The Signal Processing and Control Systems Group (SPCSG) provides collaborative and consultative professional electrical, electronic, electro-optical, and computer engineering support to clinical and biomedical research projects at the National Institutes of Health (NIH). Collaborations involving advanced real-time signal transduction, signal processing, and control have resulted in innovative advances in a wide variety of intramural research program (IRP) projects. These SPCSG capabilities and accomplishments have established the group as the focal point for this type of electrical engineering research and development at the NIH. Project and Activity Reports: Project #1: Laser Capture Microdissection Technology Laser Capture Microdissection (LCM) technologies have been developed in collaboration with NCI, NICHD, and OD. LCM technologies provide a method for one-step procurement of selected human cell populations from histopathology slides containing complex, heterogeneous tissue. The targeted regions are comprised of either cells from a specific pathology, or normal control cells. Due to the homogeneity of the dissected tissue, there is a significant increase in the value of subsequent genetic analysis results. Prior to the development of LCM, dissected tissues were often contaminated with wrong cells, therefore limiting the practical value of downstream molecular analysis. LCM is being used in the Cancer Genome Anatomy Project (CGAP) to catalog genes which are expressed during cancer progression. The SPCSG is responsible for many aspects of the LCM technology development. Example SPCSG design and development responsibilities include: laser diode control electronics, instrumentation computer control software, image and data archiving, system automation, system networking, and telemedicine. In FY99, the NIH LCM development team focused on the development of the single cell microdissection system, and novel electro-mechanical systems for specialized LCM applications. Specific joint accomplishments include: 1) refinement of the single cell microdissection system using custom software and hardware; and 2) development of system software and electronics for a LCM Tape system aimed at lab-on-a-chip and non-contact applications. In FY2K, the SPCSG will build upon FY99 accomplishments, as well as explore new areas crucial to advancing LCM technology. The LCM technology is rapidly evolving, and requires continual electronic hardware design enhancements and software development. For example, the SPCSG plans to continue the LCM Tape system development which will enable the evaluation of non-contact tissue microdissection, and high- throughput automation techniques. Also in FY2K, it will be necessary to support the NIH LCM core facility, as well as stand alone LCM systems at NIH. Project #2: cDNA Microarray SystemA cDNA Microarray system has been developed in collaboration with NHGRI, NCI, NIEHS, and OD. The cDNA Microarray system is used to study thousands of genes simultaneously, an advance that will help examine the complex relationships between individual genes. The system is comprised of an Arrayer and a Scanner. The Arrayer generates high-density microarrays of expressed sequence tags (ESTs) on microscope slides. The Scanner provides a means of obtaining quantitative measures of the extent of hybridization of flourescently tagged genetic messenger molecules to the ESTs in the microarray. cDNA Microarray technologies are being used in the Cancer Genome Anatomy Project (CGAP) for gene discovery and analysis of gene expression patterns in human tissue biopsies. The SPCSG is responsible for many aspects of the cDNA Microarray system design. Some example responsibilities include: custom electronics design for signal conditioning and data acquisition; motion control hardware development; custom software specification for system control and data processing; and system integration. In FY99, the cDNA Microarray system has been significantly improved through the development of a second generation data acquisition and control program for the Scanner. This software development required the design of new data acquisition electronics and computer hardware. Also in FY99, the collaborative development of three new cDNA Microarray systems has been initiated for NHGRI and NCI. In FY2K, the SPCSG will continue to improve the performance of the cDNA Microarray system. For example, the SPCSG plans to characterize the existing system components and configuration. The results of this analysis should enable us to improve the overall system performance by increasing the speed, sensitivity, dynamic range, and/or resolution of detection. These improvements are anticipated to result from custom pre-amp circuitry, photomultiplier tube temperature control, software alterations, optimal component selection, and/or optics modifications. Additionally, the SPCSG and project collaborators would like to explore completely new methodologies and system configurations that may prove to be advantageous as more challenging IRP research questions develop. Project #3: High Speed Optical Multichannel Analyzer An Ultra-Rapid Scanning Spectrometer (URSS) system has been developed in collaboration with NHLBI and OD. The URSS system was designed to obtain data, through the measurement of time-resolved absorption spectra, on the kinetic reaction mechanisms of biological preparations such as cytochrome oxidase and bacteriorhodopsin. Although the URSS system has proven to be a powerful tool over the years, studies have shown that a higher performance URSS system is required. Consequently, the research and design of an advanced, second-generation, URSS instrument has been initiated. With the exception of the optics subsystem, the SPCSG is responsible for the development of the entire system. Design and development areas include: photodiode analog interface circuitry, data acquisition and timing circuitry, system integration, and instrument software development. In FY99, the SPCSG continued the design and development of the second-generation 96-channel URSS system. For various reasons, the development was divided into two phases. The first phase includes: 1) data acquisition hardware design, 2) system control and timing hardware design, and 3) development of a custom application program to provide a user interface and hardware control. The second phase primarily includes the design of the photodiode analog interface circuitry. In FY99, the SPCSG completed acceptance testing of the contracted data acquisition hardware. The acceptance testing uncovered several contractor design flaws which required extensive SPCSG effort to resolve. In parallel to the contract effort, the SPCSG developed the system control/timing hardware and system software. These new subsystems have all been integrated with the existing analog interface circuitry to test the entire URSS system operation. Preliminary tests indicated a significant improvement in the overall URSS system performance. Also in FY99, the SPCSG continued the research and development required for the second phase of the project, which involved evaluation of new designs optimized to reduce electronic noise in the analog circuitry interfacing with the 96 photodiodes. In FY2K, the SPCSG will continue the second phase of the URSS system upgrade by developing the 96-channel photodiode analog interface circuitry. Some planned improvements include: higher signal-to-noise ratios, faster sampling rates, and possibly variable amplification and offset. This phase of the project will require electronic circuit design, printed circuit board layout design and assembly, and final testing and calibration. Project #4: Electron Paramagnetic Resonance Spectrometer/Imager An Electron Paramagnetic Resonance (EPR) Spectrometer/Imager system has been developed in collaboration with NCI and NIDDK. The EPR system was designed to perform noninvasive in-vivo imaging and spectroscopy. The EPR system represents the first reported low frequency pulsed EPR spectrometer/imager to be developed for the purposes of in-vivo imaging of paramagnetic species such as free radicals. Due to the EPR spectral properties of paramagnetic spin probes, EPR imaging can provide functional/physiological images, which can be co-registered with anatomical images. Over the recent years, this project has required considerable electrical engineering research and development. For example, a specialized 300 Megasamples per second digitizer-averager was designed by SPCSG staff to increase the signal-to-noise ratio while maintaining high pulse excitation repetition rates. Currently, the EPR system is being utilized for small animal imaging studies. SPCSG design responsibilities on this project include: data acquisition system design, digital signal processing algorithm development, radio-frequency equipment design, control software development, and system integration. In FY99, the SPCSG contributed to the design and development of a second EPR system. This second EPR system will be used for EPR technology development, while the first EPR system will be dedicated to physiological experiments involving small animal imaging. Collaboratively, the SPCSG designed and constructed the transmitter and receiver radio-frequency subsystems. These designs included enhancements which should improve the signal-to-noise ratio, therefore increasing the efficiency of the EPR system. One design objective was to reduce susceptibility to electromagnetic interference and other sources of signal degradation. The SPCSG also evaluated various commercial high-speed data acquisition systems. The evaluation effort resulted in the purchase of a new digitizer/averager system which will be integrated into the EPR systems. The SPCSG has been performing acceptance tests on this new data acquisition system. These tests have required software development to control the data acquisition process and provide a user interface. The SPCSG has continued efforts to incorporate modern DSP communication technologies into the overall EPR system. In FY2K, the SPCSG plans to fully integrate the new data acquisition subsystem into the EPR systems. Once completed, extensive testing will be performed to re-evaluate certain system design issues, such as sampling rate requirements. In the past, these tests have been difficult to conduct due to the specifications of the existing data acquisition system. Also in FY2K, the SPCSG plans to research and implement subsampling and pseudo-random excitation techniques, as well as continue the integration of DPS technologies to improve system performance and flexibility. Project #5: Chromosome Microdissection SystemA Chromosome Microdissection system is being developed in collaboration with NHGRI and OD. The Chromosome Microdissection system is required to cut and recover fragments out of stained chromosomes. This technology will facilitate the research of diseases associated with specific chromosomal abnormalities, such as translocations, inversions, and deletions. The system will automate a large portion of the dissection process, resulting in higher throughput, greater accuracy, and shorter training periods for users. The SPCSG is responsible for many aspects of the Chromosome Microdissection system design. Some example SPCSG responsibilities are: motion control hardware development, custom software development for process and motion control, image acquisition and processing, and system integration. In FY99, the SPCSG designed and developed custom electronic hardware and software which was integrated with the existing Cell Robotics Workstation system. In conjunction with the new mechanical hardware designed by collaborators, these SPCSG developments achieved the precise motion control required for chromosome microdissection. The custom software controls various motors and actuators, and processes images to derive actual real-time physical positions. Via an elaborate graphical user interface, the application program semi-automates the dissection procedure, greatly reducing the manual dexterity required from an operator. The SPCSG software successfully maintains the original functionality of the Cell Robotics Workstation system. In FY2K, the SPCSG will continue to develop the electronic hardware and software to accommodate planned mechanical and optical enhancements in the Chromosome Microdissection system. In order to improve the accuracy of the microdissection, a new laser system will be developed to very sharply demarcate the chromosome material. The SPCSG also plans software modifications to further streamline the microdissection process. Project #6: Tissue Microarray Technology Tissue Microarray technology is being developed in collaboration with NHGRI. New techniques, such as cDNA microarray analysis, have enabled measurement of the expression of thousands of genes in a single experiment. These genome screening tools can comprehensively survey one tumor at a time; however, analysis of hundreds of specimens from patients in different stages of disease is needed to establish the diagnostic, prognostic, and therapeutic importance of each of the emerging gene candidates. To meet this need, a high- throughput automated Tissue Microarray system is being developed to facilitate gene expression and copy number surveys of very large numbers of tumors. More than 1000 cylindrical tissue biopsies from individual tumors can be distributed in a single tumor microarray. In addition to the actual arraying process development, other areas critical to the successful development of the technology include: donor tissue marking and subsequent arraying automation; microarray database development; microarray analysis automation (e.g. fluorescence in situ hybridization (FISH)); and Tissue Microarray core facility logistics. The SPCSG is responsible for many aspects of the Tissue Microarray system design. Some example responsibilities are: custom software development for system automation; motion control hardware design; image acquisition and processing; database development; and system integration. In FY99, the SPCSG has developed an extensive application program for the high-throughput Tissue Microarray system. The custom software controls various motors and actuators, and processes images to derive actual real-time physical positions. Via a graphical user interface, the application program also semi-automates the arraying process. The SPCSG has worked with collaborators to test new mechanical designs and suggest overall system improvements. Also in FY99, donor tissue marking methods, target detection techniques, and donor tissue electronic identification schemes have been collaboratively developed. In FY2K, the SPCSG plans to complete the motion control and user interface software for the Tissue Microarray system. The SPCSG will also complete the design and implementation of donor tissue marking strategies required for arraying automation. The SPCSG also plans to collaboratively design and develop the next generation Tissue Microarray system which will be more fully automated. These future developments will address the recent interest from NCI and NIH in establishing a central Tissue Microarray core facility. Project #7: fMRI and PET Imaging Audio Stimulation and Adaptive Speech/Noise Processing Technology fMRI and PET Imaging Audio Stimulation and Adaptive Speech/Noise Processing technologies are being developed in collaboration with NIDCD and OD. Dr. Braun develops functional imaging techniques used to characterize brain activation patterns in normal subjects and individuals with neurological disorders affecting human communication. For example, Dr. Braun is interested in Tourette?s syndrome, and in particular, with the manifestation of speech impediment and facial tics. Ideally, the research team plans to use a high field fMRI to study the associated region of the brain while simultaneously collecting visual and audio data from the patient. The integration of various types of audio stimulation, adaptive noise cancellation, and speech processing into the fMRI and PET imaging studies should facilitate Dr. Brauns research. The SPCSG design responsibilities on this project include: audio recording and playback design, data acquisition system design, digital signal processing algorithm development, control software development, and system integration. In FY99, the project team has identified two companies interested in the collaborative research and development of MRI Adaptive Speech/Noise Processing technologies. At present, there is no existing MRI audio system that completely meets the requirements of this project. However, the identified companies offer many basic components and the MRI audio experience necessary for the technology development. A sound survey has been completed to characterize the MRI audible noise. Also in FY99, the SPCSG has been responsible for the recording and processing of MRI audible noise, which will be used to simulate a MRI environment during PET studies. In FY2K, the SPCSG would like to establish a formal collaborative relationship with at least one of the companies identified in FY99. This relationship would provide the basic underlying resources required for the MRI Adaptive Speech/Noise Processing technology development. Extensive custom electronic and mechanical hardware would need to be designed and integrated with the commercial systems. Additionally, digital signal processing algorithms must be developed in order to perform the adaptive noise cancellation. Project #8: 3D Ultrasound Contrast Imaging Techniques New 3D Ultrasound Contrast Imaging techniques are being developed in collaboration with NHLBI. The collaboration will probably involve others from NIH and Duke University. Dr. Panza is primarily interested in the three-dimensional study of myocardial perfusion, although these new techniques may be applied in many research areas involving the use of ultrasound imaging. Most of the new imaging techniques have been published, and have proven to be advantageous in 2D ultrasound imaging systems. The implementation of these imaging techniques in a 3D ultrasound imaging system may provide even more noteworthy results than those obtained in 2D systems. There are several imaging techniques which could be evaluated, for example: trigger/gate imaging; pulse inversion harmonic imaging; amplitude modulation harmonic imaging; pulse inversion Doppler imaging; and amplitude modulation Doppler imaging. The evaluation of these new imaging techniques would be completed using a modified Volumetrics system, but would also require the SPCSG to design and development a custom data acquisition system and signal processing algorithms. The 3D Ultrasound Contrast Imaging project was initiated in FY99. SPCSG staff participated in preliminary meetings to discuss the research objectives, system specifications, and logistics of collaborating with Volumetrics Medical Imaging. The SPCSG has developed the cursory requirements of the stand-alone 16-channel parallel data acquisition system and downstream signal processing software. It appears that approximately 41 Msamples of radio- frequency signals will be digitized per volume (16 cm depth; 40 Msamples/second). The NIH signal processing algorithms are necessary to process the echo signals resulting from the new transmit pulse sequences. Example signal processing functions include: filtering and noise reduction, amplification, pulse inversion processing, amplitude modulation detection, data compression/formatting, and data storage/output. The data will be sent back to the Volumetrics system for final processing and display. In FY2K, the SPCSG and Dr. Panza plan to establish a formal working relationship with Volumetrics Medical Imaging to develop the new 3D Ultrasound Contrast Imaging techniques. Subsequently, project development will begin with the SPCSG design of the new data acquisition system and signal processing algorithms. Hardware issues involving the integration of the Volumetrics system and the new NIH data acquisition system must be addressed. Additional SPCSG responsibilities could include: design of custom radio-frequency devices, development of software for instrument control, and system integration. Project #9: Vascular Pathology of Fabry Disease A system used to study the vascular pathology of Fabry disease is being developed in collaboration with NINDS and OD. Fabry disease is an X-linked recessive disorder secondary to deficient levels of lysosomal alpha galactosidase A. This results in the abnormal deposition and accumulation of the enzyme substrate ceramidetrihexoside (CTH) in the central and peripheral nervous system, vascular endothelial cells, renal epithelium and myocardium. An increased incidence of stroke is found in male hemizygotes in the fourth and fifth decades, the etiology of which is unclear but a small vessel and posterior circulation distribution is found. A greater understanding of the vascular biology in Fabry disease will enable this increased stroke risk to be understood etiologically and in reference to defining risk factors. Enzyme replacement therapy for Fabry disease is currently undergoing evaluation so that increased understanding of vessel biology may allow prediction of therapeutic efficacy. The current patient study allows calculation of forearm brachial artery blood flow, forearm vascular bed flow, arterial wave speed and arterial vessel diameter (radial artery during investigation and brachial and radial post hoc) in response to intra-arterial acetylcholine (ACH), a nitric oxide inhibitor (LMNA) and the arterial vasodilator sodium nitroprusside. From these data and interventions in Fabry disease patients and controls we expect to be able to define the vascular pathology of Fabry disease. The SPCSG is responsible for many aspects of the biophysical signal transduction, data acquisition, and system integration. In FY99, SPCSG staff collaboratively designed and developed a data acquisition system to record various signals, such as ECG, invasive arterial blood pressure, external pulse, and pulse oximetry. The development required interfacing to a commercial patient monitor and pulse oximetry monitor. The SPCSG also developed software to determine arterial wave speed based on these biophysical measurements. The presence of SPCSG staff is required during the actual patient treatment. In FY2K, the SPCSG will continue to participate in the patient study and will develop the software analysis tools needed to process the forthcoming study data.
| Subramanian, Sankaran; Koscielniak, Janusz W; Devasahayam, Nallathamby et al. (2007) A new strategy for fast radiofrequency CW EPR imaging: direct detection with rapid scan and rotating gradients. J Magn Reson 186:212-9 |
| Vogel, Abby; Chernomordik, Victor V; Riley, Jason D et al. (2007) Using noninvasive multispectral imaging to quantitatively assess tissue vasculature. J Biomed Opt 12:051604 |
| Hassan, Moinuddin; Riley, Jason; Chernomordik, Victor et al. (2007) Fluorescence lifetime imaging system for in vivo studies. Mol Imaging 6:229-36 |
| Husain, Fatima T; Fromm, Stephen J; Pursley, Randall H et al. (2006) Neural bases of categorization of simple speech and nonspeech sounds. Hum Brain Mapp 27:636-51 |
| Pursley, Randall H; Salem, Ghadi; Devasahayam, Nallathamby et al. (2006) Integration of digital signal processing technologies with pulsed electron paramagnetic resonance imaging. J Magn Reson 178:220-7 |
| Finkel, Julia C; Besch, Virginia G; Hergen, Adrienne et al. (2006) Effects of aging on current vocalization threshold in mice measured by a novel nociception assay. Anesthesiology 105:360-9 |
| Grover, Amelia C; Tangrea, Michael A; Woodson, Karen G et al. (2006) Tumor-associated endothelial cells display GSTP1 and RARbeta2 promoter methylation in human prostate cancer. J Transl Med 4:13 |
| Pursley, Randall H; Salem, Ghadi; Pohida, Thomas J et al. (2005) Direct detection and time-locked subsampling applied to pulsed electron paramagnetic resonance imaging. Rev Sci Instrum 76:1-6 |
| Tangrea, Michael A; Chuaqui, Rodrigo F; Gillespie, John W et al. (2004) Expression microdissection: operator-independent retrieval of cells for molecular profiling. Diagn Mol Pathol 13:207-12 |
| Pollock, Pamela M; Harper, Ursula L; Hansen, Katherine S et al. (2003) High frequency of BRAF mutations in nevi. Nat Genet 33:19-20 |
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