Abstract: An echo-based single point imaging (ESPI) system (10) providing high-resolution oxygen images of a sample is disclosed. The ESPI system (10) employs spin echo detection of the resonance from a spin probe and concurrent Single Point Imaging (SPI) for spatial encoding of the oxygen concentration within the sample. Images are derived by comparing spin echo intensities of two images reconstructed at two time points selected at identical time intervals on either side of a refocusing pulse, eliminating artifacts associated with sample magnetic susceptibility and field inhomogeneity effects.

Abstract: An electron paramagnetic resonance imaging system that includes means for continuously irradiating a sample with RF irradiation; means for imposing on the sample a sinusoidally varying magnetic field along with rotating gradients for spatial encoding; means for directly detecting signal data from the sample, without using field modulation, while irradiating the sample with RF radiation continuously, the means for directly detecting having means for sweeping the sinusoidally varying magnetic field; and means for processing the signal data, using means including a digital signal processor.

Abstract: An electron paramagnetic resonance imaging system that includes means for continuously irradiating a sample with RF irradiation; means for imposing on the sample a sinusoidally varying magnetic field along with rotating gradients for spatial encoding; means for directly detecting signal data from the sample, without using field modulation, while irradiating the sample with RF radiation continuously, the means for directly detecting having means for sweeping the sinusoidally varying magnetic field; and means for transmitting, receiving and processing the signal data, using means including a digital signal processor.

Abstract: An echo-based single point imaging (ESPI) system (10) providing high-resolution oxygen images of a sample is disclosed. The ESPI system (10) employs spin echo detection of the resonance from a spin probe and concurrent Single Point Imaging (SPI) for spatial encoding of the oxygen concentration within the sample. Images are derived by comparing spin echo intensities of two images reconstructed at two time points selected at identical time intervals on either side of a refocusing pulse, eliminating artifacts associated with sample magnetic susceptibility and field inhomogeneity effects.

Abstract: An electron paramagnetic resonance imaging system that includes means for continuously irradiating a sample with RF irradiation; means for imposing on the sample a sinusoidally varying magnetic field along with rotating gradients for spatial encoding; means for directly detecting signal data from the sample, without using field modulation, while irradiating the sample with RF radiation continuously, the means for directly detecting having means for sweeping the sinusoidally varying magnetic field; and means for transmitting, receiving and processing the signal data, using means including a digital signal processor.

Abstract: An electron paramagnetic resonance imaging system that includes means for continuously irradiating a sample with RF irradiation; means for imposing on the sample a sinusoidally varying magnetic field along with rotating gradients for spatial encoding; means for directly detecting signal data from the sample, without using field modulation, while irradiating the sample with RF radiation continuously, the means for directly detecting having means for sweeping the sinusoidally varying magnetic field; and means for processing the signal data, using means including a digital signal processor.

Abstract: Disclosed is a method for determining the redox status of a region of interest in an animal tissue. The method includes administering a nitroxyl contrast agent to the region of interest, obtaining a magnetic resonance image of the region of interest, determining the amount of reduced nitroxyl contrast agent in the region of interest, and thereby determining the redox status of the region of interest.

Abstract: A radiofrequency (RF) coil design, suitable for detecting time domain electron paramagnetic resonance (EPR) responses from spin probes after pulsed excitation using radiofrequency irradiation (60-400 MHz), is configured in an array of numerous surface coils of appropriate diameters connected in a parallel or axial configuration with appropriate spacing between individual surface coils to form a volume type resonator.

Abstract: A system for performing pulsed RF FT EPR spectroscopy and imaging includes an ultra-fast excitation subsystem and an ultra-fast data acquisition subsystem. Additionally, method for measuring and imaging in vivo oxygen and free radicals or for performing RF FT EPR spectroscopy utilizes short RF excitations pulses and ultra-fast sampling, digitizing, and summing steps.

Abstract: A gated RF preamplifier used in system for performing pulsed RF FT EPR spectroscopy and imaging or MRI. The RF preamplifier does not overload during a transmit cycle so that recovery is very fast to provide for ultra-fast data acquisition in an ultra-fast excitation subsystem. The preamplifier includes multiple low-gain amplification stages with high-speed RF gates inserted between stages that are switched off to prevent each stage from overloading during the transmit cycle.

Abstract: A system for performing pulsed RF FT EPR spectroscopy and imaging includes an ultra-fast excitation subsystem and an ultra-fast data acquisition subsystem. Additionally, method for measuring and imaging in vivo oxygen and free radicals or for performing RF FT EPR spectroscopy utilizes short RF excitations pulses and ultra-fast sampling, digitizing, and summing steps.

Abstract: An EPR imager and spectrometer includes pulse generating system for generating broadband pulses having an RF carrier frequency that is not highly absorbed by biological samples. The pulse generating system includes up and down chirp convertors for frequency modulating a carrier frequency pulse and compressing the frequency modulated pulse to form a broadband excitation pulse of high energy. Such a machine could form the basis of a clinical imaging device capable of high sensitivity to free radical species in human patients.

Abstract: An EPR imager and spectrometer includes pulse generating system for generating broadband pulses having an RF carrier frequency that is not highly absorbed by biological samples. The pulse generating system includes up and down chirp convertors for frequency modulating a carrier frequency pulse and compressing the frequency modulated pulse to form a broadband excitation pulse of high energy. Such a machine could form the basis of a clinical imaging device capable of high sensitivity to free radical species in human patients.