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New methods for arterial diameter measurement from B-mode images

ULTRASOUND IN MEDICINE AND BIOLOGY 1996年第1期22卷 25-34页

作者： Stadler, RW Karl, WC Lees, RS HARVARD UNIV MITDIV HLTH SCI & TECHNOLCAMBRIDGEMA BOSTON UNIV DEPT ELECT COMP & SYST ENGNBOSTONMA 02215

Arterial diameter is an important parameter of vascular physiology in vivo, Noninvasive measurements of arterial diameter can be used in the assessment of endothelium-dependent vasoreactivity (EDV) and arterial compliance, Measurements of EDV may serve for assessment of early atherosclerosis, The potential value of EDV measurements with specificity for individual subjects is a strong motivation for improvements in the ultrasonic measurement of arterial diameter, This article presents and evaluates new methods for the measurement and tracking of arterial diameter from B-mode images, B-mode images acquired in planes longitudinal to the vessel and in planes rotated slightly off of the vessel axis (''skew'') are considered, The cross-sections of arteries in these planes are modeled as parabola pairs or as ellipses, For the brachial artery, the variance of caliper-based diameter estimates (0.0139 mm(2)) is twice as large as that of elliptical-model-based diameter estimates (0.0072 mm(2)) and five times as large as parabolic-model-based diameter estimates (0.0027 mm(2)), Diameter estimates from the skew and longitudinal planes perform equivalently in limited-motion quantitative comparisons, However, diameter estimates from skew planes are less sensitive to translational motions of the artery, Also, translational motions are unambiguously represented in the skew image, thus facilitating compensatory motions of the transducer, The methods described here are relatively simple to implement and may provide adequate resolution for noninvasive assessment of EDV with individual specificity.

关键词： ultrasound computer-assisted image processing dilation atherosclerosis endothelial-derived relaxing factor arterial compliance

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Reliability of tarsal bone segmentation and its contribution to MR kinematic analysis methods

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computerIZED MEDICAL IMAGING AND GRAPHICS 2007年第7期31卷 523-530页

作者： Wolf, P. Lueehinger, R. Stacoff, A. Boesiger, P. Stuessi, E. Swiss Fed Inst Technol ETH Honggerberg HCI E451 Inst Biomech CH-8093 Zurich Switzerland Univ Zurich ETH Zurich Inst Biomed Engn CH-8092 Zurich Switzerland

The Purpose of this study was to determine the reliability of tarsal bone segmentation based on magnetic resonance (MR) imaging using commercially available software. All tarsal bones of five subjects were segmented five times each by two operators. Volumes and second moments of volume were calculated and used to determine the intra- as well as interoperator reproducibility. The results show that these morphological parameters had excellent interclass correlation coefficients (> 0.997) indicating that the presented tarsal bone segmentation is a reliable procedure and that operators are in fact interchangeable. The consequences on differences in MR kinematic analysis methods of segmentation due to repetition were also determined. It became evident that one analysis method - fitting surface point clouds - was considerable less affected by repeated segmentation (cuboid: up to 0.2 degrees, other tarsal bones Lip to OX) compared to a method using principal axes (cuboid up to 6.7 degrees, other tarsal bones up to 0.8 degrees). Thus, the former method is recommended for investigations of tarsal bone kinematics by MR imaging. (c) 2007 Elsevier Ltd. All rights reserved.

关键词： tarsus computer-assisted image processing reliability methods of MR kinematic analyses

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Can color inhomogeneity of bruises be used to establish their age?

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JOURNAL OF BIOPHOTONICS 2011年第10期4卷 759-767页

作者： Stam, Barbara van Gemert, Martin J. C. van Leeuwen, Ton G. Teeuw, Arianne H. van der Wal, Allard C. Aalders, Maurice C. G. Univ Amsterdam Acad Med Ctr Dept Biomed Engn & Phys NL-1105 AZ Amsterdam Netherlands Univ Twente MIRA Inst Biomed Technol & Tech Med Biomed Opt Grp NL-7500 AE Enschede Netherlands Univ Twente Fac Sci & Technol NL-7500 AE Enschede Netherlands Univ Amsterdam Acad Med Ctr Child Protect Team NL-1105 AZ Amsterdam Netherlands Univ Amsterdam Acad Med Ctr Dept Pediat NL-1105 AZ Amsterdam Netherlands Univ Amsterdam Acad Med Ctr Dept Pathol NL-1105 AZ Amsterdam Netherlands

Bruises become spatially inhomogeneous during the healing process;a smaller red-blue core area, caused by hemoglobin, is surrounded by a larger yellow area, caused by bilirubin, which is enzymatically formed from hemoglobin. These two areas develop at different rates and hence carry information about the age of the bruise. We present a proof of principle demonstration that the age of bruises can be determined via an inverse procedure using a mathematical model and daily measurements of these two areas using a hyperspectral imaging system. The inaccuracy found is 2.3% for fresh bruises and 3 to 24% for bruises up to 3 days old. In conclusion, color inhomogeneity of bruises can be used to determine their age. We expect that future age determination of bruises by the inverse procedure described here, possibly also including the distribution of concentrations in the areas will open up a new phase in clinical bruise classification. [GRAPHICS] Measured and simulated hemoglobin and bilirubin areas over time.

关键词： contusion computer-assisted image processing near-infrared spectroscopy diagnostic imaging computer simulation

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Automatic segmentation of hepatocellular carcinoma on dynamic contrast-enhanced MRI based on deep learning

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PHYSICS IN MEDICINE AND BIOLOGY 2024年第6期69卷 065008-065008页

作者： Luo, Xiao Li, Peiwen Chen, Hongyi Zhou, Kun Piao, Sirong Yang, Liqin Hu, Bin Geng, Daoying Fudan Univ Shanghai Peoples R China Fudan Univ Shanghai Peoples R China Chinese Acad Med Sci & Peking Union Med Coll Chinese Acad Med Sci & Peking Union MedicalCollege Dept Radiol Beijing Peoples R China Shanghai Engn Res Ctr Intelligent Imaging Crit Bra Shanghai Peoples R China Fudan Univ Inst Funct & Mol Med Imaging Shanghai Peoples R China

Objective. Precise hepatocellular carcinoma (HCC) detection is crucial for clinical management. While studies focus on computed tomography-based automatic algorithms, there is a rareness of research on automatic detection based on dynamic contrast enhanced (DCE) magnetic resonance imaging. This study is to develop an automatic detection and segmentation deep learning model for HCC using DCE. Approach: DCE images acquired from 2016 to 2021 were retrospectively collected. Then, 382 patients (301 male;81 female) with 466 lesions pathologically confirmed were included and divided into an 80% training-validation set and a 20% independent test set. For external validation, 51 patients (42 male;9 female) in another hospital from 2018 to 2021 were included. The U-net architecture was modified to accommodate multi-phasic DCE input. The model was trained with the training-validation set using five-fold cross-validation, and furtherly evaluated with the independent test set using comprehensive metrics for segmentation and detection performance. The proposed automatic segmentation model consisted of five main steps: phase registration, automatic liver region extraction using a pre-trained model, automatic HCC lesion segmentation using the multi-phasic deep learning model, ensemble of five-fold predictions, and post-processing using connected component analysis to enhance the performance to refine predictions and eliminate false positives. Main results. The proposed model achieved a mean dice similarity coefficient (DSC) of 0.81 +/- 0.11, a sensitivity of 94.41 +/- 15.50%, a precision of 94.19 +/- 17.32%, and 0.14 +/- 0.48 false positive lesions per patient in the independent test set. The model detected 88% (80/91) HCC lesions in the condition of DSC > 0.5, and the DSC per tumor was 0.80 +/- 0.13. In the external set, the model detected 92% (58/62) lesions with 0.12 +/- 0.33 false positives per patient, and the DSC per tumor was 0.75 +/- 0.10. Significance. This study developed

关键词： hepatocellular carcinoma deep learning computer-assisted image processing

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Methodological considerations in quantification of oncological FDG PET studies

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EUROPEAN JOURNAL OF NUCLEAR MEDICINE AND MOLECULAR IMAGING 2010年第7期37卷 1408-1425页

作者： Vriens, Dennis Visser, Eric P. de Geus-Oei, Lioe-Fee Oyen, Wim J. G. Radboud Univ Nijmegen Med Ctr Dept Nucl Med NL-6500 HB Nijmegen Netherlands

This review aims to provide insight into the factors that influence quantification of glucose metabolism by FDG PET images in oncology as well as their influence on repeated measures studies (i.e. treatment response assessment), offering improved understanding both for clinical practice and research. Structural PubMed searches have been performed for the many factors affecting quantification of glucose metabolism by FDG PET. Review articles and references lists have been used to supplement the search findings. Biological factors such as fasting blood glucose level, FDG uptake period, FDG distribution and clearance, patient motion (breathing) and patient discomfort (stress) all influence quantification. Acquisition parameters should be adjusted to maximize the signal to noise ratio without exposing the patient to a higher than strictly necessary radiation dose. This is especially challenging in pharmacokinetic analysis, where the temporal resolution is of significant importance. The literature is reviewed on the influence of attenuation correction on parameters for glucose metabolism, the effect of motion, metal artefacts and contrast agents on quantification of CT attenuation-corrected images. Reconstruction settings (analytical versus iterative reconstruction, post-reconstruction filtering and image matrix size) all potentially influence quantification due to artefacts, noise levels and lesion size dependency. Many region of interest definitions are available, but increased complexity does not necessarily result in improved performance. Different methods for the quantification of the tissue of interest can introduce systematic and random inaccuracy. This review provides an up-to-date overview of the many factors that influence quantification of glucose metabolism by FDG PET.

关键词： F-18-Fluorodeoxyglucose Positron emission tomography Pharmacokinetics computer-assisted image processing Reference standards

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Evaluation of layer decomposition for multiframe quantitative coronary angiography

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MEDICAL PHYSICS 2002年第3期29卷 311-318页

作者： Close, RA Abbey, CK Morioka, CA Whiting, JS Cedars Sinai Med Ctr Div Med Phys & Imaging Los Angeles CA 90048 USA

Multiframe quantitative coronary angiography is typically performed by averaging measurements of artery diameter over multiple frames. This approach reduces errors attributable to random noise but may not reduce systematic errors caused by background structures, nonlinear system response, and motion blur. We attempt to reduce these sources of error by decomposing the image sequence into moving layers, one of which includes the artery. We embed simulated arteries into clinical angiographic sequences so that the true vessel dimensions are known accurately. The measurement tasks are minimum diameter, geometric percent stenosis, and densitometric percent stenosis. We compare measurements for single and multiple raw images, single images with fixed mask subtraction, single and multiple images with layered background subtraction, and time-averaged layer images. We find that both multiframe averaging and layer decomposition significantly improve geometric and densitometric accuracy compared with single-frame measurements. The best results were obtained by averaging measurements from multiple frames of layered background-subtracted images. (C) 2002 American Association of Physicists in Medicine.

关键词： computer-assisted image processing coronary angiography radiographic image enhancement stenosis

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Reliability of neuroanatomical measurements in a multisite longitudinal study of youth at risk for psychosis

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HUMAN BRAIN MAPPING 2014年第5期35卷 2424-2434页

作者： Cannon, Tyrone D. Sun, Frank McEwen, Sarah Jacobson Papademetris, Xenophon He, George van Erp, Theo G. M. Jacobson, Aron Bearden, Carrie E. Walker, Elaine Hu, Xiaoping Zhou, Lei Seidman, Larry J. Thermenos, Heidi W. Cornblatt, Barbara Olvet, Doreen M. Perkins, Diana Belger, Aysenil Cadenhead, Kristin Tsuang, Ming Mirzakhanian, Heline Addington, Jean Frayne, Richard Woods, Scott W. McGlashan, Thomas H. Constable, R. Todd Qiu, Maolin Mathalon, Daniel H. Thompson, Paul Toga, Arthur W. Yale Univ Dept Psychol New Haven CT 06520 USA Univ Calif Los Angeles Dept Psychiat & Biobehav Sci Los Angeles CA 90024 USA Yale Univ Dept Diagnost Radiol New Haven CT 06520 USA Yale Univ Dept Biomed Engn New Haven CT 06520 USA Univ Calif Irvine Dept Psychiat & Human Behav Irvine CA 92717 USA Emory Univ Dept Psychiat Atlanta GA 30322 USA Emory Univ Biomed Imaging Technol Ctr Atlanta GA 30322 USA Beth Israel Deaconess Med Ctr Dept Psychiat Boston MA 02215 USA Harvard Univ Sch Med Boston MA USA Zucker Hillside Hosp Dept Psychiat Great Neck NY USA Univ N Carolina Dept Psychiat Chapel Hill NC USA Univ Calif San Diego Dept Psychiat San Diego CA 92103 USA Univ Calgary Dept Psychiat Calgary AB Canada Univ Calgary Dept Radiol Calgary AB Canada Yale Univ Dept Psychiat New Haven CT 06520 USA Univ Calif San Francisco Dept Psychiat San Francisco CA USA Univ Calif Los Angeles Dept Neurol Los Angeles CA 90024 USA

Multisite longitudinal neuroimaging designs are used to identify differential brain structural change associated with onset or progression of disease. The reliability of neuroanatomical measurements over time and across sites is a crucial aspect of power in such studies. Prior work has found that while within-site reliabilities of neuroanatomical measurements are excellent, between-site reliability is generally more modest. Factors that may increase between-site reliability include standardization of scanner platform and sequence parameters and correction for between-scanner variations in gradient nonlinearities. Factors that may improve both between- and within-site reliability include use of registration algorithms that account for individual differences in cortical patterning and shape. In this study 8 healthy volunteers were scanned twice on successive days at 8 sites participating in the North American Prodrome Longitudinal Study (NAPLS). All sites employed 3 Tesla scanners and standardized acquisition parameters. Site accounted for 2 to 30% of the total variance in neuroanatomical measurements. However, site-related variations were trivial (<1%) among sites using the same scanner model and 12-channel coil or when correcting for between-scanner differences in gradient nonlinearity and scaling. Adjusting for individual differences in sulcal-gyral geometries yielded measurements with greater reliabilities than those obtained using an automated approach. Neuroimaging can be performed across multiple sites at the same level of reliability as at a single site, achieving within- and between-site reliabilities of 0.95 or greater for gray matter density in the majority of voxels in the prefrontal and temporal cortical surfaces as well as for the volumes of most subcortical structures. Hum Brain Mapp 35:2424-2434, 2014. (c) 2013 Wiley Periodicals, Inc.

关键词： amygdala reproducibility of results hippocampus cerebral cortex neuroanatomy thalamus computer-assisted image processing magnetic resonance imaging

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Automated lesion detection in panoramic dental radiographs

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ORAL RADIOLOGY 2016年第2期32卷 111-118页

作者： Birdal, Ramiz Gorkem Gumus, Ergun Sertbas, Ahmet Birdal, Ilda Sinem Istanbul Univ Dept Comp Engn Istanbul Turkey Istanbul Medeniyet Univ Dept Anat Istanbul Turkey

Objectives Even in the presence of physical indicators like pain, tumor, color, and function loss, determining the exact size or location of acute dental apical diseases is challenging. Even harder to detect is chronic apical periodontitis, which is asymptomatic. In such circumstances, use of dental radiography is especially beneficial. However, radiographs are not sufficient by themselves, and require interpretation by a well-trained dental specialist. Nevertheless, owing to the human factor, mistakes leading to incorrect treatment can be made by specialists because of a wrong diagnosis. This study aimed to introduce an automated dental apical lesion detection methodology by assessing changes in hard tissue structures. The system consists of modules for jaw separation, tooth segmentation, root localization, and lesion detection. Methods Panoramic radiographs are used to improve the process of diagnosis. Unlike the column-sum methodology used in previous studies, the upper and lower jaws are separated using discrete wavelet transformation along with polynomial regression to obtain a better jaw separation curve. Subsequently, angular radial scanning is used to segment the teeth and capture the location of the tooth roots. At the last step, for each detected root, region growing is performed to detect possible lesions surrounding the root apices. Results The results for test samples indicate that use of the above-mentioned methods with proposed threshold selection is an effective way for discriminating anatomic structures from lesions, which is our main concern. Conclusions The findings prove that the proposed methodology can be used efficiently as an assistant for examination of radiographs.

关键词： Endodontics Panoramic radiography Periapical disease computer-assisted image processing computer-assisted diagnosis

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Functional magnetic resonance imaging for neurosurgical planning in neurooncology

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EUROPEAN RADIOLOGY 2004年第7期14卷 1143-1153页

作者： Vlieger, EJ Majoie, CB Leenstra, S den Heeten, GJ Acad Med Ctr Dept Radiol NL-1100 DD Amsterdam Netherlands Acad Med Ctr Dept Neurosurg NL-1100 DD Amsterdam Netherlands

Functional magnetic resonance imaging (fMRI) is a non-invasive technique that is widely available and can be used to determine the spatial relationships between tumor tissue and eloquent brain areas. Within certain limits, this functional information can be applied in the field of neurosurgery as a pre-operative mapping tool to minimize damage to eloquent brain areas. In this article, we review the literature on the use of fMRI for neurosurgical planning. The issues addressed are: (1) stimulation paradigms, (2) the influence of tumors on the blood oxygenation level-dependent (BOLD) signal, (3) post-processing the fMRI time course, (4) integration of fMRI results into neuronavigation systems, (5) the accuracy of fMRI and (6) fMRI compared to intra-operative mapping (IOM).

关键词： functional magnetic resonance imaging computer-assisted image processing neurosurgery neuronavigation brain neoplasm

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Three-dimensional echocardiography: The gateway to virtual reality!

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ECHOCARDIOGRAPHY-A JOURNAL OF CARDIOVASCULAR ULTRASOUND AND ALLIED TECHNIQUES 1999年第5期16卷 417-423页

作者： Bruining, N Roelandt, JRTC Grunst, G Berlage, T Waldinger, J Mumm, B Erasmus Med Ctr Rotterdam Dept Cardiol Thoraxctr Rotterdam Netherlands

Virtual reality (VR) is one of the latest developments in cardiac three-dimensional (3-D) ultrasound. A VR heart model linked to 3-D echocardiographic image datasets provides the observers spatial information regarding a 3-D image dataset and prevents the "lost in space effect" in difficult and relevant coupled diseases when integrated into 3-D reconstruction software. Standardized echocardiographic views can be selected within the integrated developed VR heart model, and this is the first step to automatic 3-D computations with minimal operator interaction. VR heart models open exciting opportunities in. the field of teaching echocardiographic cardiology, diagnosis, and examinable states.

关键词： echocardiography computer-assisted image processing heart diseases

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