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At least 217 records · Page 12Linked to original sources
PubMed2003

Multimodal integration of high-resolution EEG and functional magnetic resonance imaging data: a simulation study.

Previous simulation studies have stressed the importance of the use of fMRI priors in the estimation of cortical current density. However, no systematic variations of signal-to-noise ratio (SNR) and number of electrodes were explicitly taken into account in the estimation process. In this simulation study we considered the utility of including information as estimated from fMRI. This was done by using as the dependent variable both the correlation coefficient and the relative error between the imposed and the estimated waveforms at the level of cortical region of interests (ROI). A realistic head and cortical surface model was used. Factors used in the simulations were the different values of SNR of the scalp-generated data, the different inverse operators used to estimated the cortical source activity, the strengths of the fMRI priors in the fMRI-based inverse operators, and the number of scalp electrodes used in the analysis. Analysis of variance results suggested that all the considered factors significantly afflict the correlation and the relative error between the estimated and the simulated cortical activity. For the ROIs analyzed with simulated fMRI hot spots, it was observed that the best estimation of cortical source currents was performed with the inverse operators that used fMRI information. When the ROIs analyzed do not present fMRI hot spots, both standard (i.e., minimum norm) and fMRI-based inverse operators returned statistically equivalent correlation and relative error values.

Analysis of Variance↗
PubMed2005

General consumer communication tools for improved image management and communication in medicine.

We elected to explore new technologies emerging on the general consumer market that can improve and facilitate image and data communication in medical and clinical environment. These new technologies developed for communication and storage of data can improve the user convenience and facilitate the communication and transport of images and related data beyond the usual limits and restrictions of a traditional picture archiving and communication systems (PACS) network. We specifically tested and implemented three new technologies provided on Apple computer platforms. (1) We adopted the iPod, a MP3 portable player with a hard disk storage, to easily and quickly move large number of DICOM images. (2) We adopted iChat, a videoconference and instant-messaging software, to transmit DICOM images in real time to a distant computer for conferencing teleradiology. (3) Finally, we developed a direct secure interface to use the iDisk service, a file-sharing service based on the WebDAV technology, to send and share DICOM files between distant computers. These three technologies were integrated in a new open-source image navigation and display software called OsiriX allowing for manipulation and communication of multimodality and multidimensional DICOM image data sets. This software is freely available as an open-source project at http://homepage.mac.com/rossetantoine/OsiriX. Our experience showed that the implementation of these technologies allowed us to significantly enhance the existing PACS with valuable new features without any additional investment or the need for complex extensions of our infrastructure. The added features such as teleradiology, secure and convenient image and data communication, and the use of external data storage services open the gate to a much broader extension of our imaging infrastructure to the outside world.

Communication↗
PubMed2005

Surgical treatment of advanced-stage carcinoid tumors: lessons learned.

OBJECTIVE: To evaluate clinical outcomes in a large group of advanced-stage carcinoid patients (stage IV) following multimodal surgical therapy. SUMMARY BACKGROUND DATA: Patients with advanced-stage carcinoid have traditionally experienced poor 5-year survival (18%-30%). Few recent series have evaluated a large number of patients treated with aggressive surgical rescue therapy. METHODS: This single-center retrospective review analyzes the records of 82 consecutive carcinoid patients treated by the same 2 surgeons, from August 1998 through August 2004 with a 3- to 72-month follow-up. RESULTS: Surprisingly, one third of 26 (32%) patients were found to have intestinal obstructions; 10 being moribund at presentation. Mesenteric encasement with intestinal ischemia was successfully relieved in 10 of 12 cases. Five of eighty-two "terminal" patients were rendered free of macroscopic disease. Karnofsky performance scores improved from 65 to 85 (P < 0.0001). Two- and four-year survival for patients with no or unilateral liver metastases (n = 23) was 89%, while 2- and 4-year survival for patients with bilateral liver disease (n = 59) was 68% and 52% (P = 0.072), respectively. CONCLUSION: We think that all patients with advanced-stage carcinoid should be evaluated for possible multimodal surgical therapy. Primary tumors should be resected, even in the presence of distant metastases to prevent future intestinal obstruction. The "wait and see" method of management of this slow-growing cancer no longer has merit. We offer an algorithm for the surgical evaluation and management of these patients.

Adolescent↗
PubMed2002

Bump-hunting for the proficiency tester--searching for multimodality.

Kernel density estimation is a method for producing a smooth density approximation to a dataset and avoiding some of the problems associated with histograms. If it is used with a degree of smoothing determined by a fitness for purpose criterion, it can be applied to proficiency test data in order to test for multimodality in the z-scores. The bootstrap is an essential additional technique to determine how rugged the initially estimated kernel density is: the random resampling of the data in the bootstrap simulates a complete blind repeat of the proficiency test. In addition, useful estimates of the standard error of a mode can be thus obtained. It is suggested that a mode and its standard error can be used as an assigned value and its standard uncertainty.

Journal Article↗
PubMed2004

Circular distributions based on nonnegative trigonometric sums.

A new family of distributions for circular random variables is proposed. It is based on nonnegative trigonometric sums and can be used to model data sets which present skewness and/or multimodality. In this family of distributions, the trigonometric moments are easily expressed in terms of the parameters of the distribution. The proposed family is applied to two data sets, one related with the directions taken by ants and the other with the directions taken by turtles, to compare their goodness of fit versus common distributions used in the literature.

Animals↗
PubMed2002

Precise modelling of the eye for proton therapy of intra-ocular tumours.

A new method is described that allows precise modelling of organs at risk and target volume for radiation therapy of intra-ocular tumours. The aim is to optimize the dose distribution and thus to reduce normal tissue complication probability. A geometrical 3D model based on elliptic shapes was developed that can be used for multimodal model-based segmentation of 3D patient data. The tumour volume cannot be clearly identified in CT and MR data, whereas the tumour outline can be discriminated very precisely in fundus photographs. Therefore, a multimodal 2D fundus diagram was developed, which allows us to correlate and display simultaneously information extracted from the eye model, 3D data and the fundus photograph. Thus, the connection of fundus diagram and 3D data is well-defined and the 3D volume can be calculated directly from the tumour outline drawn onto the fundus photograph and the tumour height measured by ultrasound. The method allows the calculation of a precise 3D eye model of the patient, including the different structures of the eye as well as the tumour volume. The method was developed as part of the new 3D treatment planning system OCTOPUS for proton therapy of ocular tumours within a national research project together with the Hahn-Meitner-Institut Berlin.

Eye Neoplasms↗
PubMed2000

High-Resolution Study of the BaI A(2)Pi Electronic State.

Near-infrared and visible spectra of the A(2)Pi-X(2)Sigma(+), C(2)Pi(1/2)-A(2)Pi(1/2), C(2)Pi(1/2)-B(2)Sigma(+), and C(2)Pi(1/2)-X(2)Sigma(+) band systems of the BaI molecule were recorded by using Fourier transform spectroscopy (FTS). The spectra were produced from the chemiluminescent reaction Ba + I(2) and also by using laser-induced fluorescence (LIF) technique in which the laser sources were a Ti:sapphire single-mode laser, a dye single-mode laser, and a Kr(+) multimode ion laser. Resolved rotational data, originating from 19 vibrational levels (0 </= v </= 5 and 7 </= v </= 19) of the A(2)Pi state, 24 vibrational levels (0 </= v </= 18 and 20 </= v </= 24) of the X(2)Sigma(+) state, and 8 vibrational levels (1 </= v </= 2 and 9 </= v </= 14) of the C(2)Pi state, were used in the final analysis. Previously recorded data for the B(2)Sigma(+)-X(2)Sigma(+) and C(2)Pi-X(2)Sigma(+) systems, taken from R. F. Gutterres, J. Vergès, and C. Amiot, J. Mol. Spectrosc. 196, 29-44 (1999) and from C. A. Leach, A. A. Tsekouras, and R. N. Zare, J. Mol. Spectrosc. 153, 59-72 (1992), were added to the present work data field. Accurate and improved molecular constants, for the X(2)Sigma(+), B(2)Sigma(+), A(2)Pi, and C(2)Pi states, were derived from a simultaneous treatment of the whole data set. Copyright 2000 Academic Press.

Journal Article↗
PubMed1994

Computer supported multimodal bed-side monitoring for neuro intensive care.

Multimodal monitoring in neuro-intensive care requires computer supported data analysis and archiving. This paper describes a computer system that is able to integrate the results of analysis of intracranial pressure, cerebral perfusion pressure, transcranial Doppler blood flow velocity, jugular bulb oxygen saturation, laser Doppler blood flow, near infrared spectroscopy. A research-oriented software installed in a standard IBM PC equipped with a low-cost analog-to-digital converter allows a broad spectrum of waveform analyses, from calculation of simple mean values to a selective waveform detection and cross-correlation analysis. The architecture for the signal processing algorithm, the principles of system interfacing and data presentation are discussed briefly. Results from two years of multimodal monitoring in neuro-intensive care show that, apart from simple recording of time trends of monitored variables, certain calculated parameters are particularly useful in the continuous assessment of cerebral haemodynamic and compensatory reserves. Such parameters include: transcranial Doppler pulsatility indices, the dependence between blood flow velocity or laser Doppler flux and cerebral perfusion pressure and the correlation coefficient between pulse amplitude and mean intracranial pressure.

Adolescent↗
PubMed2026

Retinopathy caused by a primary immune regulatory disorder - the spectrum of AIRE-associated retinopathy: case series and literature review.

BACKGROUND/OBJECTIVE: Retinal involvement in autoimmune polyendocrine syndrome type 1 (APS1), a rare monogenic autoimmune disorder caused by mutations in the AIRE gene, is increasingly recognised but remains poorly defined. Prior reports suggest a variable phenotype, ranging from mild changes to severe vision loss, often presumed untreatable. We explored the range of retinal phenotypes associated with AIRE gene deficiency in a multicentre case series of patients with APS1. METHODS: We performed a retrospective case note review of patients with molecularly confirmed APS1 from tertiary ophthalmic centres. Clinical history, multimodal retinal imaging, electrophysiology, genetic data, and treatment regimens were analysed. Histopathology was available in one case postmortem. RESULTS: Records were reviewed from five unrelated female patients. Median age was 14 years at onset of ocular involvement and 33 years at most recent follow up. Some findings from two cases have been previously reported. Three distinct pathogenic AIRE variants contributing to biallelic genotypes were observed. Retinal findings ranged from structurally and functionally normal to advanced degeneration. One patient demonstrated sharp zonal atrophy on histopathology. Inflammatory features predominated in two cases, both showing durable vision preservation with periocular or systemic immunomodulation. One patient demonstrated four years of disease stabilisation with rituximab. No consistent genotype-phenotype correlation emerged. CONCLUSION: AIRE-associated retinopathy encompasses a diverse spectrum, from clinically silent to profound degeneration. Early, targeted immunomodulation might preserve vision in selected cases. These findings advocate for ophthalmic surveillance in APS1, and support further investigation into predictive biomarkers and possible tailored immunotherapy in this vision-threatening autoimmune disorder.

Humans↗
PubMedDate not supplied

Coregistered tomographic x-ray and optical breast imaging: initial results.

We describe what is, to the best of our knowledge, the first pilot study of coregistered tomographic x-ray and optical breast imaging. The purpose of this pilot study is to develop both hardware and data processing algorithms for a multimodality imaging method that provides information that neither x-ray nor diffuse optical tomography (DOT) can provide alone. We present in detail the instrumentation and algorithms developed for this multimodality imaging. We also present results from our initial pilot clinical tests. These results demonstrate that strictly coregistered x-ray and optical images enable a detailed comparison of the two images. This comparison will ultimately lead to a better understanding of the relationship between the functional contrast afforded by optical imaging and the structural contrast provided by x-ray imaging.

Aged↗
PubMed1992

Further development and clinical application of the stereotactic operating microscope.

Implementation of a Vicom-VME image processing workstation for the frameless stereotactic operating microscope system has allowed an improved interpolation algorithm for more accurate reconstruction of three-dimensional data, the integration graphically of multimodality imaging information, an additional stereotactic graphics display outside of the microscope optics and optional three-dimensional displays through communication with a Convex mini-supercomputer. A precision-milled coupling for reproducible attachment of the spark gap bracket to the microscope has eliminated the need for that transformation calculation during each case. Clinical utility has been greatest in providing navigational guidance to small subcortical or deep lesions and in defining the extent of preoperatively planned resection of larger, infiltrating tumors. Mean accuracy in the past 17 cases has been 3.5-6.5 mm. The frameless methodology has also enabled extracranial stereotactic surgical procedures in 7 patients.

Brain Neoplasms↗
PubMed2003

Human cerebellum: surface-assisted cortical parcellation and volumetry with magnetic resonance imaging.

We describe a system of surface-assisted parcellation (SAP) of the human cerebellar cortex derived from neural systems functional and behavioral anatomy. This system is based on MRI and preserves the unique morphologic and topographic features of the individual cerebellum. All major fissures of the cerebellum were identified and traced in the flattened representation of the cerebellar cortex using the program "FreeSurfer." Parcellation of the cerebellar cortex followed using the fissure information in conjunction with landmarks using the program "Cardviews" to create 64 gyral-based cerebellar parcellation units. Computer-assisted algorithms enable the execution of the cerebellar parcellation procedure as well as volumetric measurements and topographic localization. The SAP technique makes it possible to represent multimodal structural and functional imaging data on the flattened surface of the cerebellar cortex as illustrated in one functional MRI experiment.

Adult↗
PubMed2004

Local sensory cues and place cell directionality: additional evidence of prospective coding in the hippocampus.

In tasks involving goal-directed, stereotyped trajectories on uniform tracks, the spatially selective activity of hippocampal principal cells depends on the animal's direction of motion. Principal cell ensemble activity while the rat moves in opposite directions through a given location is typically uncorrelated. It is shown here, with data from three experiments, that multimodal, local sensory cues can change the directional properties of CA1 pyramidal cells, inducing bidirectionality in a significant proportion of place cells. For a majority of these bidirectional place cells, place field centers in the two directions of motion were displaced relative to one another, as would be the case if the cells were representing a position in space approximately 5-10 cm ahead of the rat or if place cells were subject to strong accommodation or inhibition in the latter half of their input fields. However, place field density was not affected by the presence of local cues, but in the experimental condition with the most salient sensory cues, the CA1 population vectors in the "cue-rich" condition were sparser and changed more quickly in space than in the "cue-poor" condition. These results suggest that "view-invariant" object representations are projected to the hippocampus from lower cortical areas and can have the effect of increasing the correlation of the hippocampal input vectors in the two directions, hence decreasing the orthogonality of hippocampal output.

Animals↗
PubMed1999

Techniques of pneumonectomy. Pleural pneumonectomy.

This article reviews the preoperative assessment and selection of patients for extrapleural pneumonectomy, the surgical technique, and recent data outlining our experience with multimodality therapy for MPM.

Humans↗
PubMed2002

Engineering and algorithm design for an image processing Api: a technical report on ITK--the Insight Toolkit.

We present the detailed planning and execution of the Insight Toolkit (ITK), an application programmers interface (API) for the segmentation and registration of medical image data. This public resource has been developed through the NLM Visible Human Project, and is in beta test as an open-source software offering under cost-free licensing. The toolkit concentrates on 3D medical data segmentation and registration algorithms, multimodal and multiresolution capabilities, and portable platform independent support for Windows, Linux/Unix systems. This toolkit was built using current practices in software engineering. Specifically, we embraced the concept of generic programming during the development of these tools, working extensively with C++ templates and the freedom and flexibility they allow. Software development tools for distributed consortium-based code development have been created and are also publicly available. We discuss our assumptions, design decisions, and some lessons learned.

Algorithms↗
PubMedDate not supplied

[Value of the studies of multimodal evoked potentials for evaluation of neurotoxic effects of combined exposure to lead, copper and zinc].

Central nervous system dysfunction was studied in workers with occupational exposure to Pb+Cu+Zn by measuring somatosensory evoked potentials of short and long latency, visual evoked potentials and brain-stem evoked auditory potentials. The tests were done in 40 workers with a history of exposure from 6 to 19 (mean 14.3) years in a copper foundry. Pb poisoning was not diagnosed in them, but 18 workers had some abnormalities of heme synthesis. Pb concentration in blood was from 11.4 to 62.8 (mean 35.7) mcg% in the whole group. Pb concentration in air in the foundry exceeded 1.1-175 times the MAC value, the concentration of CU exceeded it 7.25 times. Zn concentration was half the MAC value. No significant abnormalities were found in the parameters of multimodal evoked potentials. The obtained data suggest a protective effect of copper and zinc on heme , Pb blood level and conduction velocity of somatosensory, visual and auditory impulses in workers exposed to high Pb air concentration.

Air Pollutants, Occupational↗
PubMed1995

Assessment and significance of diploid-range epithelial populations in DNA aneuploid breast carcinomas using multi-parametric flow cytometry.

A 2-color (PI, cytokeratin--FITC) multi-parametric analysis of intact cells was used to reveal diploid-range epithelial populations by flow cytometry in 108 consecutive DNA aneuploid breast carcinomas. Thirty-eight tumors (35%) contained a significant diploid range epithelial population, defined as cytokeratin-positive cells having a DNA content indistinguishable from that of endogenous lymphocytes and comprising at least 20% of all cytokeratin-positive cells. An additional 23 cases (21%) contained a minor diploid range epithelial population having a normal DNA content and comprising only 5-20% of all cytokeratin-positive cells. Multiple DNA aneuploid stemlines were present in 24 cases (22%). Diploid-range populations were more frequent (91%) in tetraploid cases than in hyperdiploid (32%), hypodiploid (17%) or hypertetraploid cases (20%). The presence of diploid epithelial populations and/or multiple aneuploid stemlines correlated with histologic parameters, including an extensive intraductal component (unimodal--4% vs. multi-modal--57%, P = 0.001), heterogeneous differentiation (unimodal--0% vs. multi-modal--52%, P = 0.001), and multi-focal growth with residual interspersed benign tissue (unimodal--8% vs. multimodal--57%, P = 0.01). These data show that diploid-range epithelial cells are frequent in aneuploid breast carcinomas analyzed by flow cytometry. In some tumors, these populations undoubtedly reflect the presence of residual benign epithelium. The numerical dominance of other histograms by near-diploid measurements suggests the presence of diploid-range neoplastic stemlines which would be 'hidden' by contaminating host-derived cells in single parameter DNA histograms. Finally, the correlation of DNA content heterogeneity with distinctive histologic patterns of breast neoplasia implies that co-existing stemlines may have biological significance in the progression of some tumors.

Aneuploidy↗
PubMed2026

Multimodal risk assessment for oral potentially malignant disorders: Integrating patient-centered and specimen-derived data.

BACKGROUND: Oral potentially malignant disorders exhibit heterogeneous malignant transformation risk that clinical approaches fail to adequately predict. Histopathologic dysplasia grading, the reference standard of risk assessment, is associated with poor interobserver reliability and limited prognostic discrimination. It is necessary to define other potential patient- and tissue-associated risk modifiers to improve patient-specific disease prediction. TYPES OF STUDIES REVIEWED: PubMed was queried for patient- and specimen-derived factors as they relate to oral cancer and oral potentially malignant disorders, with preference for systematic review and meta-analysis articles published within the past 5 years. When not available, guidelines from the American Cancer Society, National Cancer Institute, or other national organizations or the most recent best articles were referenced to support the data presented. RESULTS: Within patient-associated factors, validated measures of tobacco and alcohol exposure, clinical lesion characteristics, systemic health factors including metabolic syndrome components, comorbidity risk, and dental health indexes were found. Within specimen-derived data, tissue-based analyses encompassing histopathology and advanced molecular profiling (genomic, epigenomic, transcriptomic, spatial approaches), blood-based germline and somatic mutation analysis, and saliva-based microbiome characterization and inflammatory biomarker assessment were addressed. PRACTICAL IMPLICATIONS: Malignant transformation reflects intersecting patient and specimen risk pathways that affect each patient differently; no single modality captures this complexity. Realizing precision prognostication in oral precancer will require coordinated expansion and standardization of data collection across research groups. This review is intended to guide covariate selection for prospective study design, improve reproducibility, and ultimately enable the development of validated multimodal risk prediction tools for clinical deployment.

Humans↗