Jay Porter

A desktop magnetic resonance imaging system

Modern magnetic resonance imaging (MRI) systems consist of several complex, high cost subsystems. The cost and complexity of these systems often makes them impractical for use as routine laboratory instruments, limiting their use to hospitals and dedicated laboratories. However, advances in the consumer electronics industry have led to the widespread availability of inexpensive radio-frequency integrated circuits with exceptional abilities. We have developed a small, low-cost MR system derived from these new components. When combined with inexpensive desktop magnets, this type of MR scanner has the promise of becoming standard laboratory equipment for both research and education. This paper describes the development of a prototype desktop MR scanner utilizing a 0.21 T permanent magnet with an imaging region of approximately 2 cm diameter. The system uses commercially available components where possible and is programmed in LabVIEW software. Results from 3D data sets of resolution phantoms and fixed, newborn mice demonstrate the capability of this system to obtain useful images from a system constructed for approximately

A sixteen-channel multiplexing upgrade for single channel receivers

13 500.

A labVIEW based magnetic resonance imaging console

With the increasing interest in phased arrays in magnetic resonance imaging, imaging system receivers capable of acquiring larger number of parallel signals are needed. Suggested techniques for rapid imaging propose the use of arrays with as many as 128 elements. While simply duplicating the number of receiver chains as needed is a viable technique, it quickly becomes both cumbersome and expensive. Time domain multiplexing offers an alternative solution to this problem. By using RF multiplexing switches, a single receiver can be upgraded to an array receiver capable of multi-channel data acquisition giving users array capability. Additionally, it can be used to dramatically increase acquisition capability of multiple receiver systems. This paper reports results from a multiplexing system upgrade, which converts a single channel standard clinical imaging system to a 16-channel array system. The upgrade includes both the RF multiplexing front-end and an external data acquisition system with image processing capability. Issues concerning the implementation of high channel-count multiplexers are also discussed.

MR flow measurement using RF phase gradients in receiver coil arrays

In in effort to create an affordable magnetic resonance imaging system suitable for research use, a personal computer (PC) based MRI console is currently being designed and studied. National Instruments LabVIEW, a virtual instrumentation development system, is being used to create the necessary system control and data processing software. The interface to the external hardware is done through the use of generic PC data acquisition cards. It is only recently that personal computers and PC based data acquisition cards have become fast enough to meet the stringent requirements of this application. This paper presents the console design and results from laboratory testing.

A 16 channel time-multiplexed head coil array for functional MR imaging

Radio frequency (RF) phase gradients in the receiver coil field pattern can encode flow velocity information in magnetic resonance (MR) images in the form of phase variations. These phase variations are not readily observed in MR images because they are relatively small compared to phase variations caused by static magnetic field (B/sub 0/) inhomogeneities, susceptibility variations, and other sources. However, the phase contributions from these other sources are independent of the receiver coil. Therefore, the RF phase gradient encoded flow information can be recovered by subtracting images obtained simultaneously using arrays of independent receiver coils and a multiple channel receiver. This flow velocity information can be extracted retrospectively from standard imaging sequences, including flow-compensated sequences. No additional time is required for the flow study as the flow measurements are made using sequences chosen for optimal imaging, and the images from each coil are obtained simultaneously. Initial results indicate that sufficient sensitivity is obtained to make flow measurements in the range of velocities commonly found in the carotid arteries and other major vessels. In principle, the method works with only two receiver coils. However, additional elements provide additional phase measurements that can be used to increase accuracy, remove ambiguities in flow direction or velocity calculations, and increase the region over which velocity measurements can be accurately made.<<ETX>>

A course in innovative product design: A collaboration between architecture, business, and engineering

Functional magnetic resonance imaging (fMRI) of the brain relies on small signal differences caused by changes in regional blood volume during task activation. At commonly used field strengths the signal differences are extremely small, but useable. This paper presents a time-multiplexed sixteen channel surface coil array for fMRI. The new coil obtains a factor of two or more improvement in the signal-to-noise ratio (SNR) as compared to the standard head coil in the visual and motor cortex. Additionally, the SNR is nearly as high as the standard coil in the center of the brain.

A modular time domain multiplexer for large array magnetic resonance imaging

The importance of innovation and entrepreneurship has grown significantly over the past decade. Institutions of higher education have recognized the increasing level of importance being placed globally on producing college graduates with the skills to innovate new products and services, and many are rising to the occasion. Recently, Texas A&M University has established a small business accelerator available to all students. In addition, the University has supported the development of a new course where junior and senior students across the University can interact and learn about ideation, innovative product development, and entrepreneurship. Looking across the literature, most institutions are moving in a direction of fostering entrepreneurship through interdisciplinary courses either within engineering, business or through partnerships between both. This new course is novel in that, in addition to integrating product development with entrepreneurship, it also incorporates the ideation and innovation processes through involvement of the College of Architecture. By embedding architecture students into the teams of engineering and business students, expertise in these areas is added to the teams. Finally, the course exposes all students to new tools such as the lean startup method and Launchpad Central.

Development of a novel Modular Integrated Stackable Layer — Analog System Environment (MISL — ASE) platform for embedded systems education

Simultaneous acquisition of MR signals from array coils provides improved signal-to-noise ratio in MR imaging. RF coil arrays of up to four channels are commonly used, and emerging applications such as functional imaging and MR microscopy could benefit from the use of even larger arrays. This paper extends previous work by the authors in time-domain multiplexing (TDM) of MR receivers to enable simultaneous acquisition from arrays of sixteen or more elements. A modular TDM unit is developed, based upon a printed circuit four channel multiplexer board. Using this modular system a sixteen channel multiplexer has been developed and tested.<<ETX>>

Integration of Heat Conduction Measurement Systems Into Engineering Technology Education

With the support of Texas Instruments and NASA, a novel Modular Integrated Stackable Layer - Analog System Environment (MISL - ASE) platform has been developed to provide a comprehensive educational hardware environment for three embedded system design courses and two capstone design courses in the Electronic Systems Engineering Technology (ESET) program at Texas A&M University. The MISL-ASE platform uses the TI-MSP430 intelligence layer of the MISL architecture as the main core and control system that can be directly interfaced to the ASE board. Moreover, the MISL-ASE platform encompasses various analog and digital peripherals, such as GPIO outputs/inputs, LEDs, 7-segment displays, audio system, switches, keypad, and TFT LCD with touch screen, typical signal conditioning circuits such as A/D and D/A conversion for analog voltage simulation, battery life and light density measurement, 3-axis accelerometer, high-resolution external ADC converter, multiple analog signal generators, and motor control, etc. Several communication interfaces and protocols are also available such as UART (USB, RS-232/485, Bluetooth, and Zigbee), SPI (Ethernet, Wi-Fi, Micro SD card, and flash memory), I2C (DAC and EEPROM), and 1-wire communication devices. Additionally, the robust design of the ASE board facilitates it being interfaced to a number of other embedded intelligence boards such as the Launchpad development system. This paper will discuss the overall design and capabilities of the MISL-ASE platform and the development of a series of laboratory assignments that can be accomplished using this novel MISL-ASE environment in the area of analog electronics, digital interfacing, and communications.

Design of matching networks for low noise preamplifiers

Modern engineering technology education necessitates realistic, cross disciplinary research projects. Maintaining these research opportunities within the university is an effective way for undergraduate students to practice their profession while assisting with graduate level research. In the heat conduction laboratory, the Mechanical Engineering Department at Texas A&M has joined with the Department of Engineering Technology and Industrial Distribution to create a novel learning environment beneficial to both students and professors. The goal of this project is to design and implement an improved thermal test chamber using mechatronic concepts. Similarly, the educational goal is to have engineering technology students apply their classroom based learning to a real-world application and to coordinate their efforts with a diverse background of advisors and engineers.Copyright