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Comparison of mandibular bone microarchitecture between micro-CT and CBCT images

DENTOMAXILLOFACIAL RADIOLOGY 2015年第5期44卷 20140322页

作者： Panmekiate, S. Ngonphloy, N. Charoenkarn, T. Faruangsaeng, T. Pauwels, R. Chulalongkorn Univ Fac Dent Dept Radiol Bangkok Thailand Katholieke Univ Leuven Fac Med Oral Imaging Ctr OMFS IMPATH Res GrpDept Imaging & Pathol Leuven Belgium

Objectives: To compare microarchitecture parameters of bone samples scanned using micro-CT (RCT) to those obtained by using CBCT. Methods: A bone biopsy trephine bur (3 x 10 mm) was used to remove 20 cylindrical bone samples from 20 dry hemimandibles. Samples were scanned using mu CT (mu CT 35;SCANCO Medical, Briittisellen, Switzerland) with a voxel size of 20 mu m and CBCT (3D Accuitomo 170;J. Morita, Kyoto, Japan) with a voxel size of 80 mu m. All corresponding sample scans were aligned and cropped. image analysis was carried out using BoneJ, including the following parameters: skeleton analysis, bone surface per total volume (BS/TV), bone volume per total volume (BV/TV), connectivity density, anisotropy, trabecular thickness and spacing, structure model index, plateness and fractal dimension. Pearson and Spearman correlation coefficients (R) were calculated. CBCT values were then calibrated using the slope of the linear fit with the mu CT values. The mean error after calibration was calculated and normalized to the standard deviation of the mu CT values. Results: R-values ranged between 0.05 (plateness) and 0.83 (BS/TV). Correlation was significant for both Spearman and Pearson's R for 8 out of 16 parameters. After calibration, the smallest normalized error was found for BV/TV (0.48). For other parameters, the error range was 0.58-2.10. Conclusions: Despite the overall correlation, this study demonstrates the uncertainty associated with using bone microarchitecture parameters on CBCT images. Although clinically relevant parameter ranges are not available, the errors found in this study may be too high for some parameters to be considered for clinical application.

关键词： cone-beam computed tomography microcomputed tomography bone bone quality computer-assisted image processing

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Thermal Imaging-An Emerging Modality for Breast Cancer Detection: A Comprehensive Review

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JOURNAL OF MEDICAL SYSTEMS 2020年第8期44卷 136-136页

作者： Hakim, Aayesha Awale, R. N. Veermata Jijabai Technol Inst Mumbai Maharashtra India

Breast cancer is not preventable. To reduce the death rate and improve the survival chances of breast cancer patients, early and accurate detection is the only panacea. Delay in diagnosis of this disease causes 60% of deaths. Thermal imaging is a low-risk modality for early breast cancer decision making without injecting any form of energy into the human body. Thermography as a screening tool was first introduced and well accepted in 1956. However, a study in 1977 found that it lagged behind other screening tools and is subjective. Soon after, its use was discontinued. This review discusses various screening tools used to detect breast cancer with a focus on thermography along with their advantages and shortcomings. With the maturation of thermography equipment and technological advances, this technique is emerging and has become the refocus of many biomedical researchers across the globe in the past decade. This study dispenses an exhaustive review of the work done related to interpretation of breast thermal variations and confers the discipline, frameworks, and methodologies used by different authors to diagnose breast cancer. Different performance metrics like accuracy, specificity, and sensitivity have also been examined. This paper outlines the most pressing research gaps for future work to improvise the accuracy of results for diagnosis of breast abnormalities using image processing tools, mathematical modelling and artificial intelligence. However, supplementary research is needed to affirm the potential of this technology for predicting breast cancer risk effectively. Altogether, our findings inform that it is a promising research problem and a potential solution for early detection of breast cancer in younger women.

关键词： Breast cancer Thermograph Infrared imaging Thermal imaging computer-assisted image processing Breast thermogram

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Progressive Data Transmission for Anatomical Landmark Detection in a Cloud

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METHODS OF INFORMATION IN MEDICINE 2012年第3期51卷 268-278页

作者： Sofka, M. Ralovich, K. Zhang, J. Zhou, S. K. Comaniciu, D. Siemens Corp Res Princeton NJ 08540 USA Tech Univ Munich D-85748 Garching Germany

Background: In the concept of cloud-computing-based systems, various authorized users have secure access to patient records from a number of care delivery organizations from any location. This creates a growing need for remote visualization, advanced image processing, state-of-the-art image analysis, and computer aided diagnosis. Objectives: This paper proposes a system of algorithms for automatic detection of anatomical landmarks in 3D volumes in the cloud computing environment. The system addresses the inherent problem of limited bandwidth between a (thin) client, data center, and data analysis server. Methods: The problem of limited bandwidth is solved by a hierarchical sequential detection algorithm that obtains data by progressively transmitting only image regions required for processing. The client sends a request to detect a set of landmarks for region visualization or further analysis. The algorithm running on the data analysis server obtains a coarse level image from the data center and generates landmark location candidates. The candidates are then used to obtain image neighborhood regions at a finer resolution level for further detection. This way, the landmark locations are hierarchically and sequentially detected and refined. Results: Only image regions surrounding landmark location candidates need to be trans- mitted during detection. Furthermore, the image regions are lossy compressed with JPEG 2000. Together, these properties amount to at least 30 times bandwidth reduction while achieving similar accuracy when compared to an algorithm using the original data. Conclusions: The hierarchical sequential algorithm with progressive data transmission considerably reduces bandwidth requirements in cloud-based detection systems.

关键词： Cloud computing machine learning pattern recognition system computer-assisted image processing image compression

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Nonlinear Dynamics in the Progression of Atherosclerotic Fatty Streaks: Morphometric Analysis

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Microscopy and Microanalysis 2002年第6期6卷 532-541页

作者： Peter J. Bugelski Beverly E. Maleeff Anne M. Klinkner Calvert S. Louden Timothy K. Hart Department of Safety Assessment SmithKline Beecham Pharmaceuticals Safety Assessment-US UE0462 709 Swedeland Road King of Prussia PA 19406

Atherosclerotic lesions are heterogeneous in terms of their cellular and lipid composition. While heterogeneity can be the result of stochastic noise, an alternate hypothesis is that the differences observed among individual lesions arise from deterministic chaos. Five New Zealand white rabbits were fed a diet containing 0.15% cholesterol for 6 months. Segments of the aorta were fixed in formalin, stained en bloc with Nile red (NR) and filipin (F), and en face fluorescence microscopy was used to map the distribution of lipids in fatty streaks (FS). The smallest lesions detected stained only with filipin. Larger lesions stained with both Nile red and filipin and two distinct regions of Nile red staining, NR-orange (rich in polar lipids) and NR-yellow (rich in neutral lipids) were observed. Digital overlays revealed a “nested” arrangement of F, NR-orange, and NR-yellow. The lesions also showed marked heterogeneity in their lipid composition. Thus, although initially similar, as FS increased in size, their composition became divergent, suggesting that the ultimate composition of a FS was highly sensitive to its initial composition. Sensitivity to initial condition is one of the hallmarks of deterministic systems. To determine if FS were self-similar, another hallmark of deterministic chaos, the borders of the different regions defined by NR and F staining were subjected to fractal analysis. For each lesion, the borders of the F, NR-orange, and NR-yellow regions were found to be fractal. Return maps were constructed for the differently stained regions. Analysis of the entire 104-lesion data set showed that although the data could be described by a four-parameter logistic model, the population was not chaotic. However, return maps drawn for the maxima of the NR-orange stained regions demonstrated chaos. Taken together, the data suggest that deterministic chaos plays a role in the evolution of atheromatous disease but, in common with most biologic systems, as the lesions

关键词： filipin Nile red computer-assisted image processing deterministic chaos fractal dimension succession ecology

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Volumetric flow mapping for microvascular networks by bimodality imaging with light microscope and laser Doppler imager

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MICROSCOPY RESEARCH AND TECHNIQUE 2004年第3期65卷 130-138页

作者： Sun, Y Verbeuren, TJ Vallez, MO Nilsson, GE Sjöberg, F Univ Rhode Isl Dept Elect & Comp Engn Biomed Engn Program Kingston RI 02881 USA Inst Rech Servier Div Angiol F-92150 Suresnes France Linkoping Univ Dept Biomed Engn S-58185 Linkoping Sweden Linkoping Univ Hosp Dept Hand & Plast Surg & Anesthesiol & Intens Car S-58185 Linkoping Sweden

A method was developed to produce a composite image of microvascular networks with grayscales proportional to volumetric flows. Velocities in arterioles and venules were assessed with a high-resolution laser Doppler imager (LDI). The vascular structures were quantified from the micrograph with a computerized vessel detection algorithm. After registering the detected vascular network with the LDI scan, volumetric flows were calculated along the centerlines of the vessels. In vivo data were obtained from the hamster cheek pouch in 6 studies. Flow continuity of the flow map was evaluated by comparing the main flow (Q) with the sum of branch flows (Q(s)), averaging over the respective vessel segments incident to each bifurcation. The method was reproducible across the 6 studies with the correlation coefficient (r) between Q(s) and Q ranging from 0.913 to 0.986. In all, over 20,000 flow estimates from 360 vessel segments (24-160 mum in diameter) at 166 bifurcations were analyzed. With flow normalized between 0 and 1, the linear regression yielded: Q(s) = 1.03 Q + 0.006;r = 0.952, n = 166, P < 0.0005. The bimodality imaging method exploits a large amount of velocity and diameter data, and therefore should be useful for studying heterogeneous flows in the microvasculature. (C) 2004 Wiley-Liss, Inc.

关键词： blood flow microvascular network laser Doppler flowmetry computer-assisted image processing methodology hamster cheek pouch

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Automatic detection of osteoporosis based on hybrid genetic swarm fuzzy classifier approaches

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DENTOMAXILLOFACIAL RADIOLOGY 2016年第7期45卷 20160076-20160076页

作者： Kavitha, Muthu Subash Kumar, Pugalendhi Ganesh Park, Soon-Yong Huh, Kyung-Hoe Heo, Min-Suk Kurita, Takio Asano, Akira An, Seo-Yong Chien, Sung-Il Kyungpook Natl Univ Sch Elect Engn Daegu South Korea Anna Univ Dept Informat Technol Reg Campus Coimbatore Tamil Nadu India Kyungpook Natl Univ Sch Comp Sci & Engn Daegu South Korea Seoul Natl Univ Sch Dent Dept Oral & Maxillofacial Radiol Seoul South Korea Hiroshima Univ Grad Sch Engn Hiroshima Japan Kansai Univ Fac Informat Osaka Japan Kyungpook Natl Univ Sch Dent Dept Oral & Maxillofacial Radiol Daegu South Korea

Objectives: This study proposed a new automated screening system based on a hybrid genetic swarm fuzzy (GSF) classifier using digital dental panoramic radiographs to diagnose females with a low bone mineral density (BMD) or osteoporosis. Methods: The geometrical attributes of both the mandibular cortical bone and trabecular bone were acquired using previously developed software. Designing an automated system for osteoporosis screening involved partitioning of the input attributes to generate an initial membership function (MF) and a rule set (RS), classification using a fuzzy inference system and optimization of the generated MF and RS using the genetic swarm algorithm. Fivefold cross-validation (5-FCV) was used to estimate the classification accuracy of the hybrid GSF classifier. The performance of the hybrid GSF classifier has been further compared with that of individual genetic algorithm and particle swarm optimization fuzzy classifiers. Results: Proposed hybrid GSF classifier in identifying low BMD or osteoporosis at the lumbar spine and femoral neck BMD was evaluated. The sensitivity, specificity and accuracy of the hybrid GSF with optimized MF and RS in identifying females with a low BMD were 95.3%, 94.7% and 96.01%, respectively, at the lumbar spine and 99.1%, 98.4% and 98.9%, respectively, at the femoral neck BMD. The diagnostic performance of the proposed system with femoral neck BMD was 0.986 with a confidence interval of 0.942-0.998. The highest mean accuracy using 5-FCV was 97.9%. with femoral neck BMD. Conclusions: The combination of high accuracy along with its interpretation ability makes this proposed automatic system using hybrid GSF classifier capable of identifying a large proportion of undetected low BMD or osteoporosis at its early stage.

关键词： panoramic radiograph computer-assisted image processing osteoporosis

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Effects of exposure parameters and slice thickness on detecting clear and unclear mandibular canals using cone beam CT

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DENTOMAXILLOFACIAL RADIOLOGY 2017年第4期46卷 20160315-20160315页

作者： Jasa, Gainer R. Shimizu, Mayumi Okamura, Kazutoshi Tokumori, Kenji Takeshita, Yohei Weerawanich, Warangkana Yoshiura, Kazunori Univ Republica Oral Radiol Div Montevideo Uruguay Kyushu Univ Hosp Dept Oral & Maxillofacial Radiol Fukuoka Japan Kyushu Univ Fac Dent Sci Dept Oral & Maxillofacial Radiol Fukuoka Japan Teikyo Univ Fac Fukuoka Med Technol Dept Radiol Technol Fukuoka Japan

Objectives: The purpose of this study was to clarify the effects of exposure parameters and image-processing methods when using CBCT to detect clear and unclear mandibular canals (MCs). Methods: 24 dry half mandibles were divided into 2 groups with clear and unclear MCs based on a previous CBCT study. Mandibles were scanned using a CBCT system with varying exposure parameters (tube voltages 60 kV, 70 kV and 90 kV;and tube currents 2mA, 5mA, 10mA and 15mA) to obtain a total of 144 scans. The images were processed with different slice thicknesses using imageJ software (National Institutes of Health, Bethesda, MD). Five radiologists evaluated the cross-sectional images of the first molar region to detect the MCs. The diagnostic accuracy of varying exposure parameters and image-processing conditions was compared with the area under the curve (Az) in receiver-operating characteristic analysis. Results: The Az values for clear MCs were higher than those for unclear MCs (p < 0.0001). With increasing exposure voltages and currents, Az values increased, but no significant differences were found with high voltages and currents in clear MCs (p = 1.0000 and p = 0.9340). The Az values of serial images were higher than those of overlaid images (p, 0.0001), and those for thicker slices were higher than those for thinner slices (p, 0.0001). Conclusions: Our findings indicate that detection of unclear MCs requires either higher exposure parameters or processing of the images with thicker slices. To detect clear MCs, lower exposure parameters can be used.

关键词： CBCT mandible computer-assisted image processing image quality

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The precision of gingival recession measurements is increased by an automated curvature analysis method

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BMC ORAL HEALTH 2021年第1期21卷 505-505页

作者： Kuralt, Marko Gaspersic, Rok Fidler, Ales Univ Med Ctr Ljubljana Dept Restorat Dent & Endodont Hrvatski Trg 6 Ljubljana 1000 Slovenia Univ Ljubljana Fac Med Ljubljana Slovenia Univ Med Ctr Ljubljana Dept Oral Med & Periodontol Ljubljana Slovenia Univ Ljubljana Fac Med Dept Oral Med & Periodontol Ljubljana Slovenia Univ Ljubljana Fac Med Dept Endodont & Operat Dent Ljubljana Slovenia

Background The extent of gingival recession represents one of the most important measures determining outcome of periodontal plastic surgery. The accurate measurements are, thus, critical for optimal treatment planning and outcome evaluation. Present study aimed to introduce automated curvature-based digital gingival recession measurements, evaluate the agreement and reliability of manual measurements, and identify sources of manual variability. Methods Measurement of gingival recessions was performed manually by three examiners and automatically using curvature analysis on representative cross-sections (n = 60). Cemento-enamel junction (CEJ) and gingival margin (GM) measurement points selection was the only variable. Agreement and reliability of measurements were analysed using intra- and inter-examiner correlations and Bland-Altman plots. Measurement point selection variability was evaluated with manual point distance deviation from an automatic point. The effect of curvature on manual point selection was evaluated with scatter plots. Results Bland-Altman plots revealed a high variability of examiner's recession measurements indicated by high 95% limits of agreement range of approximately 1 mm and several outliers beyond the limits of agreement. CEJ point selection was the main source of examiner's variability due to smaller curvature values than GM, i.e., median values of - 0.98 mm(- 1) and - 4.39 mm(- 1), respectively, indicating straighter profile for CEJ point. Scatter plots revealed inverse relationship between curvature and examiner deviation for CEJ point, indicating a threshold curvature value around 1 mm(- 1). Conclusions Automated curvature-based approach increases the precision of recession measurements by reproducible measurement point selection. Proposed approach allows evaluation of teeth with indistinguishable CEJ that could be not be included in the previous studies.

关键词： Gingival recession computer-assisted image processing Dental models Cementoenamel junction Observer variation computer-assisted image interpretation reproducibility of results

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Three-dimensional aortic geometry mapping via registration of non-gated contrast-enhanced or gated and respiratory-navigated MR angiographies

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JOURNAL OF CARDIOVASCULAR MAGNETIC RESONANCE 2024年第1期26卷 100992-100992页

作者： Dux-Santoy, Lydia Rodriguez-Palomaresa, Jose F. Teixido-Tura, Gisela Garrido-Oliver, Juan Carrasco-Poves, Alejandro Morales-Galan, Alberto Ruiz-Munoz, Aroa Casas, Guillem Valente, Filipa Galian-Gay, Laura Fernandez-Galera, Ruben Olivero, Ruperto Cuellar-Calabria, Hug Roque, Albert Burcet, Gemma Barrabes, Jose A. Ferreira-Gonzalez, Ignacio Guala, Andrea Vall Hebron Inst Recerca VHIR Barcelona Spain Inst Salud Carlos III CIBER Enfermedades Cardiovasc CIBER CV Madrid Spain Hosp Univ Vall Hebron Dept Cardiol Barcelona Spain Univ Autonoma Barcelona Dept Med Bellaterra Spain Hosp Univ Vall Hebron Dept Radiol Barcelona Spain Inst Salud Carlos III CIBER Epidemiol & Salud Publ CIBERESP Madrid Spain Vall Hebron Res Inst Cardiovasc Dis Pg Vall Hebron 119-129 Barcelona 08035 Spain Hosp Valle De Hebron Dept Cardiol Pg Vall Hebron 119-129 Barcelona 08035 Spain

Background: The measurement of aortic dimensions and their evolution are key in the management of patients with aortic diseases. Manual assessment, the current guideline-recommended method and clinical standard, is subjective, poorly reproducible, and time-consuming, limiting the capacity to track aortic growth in everyday practice. Aortic geometry mapping (AGM) via image registration of serial computed tomography angiograms outperforms manual assessment, providing accurate and reproducible 3D maps of aortic diameter and growth rate. This observational study aimed to evaluate the accuracy and reproducibility of AGM on non-gated contrast-enhanced (CE-) and cardiac- and respiratory-gated (GN-) magnetic resonance angiographies (MRA). Methods: Patients with thoracic aortic disease followed with serial CE-MRA (n = 30) or GN-MRA (n = 15) acquired at least 1 year apart were retrospectively and consecutively identified. Two independent observers measured aortic diameters and growth rates (GR) manually at several thoracic aorta reference levels and with AGM. Agreement between manual and AGM measurements and their inter-observer reproducibility were compared. Reproducibility for aortic diameter and GR maps assessed with AGM was obtained. Results: Mean follow-up was 3.8 +/- 2.3 years for CE- and 2.7 +/- 1.6 years for GN-MRA. AGM was feasible in the 93% of CE-MRA pairs and in the 100% of GN-MRA pairs. Manual and AGM diameters showed excellent agreement and inter-observer reproducibility (ICC>0.9) at all anatomical levels. Agreement between manual and AGM GR was more limited, both in the aortic root by GN-MRA (ICC=0.47) and in the thoracic aorta, where higher accuracy was obtained with GN- than with CE-MRA (ICC=0.55 vs 0.43). The inter-observer reproducibility of GR by AGM was superior compared to manual assessment, both with CE- (thoracic: ICC= 0.91 vs 0.51) and GN-MRA (root: ICC=0.84 vs 0.52;thoracic: ICC=0.93 vs 0.60). AGM-based 3D aortic size and growth maps were highly repr

关键词： Aortic aneurysm Aortic dilation Magnetic Resonance Angiography computer-assisted image processing Aortic growth rate

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Study of edge detection task in dental panoramic radiographs

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DENTOMAXILLOFACIAL RADIOLOGY 2013年第7期42卷 20120391-20120391页

作者： Grafova, L. Kasparova, M. Kakawand, S. Prochazka, A. Dostalova, T. Inst Chem Technol Fac Chem Engn Dept Comp & Control Engn CR-16628 Prague 6 Czech Republic Charles Univ Prague Dept Stomatol Fac Med 2 Prague Czech Republic

The purpose of this study is (1) to introduce a new approach for edge detection in orthopantograms (OPGs) and an improved automatic parameter selector for common edge detectors, (2) to present a comparison between our novel approach with common edge detectors and (3) to provide faster outputs without compromising quality. A new approach for edge detection based on statistical measures was introduced: (1) a set of N edge detection results is calculated from a given input image and a selected type of edge detector, (2) N correspondence maps are constructed from N edge detection results, (3) probabilities and average probabilities are computed, (4) an overall correspondence is evaluated for each correspondence map and (5) the correspondence map providing the best overall correspondence is taken as the result of edge detection procedure. A comparison with common edge detectors (the Roberts, Prewitt, Sobel, Laplacian of the Gaussian and Canny methods) with various parameter settings (304 combinations for each test image) was carried out. The methods were assessed objectively [edge mismatch error (EME), modified Hausdorff distance (MHD) and principal component analysis] and subjectively by experts in dentistry and based on time demands. The suitability of the new approach for edge detection in OPGs was confirmed by experts. The current conventional methods in edge detection in OPGs are inadequate (none of the tested methods reach an EME value or MHD value below 0.1). Our proposed approach for edge detection shows promising potential for its implementation in clinical dentistry. It enhances the accuracy of OPG interpretation and advances diagnosis and treatment planning.

关键词： panoramic radiography medical imaging computer-assisted image processing

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