Fabian Torres - Academia.edu (original) (raw)
Papers by Fabian Torres
Spei Domus, 2015
Introduction. Similarities between the bodies of pigs and humans have encouraged studies in compa... more Introduction. Similarities between the bodies of pigs and humans have encouraged studies in comparative anatomy, trying to describe in detail the anatomical variations that could influence in the xenotransplantation, given that advances in genetics, immunology and biotechnology are large, this possibility is not far. The objective of this work was to make contributions to the vascular study of porcine heart. Methodology. 60 porcine hearts, with an average of 5 months old and weighing 85-95kg were obtained from plant Vijagual. After receipt hearts were kept in water for 6 hours, then they were perfused with polyester resin semi-synthetic and mineral blue color, moreover the left coronary artery was perfused with red mineral color. Subsequently, the hearts were subjected to a process of partial corrosion with potassium hydroxide (15%), then the coronary sinus and its tributary branches were dissected from its origin to its distal segments, path, shapes, sizes, anastomosis and presen...
Journal of healthcare engineering, 2018
The intraoperative registration of preoperative CT volumes is a key process of most computer-assi... more The intraoperative registration of preoperative CT volumes is a key process of most computer-assisted orthopedic surgery (CAOS) systems. In this work, is reported a new method for automatic registration of long bones, based on the segmentation of the bone cortical in intraoperative 3D ultrasound images. A bone classifier was developed based on features, obtained from the principal component analysis of the Hessian matrix, of every voxel in an intraoperative ultrasound volume. 3D freehand ultrasound was used for the acquisition of the intraoperative ultrasound volumes. Corresponding bone surface segmentations in ultrasound and preoperative CT imaging were used for the intraoperative registration. Validation on a phantom of the tibia produced encouraging results, with a maximum mean segmentation error of 0.34mm (SD=0.26mm) and a registration accuracy error of 0.64mm (SD=0.49mm).
SPIE Proceedings, 2013
Image-guided interventions allow the physician to have a better planning and visualization of a p... more Image-guided interventions allow the physician to have a better planning and visualization of a procedure. 3D freehand ultrasound is a non-invasive and low-cost imaging tool that can be used to assist medical procedures. This tool can be used in the diagnosis and treatment of breast cancer. There are common medical practices that involve large needles to obtain an accurate diagnosis and treatment of breast cancer. In this study we propose the use of 3D freehand ultrasound for planning and guiding such procedures as core needle biopsy and radiofrequency ablation. The proposed system will help the physician to identify the lesion area, using image-processing techniques in the 3D freehand ultrasound images, and guide the needle to this area using the information of position and orientation of the surgical tools. We think that this system can upgrade the accuracy and efficiency of these procedures.
SPIE Proceedings, 2013
Computer Assisted Orthopedic Surgery (CAOS) requires a correct registration between the patient i... more Computer Assisted Orthopedic Surgery (CAOS) requires a correct registration between the patient in the operating room and the virtual models representing the patient in the computer. In order to increase the precision and accuracy of the registration a set of new techniques that eliminated the need to use fiducial markers have been developed. The majority of these newly developed registration systems are based on costly intraoperative imaging systems like Computed Tomography (CT scan) or Magnetic resonance imaging (MRI). An alternative to these methods is the use of an Ultrasound (US) imaging system for the implementation of a more cost efficient intraoperative registration solution. In order to develop the registration solution with the US imaging system, the bone surface is segmented in both preoperative and intraoperative images, and the registration is done using the acquire surface. In this paper, we present the a preliminary results of a new approach to segment bone surface from ultrasound volumes acquired by means 3D freehand ultrasound. The method is based on the enhancement of the voxels that belongs to surface and its posterior segmentation. The enhancement process is based on the information provided by eigenanalisis of the multiscale 3D Hessian matrix. The preliminary results shows that from the enhance volume the final bone surfaces can be extracted using a singular value thresholding.
14th International Symposium on Medical Information Processing and Analysis, 2018
Abdominal electrocardiography (AECG) is an indirect method for obtaining a continuous reading of ... more Abdominal electrocardiography (AECG) is an indirect method for obtaining a continuous reading of fetal heart rate and is widely used during pregnancy as a method for assessing fetal well-being. Information obtained by AECG is used for early identification of fetal risk and may help in the anticipation of future complications; however, improper interpretation of the AECG recordings, related with inter- and intra-individual variability, may lead to inadequate treatments that can cause the death of the fetus. A set of 33 indices (4 maternal, 5 temporals, 23 time-frequency and 1 non-linear), extracted from AECG recordings and maternal information, were tested with a Random Forest (RF) classification method for the identification of normal fetuses and fetuses with intrauterine growth restriction. Because RFs may perform poorly when confronted with a high number of features compared to the number of training data available, a Genetic Algorithm (GA) was used to select the minimum set of features that improves the outcome of the RF. The accuracy of the RF method using the 33 indices was of 60%. After a run of the GA, the best individual in the last generation had an accuracy value of 85% and reduced the number of used indices from 33 to 11.
Spei Domus, 2015
Introduction. Similarities between the bodies of pigs and humans have encouraged studies in compa... more Introduction. Similarities between the bodies of pigs and humans have encouraged studies in comparative anatomy, trying to describe in detail the anatomical variations that could influence in the xenotransplantation, given that advances in genetics, immunology and biotechnology are large, this possibility is not far. The objective of this work was to make contributions to the vascular study of porcine heart. Methodology. 60 porcine hearts, with an average of 5 months old and weighing 85-95kg were obtained from plant Vijagual. After receipt hearts were kept in water for 6 hours, then they were perfused with polyester resin semi-synthetic and mineral blue color, moreover the left coronary artery was perfused with red mineral color. Subsequently, the hearts were subjected to a process of partial corrosion with potassium hydroxide (15%), then the coronary sinus and its tributary branches were dissected from its origin to its distal segments, path, shapes, sizes, anastomosis and presen...
Journal of healthcare engineering, 2018
The intraoperative registration of preoperative CT volumes is a key process of most computer-assi... more The intraoperative registration of preoperative CT volumes is a key process of most computer-assisted orthopedic surgery (CAOS) systems. In this work, is reported a new method for automatic registration of long bones, based on the segmentation of the bone cortical in intraoperative 3D ultrasound images. A bone classifier was developed based on features, obtained from the principal component analysis of the Hessian matrix, of every voxel in an intraoperative ultrasound volume. 3D freehand ultrasound was used for the acquisition of the intraoperative ultrasound volumes. Corresponding bone surface segmentations in ultrasound and preoperative CT imaging were used for the intraoperative registration. Validation on a phantom of the tibia produced encouraging results, with a maximum mean segmentation error of 0.34mm (SD=0.26mm) and a registration accuracy error of 0.64mm (SD=0.49mm).
SPIE Proceedings, 2013
Image-guided interventions allow the physician to have a better planning and visualization of a p... more Image-guided interventions allow the physician to have a better planning and visualization of a procedure. 3D freehand ultrasound is a non-invasive and low-cost imaging tool that can be used to assist medical procedures. This tool can be used in the diagnosis and treatment of breast cancer. There are common medical practices that involve large needles to obtain an accurate diagnosis and treatment of breast cancer. In this study we propose the use of 3D freehand ultrasound for planning and guiding such procedures as core needle biopsy and radiofrequency ablation. The proposed system will help the physician to identify the lesion area, using image-processing techniques in the 3D freehand ultrasound images, and guide the needle to this area using the information of position and orientation of the surgical tools. We think that this system can upgrade the accuracy and efficiency of these procedures.
SPIE Proceedings, 2013
Computer Assisted Orthopedic Surgery (CAOS) requires a correct registration between the patient i... more Computer Assisted Orthopedic Surgery (CAOS) requires a correct registration between the patient in the operating room and the virtual models representing the patient in the computer. In order to increase the precision and accuracy of the registration a set of new techniques that eliminated the need to use fiducial markers have been developed. The majority of these newly developed registration systems are based on costly intraoperative imaging systems like Computed Tomography (CT scan) or Magnetic resonance imaging (MRI). An alternative to these methods is the use of an Ultrasound (US) imaging system for the implementation of a more cost efficient intraoperative registration solution. In order to develop the registration solution with the US imaging system, the bone surface is segmented in both preoperative and intraoperative images, and the registration is done using the acquire surface. In this paper, we present the a preliminary results of a new approach to segment bone surface from ultrasound volumes acquired by means 3D freehand ultrasound. The method is based on the enhancement of the voxels that belongs to surface and its posterior segmentation. The enhancement process is based on the information provided by eigenanalisis of the multiscale 3D Hessian matrix. The preliminary results shows that from the enhance volume the final bone surfaces can be extracted using a singular value thresholding.
14th International Symposium on Medical Information Processing and Analysis, 2018
Abdominal electrocardiography (AECG) is an indirect method for obtaining a continuous reading of ... more Abdominal electrocardiography (AECG) is an indirect method for obtaining a continuous reading of fetal heart rate and is widely used during pregnancy as a method for assessing fetal well-being. Information obtained by AECG is used for early identification of fetal risk and may help in the anticipation of future complications; however, improper interpretation of the AECG recordings, related with inter- and intra-individual variability, may lead to inadequate treatments that can cause the death of the fetus. A set of 33 indices (4 maternal, 5 temporals, 23 time-frequency and 1 non-linear), extracted from AECG recordings and maternal information, were tested with a Random Forest (RF) classification method for the identification of normal fetuses and fetuses with intrauterine growth restriction. Because RFs may perform poorly when confronted with a high number of features compared to the number of training data available, a Genetic Algorithm (GA) was used to select the minimum set of features that improves the outcome of the RF. The accuracy of the RF method using the 33 indices was of 60%. After a run of the GA, the best individual in the last generation had an accuracy value of 85% and reduced the number of used indices from 33 to 11.