We describe the second generation of a 3D-Ultrasound Computer Tomography (USCT) system. After we ... more We describe the second generation of a 3D-Ultrasound Computer Tomography (USCT) system. After we achieved in the first generation a device with sub-wavelength resolution and three imaging modalities (reflection, attenuation, speed of sound) and tested it with static phantoms, we developed a device for in-vivo imaging. In the new system the geometry of transducers and their spatial distribution is optimized
Proceedings of the 2011 Conference on Design & Architectures for Signal & Image Processing (DASIP), 2011
Abstract As today's standard screening methods frequently fail to diagnose breast cancer bef... more Abstract As today's standard screening methods frequently fail to diagnose breast cancer before metastases have developed, earlier breast cancer diagnosis is still a major challenge. Three-dimensional ultrasound computer tomography promises high-quality ...
2010 IEEE International Ultrasonics Symposium, 2010
Our D Ultrasound Computer Tomograph for breast imaging uses unfocused transducers grouped on a la... more Our D Ultrasound Computer Tomograph for breast imaging uses unfocused transducers grouped on a large non-planar aperture and synthetic aperture focusing in 3D. Technical feasibility limits the number of transducer positions to a sparse aperture, causing artifacts due to grating lobe effects in the resulting images. To suppress the artifacts, a median filter is applied to special pressure distributions, which are derived for each image point. After filtering the distributions are summed up for reconstruction. This approach reduces the artifacts significantly. For a phantom of ten nylon threads (0.2 mm diameter) an increase of contrast (SDNR) from 7.6 to 35.9 could be achieved. Also more complex phantoms showed significant reduction. The presented approach is simple and very effective, and can be easily integrated into the applied synthetic aperture focusing technique.
IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control, 2015
Ultrasound is frequently used to evaluate suspicious masses in breasts. These evaluations could b... more Ultrasound is frequently used to evaluate suspicious masses in breasts. These evaluations could be improved by taking advantage of advanced imaging algorithms, which become feasible for low frequencies if accurate knowledge about the phase and amplitude of the wave field illuminating the volume of interest is available. In this study, we compare five imaging and inversion methods: time-of-flight tomography, synthetic aperture focusing technique, backpropagation, Born inversion, and contrast source inversion. All methods are tested on the same full-wave synthetic data representing a 2-D scan using a circular array enclosing a cancerous breast submerged in water. Of the tested methods, only contrast source inversion yielded an accurate reconstruction of the speed-ofsound profile of the tumor and its surroundings, because only this method takes effects such as multiple scattering, refraction, and diffraction into account.
At Forschungszentrum Karlsruhe, a new imaging system for early diagnosis of breast cancer is curr... more At Forschungszentrum Karlsruhe, a new imaging system for early diagnosis of breast cancer is currently developed. The 3D Ultrasound Computer Tomography (USCT) is based on approx. 2000 ultrasound transducers which produce 20 GB of raw data consisting of 3.5 mio. A-scans (amplitude scans) for one image. The large number of A-scans, the large amount of data and the complex relationship between raw data and reconstructed image makes analysis, understanding and further development difficult for the scientists and especially for new employees and students. For this reason, an interactive graphical user interface (GUI) was developed using MATLAB. It integrates existent analysis methods and is easily extendable with new functionality via a plugin concept. The software provides several visualization functions for the raw data, the reconstructed 3D images, the USCT aperture and the relationships between them. The software shows the capability of MATLAB as programming language for numerical so...
At Forschungszentrum Karlsruhe, a new imaging system for early diagnosis of breast cancer is curr... more At Forschungszentrum Karlsruhe, a new imaging system for early diagnosis of breast cancer is currently developed. The 3D Ultrasound Computer Tomograph (USCT) consists of approximately 2000 ultrasound transducers, which produce 3.5 million A-scans (amplitude scans) summing up to 20 GB of raw data for one image. The large number of A-scans, the large amount of data and the complex relationship between raw data and reconstructed image makes analysis, understanding and further development difficult for the scientists and especially for new employees and students. For this reason, an interactive graphical user interface (GUI) was developed using MATLAB. It integrates existent analysis methods and is easily extendable with new functionality via a plugin concept. The software provides several visualization functions for the raw data, the reconstructed 3D images, the USCT aperture and the relationships between them. This approaches demonstrate that MATLAB is not only applicable as programmi...
The quality of ultrasound computed tomography imaging is primarily determined by the accuracy of ... more The quality of ultrasound computed tomography imaging is primarily determined by the accuracy of ultrasound transit time measurement. A major problem in analysis is the overlap of signals making it difficult to detect the correct transit time. The current standard is to apply a matched-filtering approach to the input and output signals. This study compares the matched-filtering technique with active set deconvolution to derive a transit time spectrum from a coded excitation chirp signal and the measured output signal. The ultrasound wave travels in a direct and a reflected path to the receiver, resulting in an overlap in the recorded output signal. The matched-filtering and deconvolution techniques were applied to determine the transit times associated with the two signal paths. Both techniques were able to detect the two different transit times; while matched-filtering has a better accuracy (0.13 μs versus 0.18 μs standard deviations), deconvolution has a 3.5 times improved side-lo...
The KIT 3D USCT was tested in a pilot study on ten patients. The primary goals of the pilot study... more The KIT 3D USCT was tested in a pilot study on ten patients. The primary goals of the pilot study were to test the USCT device, the data acquisition protocols, the image reconstruction methods and the image fusion techniques in a clinical environment. The study was conducted successfully; the data acquisition could be carried out for all patients with an average imaging time of six minutes per breast. First reconstructions provide promising images. Overlaid volumes of the modalities show qualitative and quantitative information at a glance. The results led to further optimization of the system and the data acquisition protocol.
At Forschungszentrum Karlsruhe an ultrasound computer tomograph for breast imaging in 3D is under... more At Forschungszentrum Karlsruhe an ultrasound computer tomograph for breast imaging in 3D is under development. The aim of this project is the support of early diagnosis of breast cancer. The process of reconstructing the 20 GB of measurement data into a visual 3D volume is very compute intensive. The re-construction algorithms are written in Matlab. As a calculation platform we are using grid technologies based on gLite, which provides a powerful computing infrastructure. This paper describes how we distribute our existing Matlab application to gLite resources. The current shortcomings of gLite are overcome by the use of pilot-jobs. Our implementation of pilot-jobs is described and a performance evaluation is presented.
The Journal of the Acoustical Society of America, 2014
ABSTRACT The KIT 3D USCT surrounds the breast with ultrasound transducers on a 3D aperture and em... more ABSTRACT The KIT 3D USCT surrounds the breast with ultrasound transducers on a 3D aperture and emits and receives nearly spherical wave fronts for synthetic aperture focusing. This full 3D system achieves isotropic 3D resolution, has a nearly spatial invariant point spread function, and allows fast data acquisition. The 3D USCT device is equipped with 2041 ultrasound transducers. The acquisition is carried out by sequentially selecting a single emitter, sending a chirp at 2.5 MHz center frequency and recording the transmitted and reflected waves with all receivers. Rotational and translational movement of the aperture is applied to enhance the image contrast. Up to 40 GB of raw data is acquired with 480 parallel channels for digitization at 12 bit and 20 MHz sampling frequency. In a first pilot study, ten patients with different lesions were imaged. Speed of sound, attenuation, and reflection images of each patient were derived from the raw data. Overlaid volumes of the modalities show qualitative and quantitative information at a glance. The results are promising because the breasts' tissue structures and cancerous lesions could be identified in the USCT images.
The Journal of the Acoustical Society of America, 2014
ABSTRACT In previous work we optimized the aperture of our 3D Ultrasound Computer Tomography (USC... more ABSTRACT In previous work we optimized the aperture of our 3D Ultrasound Computer Tomography (USCT) system with emphasis on reflection tomography. Based on the promising clinical results with speed of sound and attenuation images, the next generation aperture will be upgraded to contain also optimization for transmission tomography. The main changes to be implemented in aperture, transducers, and transducer arrays are: (1) Overall 3D aperture: due to the shape of the buoyant breast a simpler hemispherical aperture can be applied. (2) The diameter of the aperture will be increased and the diameter of the transducers will be decreased for further homogenization of the illumination. (3) The disjunctive sampling of the transducers will be increased and the transducers will be distributed randomly to enhance the uniformity of transmission tomography. (4) Transducers will be connected both as emitters and receivers to decrease the need for mechanical movement of the aperture.
Medical Imaging 2014: Ultrasonic Imaging and Tomography, 2014
ABSTRACT An essential processing step for comparison of Ultrasound Computer Tomography images to ... more ABSTRACT An essential processing step for comparison of Ultrasound Computer Tomography images to other modalities, as well as for the use in further image processing, is to segment the breast from the background. In this work we present a (semi-) automated 3D segmentation method which is based on the detection of the breast boundary in coronal slice images and a subsequent surface fitting. The method was evaluated using a software phantom and in-vivo data. The fully automatically processed phantom results showed that a segmentation of approx. 10% of the slices of a dataset is sufficient to recover the overall breast shape. Application to 16 in-vivo datasets was performed successfully using semi-automated processing, i.e. using a graphical user interface for manual corrections of the automated breast boundary detection. The processing time for the segmentation of an in-vivo dataset could be significantly reduced by a factor of four compared to a fully manual segmentation. Comparison to manually segmented images identified a smoother surface for the semi-automated segmentation with an average of 11% of differing voxels and an average surface deviation of 2mm. Limitations of the edge detection may be overcome by future updates of the KIT USCT system, allowing a fully-automated usage of our segmentation approach.
ABSTRACT As today’s standard screening methods frequently fail to diagnose breast cancer before m... more ABSTRACT As today’s standard screening methods frequently fail to diagnose breast cancer before metastases have developed, earlier breast cancer diagnosis is still a major challenge. Three-dimensional ultrasound computer tomography promises high-quality images of the breast, but is currently limited by a time-consuming image reconstruction. In this work, we investigate the acceleration of the image reconstruction by GPUs and FPGAs. We compare the obtained performance results with a recent multi-core CPU. We show that both architectures are able to accelerate processing, whereas the GPU reaches the highest performance. Furthermore, we draw conclusions in terms of applicability of the accelerated reconstructions in future clinical application and highlight general principles for speed-up on GPUs and FPGAs.
Conference proceedings : ... Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Annual Conference, 2007
This paper presents a method for geometrical and time-delay auto-calibration of an ultrasonic com... more This paper presents a method for geometrical and time-delay auto-calibration of an ultrasonic computed tomography (USCT) system. The algorithms used for the calibration are based on the principles similar to the global positioning system (GPS) navigation. Ultrasonic transmitters and receivers in USCT can be viewed like satellite transmitters and mobile receiver units in GPS. However, unlike in GPS, none of the positions of the transmitters or receivers in USCT are assumed to be known and all are the to-be-calibrated unknowns. The presented method is capable of calibrating the positions of all ultrasonic transducers and their individual time delays at once. No calibration phantoms are necessary.
2012 IEEE International Ultrasonics Symposium, 2012
ABSTRACT We designed and built a 3D ultrasound computer tomography (USCT) device with a nearly is... more ABSTRACT We designed and built a 3D ultrasound computer tomography (USCT) device with a nearly isotropic and spatially invariant 3D point spread function, to be tested in a clinical study. The objective of this work was to image two healthy volunteers and to evaluate the USCT volumes in comparison to corresponding Magnetic Resonance Images (MRI). The here presented volumes are reflectivity images generated with 3D synthetic aperture focusing technique. The volunteers were imaged with different parameterizations of the data acquisition. The data acquisition time was between four and twelve minutes. For both volunteers we found that the breast surface and inner structures are clearly shown in the USCT volume and fit the structures given by the MRI.
We describe the second generation of a 3D-Ultrasound Computer Tomography (USCT) system. After we ... more We describe the second generation of a 3D-Ultrasound Computer Tomography (USCT) system. After we achieved in the first generation a device with sub-wavelength resolution and three imaging modalities (reflection, attenuation, speed of sound) and tested it with static phantoms, we developed a device for in-vivo imaging. In the new system the geometry of transducers and their spatial distribution is optimized
Proceedings of the 2011 Conference on Design & Architectures for Signal & Image Processing (DASIP), 2011
Abstract As today's standard screening methods frequently fail to diagnose breast cancer bef... more Abstract As today's standard screening methods frequently fail to diagnose breast cancer before metastases have developed, earlier breast cancer diagnosis is still a major challenge. Three-dimensional ultrasound computer tomography promises high-quality ...
2010 IEEE International Ultrasonics Symposium, 2010
Our D Ultrasound Computer Tomograph for breast imaging uses unfocused transducers grouped on a la... more Our D Ultrasound Computer Tomograph for breast imaging uses unfocused transducers grouped on a large non-planar aperture and synthetic aperture focusing in 3D. Technical feasibility limits the number of transducer positions to a sparse aperture, causing artifacts due to grating lobe effects in the resulting images. To suppress the artifacts, a median filter is applied to special pressure distributions, which are derived for each image point. After filtering the distributions are summed up for reconstruction. This approach reduces the artifacts significantly. For a phantom of ten nylon threads (0.2 mm diameter) an increase of contrast (SDNR) from 7.6 to 35.9 could be achieved. Also more complex phantoms showed significant reduction. The presented approach is simple and very effective, and can be easily integrated into the applied synthetic aperture focusing technique.
IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control, 2015
Ultrasound is frequently used to evaluate suspicious masses in breasts. These evaluations could b... more Ultrasound is frequently used to evaluate suspicious masses in breasts. These evaluations could be improved by taking advantage of advanced imaging algorithms, which become feasible for low frequencies if accurate knowledge about the phase and amplitude of the wave field illuminating the volume of interest is available. In this study, we compare five imaging and inversion methods: time-of-flight tomography, synthetic aperture focusing technique, backpropagation, Born inversion, and contrast source inversion. All methods are tested on the same full-wave synthetic data representing a 2-D scan using a circular array enclosing a cancerous breast submerged in water. Of the tested methods, only contrast source inversion yielded an accurate reconstruction of the speed-ofsound profile of the tumor and its surroundings, because only this method takes effects such as multiple scattering, refraction, and diffraction into account.
At Forschungszentrum Karlsruhe, a new imaging system for early diagnosis of breast cancer is curr... more At Forschungszentrum Karlsruhe, a new imaging system for early diagnosis of breast cancer is currently developed. The 3D Ultrasound Computer Tomography (USCT) is based on approx. 2000 ultrasound transducers which produce 20 GB of raw data consisting of 3.5 mio. A-scans (amplitude scans) for one image. The large number of A-scans, the large amount of data and the complex relationship between raw data and reconstructed image makes analysis, understanding and further development difficult for the scientists and especially for new employees and students. For this reason, an interactive graphical user interface (GUI) was developed using MATLAB. It integrates existent analysis methods and is easily extendable with new functionality via a plugin concept. The software provides several visualization functions for the raw data, the reconstructed 3D images, the USCT aperture and the relationships between them. The software shows the capability of MATLAB as programming language for numerical so...
At Forschungszentrum Karlsruhe, a new imaging system for early diagnosis of breast cancer is curr... more At Forschungszentrum Karlsruhe, a new imaging system for early diagnosis of breast cancer is currently developed. The 3D Ultrasound Computer Tomograph (USCT) consists of approximately 2000 ultrasound transducers, which produce 3.5 million A-scans (amplitude scans) summing up to 20 GB of raw data for one image. The large number of A-scans, the large amount of data and the complex relationship between raw data and reconstructed image makes analysis, understanding and further development difficult for the scientists and especially for new employees and students. For this reason, an interactive graphical user interface (GUI) was developed using MATLAB. It integrates existent analysis methods and is easily extendable with new functionality via a plugin concept. The software provides several visualization functions for the raw data, the reconstructed 3D images, the USCT aperture and the relationships between them. This approaches demonstrate that MATLAB is not only applicable as programmi...
The quality of ultrasound computed tomography imaging is primarily determined by the accuracy of ... more The quality of ultrasound computed tomography imaging is primarily determined by the accuracy of ultrasound transit time measurement. A major problem in analysis is the overlap of signals making it difficult to detect the correct transit time. The current standard is to apply a matched-filtering approach to the input and output signals. This study compares the matched-filtering technique with active set deconvolution to derive a transit time spectrum from a coded excitation chirp signal and the measured output signal. The ultrasound wave travels in a direct and a reflected path to the receiver, resulting in an overlap in the recorded output signal. The matched-filtering and deconvolution techniques were applied to determine the transit times associated with the two signal paths. Both techniques were able to detect the two different transit times; while matched-filtering has a better accuracy (0.13 μs versus 0.18 μs standard deviations), deconvolution has a 3.5 times improved side-lo...
The KIT 3D USCT was tested in a pilot study on ten patients. The primary goals of the pilot study... more The KIT 3D USCT was tested in a pilot study on ten patients. The primary goals of the pilot study were to test the USCT device, the data acquisition protocols, the image reconstruction methods and the image fusion techniques in a clinical environment. The study was conducted successfully; the data acquisition could be carried out for all patients with an average imaging time of six minutes per breast. First reconstructions provide promising images. Overlaid volumes of the modalities show qualitative and quantitative information at a glance. The results led to further optimization of the system and the data acquisition protocol.
At Forschungszentrum Karlsruhe an ultrasound computer tomograph for breast imaging in 3D is under... more At Forschungszentrum Karlsruhe an ultrasound computer tomograph for breast imaging in 3D is under development. The aim of this project is the support of early diagnosis of breast cancer. The process of reconstructing the 20 GB of measurement data into a visual 3D volume is very compute intensive. The re-construction algorithms are written in Matlab. As a calculation platform we are using grid technologies based on gLite, which provides a powerful computing infrastructure. This paper describes how we distribute our existing Matlab application to gLite resources. The current shortcomings of gLite are overcome by the use of pilot-jobs. Our implementation of pilot-jobs is described and a performance evaluation is presented.
The Journal of the Acoustical Society of America, 2014
ABSTRACT The KIT 3D USCT surrounds the breast with ultrasound transducers on a 3D aperture and em... more ABSTRACT The KIT 3D USCT surrounds the breast with ultrasound transducers on a 3D aperture and emits and receives nearly spherical wave fronts for synthetic aperture focusing. This full 3D system achieves isotropic 3D resolution, has a nearly spatial invariant point spread function, and allows fast data acquisition. The 3D USCT device is equipped with 2041 ultrasound transducers. The acquisition is carried out by sequentially selecting a single emitter, sending a chirp at 2.5 MHz center frequency and recording the transmitted and reflected waves with all receivers. Rotational and translational movement of the aperture is applied to enhance the image contrast. Up to 40 GB of raw data is acquired with 480 parallel channels for digitization at 12 bit and 20 MHz sampling frequency. In a first pilot study, ten patients with different lesions were imaged. Speed of sound, attenuation, and reflection images of each patient were derived from the raw data. Overlaid volumes of the modalities show qualitative and quantitative information at a glance. The results are promising because the breasts' tissue structures and cancerous lesions could be identified in the USCT images.
The Journal of the Acoustical Society of America, 2014
ABSTRACT In previous work we optimized the aperture of our 3D Ultrasound Computer Tomography (USC... more ABSTRACT In previous work we optimized the aperture of our 3D Ultrasound Computer Tomography (USCT) system with emphasis on reflection tomography. Based on the promising clinical results with speed of sound and attenuation images, the next generation aperture will be upgraded to contain also optimization for transmission tomography. The main changes to be implemented in aperture, transducers, and transducer arrays are: (1) Overall 3D aperture: due to the shape of the buoyant breast a simpler hemispherical aperture can be applied. (2) The diameter of the aperture will be increased and the diameter of the transducers will be decreased for further homogenization of the illumination. (3) The disjunctive sampling of the transducers will be increased and the transducers will be distributed randomly to enhance the uniformity of transmission tomography. (4) Transducers will be connected both as emitters and receivers to decrease the need for mechanical movement of the aperture.
Medical Imaging 2014: Ultrasonic Imaging and Tomography, 2014
ABSTRACT An essential processing step for comparison of Ultrasound Computer Tomography images to ... more ABSTRACT An essential processing step for comparison of Ultrasound Computer Tomography images to other modalities, as well as for the use in further image processing, is to segment the breast from the background. In this work we present a (semi-) automated 3D segmentation method which is based on the detection of the breast boundary in coronal slice images and a subsequent surface fitting. The method was evaluated using a software phantom and in-vivo data. The fully automatically processed phantom results showed that a segmentation of approx. 10% of the slices of a dataset is sufficient to recover the overall breast shape. Application to 16 in-vivo datasets was performed successfully using semi-automated processing, i.e. using a graphical user interface for manual corrections of the automated breast boundary detection. The processing time for the segmentation of an in-vivo dataset could be significantly reduced by a factor of four compared to a fully manual segmentation. Comparison to manually segmented images identified a smoother surface for the semi-automated segmentation with an average of 11% of differing voxels and an average surface deviation of 2mm. Limitations of the edge detection may be overcome by future updates of the KIT USCT system, allowing a fully-automated usage of our segmentation approach.
ABSTRACT As today’s standard screening methods frequently fail to diagnose breast cancer before m... more ABSTRACT As today’s standard screening methods frequently fail to diagnose breast cancer before metastases have developed, earlier breast cancer diagnosis is still a major challenge. Three-dimensional ultrasound computer tomography promises high-quality images of the breast, but is currently limited by a time-consuming image reconstruction. In this work, we investigate the acceleration of the image reconstruction by GPUs and FPGAs. We compare the obtained performance results with a recent multi-core CPU. We show that both architectures are able to accelerate processing, whereas the GPU reaches the highest performance. Furthermore, we draw conclusions in terms of applicability of the accelerated reconstructions in future clinical application and highlight general principles for speed-up on GPUs and FPGAs.
Conference proceedings : ... Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Annual Conference, 2007
This paper presents a method for geometrical and time-delay auto-calibration of an ultrasonic com... more This paper presents a method for geometrical and time-delay auto-calibration of an ultrasonic computed tomography (USCT) system. The algorithms used for the calibration are based on the principles similar to the global positioning system (GPS) navigation. Ultrasonic transmitters and receivers in USCT can be viewed like satellite transmitters and mobile receiver units in GPS. However, unlike in GPS, none of the positions of the transmitters or receivers in USCT are assumed to be known and all are the to-be-calibrated unknowns. The presented method is capable of calibrating the positions of all ultrasonic transducers and their individual time delays at once. No calibration phantoms are necessary.
2012 IEEE International Ultrasonics Symposium, 2012
ABSTRACT We designed and built a 3D ultrasound computer tomography (USCT) device with a nearly is... more ABSTRACT We designed and built a 3D ultrasound computer tomography (USCT) device with a nearly isotropic and spatially invariant 3D point spread function, to be tested in a clinical study. The objective of this work was to image two healthy volunteers and to evaluate the USCT volumes in comparison to corresponding Magnetic Resonance Images (MRI). The here presented volumes are reflectivity images generated with 3D synthetic aperture focusing technique. The volunteers were imaged with different parameterizations of the data acquisition. The data acquisition time was between four and twelve minutes. For both volunteers we found that the breast surface and inner structures are clearly shown in the USCT volume and fit the structures given by the MRI.
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