The volume, shape and size of cerebral ventricular system may change due to various pathologies d... more The volume, shape and size of cerebral ventricular system may change due to various pathologies directly or indirectly. Estimation of size of cerebral ventricles is important for evaluating changes due to growth, aging, intrinsic and extrinsic pathologies. Quantification using ex vivo techniques has considerable errors. In vivo studies using air or contrast media also introduce volumetric changes in the ventricles. Imaging of ventricular anatomy avoids these problems and allows repetitive studies following progression of ventricular system changes due to disease or natural processes. We have developed a methodology for automated extraction of ventricular system from magnetic resonance imaging. Once extracted, landmarks are located on the surface of ventricular system automatically. These landmarks are then used for calculation of the ventricular shape, volume and size. A total of 30 cases were analyzed. Physical dimensions of normal ventricles are presented in this paper.
To evaluate the role of In-111-labeled leukocyte scintigraphy in the patients with suspected post... more To evaluate the role of In-111-labeled leukocyte scintigraphy in the patients with suspected postoperative joint infection, 41 scintigraphic examinations were performed in 24 patients. Scintigrams were interpreted by the degree of accumulation of labeled leukocytes, and were classified into 3 groups: positive, intermediate, and negative. In the cases of positive leukocyte scans, definite diagnosis of infection was made in all cases except one. In the cases of negative scans, there was no evidence of infection. In 13 cases, leukocyte scintigrams were interpreted in conjunction with bone scintigrams. Definite diagnosis of infection was made in all of the cases with positive combined leukocyte/bone scan, and there was no evidence of infection in cases with negative combined leukocyte/bone scan. This study demonstrates that In-111-labeled leukocyte scintigraphy is a useful method in diagnosis of postoperative joint infection, and accuracy of the examination improves when combined with b...
Proceedings. Fourth IEEE Symposium on Bioinformatics and Bioengineering
In this paper, we propose an automatic method to segment the Sylvian fissure (SF) from T1-weighte... more In this paper, we propose an automatic method to segment the Sylvian fissure (SF) from T1-weighted magnetic resonance (MR) images. The method consists of four steps. First, morphological methods are applied to remove non-brain tissues. Then, 2D region growing is used to segment the cerebral spinal fluid (CSF) and gray matter (GM) in the SF, in which spatial relationships are used to control the region growing. A modified fuzzy c-means (FCM) clustering algorithm is introduced as well, which is more accurate than the conventional FCM method. After that, we get the 3D volume of the SF through segmenting CSF and GM slice by slice. Finally, CSF in the SF is extracted incorporating the anatomical information on a constant cortex thickness. We have demonstrated our method through both phantom and patient data.
See www.rsna.org /education /rg_cme.html. LEARNING OBJECTIVES After reading this article and taki... more See www.rsna.org /education /rg_cme.html. LEARNING OBJECTIVES After reading this article and taking the test, the reader will be able to: â…¢ Discuss the radiographic and CT findings in the major fissures and their normal variants.
A new method has been developed for multimedia enhancement of electronic teaching files created b... more A new method has been developed for multimedia enhancement of electronic teaching files created by using the standard protocols and formats offered by the Medical Imaging Resource Center (MIRC) project of the Radiological Society of North America. The typical MIRC electronic teaching file consists of static pages only; with the new method, audio and visual content may be added to the MIRC electronic teaching file so that the entire image interpretation process can be recorded for teaching purposes. With an efficient system for encoding the audiovisual record of on-screen manipulation of radiologic images, the multimedia teaching files generated are small enough to be transmitted via the Internet with acceptable resolution. Students may respond with the addition of new audio and visual content and thereby participate in a discussion about a particular case. MIRC electronic teaching files with multimedia enhancement have the potential to augment the effectiveness of diagnostic radiology teaching.
Journal of digital imaging : the official journal of the Society for Computer Applications in Radiology, 2008
Volumetric imaging (computed tomography and magnetic resonance imaging) provides increased diagno... more Volumetric imaging (computed tomography and magnetic resonance imaging) provides increased diagnostic detail but is associated with the problem of navigation through large amounts of data. In an attempt to overcome this problem, a novel 3D navigation tool has been designed and developed that is based on an alternative input device. A 3D mouse allows for simultaneous definition of position and orientation of orthogonal or oblique multiplanar reformatted images or slabs, which are presented within a virtual 3D scene together with the volume-rendered data set and additionally as 2D images. Slabs are visualized with maximum intensity projection, average intensity projection, or standard volume rendering technique. A prototype has been implemented based on PC technology that has been tested by several radiologists. It has shown to be easily understandable and usable after a very short learning phase. Our solution may help to fully exploit the diagnostic potential of volumetric imaging by...
We present a cerebral vasculature extraction method from magnetic resonance angiography (MRA) and... more We present a cerebral vasculature extraction method from magnetic resonance angiography (MRA) and provide validation for arteries. After reviewing the state-of-the-art in vasculature segmentation techniques, we introduce an automatic algorithm with robust maximal intensity searching and region growing. We present the details of the design and application of extraction validation interface. We demonstrate the artery extraction fidelity of the method with tests on both 3D phantom and real MRA images. We conclude by summarising the proposed algorithm and pointing out possible future pursuits in vessel segmentation.
International Journal of Computer Assisted Radiology and Surgery, 2007
The human orbit has numerous structures packed in a relatively small space, the study of which is... more The human orbit has numerous structures packed in a relatively small space, the study of which is essential and difficult due to complex three dimensional relationships. Available printed orbital atlases do not convey the three dimensional information and are not interactive. To overcome these limitations, we built a digital 3D orbital atlas presented in axial, coronal and sagittal planes, and as three dimensional geometric models of the muscles, bones, and eyeball. The bone models are from a CT scan, the muscle and optic nerve from a MR scan, and other components that cannot be distinguished radiologically are modeled as geometric primitives from anatomic literature. All multi-modal data including the models and images are registered into the same space to form a complete atlas. All structures in the atlas are labeled with their names. An atlas browser is developed for user-friendly manipulation and presentation of the atlas content. Each structure can be turned on or off, rotated, zoomed, or moved, either individually or in unison with other selected structures. Thus, the relationships between different structures can be studied in greater depth. The method developed to build the orbital atlas is general and can be used to create other atlases or to build patient specific geometric models. The orbital atlas may be used for studying the orbital
Abstract: We introduce and validate the Fast Talairach Transforma-tion (FTT). FTT is a rapid vers... more Abstract: We introduce and validate the Fast Talairach Transforma-tion (FTT). FTT is a rapid version of the Talairach transformation (TT) with the modified Talairach landmarks. Landmark identification is fully automatic and done in 3 steps: calculation of midsagittal plane, computing of anterior commissure (AC) and posterior commissure (PC) landmarks, and calculation of cortical landmarks. To perform these steps, we use fast and anatomy-based algorithms employing simple operations. FTT was validated for 215 diversified T1-weighted and SPGRAQ2 MRI data sets. It calculates the landmarks and warps the Talairach-Tournoux atlas fully automatically in about 5 sec on a standard computer. The average distance errors in landmark localiza-tion are (in mm): 1.16 (AC), 1.49 (PC), 0.08 (left), 0.13 (right), 0.48 (anterior), 0.16 (posterior), 0.35 (superior), and 0.52 (inferior). Extensions to FTT by introducing additional landmarks and applying nonlinear warping against the ventricular system ar...
Simulation allows students to learn fundamental skills, such as trial and error, critical thinkin... more Simulation allows students to learn fundamental skills, such as trial and error, critical thinking, and cognitive and motor skills in a safe environment that closely represents reality. Presently, there are large amounts of literature surrounding simulation in the health and medical field. The aim of this paper is to review the current literature surrounding simulation in medical ultrasound to assess if simulation is effective in teaching sonography skills, and if simulation can be used as a substitute for educating sonography students. A search for literature was conducted through databases such as PubMed, MEDLINE, and CINAHL. Key search terms included ultrasonography [MeSH] and simulation training [MeSH]. Overall, 19 studies were utilised in this review. All the literature concluded that simulation positively affects the learning process of ultrasound trainees. Furthermore, simulation is proven to be a highly valuable tool, which could replace some clinical hours and result in superior student outcomes compared with traditional teaching methods. Simulation however cannot replace traditional teaching methods entirely, and further research is needed to assess how to effectively incorporate simulation into ultrasound education.
This study included consecutive 318 pairs of posteroanterior (PA) and left lateral (LL) chest rad... more This study included consecutive 318 pairs of posteroanterior (PA) and left lateral (LL) chest radiographs taken under routinely used conditions with the patients in erect position. Major, minor and accessory fissures visualized on these radiographs were described according to their visibility, position, length and shape. On PA chest radiographs, superolateral major fissures in 54 (17%), superomedial major fissures in 20 (6%), minor fissures in 234 (74%), inferior accessory fissures in 19 (6%), superior accessory fissures in 12 (4%), left minor fissures in 16 (5%) and azygos fissure in 2 (0.6%) patients were seen. On LL chest radiographs, 266 (84%) right major fissures, 242 (76%) left major fissures, 210 (66%) minor fissures and 6 (2%) superior accessory fissures were seen. We have described the frequencies of various orientations, shapes and lengths of these fissures. This study not only supports the common knowledge of the appearances of pulmonary fissures but also explains numeric...
The lateral ventricles are major cavities in the top section of the human brain filled with cereb... more The lateral ventricles are major cavities in the top section of the human brain filled with cerebrospinal fluid (CSF). Some brain diseases cause change in shape and size of the lateral ventricles. The advancement of Alzheimer's disease (AD), for instance, is assumed to affect the hippocampus, and thus to indirectly influence the adjacent temporal horns, which are a part of the ventricular system. Manual delineation of regions of interest is time-consuming and error-prone. In this paper we are proposing a semi-automatic procedure for segmenting the lateral ventricles from human brain MR volumes. With the long-term objective of a comprehensive study of AD, particular importance is given to the inclusion of the temporal horns in the segmentation process. Method An algorithm was developed for segmenting the lateral ventricles including their temporal horns in MR images. Previous work has addressed this problem using knowledge-based [1] or fuzzy-set [2] approaches, amongst others. Our semi-automatic technique comprises several interdependent processing steps which are designed to eliminate the risk of under-and oversegmentation due to variations in shape and size of the ventricular system (Fig. 1). First, the main bodies of both lateral ventricles are pre-segmented using a constrained 3D region growing (RG) algorithm, starting from user-defined seed points. Second, an additional, less constraining RG step is applied on the ventricles' anterior and posterior ends. This is done to overcome undersegmentation which is likely to occur in this area due to narrowing of the ventricles. The combined result of both RG steps is then further evolved by a level-set method, which propagates the boundaries of the initial, constrained segmentation mask further towards the actual ventricle boundaries. Next, the segmentation of the temporal horns is addressed. A path is traced from user-defined seed points in the anterior end of each horn through the CSF towards the main bodies of the lateral ventricles. The method for tracing the paths is based on the fast-marching algorithm. It is designed in such a way that the shape of the horn is approximated even in areas where there is no visible CSF connection between a horn's end and its corresponding lateral ventricle, due to noise or lack of image resolution, as is the case for a large percentage of datasets. For this purpose, an additional outward force is applied to the tracing process, preventing the path from diverging into adjacent CSF regions while attracting it to the horn's natural course, i.e., the outer boundary of the hippocampus. A region is then grown from the path to fill the CSF of the horns, using a fast-marching approach again. Finally, the masks of the segmented structures (lateral ventricles and temporal horns) are combined to form the final desired segmentation.
The volume, shape and size of cerebral ventricular system may change due to various pathologies d... more The volume, shape and size of cerebral ventricular system may change due to various pathologies directly or indirectly. Estimation of size of cerebral ventricles is important for evaluating changes due to growth, aging, intrinsic and extrinsic pathologies. Quantification using ex vivo techniques has considerable errors. In vivo studies using air or contrast media also introduce volumetric changes in the ventricles. Imaging of ventricular anatomy avoids these problems and allows repetitive studies following progression of ventricular system changes due to disease or natural processes. We have developed a methodology for automated extraction of ventricular system from magnetic resonance imaging. Once extracted, landmarks are located on the surface of ventricular system automatically. These landmarks are then used for calculation of the ventricular shape, volume and size. A total of 30 cases were analyzed. Physical dimensions of normal ventricles are presented in this paper.
To evaluate the role of In-111-labeled leukocyte scintigraphy in the patients with suspected post... more To evaluate the role of In-111-labeled leukocyte scintigraphy in the patients with suspected postoperative joint infection, 41 scintigraphic examinations were performed in 24 patients. Scintigrams were interpreted by the degree of accumulation of labeled leukocytes, and were classified into 3 groups: positive, intermediate, and negative. In the cases of positive leukocyte scans, definite diagnosis of infection was made in all cases except one. In the cases of negative scans, there was no evidence of infection. In 13 cases, leukocyte scintigrams were interpreted in conjunction with bone scintigrams. Definite diagnosis of infection was made in all of the cases with positive combined leukocyte/bone scan, and there was no evidence of infection in cases with negative combined leukocyte/bone scan. This study demonstrates that In-111-labeled leukocyte scintigraphy is a useful method in diagnosis of postoperative joint infection, and accuracy of the examination improves when combined with b...
Proceedings. Fourth IEEE Symposium on Bioinformatics and Bioengineering
In this paper, we propose an automatic method to segment the Sylvian fissure (SF) from T1-weighte... more In this paper, we propose an automatic method to segment the Sylvian fissure (SF) from T1-weighted magnetic resonance (MR) images. The method consists of four steps. First, morphological methods are applied to remove non-brain tissues. Then, 2D region growing is used to segment the cerebral spinal fluid (CSF) and gray matter (GM) in the SF, in which spatial relationships are used to control the region growing. A modified fuzzy c-means (FCM) clustering algorithm is introduced as well, which is more accurate than the conventional FCM method. After that, we get the 3D volume of the SF through segmenting CSF and GM slice by slice. Finally, CSF in the SF is extracted incorporating the anatomical information on a constant cortex thickness. We have demonstrated our method through both phantom and patient data.
See www.rsna.org /education /rg_cme.html. LEARNING OBJECTIVES After reading this article and taki... more See www.rsna.org /education /rg_cme.html. LEARNING OBJECTIVES After reading this article and taking the test, the reader will be able to: â…¢ Discuss the radiographic and CT findings in the major fissures and their normal variants.
A new method has been developed for multimedia enhancement of electronic teaching files created b... more A new method has been developed for multimedia enhancement of electronic teaching files created by using the standard protocols and formats offered by the Medical Imaging Resource Center (MIRC) project of the Radiological Society of North America. The typical MIRC electronic teaching file consists of static pages only; with the new method, audio and visual content may be added to the MIRC electronic teaching file so that the entire image interpretation process can be recorded for teaching purposes. With an efficient system for encoding the audiovisual record of on-screen manipulation of radiologic images, the multimedia teaching files generated are small enough to be transmitted via the Internet with acceptable resolution. Students may respond with the addition of new audio and visual content and thereby participate in a discussion about a particular case. MIRC electronic teaching files with multimedia enhancement have the potential to augment the effectiveness of diagnostic radiology teaching.
Journal of digital imaging : the official journal of the Society for Computer Applications in Radiology, 2008
Volumetric imaging (computed tomography and magnetic resonance imaging) provides increased diagno... more Volumetric imaging (computed tomography and magnetic resonance imaging) provides increased diagnostic detail but is associated with the problem of navigation through large amounts of data. In an attempt to overcome this problem, a novel 3D navigation tool has been designed and developed that is based on an alternative input device. A 3D mouse allows for simultaneous definition of position and orientation of orthogonal or oblique multiplanar reformatted images or slabs, which are presented within a virtual 3D scene together with the volume-rendered data set and additionally as 2D images. Slabs are visualized with maximum intensity projection, average intensity projection, or standard volume rendering technique. A prototype has been implemented based on PC technology that has been tested by several radiologists. It has shown to be easily understandable and usable after a very short learning phase. Our solution may help to fully exploit the diagnostic potential of volumetric imaging by...
We present a cerebral vasculature extraction method from magnetic resonance angiography (MRA) and... more We present a cerebral vasculature extraction method from magnetic resonance angiography (MRA) and provide validation for arteries. After reviewing the state-of-the-art in vasculature segmentation techniques, we introduce an automatic algorithm with robust maximal intensity searching and region growing. We present the details of the design and application of extraction validation interface. We demonstrate the artery extraction fidelity of the method with tests on both 3D phantom and real MRA images. We conclude by summarising the proposed algorithm and pointing out possible future pursuits in vessel segmentation.
International Journal of Computer Assisted Radiology and Surgery, 2007
The human orbit has numerous structures packed in a relatively small space, the study of which is... more The human orbit has numerous structures packed in a relatively small space, the study of which is essential and difficult due to complex three dimensional relationships. Available printed orbital atlases do not convey the three dimensional information and are not interactive. To overcome these limitations, we built a digital 3D orbital atlas presented in axial, coronal and sagittal planes, and as three dimensional geometric models of the muscles, bones, and eyeball. The bone models are from a CT scan, the muscle and optic nerve from a MR scan, and other components that cannot be distinguished radiologically are modeled as geometric primitives from anatomic literature. All multi-modal data including the models and images are registered into the same space to form a complete atlas. All structures in the atlas are labeled with their names. An atlas browser is developed for user-friendly manipulation and presentation of the atlas content. Each structure can be turned on or off, rotated, zoomed, or moved, either individually or in unison with other selected structures. Thus, the relationships between different structures can be studied in greater depth. The method developed to build the orbital atlas is general and can be used to create other atlases or to build patient specific geometric models. The orbital atlas may be used for studying the orbital
Abstract: We introduce and validate the Fast Talairach Transforma-tion (FTT). FTT is a rapid vers... more Abstract: We introduce and validate the Fast Talairach Transforma-tion (FTT). FTT is a rapid version of the Talairach transformation (TT) with the modified Talairach landmarks. Landmark identification is fully automatic and done in 3 steps: calculation of midsagittal plane, computing of anterior commissure (AC) and posterior commissure (PC) landmarks, and calculation of cortical landmarks. To perform these steps, we use fast and anatomy-based algorithms employing simple operations. FTT was validated for 215 diversified T1-weighted and SPGRAQ2 MRI data sets. It calculates the landmarks and warps the Talairach-Tournoux atlas fully automatically in about 5 sec on a standard computer. The average distance errors in landmark localiza-tion are (in mm): 1.16 (AC), 1.49 (PC), 0.08 (left), 0.13 (right), 0.48 (anterior), 0.16 (posterior), 0.35 (superior), and 0.52 (inferior). Extensions to FTT by introducing additional landmarks and applying nonlinear warping against the ventricular system ar...
Simulation allows students to learn fundamental skills, such as trial and error, critical thinkin... more Simulation allows students to learn fundamental skills, such as trial and error, critical thinking, and cognitive and motor skills in a safe environment that closely represents reality. Presently, there are large amounts of literature surrounding simulation in the health and medical field. The aim of this paper is to review the current literature surrounding simulation in medical ultrasound to assess if simulation is effective in teaching sonography skills, and if simulation can be used as a substitute for educating sonography students. A search for literature was conducted through databases such as PubMed, MEDLINE, and CINAHL. Key search terms included ultrasonography [MeSH] and simulation training [MeSH]. Overall, 19 studies were utilised in this review. All the literature concluded that simulation positively affects the learning process of ultrasound trainees. Furthermore, simulation is proven to be a highly valuable tool, which could replace some clinical hours and result in superior student outcomes compared with traditional teaching methods. Simulation however cannot replace traditional teaching methods entirely, and further research is needed to assess how to effectively incorporate simulation into ultrasound education.
This study included consecutive 318 pairs of posteroanterior (PA) and left lateral (LL) chest rad... more This study included consecutive 318 pairs of posteroanterior (PA) and left lateral (LL) chest radiographs taken under routinely used conditions with the patients in erect position. Major, minor and accessory fissures visualized on these radiographs were described according to their visibility, position, length and shape. On PA chest radiographs, superolateral major fissures in 54 (17%), superomedial major fissures in 20 (6%), minor fissures in 234 (74%), inferior accessory fissures in 19 (6%), superior accessory fissures in 12 (4%), left minor fissures in 16 (5%) and azygos fissure in 2 (0.6%) patients were seen. On LL chest radiographs, 266 (84%) right major fissures, 242 (76%) left major fissures, 210 (66%) minor fissures and 6 (2%) superior accessory fissures were seen. We have described the frequencies of various orientations, shapes and lengths of these fissures. This study not only supports the common knowledge of the appearances of pulmonary fissures but also explains numeric...
The lateral ventricles are major cavities in the top section of the human brain filled with cereb... more The lateral ventricles are major cavities in the top section of the human brain filled with cerebrospinal fluid (CSF). Some brain diseases cause change in shape and size of the lateral ventricles. The advancement of Alzheimer's disease (AD), for instance, is assumed to affect the hippocampus, and thus to indirectly influence the adjacent temporal horns, which are a part of the ventricular system. Manual delineation of regions of interest is time-consuming and error-prone. In this paper we are proposing a semi-automatic procedure for segmenting the lateral ventricles from human brain MR volumes. With the long-term objective of a comprehensive study of AD, particular importance is given to the inclusion of the temporal horns in the segmentation process. Method An algorithm was developed for segmenting the lateral ventricles including their temporal horns in MR images. Previous work has addressed this problem using knowledge-based [1] or fuzzy-set [2] approaches, amongst others. Our semi-automatic technique comprises several interdependent processing steps which are designed to eliminate the risk of under-and oversegmentation due to variations in shape and size of the ventricular system (Fig. 1). First, the main bodies of both lateral ventricles are pre-segmented using a constrained 3D region growing (RG) algorithm, starting from user-defined seed points. Second, an additional, less constraining RG step is applied on the ventricles' anterior and posterior ends. This is done to overcome undersegmentation which is likely to occur in this area due to narrowing of the ventricles. The combined result of both RG steps is then further evolved by a level-set method, which propagates the boundaries of the initial, constrained segmentation mask further towards the actual ventricle boundaries. Next, the segmentation of the temporal horns is addressed. A path is traced from user-defined seed points in the anterior end of each horn through the CSF towards the main bodies of the lateral ventricles. The method for tracing the paths is based on the fast-marching algorithm. It is designed in such a way that the shape of the horn is approximated even in areas where there is no visible CSF connection between a horn's end and its corresponding lateral ventricle, due to noise or lack of image resolution, as is the case for a large percentage of datasets. For this purpose, an additional outward force is applied to the tracing process, preventing the path from diverging into adjacent CSF regions while attracting it to the horn's natural course, i.e., the outer boundary of the hippocampus. A region is then grown from the path to fill the CSF of the horns, using a fast-marching approach again. Finally, the masks of the segmented structures (lateral ventricles and temporal horns) are combined to form the final desired segmentation.
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