Tissue abnormality in a medical image is usually related to a dissimilar part of an otherwise hom... more Tissue abnormality in a medical image is usually related to a dissimilar part of an otherwise homogeneous image. The dissimilarity may be subtle or strong depending on the medical modality and the type of abnormal tissue. Dissimilarity within an otherwise homogeneous area of an image may not always be due to tissue abnormality. It might be due to image noise or due to variability within the same tissue type. Given this situation it is almost impossible to design and implement a generic segmentation process that will consistently give a single appropriate solution under all conditions. Hence a dissimilarity highlighting process that yields a hierarchy of segmentation results is more useful. This would benefit from high level human interaction to select the appropriate image segmentation for a particular application, because one of the capabilities of the human vision process when visualising images is its ability to visualise them at different levels of details.The purpose of this th...
The aim was to compare the accuracy of standard supplementary views and GE digital breast tomosyn... more The aim was to compare the accuracy of standard supplementary views and GE digital breast tomosynthesis (DBT) for assessment of soft tissue mammographic abnormalities. Methods: Women recalled for further assessment of soft tissue abnormalities were recruited and received standard supplementary views (typically spot compression views) and two-view GE DBT. The added value of DBT in the assessment process was determined by analysing data collected prospectively by unblinded radiologists working up the cases. Following anonymisation of cases, there was also a retrospective multireader review. The readers first read bilateral standard two-view digital mammography (DM) together with the supplementary mammographic views and gave a combined score for suspicion of malignancy on a fivepoint scale. The same readers then read bilateral standard two-view DM together with two-view DBT. Pathology data were obtained. Differences were assessed using ROC analysis. Results: The study population was 342 lesions in 322 patients. Final diagnosis was malignant in 113 cases (33%) and benign/normal in 229 cases (67%). In the prospective analysis, the performance of two-view DM plus DBT was at least equivalent to the performance of two-view DM and standard mammographic supplementary views-area under the curve (AUC) was 0.946 and 0.922 respectively, which did not reach statistical significance. Similar results were obtained for the retrospective review-AUC was 0.900 (DBT) and 0.873 (supplementary views), which did not reach statistical significance. The accuracy of GE DBT in the assessment of screendetected soft tissue abnormalities is equivalent to the use of standard supplementary mammographic views.
To develop and refine qualitative mapping and quantitative analysis techniques to define 'the... more To develop and refine qualitative mapping and quantitative analysis techniques to define 'thermal territories' of the post-partum abdomen, the caesarean section site and the infected surgical wound. In addition, to explore women's perspectives on thermal imaging and acceptability as a method for infection screening. Prospective feasibility study undertaken at a large University teaching hospital, Sheffield UK. Infrared thermal imaging of the abdomen was undertaken at the bedside on the first two days after elective caesarean section. Target recruitment: six women in each of three body mass index (BMI) categories (normal, 18.5-24.9 kg/m²; overweight 25-29.9 kg/m²; obese ≥30 kg/m²). Additionally, women presenting to the ward with wound infection were eligible for inclusion in the study. Perspectives on the use of thermal imaging and its practicality were also explored via semi-structured interviews and analysed using thematic content analysis. We recruited 20 women who had...
In Dynamic Contrast Enhanced Magnetic Resonance Imaging (DCE-MRI) for prostate cancer, there is e... more In Dynamic Contrast Enhanced Magnetic Resonance Imaging (DCE-MRI) for prostate cancer, there is early intense enhancement and rapid washout of contrast material, due to the heterogeneous and leaky characteristics of the tumour angiogenesis. These characteristics can be demonstrated by the quantitative measurement of signal enhancement with time (Time Intensity Curve). The TIC is plotted for the pixels', averaged intensity value, within a user drawn Region of Interest (ROI). The ROI, normally chosen within an area of the largest enhancement, may enclose tissues of different enhancement pattern. Hence the averaged TIC from the ROI may not represent the actual characteristics of the enclosed tissue of interest. Hierarchical Clustering-based Segmentation (HCS) is an approach to Computer Aided Monitoring (CAM) that generates a hierarchy of segmentation results to highlight the varied dissimilarities in images. As a diagnostic aid for the analysis of DCE-MR image data, the process starts with the HCS process applied to all the DCE-MR temporal frames of a slice. HCS process output provides heat map images based on the normalised average pixel value of the various dissimilar regions. TIC of the contrast wash-in, wash-out process are then plotted for suspicious regions confirmed by the user. In this paper we have demonstrated how the HCS process as a semiquantitative analytical tool to analyse the DCE MR images of the Prostate complements the radiologist's interpretation of DCE MR images.
Application of Infrared to Biomedical Sciences, 2017
Measurement of body temperature is one of the cornerstones of clinical assessment in medicine. Sk... more Measurement of body temperature is one of the cornerstones of clinical assessment in medicine. Skin, the largest organ of the human body, is essentially a temperature mosaic determined by the rate of blood flow through arterioles and capillaries adjacent to the skin. This makes the conventional methods of 'spot' measurement rather limited in providing detailed information of regional skin temperature. Infrared (IR) thermal imaging however has the potential to provide a robust method of surface temperature mapping in disease states where pathology disturbs the 'normal' distribution of blood flow to skin. To advance image interpretation from the conventional qualitative narrative to a quantitative and robust system, analytical developments focus on digital images and require computer-aided systems to produce results rapidly and safely. Hierarchical clustering-based segmentation (HCS) provides a generic solution to the complex interpretation of thermal data (pixel by pixel) to produce clusters and boundary regions at levels not discernible by human visual processing. In this chapter, HCS has been used to aid the interpretation of wound images and to identify variations in temperature clusters around and along the surgical wound for their clinical relevance in wound infection.
Methods in molecular biology (Clifton, N.J.), 2017
Perceiving abnormal regions in the images of different medical modalities plays a crucial role in... more Perceiving abnormal regions in the images of different medical modalities plays a crucial role in diagnosis and subsequent treatment planning. In medical images to visually perceive abnormalities' extent and boundaries requires substantial experience. Consequently, manually drawn region of interest (ROI) to outline boundaries of abnormalities suffers from limitations of human perception leading to inter-observer variability. As an alternative to human drawn ROI, it is proposed the use of a computer-based segmentation algorithm to segment digital medical image data.Hierarchical Clustering-based Segmentation (HCS) process is a generic unsupervised segmentation process that can be used to segment dissimilar regions in digital images. HCS process generates a hierarchy of segmented images by partitioning an image into its constituent regions at hierarchical levels of allowable dissimilarity between its different regions. The hierarchy represents the continuous merging of similar, spa...
A study has been completed examining design issues concerning the interpretation of and dissemina... more A study has been completed examining design issues concerning the interpretation of and dissemination of multimodal medical imaging data sets to diverse audiences. To create a model data set mouse fibrosarcoma tissue was visualised via magnetic resonance imaging (MRI), Matrix-Assisted Laser Desorption/Ionisation-Mass Spectrometry (MALDI-MSI) and histology. MRI images were acquired using the 0.25T Esaote GScan; MALDI images were acquired using a Q-Star Pulsar I mass spectrometer. Histological staining of the same tissue sections used for MALDI-MSI was then carried out. Areas assigned to hemosiderin deposits due to haemorrhaging could be visualised via MRI. In the MALDI-MSI data obtained the distribution sphingomyelin species could be used to identify regions of viable tumour. Mathematical ‘up sampling’ using hierarchical clustering-based segmentation provided a sophisticated image enhancement tool for both MRI and MALDI-MS and assisted in the correlation of images.
Dynamic Contrast Enhanced Magnetic Resonance Imaging (DCE-MRI) has become an important component ... more Dynamic Contrast Enhanced Magnetic Resonance Imaging (DCE-MRI) has become an important component in the diagnostic imaging pathway and is emerging as a useful clinical technique for evaluating the severity, location, and extent of primary and recurrent cancer. But DCE-MRI typically generates around 30 images per section and image interpretation requires substantial experience to detect and categorize lesions. Tissue abnormality is usually related to a dissimilar part of an otherwise homogeneous image. Choosing the optimal post processing threshold value can be difficult because the image composition may vary depending on the acquisition parameters and the type of tissue. Hierarchical Clustering-based Segmentation (HCS) is an approach to Computer Aided Monitoring (CAM) that enables a user to define a region of interest and the process generates a hierarchy of segmentation results to highlight the varied dissimilarities that might be present. This new HCS process based CAM system offe...
PurposeTo develop customised machine vision methods for closed‐loop micro‐robotic control systems... more PurposeTo develop customised machine vision methods for closed‐loop micro‐robotic control systems. The micro‐robots have applications in areas that require micro‐manipulation and micro‐assembly in the micron and sub‐micron range.Design/methodology/approachSeveral novel techniques have been developed to perform calibration, object recognition and object tracking in real‐time under a customised high‐magnification camera system. These new methods combine statistical, neural and morphological approaches.FindingsAn in‐depth view of the machine vision sub‐system that was designed for the European MiCRoN project (project no. IST‐2001‐33567) is provided. The issue of cooperation arises when several robots with a variety of on‐board tools are placed in the working environment. By combining multiple vision methods, the information obtained can be used effectively to guide the robots in achieving the pre‐planned tasks.Research limitations/implicationsSome of these techniques were developed for...
As part of a European Union ESPRIT funded research project a flexible microrobot system has been ... more As part of a European Union ESPRIT funded research project a flexible microrobot system has been developed which can operate under an optical microscope as well as in the chamber of a scanning electron microscope (SEM). The system is highly flexible and configurable and uses a wide range of sensors in a closed-loop control strategy. This paper presents an overview of the vision system and its architecture for vision-controlled micro-manipulation. The range of different applications, e.g. assembly of hybrid microsystems, handling of biological cells and manipulation tasks inside an SEM, imposes great demands on the vision system. Fast and reliable object recognition algorithms have been developed and implemented to provide for two modes of operation: automated and semi-automated robot control. The vision system has a modular design, comprising modules for object recognition, tracking and depth estimation. Communication between the vision modules and the control system takes place via a shared memory system embedding an object database. This database holds information about the appearance and the location of all known objects. A depth estimation method based on a modified sheet-of-light triangulation method is also described. It is fully integrated in the control loop and can be used both for measuring specific points or scanning a complete field of view. Furthermore, the novel approach of electron beam triangulation in the SEM is described.
As the fields of micro- and nano-technology mature, there will be an increased need to build tool... more As the fields of micro- and nano-technology mature, there will be an increased need to build tools that are able to work in these areas. Industry will require solutions for assembling and manipulating components, much as it has done in the macro range. With this need in mind, a new set of challenges requiring novel solutions have to be met.
Xray mammography is regarded as the most effective tool for the detection and diagnosis of breast... more Xray mammography is regarded as the most effective tool for the detection and diagnosis of breast cancer, but the interpretation of mammograms is a difficult and errorprone task. Computeraided detection (CADe) systems address the problem that ...
EUROCON 2005 - The International Conference on "Computer as a Tool", 2005
Page 1. Serbia & Montenegro, Belgrade, November 22-24, 2005 A Dissimilarity Visualisation Sys... more Page 1. Serbia & Montenegro, Belgrade, November 22-24, 2005 A Dissimilarity Visualisation System for CT: Pilot Study Arul N. Selvan, Reza Saatchi, Bala P. Amavasai and Jon R. Travis Abstract - One of the capabilities of the ...
Tissue abnormality in a medical image is usually related to a dissimilar part of an otherwise hom... more Tissue abnormality in a medical image is usually related to a dissimilar part of an otherwise homogeneous image. The dissimilarity may be subtle or strong depending on the medical modality and the type of abnormal tissue. Dissimilarity within an otherwise homogeneous area of an image may not always be due to tissue abnormality. It might be due to image noise or due to variability within the same tissue type. Given this situation it is almost impossible to design and implement a generic segmentation process that will consistently give a single appropriate solution under all conditions. Hence a dissimilarity highlighting process that yields a hierarchy of segmentation results is more useful. This would benefit from high level human interaction to select the appropriate image segmentation for a particular application, because one of the capabilities of the human vision process when visualising images is its ability to visualise them at different levels of details.The purpose of this th...
The aim was to compare the accuracy of standard supplementary views and GE digital breast tomosyn... more The aim was to compare the accuracy of standard supplementary views and GE digital breast tomosynthesis (DBT) for assessment of soft tissue mammographic abnormalities. Methods: Women recalled for further assessment of soft tissue abnormalities were recruited and received standard supplementary views (typically spot compression views) and two-view GE DBT. The added value of DBT in the assessment process was determined by analysing data collected prospectively by unblinded radiologists working up the cases. Following anonymisation of cases, there was also a retrospective multireader review. The readers first read bilateral standard two-view digital mammography (DM) together with the supplementary mammographic views and gave a combined score for suspicion of malignancy on a fivepoint scale. The same readers then read bilateral standard two-view DM together with two-view DBT. Pathology data were obtained. Differences were assessed using ROC analysis. Results: The study population was 342 lesions in 322 patients. Final diagnosis was malignant in 113 cases (33%) and benign/normal in 229 cases (67%). In the prospective analysis, the performance of two-view DM plus DBT was at least equivalent to the performance of two-view DM and standard mammographic supplementary views-area under the curve (AUC) was 0.946 and 0.922 respectively, which did not reach statistical significance. Similar results were obtained for the retrospective review-AUC was 0.900 (DBT) and 0.873 (supplementary views), which did not reach statistical significance. The accuracy of GE DBT in the assessment of screendetected soft tissue abnormalities is equivalent to the use of standard supplementary mammographic views.
To develop and refine qualitative mapping and quantitative analysis techniques to define 'the... more To develop and refine qualitative mapping and quantitative analysis techniques to define 'thermal territories' of the post-partum abdomen, the caesarean section site and the infected surgical wound. In addition, to explore women's perspectives on thermal imaging and acceptability as a method for infection screening. Prospective feasibility study undertaken at a large University teaching hospital, Sheffield UK. Infrared thermal imaging of the abdomen was undertaken at the bedside on the first two days after elective caesarean section. Target recruitment: six women in each of three body mass index (BMI) categories (normal, 18.5-24.9 kg/m²; overweight 25-29.9 kg/m²; obese ≥30 kg/m²). Additionally, women presenting to the ward with wound infection were eligible for inclusion in the study. Perspectives on the use of thermal imaging and its practicality were also explored via semi-structured interviews and analysed using thematic content analysis. We recruited 20 women who had...
In Dynamic Contrast Enhanced Magnetic Resonance Imaging (DCE-MRI) for prostate cancer, there is e... more In Dynamic Contrast Enhanced Magnetic Resonance Imaging (DCE-MRI) for prostate cancer, there is early intense enhancement and rapid washout of contrast material, due to the heterogeneous and leaky characteristics of the tumour angiogenesis. These characteristics can be demonstrated by the quantitative measurement of signal enhancement with time (Time Intensity Curve). The TIC is plotted for the pixels', averaged intensity value, within a user drawn Region of Interest (ROI). The ROI, normally chosen within an area of the largest enhancement, may enclose tissues of different enhancement pattern. Hence the averaged TIC from the ROI may not represent the actual characteristics of the enclosed tissue of interest. Hierarchical Clustering-based Segmentation (HCS) is an approach to Computer Aided Monitoring (CAM) that generates a hierarchy of segmentation results to highlight the varied dissimilarities in images. As a diagnostic aid for the analysis of DCE-MR image data, the process starts with the HCS process applied to all the DCE-MR temporal frames of a slice. HCS process output provides heat map images based on the normalised average pixel value of the various dissimilar regions. TIC of the contrast wash-in, wash-out process are then plotted for suspicious regions confirmed by the user. In this paper we have demonstrated how the HCS process as a semiquantitative analytical tool to analyse the DCE MR images of the Prostate complements the radiologist's interpretation of DCE MR images.
Application of Infrared to Biomedical Sciences, 2017
Measurement of body temperature is one of the cornerstones of clinical assessment in medicine. Sk... more Measurement of body temperature is one of the cornerstones of clinical assessment in medicine. Skin, the largest organ of the human body, is essentially a temperature mosaic determined by the rate of blood flow through arterioles and capillaries adjacent to the skin. This makes the conventional methods of 'spot' measurement rather limited in providing detailed information of regional skin temperature. Infrared (IR) thermal imaging however has the potential to provide a robust method of surface temperature mapping in disease states where pathology disturbs the 'normal' distribution of blood flow to skin. To advance image interpretation from the conventional qualitative narrative to a quantitative and robust system, analytical developments focus on digital images and require computer-aided systems to produce results rapidly and safely. Hierarchical clustering-based segmentation (HCS) provides a generic solution to the complex interpretation of thermal data (pixel by pixel) to produce clusters and boundary regions at levels not discernible by human visual processing. In this chapter, HCS has been used to aid the interpretation of wound images and to identify variations in temperature clusters around and along the surgical wound for their clinical relevance in wound infection.
Methods in molecular biology (Clifton, N.J.), 2017
Perceiving abnormal regions in the images of different medical modalities plays a crucial role in... more Perceiving abnormal regions in the images of different medical modalities plays a crucial role in diagnosis and subsequent treatment planning. In medical images to visually perceive abnormalities' extent and boundaries requires substantial experience. Consequently, manually drawn region of interest (ROI) to outline boundaries of abnormalities suffers from limitations of human perception leading to inter-observer variability. As an alternative to human drawn ROI, it is proposed the use of a computer-based segmentation algorithm to segment digital medical image data.Hierarchical Clustering-based Segmentation (HCS) process is a generic unsupervised segmentation process that can be used to segment dissimilar regions in digital images. HCS process generates a hierarchy of segmented images by partitioning an image into its constituent regions at hierarchical levels of allowable dissimilarity between its different regions. The hierarchy represents the continuous merging of similar, spa...
A study has been completed examining design issues concerning the interpretation of and dissemina... more A study has been completed examining design issues concerning the interpretation of and dissemination of multimodal medical imaging data sets to diverse audiences. To create a model data set mouse fibrosarcoma tissue was visualised via magnetic resonance imaging (MRI), Matrix-Assisted Laser Desorption/Ionisation-Mass Spectrometry (MALDI-MSI) and histology. MRI images were acquired using the 0.25T Esaote GScan; MALDI images were acquired using a Q-Star Pulsar I mass spectrometer. Histological staining of the same tissue sections used for MALDI-MSI was then carried out. Areas assigned to hemosiderin deposits due to haemorrhaging could be visualised via MRI. In the MALDI-MSI data obtained the distribution sphingomyelin species could be used to identify regions of viable tumour. Mathematical ‘up sampling’ using hierarchical clustering-based segmentation provided a sophisticated image enhancement tool for both MRI and MALDI-MS and assisted in the correlation of images.
Dynamic Contrast Enhanced Magnetic Resonance Imaging (DCE-MRI) has become an important component ... more Dynamic Contrast Enhanced Magnetic Resonance Imaging (DCE-MRI) has become an important component in the diagnostic imaging pathway and is emerging as a useful clinical technique for evaluating the severity, location, and extent of primary and recurrent cancer. But DCE-MRI typically generates around 30 images per section and image interpretation requires substantial experience to detect and categorize lesions. Tissue abnormality is usually related to a dissimilar part of an otherwise homogeneous image. Choosing the optimal post processing threshold value can be difficult because the image composition may vary depending on the acquisition parameters and the type of tissue. Hierarchical Clustering-based Segmentation (HCS) is an approach to Computer Aided Monitoring (CAM) that enables a user to define a region of interest and the process generates a hierarchy of segmentation results to highlight the varied dissimilarities that might be present. This new HCS process based CAM system offe...
PurposeTo develop customised machine vision methods for closed‐loop micro‐robotic control systems... more PurposeTo develop customised machine vision methods for closed‐loop micro‐robotic control systems. The micro‐robots have applications in areas that require micro‐manipulation and micro‐assembly in the micron and sub‐micron range.Design/methodology/approachSeveral novel techniques have been developed to perform calibration, object recognition and object tracking in real‐time under a customised high‐magnification camera system. These new methods combine statistical, neural and morphological approaches.FindingsAn in‐depth view of the machine vision sub‐system that was designed for the European MiCRoN project (project no. IST‐2001‐33567) is provided. The issue of cooperation arises when several robots with a variety of on‐board tools are placed in the working environment. By combining multiple vision methods, the information obtained can be used effectively to guide the robots in achieving the pre‐planned tasks.Research limitations/implicationsSome of these techniques were developed for...
As part of a European Union ESPRIT funded research project a flexible microrobot system has been ... more As part of a European Union ESPRIT funded research project a flexible microrobot system has been developed which can operate under an optical microscope as well as in the chamber of a scanning electron microscope (SEM). The system is highly flexible and configurable and uses a wide range of sensors in a closed-loop control strategy. This paper presents an overview of the vision system and its architecture for vision-controlled micro-manipulation. The range of different applications, e.g. assembly of hybrid microsystems, handling of biological cells and manipulation tasks inside an SEM, imposes great demands on the vision system. Fast and reliable object recognition algorithms have been developed and implemented to provide for two modes of operation: automated and semi-automated robot control. The vision system has a modular design, comprising modules for object recognition, tracking and depth estimation. Communication between the vision modules and the control system takes place via a shared memory system embedding an object database. This database holds information about the appearance and the location of all known objects. A depth estimation method based on a modified sheet-of-light triangulation method is also described. It is fully integrated in the control loop and can be used both for measuring specific points or scanning a complete field of view. Furthermore, the novel approach of electron beam triangulation in the SEM is described.
As the fields of micro- and nano-technology mature, there will be an increased need to build tool... more As the fields of micro- and nano-technology mature, there will be an increased need to build tools that are able to work in these areas. Industry will require solutions for assembling and manipulating components, much as it has done in the macro range. With this need in mind, a new set of challenges requiring novel solutions have to be met.
Xray mammography is regarded as the most effective tool for the detection and diagnosis of breast... more Xray mammography is regarded as the most effective tool for the detection and diagnosis of breast cancer, but the interpretation of mammograms is a difficult and errorprone task. Computeraided detection (CADe) systems address the problem that ...
EUROCON 2005 - The International Conference on "Computer as a Tool", 2005
Page 1. Serbia & Montenegro, Belgrade, November 22-24, 2005 A Dissimilarity Visualisation Sys... more Page 1. Serbia & Montenegro, Belgrade, November 22-24, 2005 A Dissimilarity Visualisation System for CT: Pilot Study Arul N. Selvan, Reza Saatchi, Bala P. Amavasai and Jon R. Travis Abstract - One of the capabilities of the ...
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