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Moreno, R., Borga, M., Klintström, E., Brismar, T. & Smedby, Ö. (2015). Anisotropy Estimation of Trabecular Bone in Gray-Scale: Comparison Between Cone Beam and Micro Computed Tomography Data. In: João Manuel R.S. Tavares and Renato Natal Jorge (Ed.), Developments in Medical Image Processing and Computational Vision: (pp. 207-220). Springer
Open this publication in new window or tab >>Anisotropy Estimation of Trabecular Bone in Gray-Scale: Comparison Between Cone Beam and Micro Computed Tomography Data
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2015 (English)In: Developments in Medical Image Processing and Computational Vision / [ed] João Manuel R.S. Tavares and Renato Natal Jorge, Springer, 2015, p. 207-220Chapter in book (Refereed)
Abstract [en]

Measurement of anisotropy of trabecular bone has clinical relevance in osteoporosis. In this study, anisotropy measurements of 15 trabecular bone biopsies from the radius estimated by different fabric tensors on images acquired through cone beam computed tomography (CBCT) and micro computed tomography (micro-CT) were compared. The results show that the generalized mean intercept length (MIL) tensor performs better than the global gray-scale structure tensor, especially when the von Mises-Fisher kernel is applied. Also, the generalized MIL tensor yields consistent results between the two scanners. These results suggest that this tensor is appropriate for estimating anisotropy in images acquired in vivo through CBCT. 

Place, publisher, year, edition, pages
Springer, 2015
Series
Lecture Notes in Computational Vision and Biomechanics, ISSN 2212-9391 ; 19
National Category
Medical Image Processing Radiology, Nuclear Medicine and Medical Imaging
Identifiers
urn:nbn:se:liu:diva-117950 (URN)10.1007/978-3-319-13407-9_13 (DOI)978-3-319-13406-2 (ISBN)978-3-319-13407-9 (ISBN)
Available from: 2015-05-18 Created: 2015-05-18 Last updated: 2019-03-18Bibliographically approved
Klintström, E., Klintström, B., Brismar, T., Smedby, Ö. & Moreno, R. (2015). Clinical dental cone beam computed tomography - a tool for monitoring trabecular bone structure?. In: : . Paper presented at European Congress of Radiology (ECR), Vienna, Austria, March 4-8 2015 (pp. C1213).
Open this publication in new window or tab >>Clinical dental cone beam computed tomography - a tool for monitoring trabecular bone structure?
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2015 (English)Conference paper, Poster (with or without abstract) (Refereed)
Abstract [en]

Purpose

The aim of this in vitro study was to develop a method for quantitative assessment of trabecular bone micro-architecture by using three-dimensional image processing. The imaging data were acquired with cone beam computed tomography (CBCT), traditionally used for facial and temporal bone imaging but also applicable for peripheral skeleton, and with a dedicated high resolution peripheral computed tomograph (HRpQCT), used for in vivo measurements in bone research. The data from micro-computed tomography (µCT) was used as reference.

 

Methods & Materials

15 bone samples from the radius, were examined by CBCT and HRpQCT at a resolution of 80 and 82 µm, respectively. After segmentation, the bone structure parameters bone volume (BV/TV), trabecular thickness (Tb.Th), trabecular separation (Tb.Sp), trabecular number (Tb.N), trabecular nodes (Tb.Nd) and trabecular termini (Tb.Tm) were quantified. Calculations were performed on an ordinary PC using a MATLAB developed in house.

 

Results

CBCT and HRpQCT overestimated BV/TV and Tb.Th approximately three times, compared to µCT. On the other hand Tb.Nd was highly underestimated. All parameters from CBCT were strongly correlated to µCT, with correlation coefficients above 0.91 for all studied parameters (0.92-0.98) except for Tb.Tm with a correlation of 0.83. For HRpQCT the correlations were slightly weaker, varying from 0.78 to 0.95.

 

Conclusion

The strong correlations between bone structure parameters computed from CBCT and µCT suggests that CBCT may be a good alternative to HRpQCT for monitoring trabecular bone microarchitecture in vivo.

 

Keywords
Osteoporosis, Computer Applications-3D, PACS, CT, Musculoskeletal bone, Head and neck
National Category
Medical Image Processing Radiology, Nuclear Medicine and Medical Imaging
Identifiers
urn:nbn:se:liu:diva-121371 (URN)10.1594/ecr2015/C-1213 (DOI)
Conference
European Congress of Radiology (ECR), Vienna, Austria, March 4-8 2015
Available from: 2015-09-15 Created: 2015-09-15 Last updated: 2017-11-14Bibliographically approved
Moreno, R. & Smedby, Ö. (2015). Gradient-Based Enhancement of Tubular Structures in Medical Images. Medical Image Analysis, 26(1), 19-29
Open this publication in new window or tab >>Gradient-Based Enhancement of Tubular Structures in Medical Images
2015 (English)In: Medical Image Analysis, ISSN 1361-8415, E-ISSN 1361-8423, Vol. 26, no 1, p. 19-29Article in journal (Refereed) Published
Abstract [en]

Vesselness filters aim at enhancing tubular structures in medical images. The most popular vesselness filters are based on eigenanalyses of the Hessian matrix computed at different scales. However, Hessian-based methods have well-known limitations, most of them related to the use of second order derivatives. In this paper, we propose an alternative strategy in which ring-like patterns are sought in the local orientation distribution of the gradient. The method takes advantage of symmetry properties of ring-like patterns in the spherical harmonics domain. For bright vessels, gradients not pointing towards the center are filtered out from every local neighborhood in a first step. The opposite criterion is used for dark vessels. Afterwards, structuredness, evenness and uniformness measurements are computed from the power spectrum in spherical harmonics of both the original and the half-zeroed orientation distribution of the gradient. Finally, the features are combined into a single vesselness measurement. Alternatively, a structure tensor that is suitable for vesselness can be estimated before the analysis in spherical harmonics. The two proposed methods are called Ring Pattern Detector (RPD) and Filtered Structure Tensor (FST) respectively. Experimental results with computed tomography angiography data show that the proposed filters perform better compared to the state-of-the-art.

Place, publisher, year, edition, pages
Elsevier, 2015
Keywords
Vesselness, Structure Tensor, Spherical Harmonics
National Category
Medical Image Processing
Identifiers
urn:nbn:se:liu:diva-120389 (URN)10.1016/j.media.2015.07.001 (DOI)000367490800002 ()
Funder
Swedish Research Council, 2014-6153Swedish Research Council, 2012-3512Swedish Heart Lung Foundation, 2011-0376
Available from: 2015-08-04 Created: 2015-08-04 Last updated: 2017-12-04Bibliographically approved
Moreno, R., Borga, M., Klintström, E., Brismar, T. & Smedby, Ö. (2014). Correlations between fabric tensors computed on cone beam and microcomputed tomography images. In: Joao Manuel Tavares, Jorge Natal (Ed.), Manuel J.,Tavares R.S.,Jorge R.M.N. (Ed.), Computational Vision and Medical Image Processing IV: Proceedings of Eccomas Thematic Conference on Computational Vision and Medical Image Processing, VIPIMAGE 2013. Paper presented at 4th Eccomas Thematic Conference on Computational Vision and Medical Image Processing, VIPIMAGE 2013; Funchal; Portugal; 14 October 2013 through 16 October 2014 (pp. 393-398). CRC Press
Open this publication in new window or tab >>Correlations between fabric tensors computed on cone beam and microcomputed tomography images
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2014 (English)In: Computational Vision and Medical Image Processing IV: Proceedings of Eccomas Thematic Conference on Computational Vision and Medical Image Processing, VIPIMAGE 2013 / [ed] Manuel J.,Tavares R.S.,Jorge R.M.N., CRC Press, 2014, p. 393-398Conference paper, Published paper (Refereed)
Abstract [en]

Computational Vision and Medical Image Processing. VIPIMAGE 2013

contains invited lectures and full papers presented at VIPIMAGE 2013 - IV ECCOMAS Thematic Conference on Computational Vision and Medical Image Processing (Funchal, Madeira Island, Portugal, 14-16 October 2013). International contributions from 16 countries provide a comprehensive coverage of the current state-of-the-art in the fields of: 3D Vision; Computational Bioimaging and Visualization; Computational Vision and Image Processing applied to Dental Medicine; Computational Vision; Computer Aided Diagnosis, Surgery, Therapy, and Treatment; Data Interpolation, Registration, Acquisition and Compression; Image Processing and Analysis; Image Segmentation; Imaging of Biological Flows; Medical Imaging; Physics of Medical Imaging; Shape Reconstruction; Signal Processing; Simulation and Modeling; Software Development for Image Processing and Analysis; Telemedicine Systems and their Applications; Trabecular Bone Characterization; Tracking and Analysis of Movement; Virtual Reality.

Related techniques covered in this book include the level set method, finite element method, modal analyses, stochastic methods, principal and independent components analysis and distribution models. Computational Vision and Medical Image Processing. VIPIMAGE 2013 is useful to academics, researchers and professionals in Biomechanics, Biomedical Engineering, Computational Vision (image processing and analysis), Computer Sciences, Computational Mechanics and Medicine.

Place, publisher, year, edition, pages
CRC Press, 2014
Keywords
Diagnostic imaging Digital techniques Congresses, Imaging systems in medicine Congresses, Image processing Congresses, Medical informatics Congresses
National Category
Radiology, Nuclear Medicine and Medical Imaging
Identifiers
urn:nbn:se:liu:diva-97713 (URN)000338331400070 ()978-1-138-00081-0 (ISBN)
Conference
4th Eccomas Thematic Conference on Computational Vision and Medical Image Processing, VIPIMAGE 2013; Funchal; Portugal; 14 October 2013 through 16 October 2014
Note

From the Thematic Conference on Computational Vision and Medical Image Processing, Funchal, Madeira Island, Portugal, 14-16 October, 2013.

Available from: 2013-09-20 Created: 2013-09-20 Last updated: 2017-12-18Bibliographically approved
Moreno, R. (2014). Management of the Level of Coursework in PhD Education: A Case of Sweden. Journal of Applied Economics and Business Research, 4(3), 168-177
Open this publication in new window or tab >>Management of the Level of Coursework in PhD Education: A Case of Sweden
2014 (English)In: Journal of Applied Economics and Business Research, ISSN 1927-033X, E-ISSN 1927-033X, Vol. 4, no 3, p. 168-177Article in journal (Refereed) Published
Abstract [en]

PhD programs around the world include a variable amount of coursework. Using a curriculum design perspective, this paper explores the pros and cons of using different levels of coursework in PhD education. Inefficient management of coursework can jeopardize the quality of the PhD programs, since the students will be forced to devote less time to their research. On the contrary, coursework can also become a powerful teaching and learning activity that can help the PhD students to attain the intended learning outcomes of the program. However, a deep involvement of the administration and supervisors in the design of coursework is necessary for the latter case. Although the paper uses the Swedish system as a reference, most of the discussion is well applicable to most PhD programs elsewhere.

Keywords
Curriculum design, PhD studies, Intended learning outcomes, Coursework
National Category
Pedagogy Learning
Identifiers
urn:nbn:se:liu:diva-110364 (URN)
Available from: 2014-09-09 Created: 2014-09-09 Last updated: 2017-12-05Bibliographically approved
Moreno, R., Borga, M. & Smedby, Ö. (2014). Techniques for Computing Fabric Tensors: A Review. In: Carl-Fredrik Westin, Anna Vilanova, Bernhard Burgeth (Ed.), Visualization and Processing of Tensors and Higher Order Descriptors for Multi-Valued Data: (pp. 271-292). Springer Berlin/Heidelberg
Open this publication in new window or tab >>Techniques for Computing Fabric Tensors: A Review
2014 (English)In: Visualization and Processing of Tensors and Higher Order Descriptors for Multi-Valued Data / [ed] Carl-Fredrik Westin, Anna Vilanova, Bernhard Burgeth, Springer Berlin/Heidelberg, 2014, p. 271-292Chapter in book (Refereed)
Abstract [en]

The aim of this chapter is to review different approaches that have been proposed to compute fabric tensors with emphasis on trabecular bone research. Fabric tensors aim at modeling through tensors both anisotropy and orientation of a material with respect to another one. Fabric tensors are widely used in fields such as trabecular bone research, mechanics of materials and geology. These tensors can be seen as semi-global measurements since they are computed in relatively large neighborhoods, which are assumed quasi-homogeneous. Many methods have been proposed to compute fabric tensors. We propose to classify fabric tensors into two categories: mechanics-based and morphology-based. The former computes fabric tensors from mechanical simulations, while the latter computes them by analyzing the morphology of the materials. In addition to pointing out advantages and drawbacks for each method, current trends and challenges in this field are also summarized.

Place, publisher, year, edition, pages
Springer Berlin/Heidelberg, 2014
Series
Mathematics and Visualization, ISSN 1612-3786 ; Part IV
Keywords
Fabric tensors, trabecular bone, biomechanics, osteoporosis
National Category
Medical Image Processing
Identifiers
urn:nbn:se:liu:diva-109047 (URN)10.1007/978-3-642-54301-2_12 (DOI)978-3-642-54300-5 (ISBN)978-3-642-54301-2 (ISBN)
Funder
Swedish Research Council, 2006-5670
Available from: 2014-08-04 Created: 2014-08-04 Last updated: 2014-10-08Bibliographically approved
Moreno, R., Garcia, M. A. & Puig, D. (2014). Tensor Voting for Robust Color Edge Detection. In: M. Emre Celebi and Bogdan Smolka (Ed.), Advances in Low-Level Color Image Processing: (pp. 279-301). Springer Netherlands
Open this publication in new window or tab >>Tensor Voting for Robust Color Edge Detection
2014 (English)In: Advances in Low-Level Color Image Processing / [ed] M. Emre Celebi and Bogdan Smolka, Springer Netherlands, 2014, p. 279-301Chapter in book (Refereed)
Abstract [en]

This chapter proposes two robust color edge detection methods based on tensor voting. The first method is a direct adaptation of the classical tensor voting to color images where tensors are initialized with either the gradient or the local color structure tensor. The second method is based on an extension of tensor voting in which the encoding and voting processes are specifically tailored to robust edge detection in color images. In this case, three tensors are used to encode local CIELAB color channels and edginess, while the voting process propagates both color and edginess by applying perception-based rules. Unlike the classical tensor voting, the second method considers the context in the voting process. Recall, discriminability, precision, false alarm rejection and robustness measurements with respect to three different ground-truths have been used to compare the proposed methods with the state-of-the-art. Experimental results show that the proposed methods are competitive, especially in robustness. Moreover, these experiments evidence the difficulty of proposing an edge detector with a perfect performance with respect to all features and fields of application.

Place, publisher, year, edition, pages
Springer Netherlands, 2014
Series
Lecture Notes in Computational Vision and Biomechanics, ISSN 2212-9391 ; 11
Keywords
Edge detection; Perceptual methods; Tensor voting; Perceptual grouping; Non-linear approximation; Curveness and junctionness propagation; Evaluation of edge detectors
National Category
Computer Systems Medical Image Processing
Identifiers
urn:nbn:se:liu:diva-102907 (URN)10.1007/978-94-007-7584-8_9 (DOI)978-94-007-7583-1 (ISBN)978-94-007-7584-8 (ISBN)
Available from: 2014-01-07 Created: 2014-01-07 Last updated: 2014-01-24Bibliographically approved
Hlawitschka, M., Hotz, I., Kratz, A., Marai, G. E., Moreno, R., Scheuermann, G., . . . Zhang, E. (2014). Top Challenges in the Visualization of Engineering Tensor Fields. In: Carl-Fredrik Westin, Anna Vilanova, Bernhard Burgeth (Ed.), Visualization and Processing of Tensors and Higher Order Descriptors for Multi-Valued Data: (pp. 3-15). Springer Berlin/Heidelberg
Open this publication in new window or tab >>Top Challenges in the Visualization of Engineering Tensor Fields
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2014 (English)In: Visualization and Processing of Tensors and Higher Order Descriptors for Multi-Valued Data / [ed] Carl-Fredrik Westin, Anna Vilanova, Bernhard Burgeth, Springer Berlin/Heidelberg, 2014, p. 3-15Chapter in book (Refereed)
Abstract [en]

In this chapter we summarize the top research challenges in creating successful visualization tools for tensor fields in engineering. The analysis is based on our collective experiences and on discussions with both domain experts and visualization practitioners. We find that creating visualization tools for engineering tensors often involves solving multiple different technical problems at the same time—including visual intuitiveness, scalability, interactivity, providing both detail and context, integration with modeling and simulation, representing uncertainty and managing multi-fields; as well as overcoming terminology barriers and advancing research in the mathematical aspects of tensor field processing. We further note the need for tools and data repositories to encourage faster advances in the field. Our interest in creating and proposing this list is to initiate a discussion about important research issues within the visualization of engineering tensor fields.

Place, publisher, year, edition, pages
Springer Berlin/Heidelberg, 2014
Series
Mathematics and Visualization, ISSN 1612-3786 ; 2014, XV
National Category
Other Engineering and Technologies
Identifiers
urn:nbn:se:liu:diva-109048 (URN)10.1007/978-3-642-54301-2_1 (DOI)978-3-642-54300-5 (ISBN)978-3-642-54301-2 (ISBN)
Available from: 2014-08-04 Created: 2014-08-04 Last updated: 2014-09-05Bibliographically approved
Klintström, E., Smedby, Ö., Klintström, B., Brismar, T. & Moreno, R. (2014). Trabecular bone histomorphometric measurements and contrast-to-noise ratio in CBCT. Dento-Maxillo-Facial Radiology, 43(8), 20140196
Open this publication in new window or tab >>Trabecular bone histomorphometric measurements and contrast-to-noise ratio in CBCT
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2014 (English)In: Dento-Maxillo-Facial Radiology, ISSN 0250-832X, E-ISSN 1476-542X, Vol. 43, no 8, p. 20140196-Article in journal (Refereed) Published
Abstract [en]

Objectives: The aim of this study was to evaluate how imaging parameters at clinical dental CBCT affect the accuracy in quantifying trabecular bone structures, contrast-to-noise ratio (CNR) and radiation dose.

Methods: 15 radius samples were examined using CBCT (Accuitomo FPD; J. Morita Mfg., Kyoto, Japan). Nine imaging protocols were used, differing in current, voltage, rotation degree, voxel size, imaging area and rotation time. Radiation doses were measured using a KAP-meter. After segmentation, six bone structure parameters and CNR were quantified. Micro-CT images with an isotropic resolution of 20 microns were used as a gold standard.

Results: Structure parameters obtained by CBCT were strongly correlated to those by micro CT, with correlation coefficients .0.90 for all studied parameters. Bone volume and trabecular thickness were not affected by changes in imaging parameters. Increased tube current from 5 to 8 mA, decreased isotropic voxel size from 125 to 80 microns and decreased rotation anglefrom 360° to 180° affected correlations for trabecular termini negatively. Decreasing rotation degree also weakened correlations for trabecular separation and trabecular number at 80 microns voxel size. Changes in the rotation degree and tube current affected CNR significantly. The radiation dose varied between 269 and 1284 mGy cm2.

Conclusions: Trabecular bone structure can be accurately quantified by clinical dental CBCT in vitro, and the obtained structure parameters are strongly related to those obtained by micro CT. A fair CNR and strong correlations can be obtained with a low radiation dose, indicating the possibility for monitoring trabecular bone structure also in vivo.

Place, publisher, year, edition, pages
British Institute of Radiology, 2014
Keywords
CBCT; micro-computed tomography; trabecular 7 bone; histomorphometry; bone segmentation; osteoporosis
National Category
Radiology, Nuclear Medicine and Medical Imaging
Identifiers
urn:nbn:se:liu:diva-111163 (URN)10.1259/dmfr.20140196 (DOI)000346231400002 ()25168811 (PubMedID)
Available from: 2014-10-09 Created: 2014-10-09 Last updated: 2017-12-05Bibliographically approved
Klintström, E., Smedby, Ö., Moreno, R. & Brismar, T. (2014). Trabecular bone structure parameters from 3D image processing of clinical multi-slice and cone-beam computed tomography data. Skeletal Radiology, 43(2), 197-204
Open this publication in new window or tab >>Trabecular bone structure parameters from 3D image processing of clinical multi-slice and cone-beam computed tomography data
2014 (English)In: Skeletal Radiology, ISSN 0364-2348, E-ISSN 1432-2161, Vol. 43, no 2, p. 197-204Article in journal (Refereed) Published
Abstract [en]

Objective

Bone strength depends on both mineral content and bone structure. The aim of this in vitro study was to develop a method of quantitatively assessing trabecular bone structure by applying three-dimensional image processing to data acquired with multi-slice and cone-beam computed tomography using micro-computed tomography as a reference.

Materials and Methods

Fifteen bone samples from the radius were examined. After segmentation, quantitative measures of bone volume, trabecular thickness, trabecular separation, trabecular number, trabecular nodes, and trabecular termini were obtained.

Results

The clinical machines overestimated bone volume and trabecular thickness and underestimated trabecular nodes and number, but cone-beam CT to a lesser extent. Parameters obtained from cone beam CT were strongly correlated with μCT, with correlation coefficients between 0.93 and 0.98 for all parameters except trabecular termini.

Conclusions

The high correlation between cone-beam CT and micro-CT suggest the possibility of quantifying and monitoring changes of trabecular bone microarchitecture in vivo using cone beam CT.

Place, publisher, year, edition, pages
Springer, 2014
Keywords
Trabecular bone structure; Cone-beam computed tomography; Micro computed tomography; Multi-slice computed tomography; Bone segmentation
National Category
Radiology, Nuclear Medicine and Medical Imaging
Identifiers
urn:nbn:se:liu:diva-102880 (URN)10.1007/s00256-013-1766-5 (DOI)000329108500011 ()
Available from: 2014-01-07 Created: 2014-01-07 Last updated: 2017-12-06Bibliographically approved
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Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0001-5765-2964

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