The authors present the case of a patient suffering from severe traumatic brain injury who responded with reproducible intracranial pressure (ICP) crisis to infusion of Lipofundin, a fatty soybean oil-based emulsion for parenteral nutrition. During the described ICP rise, the patient remained hemodynamically stable, therefore an anaphylactic reaction seems to be unlikely. An increase of brain tissue oxygenation parallel to the ICP rise in this case is suggestive for increased cerebral blood flow as a cause of ICP elevation after application of Lipofundin. Without multimodal monitoring and data storage, the described side effect of Lipofundin in our patient would have been difficult to identify.

Accidental Falls↗
PubMed1994

A comparison of Radial Basis Function and backpropagation neural networks for identification of marine phytoplankton from multivariate flow cytometry data.

Two artificial neural network classifiers, the well-known Multi-layer Perception (MLP) (also known as the 'backpropagation network'), and the more recently developed Radial Basis Function (RBF) network, were evaluated and compared for their ability to identify multivariate flow cytometric data from five North Sea plankton groups (Dinoflagellidae, Bacillariophyceae, Prymnesiomonadida, Cryptomonadida, and other flagellates). RBF networks generally performed similarly to MLPs, and slightly better in cases where the data were markedly multimodal; RBF networks also have much shorter training times. The performance of MLPs was improved greatly by the use of a symmetrical bipolar 'transfer function' as opposed to the commonly-used asymmetric form. The issues of network optimisation and computational efficiency in use are discussed.

Evaluation Studies as Topic↗
PubMed1999

Esophageal cancer.

Carcinoma of the esophagus and gastroesophageal junction continues to be an aggressive cancer with poor prognosis, despite improved surgical results and the potential benefit of combined multimodality regimens. Additional data seem to confirm the rising incidence of adenocarcinoma, although users of nonsteroidal anti-inflammatory drugs seem to have a decreased risk. Much attention is focused on detecting high-grade dysplasia and early carcinoma with promising results using red fluorescence after preceding 5-aminolevulinic acid (ALA) sensitization. Positron emission tomography made a major breakthrough and seems to be superior to computed tomography in detecting distant metastasis as well as lymph node metastasis. Endoscopic ablation of early carcinoma results in promising early results, but a major issue remains the EUS discrimination between Tis-T1a and T1b, as the latter is frequently associated with lymph node metastasis. In the field of molecular biology, research is unraveling the role of cadherins and catenins in the mechanism underlying cell adherence, cell movement, and progress toward tumor formation. Mutations of p53 are correlated with loss of apoptosis and form an early step in progress toward carcinoma as well as mutations of other tumor-suppressing genes (eg, p16 and Rb mutations). Detection of such mutations may become useful prognostic indicators, but illustrate the genetic polymorphism influencing the susceptibility to carcinoma. Several lines of evidence suggest that the stabilizing or overriding of p53 mutant cancer cells and restoration of the wild-type tumor suppressor gene p53 may improve results of DNA damaging treatment modalities. Further research in this field may lead to new forms of anticancer therapy.

Journal Article↗
PubMed2004

Moderated histogram equalization, an automatic means of enhancing the contrast in digital light micrographs reversibly.

A means for improving the contrast in the images produced from digital light micrographs is described that requires no intervention by the experimenter: zero-order, scaling, tonally independent, moderated histogram equalization. It is based upon histogram equalization, which often results in digital light micrographs that contain regions that appear to be saturated, negatively biased or very grainy. Here a non-decreasing monotonic function is introduced into the process, which moderates the changes in contrast that are generated. This method is highly effective for all three of the main types of contrast found in digital light micrography: bright objects viewed against a dark background, e.g. fluorescence and dark-ground or dark-field image data sets; bright and dark objects sets against a grey background, e.g. image data sets collected with phase or Nomarski differential interference contrast optics; and darker objects set against a light background, e.g. views of absorbing specimens. Moreover, it is demonstrated that there is a single fixed moderating function, whose actions are independent of the number of elements of image data, which works well with all types of digital light micrographs, including multimodal or multidimensional image data sets. The use of this fixed function is very robust as the appearance of the final image is not altered discernibly when it is applied repeatedly to an image data set. Consequently, moderated histogram equalization can be applied to digital light micrographs as a push-button solution, thereby eliminating biases that those undertaking the processing might have introduced during manual processing. Finally, moderated histogram equalization yields a mapping function and so, through the use of look-up tables, indexes or palettes, the information present in the original data file can be preserved while an image with the improved contrast is displayed on the monitor screen.

Actins↗
PubMed2005

Toward an integrated profile of depression: evidence from the brain resource international database.

Clinical depression is one of the most common psychiatric disorders in adults, yet non-clinical depression in the community may go unnoticed, despite high prevalence rates and significant psychosocial impairment. The aim of the current study was to classify 1,226 individuals from a community sample on the basis of depression scores (using the Depression Anxiety Stress Scales, DASS) and to determine whether depression in a non-clinical sample differed significantly from healthy controls on a profile of multimodal measures. The data analyzed in this study included personality, emotional intelligence, cognition and psychophysiology. It was predicted that non-clinically depressed participants would differ from healthy controls on measures of personality (increased neuroticism; decreased extraversion), emotional intelligence (decreased), cognition (impairments in executive dysfunction and memory impairment), psychophysiology (increased resting-state, right-frontal activation; diminished skin conductance) after controlling for gender, age, handedness and years of education. Findings provide support for the majority of hypotheses, though no evidence was found for memory impairment or frontal hemispheric asymmetry. Longitudinal studies are needed to determine the extent to which of these findings will have utility for the prediction of depression onset and treatment response/non-response.

Adult↗
PubMed2004

Thymoma and thymic carcinoma: therapeutic approaches.

Thymomas and thymic carcinomas, which are rare epithelial tumors arising from the thymus gland, are the most common tumors of the anterior mediastinum. Thymomas are generally encapsulated, slow-growing tumors that have a "bland" histologic appearance. Thymic carcinomas possess more overtly malignant histologic features than thymomas and are more likely to present as invasive or disseminated disease. Surgery is the treatment of choice for localized thymic tumors, with complete resection being the most important prognostic factor. Complete resection also improves survival in locally invasive thymic tumors. Adjuvant postoperative radiation therapy may improve the outcome in patients with invasive disease, although the data are conflicting. Multimodal regimens, including neoadjuvant combination chemotherapy, surgery, and/or postoperative radiation therapy, are recommended for patients with advanced thymomas and thymic carcinomas. Use of octreotide plus prednisone has produced responses in thymomas, but the dosing and schedule have not been clearly defined. Prospective studies have been limited, and, as such, enrollment in clinical trials is encouraged.

Antineoplastic Agents↗
PubMed1992

Local excision of early rectal cancer.

During the past 15 years, data from numerous multimodality trials have shown significant improvement in outlook for patients with "high risk" colon and rectum cancers. In this paper, a suggested next step is to use the advance in multiple treatment approach to challenge the major toxicity of treatment in patients with rectum cancer--the permanent colostomy.

Adenocarcinoma↗
PubMed2002

Temporal bone dissection simulation--an update.

We report on our continued development of a virtual simulation for temporal bone dissection that provides stereoscopic display, haptic feedback, and aural simulation into a straightforward, comprehensive learning environment. The multimodal interface provides a seamless simulation for non-deterministic drilling and cutting of bone in the surgical context, as well as an intuitive interface for the intelligent tutor for learning regional anatomy. We present novel methodologies for integrating multimodal and multiresolution data sets, including extension to functional and structural segmentation. We will present our initial efforts to validate this environment. Through continued iterations, it is our hope that the system will provide a valuable tool for training future otologic surgeons as well as an environment for the quantitative evaluation of surgical skill.

Aged↗
PubMed2005

A health plan intervention to improve pneumococcal vaccination in the elderly.

In 1998, the Hawaii Medical Service Association, headquartered in Honolulu, partnered with a pharmaceutical manufacturer to promote pneumococcal immunization of its 33,017 Medicare cost-contract members. They disseminated newsletter articles, magazine advertisements, letters, posters, and broadcast announcements; held injection clinics; and provided physicians reminder postcards with patient labels. Medicare claims indicated that immunization rose by 13.3% in 1997, 20.7% in 1998, and 42.3% in 2000, exceeding rates in a fee-for-service control group. Moreover, the rate of hospitalization for pneumococcal pneumonia dropped after 1998. The data suggest that multimodal promotion of pneumococcal vaccine will result in more extensive immunization and less frequent hospitalization.

Aged↗
PubMed1995

ICOHR: intelligent computer based oral health record.

The majority of work on computer use in the dental field has focused on non-clinical practice management information needs. Very few computer-based dental information systems provide management support of the clinical care process, particularly with respect to quality management. Traditional quality assurance methods rely on the paper record and provide only retrospective analysis. Today, proactive quality management initiatives are on the rise. Computer-based dental information systems are being integrated into the care environment, actively providing decision support as patient care is being delivered. These new systems emphasize assessment and improvement of patient care at the time of treatment, thus building internal quality management into the caregiving process. The integration of real time quality management and patient care will be expedited by the introduction of an information system architecture that emulates the gathering and storage of clinical care data currently provided by the paper record. As a proposed solution to the problems associated with existing dental record systems, the computer-based patient record has emerged as a possible alternative to the paper dental record. The Institute of Medicine (IOM) recently conducted a study on improving the efficiency and accuracy of patient record keeping. As a result of this study, the IOM advocates the development and implementation of computer-based patient records as the standard for all patient care records. This project represents the ongoing efforts of The University of Iowa College of Dentistry's collaboration with the University of Uppsala Data Center, Uppsala, Sweden, on a computer-based patient dental record model. ICOHR (Intelligent Computer Based Oral Health Record) is an information system which brings together five important parts of the patient's dental record: medical and dental history; oral status; treatment planning; progress notes; and a Patient Care Database, generated from their clinical care information (the database is also stored in the ICOHR). ICOHR is designed to be integrated into a traditional practice management system. The components of the ICOHR system support the use of various types of clinical care quality management tools, including medical alerts, clinical care guidelines, care modifiers, and diagnostic decision support. Data input is multimodal, so the user may use both voice recognition and direct input with a digitizer board to enter information into the database. ICOHR is designed to be integrated into the clinical environment in an ergonomic fashion in order to facilitate the unobtrusive and efficient acquisition of patient information. ICOHR is currently under clinical evaluation in both private practice and institutional environments. The private practice is a large general dentistry practice with over twenty sites scattered throughout a large metropolitan area. The institutional settings are a College of Dentistry and a Hospital Dentistry program. The evaluations have started in two of the sites and the other site will be phased in during the next six months. Our demonstration of the system will include both prepared presentations of the system's various functions and provide an opportunity for hands-on use of the system for interested attendees.

Artificial Intelligence↗
PubMed2006

High-speed data transmission over a 1 km broad wavelength window multimode fiber.

For cost and design simplicity, various optical network architectures have been proposed in which downstream traffic from the optical line terminal to the optical networking unit is transmitted by carriers in the 1550 nm window, and upstream traffic by those in the 1300 nm window. A new generation of multimode fiber (MMF) has been designed to accommodate this requirement and to address technical challenges associated with fiber coupling. By restricting the number of modes at both fiber input and output, using off-the-shelf single-mode transceivers, single-wavelength 40 Gbit/s data transmission over a 1 km broad wavelength window multimode fiber has been demonstrated with only a 1.5 dB power penalty. The capacity in this new class of MMF is expected to increase with conventional technologies in single-mode fiber such as wavelength-division multiplexing and polarization multiplexing.

Journal Article↗
PubMed2001

Image fusion in open-architecture PACS-environment.

Multimodal digital imaging is common in many fields of diagnosis and therapy planning - there is great interest in matching globally, fusing or registering data from the same part of the body. In practice, there are still difficulties in customizing image fusion in hospitals. Efficient routine use of image fusion requires, among others, an image management infrastructure - a picture archiving and communication system (PACS) - to provide storage of image data in a standard digital format, intelligent image management and fault-tolerant high-speed image networking. In order to customize image fusion, advances in both fusion software and hardware are also needed. The algorithms should be automatic, fast and accurate enough. Registration of multimodal data also creates a need for different display techniques and user-friendly interfaces. Image fusion has been impractical and too tedious to be performed in routine work, but in the future, fused images will be used in clinical practice - even in teleradiological consultation.

Humans↗
PubMed2003

Automatic change detection in multimodal serial MRI: application to multiple sclerosis lesion evolution.

The automatic analysis of subtle changes between MRI scans is an important tool for assessing disease evolution over time. Manual labeling of evolutions in 3D data sets is tedious and error prone. Automatic change detection, however, remains a challenging image processing problem. A variety of MRI artifacts introduce a wide range of unrepresentative changes between images, making standard change detection methods unreliable. In this study we describe an automatic image processing system that addresses these issues. Registration errors and undesired anatomical deformations are compensated using a versatile multiresolution deformable image matching method that preserves significant changes at a given scale. A nonlinear intensity normalization method is associated with statistical hypothesis test methods to provide reliable change detection. Multimodal data is optionally exploited to reduce the false detection rate. The performance of the system was evaluated on a large database of 3D multimodal, MR images of patients suffering from relapsing remitting multiple sclerosis (MS). The method was assessed using receiver operating characteristics (ROC) analysis, and validated in a protocol involving two neurologists. The automatic system outperforms the human expert, detecting many lesion evolutions that are missed by the expert, including small, subtle changes.

Algorithms↗