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Victoria Teodorescu - One of the best experts on this subject based on the ideXlab platform.
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first experience in human beings with a permanently implantable intrasac pressure transducer for monitoring endovascular repair of abdominal aortic aneurysms
Journal of Vascular Surgery, 2006Co-Authors: Sharif H Ellozy, Alfio Carroccio, Robert A Lookstein, Michael E Minor, Claudie M Sheahan, Jacob Juta, Rolando Valenzuela, Michael D Addis, Tikva S Jacobs, Victoria TeodorescuAbstract:Objectives Endovascular stent graft repair of abdominal aortic aneurysms (AAAs) prevents rupture by excluding the aneurysm sac from systemic arterial pressure. Current surveillance protocols after endovascular aneurysm repair (EVAR) follow secondary markers of sac pressurization, namely, endoleak and sac enlargement. We report the first clinical experience with the use of a permanently implantable, ultrasound-activated Remote pressure transducer to measure intrasac pressure after EVAR. Methods Over 7 months, 14 patients underwent EVAR of an infrarenal abdominal aortic aneurysm with implantation of an ultrasound-activated Remote pressure transducer fixed to the outside of the stent graft and exposed to the excluded aortic sac. Twelve patients received modular bifurcated stent grafts, and 2 patients received aortouniiliac devices. Intrasac pressures were measured directly with an intravascular catheter and by the Remote Sensor at stent-graft deployment. Follow-up sac pressures were measured with a Remote Sensor and correlated with systemic arterial pressure at every follow-up visit. Mean follow-up was 2.6 ±1.9 months. Results Excellent concordance was found between catheter-derived and transducer-derived intrasac pressssure intraoperatively. Pulsatile waveforms were seen in all functioning transducers at each evaluation interval. One implant ceased to function at 2 months of follow-up. In 1 patient a type I endoleak was diagnosed on 1-month computed tomography (CT) scans; 3 type II endoleaks were observed. Those patients with complete exclusion of the aneurysm on CT scans had a significant difference in systemic and sac systolic pressures initially ( P P P P Conclusion This is the first report of a totally implantable chronic pressure transducer to monitor the results of EVAR in human beings. Aneurysm exclusion leads to gradual diminution of sac pressure over several months. Additional clinical follow-up will be necessary to determine whether aneurysm sac pressure monitoring can replace CT in the long-term surveillance of patients after EVAR.
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abdominal aortic aneurysm sac shrinkage after endovascular aneurysm repair correlation with chronic sac pressure measurement
Journal of Vascular Surgery, 2006Co-Authors: Sharif H Ellozy, Alfio Carroccio, Robert A Lookstein, Michael D Addis, Tikva S Jacobs, Victoria Teodorescu, Michael L MarinAbstract:Objectives Abdominal aortic aneurysm (AAA) sac shrinkage after endovascular aneurysm repair (EVAR) is considered to be evidence of clinical success. Exclusion of the sac from systemic pressure is the likely cause of shrinkage. We report our continuing clinical experience with the use of a permanently implantable, ultrasound-activated Remote pressure transducer to measure intrasac pressure and its correlation with changes in sac diameter over time. Methods Over a 22-month period, 21 patients underwent EVAR of an infrarenal AAA with implantation of an ultrasound-activated Remote pressure transducer fixed to the outside of the stent-graft and exposed to the excluded aortic sac. Intrasac pressures were measured directly with an intravascular catheter and by the Remote Sensor at the time of stent-graft deployment. Follow-up sac pressures were measured by Remote Sensor and compared with systemic arterial pressure at every follow-up visit. Mean follow-up was 11.4 ± 5.0 months (range, 1 to 26 months). Twenty patients had follow-up of ≥6 months. Mean pressure index (MPI) was calculated as the ratio of mean sac pressure to mean systemic pressure. Results Pressures could be obtained at all visits in 15 of the 21 patients. Fourteen of these 15 patients had follow-up of at least 6 months. Aneurysm sac shrinkage of >5 mm was seen in seven (50%) of these 14 patients. No aneurysm enlargement was observed in any patient. The MPI was significantly lower in patients with sac shrinkage at 6 months and at final follow-up. Conclusions Endovascular aneurysm repair results in marked reduction of sac pressure in most patients. Patients with aneurysm shrinkage after EVAR have significantly lower MPI; however, the absence of sac shrinkage does not imply persistent pressurization of the sac. Further clinical follow-up will delineate the role of long-term sac pressure monitoring in surveillance after EVAR.
Jiawei Wang - One of the best experts on this subject based on the ideXlab platform.
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deep belief network for spectral spatial classification of hyperspectral Remote Sensor data
Sensors, 2019Co-Authors: Yongchang Wang, Hongmin Gao, Yao Yang, Xiaoke Zhang, Jiawei WangAbstract:With the development of high-resolution optical Sensors, the classification of ground objects combined with multivariate optical Sensors is a hot topic at present. Deep learning methods, such as convolutional neural networks, are applied to feature extraction and classification. In this work, a novel deep belief network (DBN) hyperspectral image classification method based on multivariate optical Sensors and stacked by restricted Boltzmann machines is proposed. We introduced the DBN framework to classify spatial hyperspectral Sensor data on the basis of DBN. Then, the improved method (combination of spectral and spatial information) was verified. After unsupervised pretraining and supervised fine-tuning, the DBN model could successfully learn features. Additionally, we added a logistic regression layer that could classify the hyperspectral images. Moreover, the proposed training method, which fuses spectral and spatial information, was tested over the Indian Pines and Pavia University datasets. The advantages of this method over traditional methods are as follows: (1) the network has deep structure and the ability of feature extraction is stronger than traditional classifiers; (2) experimental results indicate that our method outperforms traditional classification and other deep learning approaches.
Sharif H Ellozy - One of the best experts on this subject based on the ideXlab platform.
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first experience in human beings with a permanently implantable intrasac pressure transducer for monitoring endovascular repair of abdominal aortic aneurysms
Journal of Vascular Surgery, 2006Co-Authors: Sharif H Ellozy, Alfio Carroccio, Robert A Lookstein, Michael E Minor, Claudie M Sheahan, Jacob Juta, Rolando Valenzuela, Michael D Addis, Tikva S Jacobs, Victoria TeodorescuAbstract:Objectives Endovascular stent graft repair of abdominal aortic aneurysms (AAAs) prevents rupture by excluding the aneurysm sac from systemic arterial pressure. Current surveillance protocols after endovascular aneurysm repair (EVAR) follow secondary markers of sac pressurization, namely, endoleak and sac enlargement. We report the first clinical experience with the use of a permanently implantable, ultrasound-activated Remote pressure transducer to measure intrasac pressure after EVAR. Methods Over 7 months, 14 patients underwent EVAR of an infrarenal abdominal aortic aneurysm with implantation of an ultrasound-activated Remote pressure transducer fixed to the outside of the stent graft and exposed to the excluded aortic sac. Twelve patients received modular bifurcated stent grafts, and 2 patients received aortouniiliac devices. Intrasac pressures were measured directly with an intravascular catheter and by the Remote Sensor at stent-graft deployment. Follow-up sac pressures were measured with a Remote Sensor and correlated with systemic arterial pressure at every follow-up visit. Mean follow-up was 2.6 ±1.9 months. Results Excellent concordance was found between catheter-derived and transducer-derived intrasac pressssure intraoperatively. Pulsatile waveforms were seen in all functioning transducers at each evaluation interval. One implant ceased to function at 2 months of follow-up. In 1 patient a type I endoleak was diagnosed on 1-month computed tomography (CT) scans; 3 type II endoleaks were observed. Those patients with complete exclusion of the aneurysm on CT scans had a significant difference in systemic and sac systolic pressures initially ( P P P P Conclusion This is the first report of a totally implantable chronic pressure transducer to monitor the results of EVAR in human beings. Aneurysm exclusion leads to gradual diminution of sac pressure over several months. Additional clinical follow-up will be necessary to determine whether aneurysm sac pressure monitoring can replace CT in the long-term surveillance of patients after EVAR.
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abdominal aortic aneurysm sac shrinkage after endovascular aneurysm repair correlation with chronic sac pressure measurement
Journal of Vascular Surgery, 2006Co-Authors: Sharif H Ellozy, Alfio Carroccio, Robert A Lookstein, Michael D Addis, Tikva S Jacobs, Victoria Teodorescu, Michael L MarinAbstract:Objectives Abdominal aortic aneurysm (AAA) sac shrinkage after endovascular aneurysm repair (EVAR) is considered to be evidence of clinical success. Exclusion of the sac from systemic pressure is the likely cause of shrinkage. We report our continuing clinical experience with the use of a permanently implantable, ultrasound-activated Remote pressure transducer to measure intrasac pressure and its correlation with changes in sac diameter over time. Methods Over a 22-month period, 21 patients underwent EVAR of an infrarenal AAA with implantation of an ultrasound-activated Remote pressure transducer fixed to the outside of the stent-graft and exposed to the excluded aortic sac. Intrasac pressures were measured directly with an intravascular catheter and by the Remote Sensor at the time of stent-graft deployment. Follow-up sac pressures were measured by Remote Sensor and compared with systemic arterial pressure at every follow-up visit. Mean follow-up was 11.4 ± 5.0 months (range, 1 to 26 months). Twenty patients had follow-up of ≥6 months. Mean pressure index (MPI) was calculated as the ratio of mean sac pressure to mean systemic pressure. Results Pressures could be obtained at all visits in 15 of the 21 patients. Fourteen of these 15 patients had follow-up of at least 6 months. Aneurysm sac shrinkage of >5 mm was seen in seven (50%) of these 14 patients. No aneurysm enlargement was observed in any patient. The MPI was significantly lower in patients with sac shrinkage at 6 months and at final follow-up. Conclusions Endovascular aneurysm repair results in marked reduction of sac pressure in most patients. Patients with aneurysm shrinkage after EVAR have significantly lower MPI; however, the absence of sac shrinkage does not imply persistent pressurization of the sac. Further clinical follow-up will delineate the role of long-term sac pressure monitoring in surveillance after EVAR.
Coffman, Richard A. - One of the best experts on this subject based on the ideXlab platform.
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Validation of a ground-based telescope-assisted hyperspectral Remote Sensor for soil measurements
'SPIE-Intl Soc Optical Eng', 2020Co-Authors: Salazar Sean, Coffman, Richard A.Abstract:The utility of the ground-based soil observation laser absorption spectrometer (SOLAS) was demonstrated through spectral reflectance measurements of five soil types during laboratory- and field-based collection. The SOLAS telescope-assisted measurements were compared with proximal measurements. The spectra that were acquired at an intermediate range of 40 meters compared well with the spectra that were acquired proximally. Specimen type, range-dependent spatial resolution, and environmental conditions are discussed. The signal-to-noise ratio (SNR) was assessed and is presented as a function of wavelength for the spectral range of the receiver for each measurement condition. The proximal measurements performed outdoors under solar illumination had the greatest SNR, while the Remote measurements performed indoors under artificial illumination had the lowest SNR. For the outdoor measurements, loss of signal was observed around the 1400- and 1900-nm bands due to long-path atmospheric water vapor absorption. The discussed future improvements to the SOLAS Remote Sensor will enable measurements of reflectance over longer ranges. Envisioned applications include Remote characterization of surface materials for large construction projects (e.g., surface mines and tailings) for geohazard investigations, or for ground truthing of current and future multispectral and hyperspectral satellite data.publishedVersio
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Validation of a ground-based telescope-assisted hyperspectral Remote Sensor for soil measurements
2020Co-Authors: Salazar Sean, Coffman, Richard A.Abstract:The utility of the ground-based soil observation laser absorption spectrometer (SOLAS) was demonstrated through spectral reflectance measurements of five soil types during laboratory- and field-based collection. The SOLAS telescope-assisted measurements were compared with proximal measurements. The spectra that were acquired at an intermediate range of 40 meters compared well with the spectra that were acquired proximally. Specimen type, range-dependent spatial resolution, and environmental conditions are discussed. The signal-to-noise ratio (SNR) was assessed and is presented as a function of wavelength for the spectral range of the receiver for each measurement condition. The proximal measurements performed outdoors under solar illumination had the greatest SNR, while the Remote measurements performed indoors under artificial illumination had the lowest SNR. For the outdoor measurements, loss of signal was observed around the 1400- and 1900-nm bands due to long-path atmospheric water vapor absorption. The discussed future improvements to the SOLAS Remote Sensor will enable measurements of reflectance over longer ranges. Envisioned applications include Remote characterization of surface materials for large construction projects (e.g., surface mines and tailings) for geohazard investigations, or for ground truthing of current and future multispectral and hyperspectral satellite data
Suya You - One of the best experts on this subject based on the ideXlab platform.
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Automatic reconstruction of cities from Remote Sensor data
2009 IEEE Computer Society Conference on Computer Vision and Pattern Recognition Workshops, CVPR Workshops 2009, 2009Co-Authors: Charalambos Poullis, Suya YouAbstract:In this paper, we address the complex problem of rapid modeling of large-scale areas and present a novel approach for the automatic reconstruction of cities from Remote Sensor data. The goal in this work is to automatically create lightweight, watertight polygonal 3D models from LiDAR data (Light Detection and Ranging) captured by an airborne scanner. This is achieved in three steps: preprocessing, segmentation and modeling, as shown in Figure 1. Our main technical contributions in this paper are: (i) a novel, robust, automatic segmentation technique based on the statistical analysis of the geometric properties of the data, which makes no particular assumptions about the input data, thus having no data dependencies, and (ii) an efficient and automatic modeling pipeline for the reconstruction of large-scale areas containing several thousands of buildings. We have extensively tested the proposed approach with several city-size datasets including downtown Baltimore, downtown Denver, the city of Atlanta, downtown Oakland, and we present and evaluate the experimental results.
