Abstract: This work presents the performance and validation of an augmented reality (AR) system t... more Abstract: This work presents the performance and validation of an augmented reality (AR) system to help the surgeon for trocar placement in laparoscopic surgery. The virtual organs are obtained by taking previous computed tomography (CT) or magnetic resonance (MR) ...
ABSTRACT This paper describes the image registration block developed in the hepatic planner HepaP... more ABSTRACT This paper describes the image registration block developed in the hepatic planner HepaPlan. The proposed method is intended to support clinical decisions about treatment of liver pathologies. The initial stage is the segmentation of the liver tissue as well as its internal structures and tumours in contrast-enhanced CT volumes. The second stage is non-rigid motion compensation due to CT data are acquired at different times, in arterial phase and venous phase. This image registration is necessary in order to fusion contrast-enhanced CT data and then to ease 3D volumetric measures, visualization of the liver and tumour, and to make comparisons with studies of the same patient at earlier times.
This paper presents an algorithm for a 3D segmentation of the aorta artery in magnetic resonance ... more This paper presents an algorithm for a 3D segmentation of the aorta artery in magnetic resonance images (MRI). The purpose is to project the 3D segmented aorta in the patient's abdomen with an augmented reality (AR) system to help the surgeon in laparoscopic interventions. In order to obtain accurate results in the segmentation process a marker-controlled watershed algorithm is used.
In this paper, a procedure to experimentally simulate the behavior of the liver when the pneumope... more In this paper, a procedure to experimentally simulate the behavior of the liver when the pneumoperitoneum technique is applied in laparoscopic surgery is presented, as well as methodology to make the comparison of each sample before and after insufflating the gas. This comparison is carried out using the 3D reconstruction of the volume from the CT images when either pneumoperitoneum is applied and when it is not. This methodology has showed that there are perceptible changes of volume when the pneumoperitoneum is applied.
Purpose. This work presents the protocol carried out in the development and validation of an augm... more Purpose. This work presents the protocol carried out in the development and validation of an augmented reality system which was installed in an operating theatre to help surgeons with trocar placement during laparoscopic surgery. The purpose of this validation is to demonstrate the improvements that this system can provide to the field of medicine, particularly surgery. Method. Two experiments that were noninvasive for both the patient and the surgeon were designed. In one of these experiments the augmented reality system was used, the other one was the control experiment, and the system was not used. The type of operation selected for all cases was a cholecystectomy due to the low degree of complexity and complications before, during, and after the surgery. The technique used in the placement of trocars was the French technique, but the results can be extrapolated to any other technique and operation. Results and Conclusion. Four clinicians and ninety-six measurements obtained of twenty-four patients (randomly assigned in each experiment) were involved in these experiments. The final results show an improvement in accuracy and variability of 33% and 63%, respectively, in comparison to traditional methods, demonstrating that the use of an augmented reality system offers advantages for trocar placement in laparoscopic surgery.
ABSTRACT The analysis of retinal blood vessels provides useful information for medical diagnosis ... more ABSTRACT The analysis of retinal blood vessels provides useful information for medical diagnosis of several diseases such as cardiovascular risk or diabetic and hypertensive retinopathy. These diseases affect retinal vessels so that an abnormal calibre of veins or arteries could indicate the presence of some of them. So, before analysing vessel calibres, it is interesting to distinguish between vein and artery. This paper is focused on studying the appearance of the retinal vascular network in different color spaces (RGB and HSV) to extract the most discriminant vessel features and classify the retinal vascular network as venous or arterial. The method for vessel classification has been evaluated on a public image database which facilitates further comparison with other state-of-the-art algorithms. The classification results are promising: 0.861 and 0.862 of sensitivity for vein and artery discrimination, respectively, which improve previous results of the literature. Once the vascular network has been classified, it would be possible to obtain different measures as the arterio-venous ratio (AVR), an essential parameter in the diagnosis of many diseases.
Proceedings of the International Conference on Bio-inspired Systems and Signal Processing, 2015
ABSTRACT In this work, different combinations of dissimilarity coefficients and clustering algori... more ABSTRACT In this work, different combinations of dissimilarity coefficients and clustering algorithms are compared in order to separate FTIR data in different classes. For this purpose, a dataset of eighty five spectra of four types of sample cells acquired with two different protocols are used (fixed and unfixed). Five dissimilarity coefficients were assessed by using three types of unsupervised classifiers (K-means, K-medoids and Agglomerative Hier-archical Clustering). We introduce in particular a new spectral representation by detecting the signals’ peaks and their corresponding dynamics and widths. The motivation of this representation is to introduce invariant properties with respect to small spectra shifts or intensity variations. As main results, the dissimilarity measure called Spectral Information Divergence obtained the best classification performance for both treatment protocols when is used over the proposed spectral representation.
IEEE-EMBS International Conference on Biomedical and Health Informatics (BHI), 2014
ABSTRACT This paper presents a comparison between different image registration approaches to regi... more ABSTRACT This paper presents a comparison between different image registration approaches to register infrared (IR) and hematoxylin and eosin (H&E) stained images. This registration will be needed as the first step of a new process based on mid-IR images, that will help clinicians in cancer early diagnosis, providing them with more information about the tissue under examination. The aim of the registration step is to translate the segmented areas of interest in cancer diagnosis from the H&E images to the IR images, reducing the process of segmentation to the stained images. Being able to perform an automatic segmentation of these regions, the amount of data to be analysed will be drastically reduced increasing the speed of the process. The results of this paper show that the projective transformation approach is the best option to register these kinds of images using a reasonable number of keypoints.
IEEE-EMBS International Conference on Biomedical and Health Informatics (BHI), 2014
ABSTRACT This paper presents a system for detecting mor-phometric properties of bladder mucosa im... more ABSTRACT This paper presents a system for detecting mor-phometric properties of bladder mucosa images obtained with a cystoscope. These properties are calculated for obtaining information about the probability of tumour recurrence. For this purpose, illumination problems of these images have been corrected to apply a vessels segmentation algorithm. Finally, the number of bifurcations of the vascular tree and a ratio Vessels/Bladder area are calculated to validate the hypothesis mentioned above. This validation is carried out with 20 images of bladder mucosa obtaining very promising results, in particular the presented algorithm achieves a sensibility of 0.8571 and a specificity of 1. Consequently, the system proposed in this paper shows valuable properties for the specific objective pointed, i.e, the characterization of the bladder tumour recurrence.
The VESSEL12 (VESsel SEgmentation in the Lung) challenge objectively compares the performance of ... more The VESSEL12 (VESsel SEgmentation in the Lung) challenge objectively compares the performance of different algorithms to identify vessels in thoracic computed tomography (CT) scans. Vessel segmentation is fundamental in computer aided processing of data generated by 3D imaging modalities. As manual vessel segmentation is prohibitively time consuming, any real world application requires some form of automation. Several approaches exist for automated vessel segmentation, but judging their relative merits is difficult due to a lack of standardized evaluation. We present an annotated reference dataset containing 20 CT scans and propose nine categories to perform a comprehensive evaluation of vessel segmentation algorithms from both academia and industry. Twenty algorithms participated in the VESSEL12 challenge, held at International Symposium on Biomedical Imaging (ISBI) 2012. All results have been published at the VESSEL12 website http://vessel12.grand-challenge.org. The challenge remains ongoing and open to new participants. Our three contributions are: (1) an annotated reference dataset available online for evaluation of new algorithms; (2) a quantitative scoring system for objective comparison of algorithms; and (3) performance analysis of the strengths and weaknesses of the various vessel segmentation methods in the presence of various lung diseases.
Abstract: This work presents the performance and validation of an augmented reality (AR) system t... more Abstract: This work presents the performance and validation of an augmented reality (AR) system to help the surgeon for trocar placement in laparoscopic surgery. The virtual organs are obtained by taking previous computed tomography (CT) or magnetic resonance (MR) ...
ABSTRACT This paper describes the image registration block developed in the hepatic planner HepaP... more ABSTRACT This paper describes the image registration block developed in the hepatic planner HepaPlan. The proposed method is intended to support clinical decisions about treatment of liver pathologies. The initial stage is the segmentation of the liver tissue as well as its internal structures and tumours in contrast-enhanced CT volumes. The second stage is non-rigid motion compensation due to CT data are acquired at different times, in arterial phase and venous phase. This image registration is necessary in order to fusion contrast-enhanced CT data and then to ease 3D volumetric measures, visualization of the liver and tumour, and to make comparisons with studies of the same patient at earlier times.
This paper presents an algorithm for a 3D segmentation of the aorta artery in magnetic resonance ... more This paper presents an algorithm for a 3D segmentation of the aorta artery in magnetic resonance images (MRI). The purpose is to project the 3D segmented aorta in the patient's abdomen with an augmented reality (AR) system to help the surgeon in laparoscopic interventions. In order to obtain accurate results in the segmentation process a marker-controlled watershed algorithm is used.
In this paper, a procedure to experimentally simulate the behavior of the liver when the pneumope... more In this paper, a procedure to experimentally simulate the behavior of the liver when the pneumoperitoneum technique is applied in laparoscopic surgery is presented, as well as methodology to make the comparison of each sample before and after insufflating the gas. This comparison is carried out using the 3D reconstruction of the volume from the CT images when either pneumoperitoneum is applied and when it is not. This methodology has showed that there are perceptible changes of volume when the pneumoperitoneum is applied.
Purpose. This work presents the protocol carried out in the development and validation of an augm... more Purpose. This work presents the protocol carried out in the development and validation of an augmented reality system which was installed in an operating theatre to help surgeons with trocar placement during laparoscopic surgery. The purpose of this validation is to demonstrate the improvements that this system can provide to the field of medicine, particularly surgery. Method. Two experiments that were noninvasive for both the patient and the surgeon were designed. In one of these experiments the augmented reality system was used, the other one was the control experiment, and the system was not used. The type of operation selected for all cases was a cholecystectomy due to the low degree of complexity and complications before, during, and after the surgery. The technique used in the placement of trocars was the French technique, but the results can be extrapolated to any other technique and operation. Results and Conclusion. Four clinicians and ninety-six measurements obtained of twenty-four patients (randomly assigned in each experiment) were involved in these experiments. The final results show an improvement in accuracy and variability of 33% and 63%, respectively, in comparison to traditional methods, demonstrating that the use of an augmented reality system offers advantages for trocar placement in laparoscopic surgery.
ABSTRACT The analysis of retinal blood vessels provides useful information for medical diagnosis ... more ABSTRACT The analysis of retinal blood vessels provides useful information for medical diagnosis of several diseases such as cardiovascular risk or diabetic and hypertensive retinopathy. These diseases affect retinal vessels so that an abnormal calibre of veins or arteries could indicate the presence of some of them. So, before analysing vessel calibres, it is interesting to distinguish between vein and artery. This paper is focused on studying the appearance of the retinal vascular network in different color spaces (RGB and HSV) to extract the most discriminant vessel features and classify the retinal vascular network as venous or arterial. The method for vessel classification has been evaluated on a public image database which facilitates further comparison with other state-of-the-art algorithms. The classification results are promising: 0.861 and 0.862 of sensitivity for vein and artery discrimination, respectively, which improve previous results of the literature. Once the vascular network has been classified, it would be possible to obtain different measures as the arterio-venous ratio (AVR), an essential parameter in the diagnosis of many diseases.
Proceedings of the International Conference on Bio-inspired Systems and Signal Processing, 2015
ABSTRACT In this work, different combinations of dissimilarity coefficients and clustering algori... more ABSTRACT In this work, different combinations of dissimilarity coefficients and clustering algorithms are compared in order to separate FTIR data in different classes. For this purpose, a dataset of eighty five spectra of four types of sample cells acquired with two different protocols are used (fixed and unfixed). Five dissimilarity coefficients were assessed by using three types of unsupervised classifiers (K-means, K-medoids and Agglomerative Hier-archical Clustering). We introduce in particular a new spectral representation by detecting the signals’ peaks and their corresponding dynamics and widths. The motivation of this representation is to introduce invariant properties with respect to small spectra shifts or intensity variations. As main results, the dissimilarity measure called Spectral Information Divergence obtained the best classification performance for both treatment protocols when is used over the proposed spectral representation.
IEEE-EMBS International Conference on Biomedical and Health Informatics (BHI), 2014
ABSTRACT This paper presents a comparison between different image registration approaches to regi... more ABSTRACT This paper presents a comparison between different image registration approaches to register infrared (IR) and hematoxylin and eosin (H&E) stained images. This registration will be needed as the first step of a new process based on mid-IR images, that will help clinicians in cancer early diagnosis, providing them with more information about the tissue under examination. The aim of the registration step is to translate the segmented areas of interest in cancer diagnosis from the H&E images to the IR images, reducing the process of segmentation to the stained images. Being able to perform an automatic segmentation of these regions, the amount of data to be analysed will be drastically reduced increasing the speed of the process. The results of this paper show that the projective transformation approach is the best option to register these kinds of images using a reasonable number of keypoints.
IEEE-EMBS International Conference on Biomedical and Health Informatics (BHI), 2014
ABSTRACT This paper presents a system for detecting mor-phometric properties of bladder mucosa im... more ABSTRACT This paper presents a system for detecting mor-phometric properties of bladder mucosa images obtained with a cystoscope. These properties are calculated for obtaining information about the probability of tumour recurrence. For this purpose, illumination problems of these images have been corrected to apply a vessels segmentation algorithm. Finally, the number of bifurcations of the vascular tree and a ratio Vessels/Bladder area are calculated to validate the hypothesis mentioned above. This validation is carried out with 20 images of bladder mucosa obtaining very promising results, in particular the presented algorithm achieves a sensibility of 0.8571 and a specificity of 1. Consequently, the system proposed in this paper shows valuable properties for the specific objective pointed, i.e, the characterization of the bladder tumour recurrence.
The VESSEL12 (VESsel SEgmentation in the Lung) challenge objectively compares the performance of ... more The VESSEL12 (VESsel SEgmentation in the Lung) challenge objectively compares the performance of different algorithms to identify vessels in thoracic computed tomography (CT) scans. Vessel segmentation is fundamental in computer aided processing of data generated by 3D imaging modalities. As manual vessel segmentation is prohibitively time consuming, any real world application requires some form of automation. Several approaches exist for automated vessel segmentation, but judging their relative merits is difficult due to a lack of standardized evaluation. We present an annotated reference dataset containing 20 CT scans and propose nine categories to perform a comprehensive evaluation of vessel segmentation algorithms from both academia and industry. Twenty algorithms participated in the VESSEL12 challenge, held at International Symposium on Biomedical Imaging (ISBI) 2012. All results have been published at the VESSEL12 website http://vessel12.grand-challenge.org. The challenge remains ongoing and open to new participants. Our three contributions are: (1) an annotated reference dataset available online for evaluation of new algorithms; (2) a quantitative scoring system for objective comparison of algorithms; and (3) performance analysis of the strengths and weaknesses of the various vessel segmentation methods in the presence of various lung diseases.
Uploads
Papers by F. López-mir