Search results for "image processing"
showing 10 items of 3285 documents
Evaluation of ultrasound transmission velocity and 3-dimensional radiology in different bone types for dental implantology: a comparative ex vivo stu…
2013
Objective To evaluate ultrasound transmission velocity (UTV) for assessment of mechanical bone quality, an ex vivo comparison of different bone types measured with UTV, 2-dimensional (2D) histomorphometry and with 3-dimensional (3D) radiology (cone-beam computerized tomography [CBCT], computerized microtomography [μCT]) was conducted. Study Design Clinical cortical, cancellous, and mixed bone (each n = 6) was measured via UTV (m/s), CBCT (white pixel/black pixel ratio [WP/BP]), μCT (bone volume/total volume [μBV/TV]), and histomorphometry (bone volume/total volume [hBV/TV]). UTV values were correlated with 2D-histomorphometry and 3D-radiologic results. Results For the cortical, cancellous, …
Three-dimensional imaging of cardiac mass lesions by transesophageal echocardiographic computed tomography.
1994
Three-dimensional echocardiography is a new imaging technique that allows more realistic visualization of cardiac morphology. This study presents data about the diagnostic potentials of this technique concerning cardiac mass lesions, as well as its feasibility in clinical application. After the conventional investigation, multiple cross-sectional images were obtained during automatic forward advancement of a monoplane transducer mounted on a transesophageal probe. Three-dimensional reconstruction and volume determination were performed off line. Twenty-four patients were studied. In 14 cases results of echocardiographic computed tomography (echo-CT) were compared with those of monoplane/bip…
Enhancement of Gamma Oscillations Indicates Preferential Processing of Native over Foreign Phonemic Contrasts in Infants
2013
Young infants discriminate phonetically relevant speech contrasts in a universal manner, that is, similarly across languages. This ability fades by 12 months of age as the brain builds language-specific phonemic maps and increasingly responds preferentially to the infant's native language. However, the neural mechanisms that underlie the development of infant preference for native over non-native phonemes remain unclear. Since gamma-band power is known to signal infants' preference for native language rhythm, we hypothesized that it might also indicate preference for native phonemes. Using high-density electroencephalogram/event-related potential (EEG/ERP) recordings and source-localization…
Imaging processing for CT angiography of the cervicocranial arteries: evaluation of reformatting technique.
2007
Purpose. The aim of this study was to compare computed tomography angiography (CTA) sliding-thin-slab (STS) multiplanar reformatting (MPR), STS maximum intensity projection (MIP) and three-dimensional (3D) volume rendering (VR) reformatting techniques in the evaluation of cervicocranial arteries. Materials and methods. Twenty patients examined with multislice CT were included in this study. CTA images were reformatted as STS-MIP, STS-MPR and 3DVR in orthogonal planes and in the oblique-coronal plane. Images were evaluated in consensus by two radiologists, with a third radiologist to resolve discordances in grading image quality parameters. The Spearman correlation analysis was performed to …
Reproducible coronary plaque quantification by multislice computed tomography
2007
BACKGROUND: The aim of this study was to investigate reproducibility and accuracy of computer-assisted coronary plaque measurements by multislice computed tomography coronary angiography (QMSCT-CA). METHODS AND RESULTS: Forty-eight patients undergoing MSCT-CA and coronary arteriography for symptomatic coronary artery disease and quantitative intravascular ultrasound (IVUS, QCU) were examined. Two investigators performed the QMSCT-CA twice and a third investigator performed the QCU, all blinded for each other's results. There was no difference found for the matched region of interest (ROI) lengths (QCU 29.4 +/- 13 mm vs. QMSCT-CA 29.6 +/- 13 mm, P = 0.6; total length = 1,400 mm). The compari…
Influence of convolution filtering on coronary plaque attenuation values: observations in an ex vivo model of multislice computed tomography coronary…
2007
Attenuation variability ( measured in Hounsfield Units, HU) of human coronary plaques using multislice computed tomography (MSCT) was evaluated in an ex vivo model with increasing convolution kernels. MSCT was performed in seven ex vivo left coronary arteries sunk into oil followingthe instillation of saline (1/infinity) and a 1/50 solution of contrast material ( 400 mgI/ml iomeprol). Scan parameters were: slices/ collimation, 16/0.75 mm; rotation time, 375 ms. Four convolution kernels were used: b30f-smooth, b36f-medium smooth, b46f-medium and b60f-sharp. An experienced radiologist scored for the presence of plaques and measured the attenuation in lumen, calcified and noncalcified plaques …
Value of magnetic-resonance cholangio-pancreatography (MRCP) after unsuccessful endoscopic-retrograde cholangio-pancreatography (ERCP).
1997
Background and Study Aims: The present study tries to evaluate the success rate of MRCP when two attempts by experts to perform ERCP in a center failed. Patients and Methods: From March 1996 to December 1996 thirteen patients fulfilled the inclusion criteria. The MR cholangiopancreatograms were acquired using commercially available software in a clinical MR scanner (Magnetom Expert 1T-Scanner, Siemens, Erlangen, Germany). MRCP utilized heavily T2-weighted turbo-spin echo sequences with fat supression (HASTE). Maximum intensity projection (MIP) of the pancreatic duct and biliary tree was then carried out. Additionally, T1-weighted sequences were obtained using the breath-hold technique. Resu…
Computer-Aided Detection for Prostate Cancer Detection based on Multi-Parametric Magnetic Resonance Imaging
2017
International audience; Prostate cancer (CaP) is the second most diagnosed cancer in men all over the world. In the last decades, new imaging techniques based on magnetic resonance imaging (MRI) have been developed improving diagnosis. In practice, diagnosis is affected by multiple factors such as observer variability and visibility and complexity of the lesions. In this regard, computer-aided detection and diagnosis (CAD) systems are being designed to help radiologists in their clinical practice. We propose a CAD system taking advantage of all MRI modalities (i.e., T2-W-MRI, DCE-MRI, diffusion weighted (DW)-MRI, MRSI). The aim of this CAD system was to provide a probabilistic map of cancer…
FDG-PET and CSF phospho-tau for prediction of cognitive decline in mild cognitive impairment
2006
Specific patterns of cortical glucose metabolism disturbances and increased CSF phospho-tau (p-tau(181)) concentrations could be demonstrated to predict cognitive decline and shift to dementia in amnestic mild cognitive impairment (MCI). But comparisons of both diagnostic tools have not been undertaken so far. The aim of the study was to compare (18)F-fluoro-2-deoxy-d-glucose positron emission tomography (FDG-PET) findings and CSF phospho-tau (p-tau(181)) measurements in the prediction of cognitive deterioration and conversion to dementia in MCI. During follow-up (mean 19 months) eight of 16 patients (50%) showed progressive cognitive decline, and four patients shifted to dementia. Patholog…
Computer-Aided Detection and diagnosis for prostate cancer based on mono and multi-parametric MRI: A review
2015
Prostate cancer is the second most diagnosed cancer of men all over the world. In the last few decades, new imaging techniques based on Magnetic Resonance Imaging (MRI) have been developed to improve diagnosis. In practise, diagnosis can be affected by multiple factors such as observer variability and visibility and complexity of the lesions. In this regard, computer-aided detection and computer-aided diagnosis systems have been designed to help radiologists in their clinical practice. Research on computer-aided systems specifically focused for prostate cancer is a young technology and has been part of a dynamic field of research for the last 10years. This survey aims to provide a comprehen…