University of Virginia Patent Foundation

Other

Center for Innovative Technology

James R Brookeman

John P Mugler, Iii

Kai Ruppert

Michael B Merickel

Bastiaan Driehuys

Michael Salerno

Klaus D Hagspiel

Dennis Fujii

Charles S Carman

Carlos R Ayers

Ann H Adams

A magnetic resonance imaging 'MRI' method and apparatus for lengthening the usable echo-train duration and reducing the power deposition for imaging is provided. The method explicitly considers the t1 and t2 relaxation times for the tissues of interest, and permits the desired image contrast to be incorporated into the tissue signal evolutions corresponding to the long echo train. The method provides a means to shorten image acquisition times and/or increase spatial resolution for widely-used spin-echo train magnetic resonance techniques, and enables high-field imaging within the safety guidelines established by the Food and Drug Administration for power deposition in human MRI.

Method and apparatus for spin-echo-train MR imaging using prescribed signal evolutions

Method and system that provides, among other things, the capability for using hyperpolarized xenon-129 as a probe to non-invasively and non-destructively characterize important properties of certain structures or materials into which hyperpolarized xenon-129 can be introduced and wherein the xenon exists in two or more chemically-shifted states that are in exchange High-resolution MR images can be generated in a fraction of a second wherein the associated signal intensities reflect material properties that characterize the gas exchange among the different states. For example, in the human or animal lung, the system and related method can exploit the differences in gas-exchange characteristics between healthy and diseased lung tissue to generate high-resolution, high signal-to-noise cross-sectional MR images that permit non-invasive regional detection of variations in lung tissue structure with a combination of spatial and temporal resolution that is unmatched by any current imaging modality.

Exchange-weighted xenon-129 nuclear magnetic resonance system and related method

A system and method for using hyperpolarized noble gases together with an appropriately designed and optimized magnetic resonance imaging pulse sequence to rapidly acquire static or dynamic magnetic resonance images. The strong magnetic resonance signal from hyperpolarized gases, combined with the present magnetic resonance imaging technique, presents the opportunity for the imaging of gases with both high spatial and high temporal resolution. One potential application for such a method is the direct, dynamic visualization of gas flow, which would be extremely useful for characterizing a variety of fluid systems. In the medical field, one such system of substantial importance is the lung. The system and method provides for visualizing regional ventilatory patterns throughout the respiratory cycle with high temporal and high spatial resolution. The low sensitivity to susceptibility artifacts permits good image quality to be obtained in various orientations. Depending on the application, temporal resolution can be traded for anatomical coverage. Such application of dynamic imaging of the lung using hyperpolarized gases will provide unique information on the physiology and pathophysiology of the lung, and has the potential for many clinically-relevant applications.

Optimized high-speed magnetic resonance imaging method and system using hyperpolarized noble gases

A methodology, system and computer program product for designing and optimizing a rapid magnetic resonance imaging pulse sequence for creating images of a gas or gas-filled structure with substantially reduced diffusion-induced signal attenuation during the course of data acquisition compared to that for currently available magnetic resonance imaging techniques is disclosed. The methodology and system allows desirable combinations of image signal-to-noise ration, spatial resolution and temporal resolution to be achieved that were heretofore not possible. For example, magnetic resonance imaging of hyperpolarized noble gases, which recently has shown significant promise for several medical imaging applications, particularly imaging of the human lung, can be improved. Pulse sequences designed according to the subject methods permit signal levels to be achieved that are up to ten times higher than those possible with the gradient-echo methods now commonly used for hyperpolarized-gas imaging. This signal increase can be traded for substantially lower does, and hence much lower cost, of the hyperpolarized-gas agent. The methodology and system will also be useful for non-biological applications of hyperpolarized gases for example material science studies, as well as for magnetic resonance imaging of any other gas for biological or non-biological applications. Pulse sequences designed according to the subject methods can also serve as the foundation for a variety of specialized gas-imaging pulse sequences, such as those for apparent-diffusion-coefficient, dynamic or oxygen-concentration imaging.

Method and system for rapid magnetic resonance imaging of gases with reduced diffusion-induced signal loss

A method and an apparatus for using hyperpolarized xenon-129 and magnetic resonance imaging or spectroscopy as a probe to non-invasively and non-destructively characterize important properties of certain structures or materials with high spatial and temporal resolution, resulting in high-resolution magnetic resonance images wherein the associated signal intensities reflect a property of interest of at least one of the compartments. Hyperpolarized xenon-129 is introduced into two compartments between which xenon-129 can be exchanged, for example, into the blood vessels of mammal organs and the tissue of said organ or into compartments within inorganic objects. Due to chemical shift and applied magnetic field strength, the hyperpolarized xenon-129 introduced into the first compartment has a different resonant frequency from the hyperpolarized xenon-129 introduced into the second compartment.

Exchange-based NMR imaging and spectroscopy of hyperpolarized xenon-129

A method of screening for pulmonary embolism uses gaseous phase polarized Xe which is injected directly into the vasculature of a subject. The gaseous Xe can be delivered in a controlled manner such that the gas substantially dissolves into the vasculature proximate to the injection site. Alternatively, the gas can be injected such that it remains as a gas in the bloodstream for a period of time (such as about 8-29 seconds). The injectable formulation of polarized Xe gas is presented in small quantities of (preferably isotopically enriched) hyperpolarized Xe and can provide high-quality vasculature MRI images or NMR spectroscopic signals with clinically useful signal resolution or intensity. One method injects the polarized Xe as a gas into a vein and also directs another quantity of polarized gas into the subject via inhalation. In this embodiment, the perfusion uptake allows arterial signal information and the injection (venous side) allows venous signal information. The dual delivery is used to generate a combined introduction path with a more complete image signal of both the arterial and venous side of the pulmonary vasculature. In this NMR imaging method, the pulmonary embolism screening method can use the same NMR chest coil for the excitation and detection of the Xe signals. The direct injection of small quantities of gas at particular sites along the vasculature targets specific target regions to provide increased signal intensity NMR images. The disclosure also includes related methods directed to other diagnostic vasculature regions physiological and conditions. Associated delivery and dispensing systems and methods, containers, and quantitative formulations of the polarized gas are also described.

Diagnostic procedures using direct injection of gaseous hyperpolarized 129Xe and associated systems and products

A new three-dimensional (3D) MR imaging pulse sequence can produce over 100 high-resolution, high-contrast images in as little as 6 minutes of imaging time. Without additional imaging time, this same image data can be post-processed to yield high-resolution, high-contrast images in any arbitrary orientation. Thus, this new pulse sequence technique provides detailed yet comprehensive coverage. The method of this invention relates to a preparation-acquisition-recovery sequence cycle. The first step is magnetization preparation (MP) period. The MP period can emply a series of RF pulses, gradient field pulses, and/or time delays to encode the desired contrast properties in the form of longitudinal magnetization. A data acquisition period includes at least two repetitions of a gradient echo sequence to acquire data for a fraction of k-space. A magnetization recovery period is provided which allows T1 and T2 relaxation before the start of the next sequence cycle. The MP, data acquisition and magnetization recovery steps are repeated until a predetermined k-space volume is sampled.

Three-dimensional magnetic resonance imaging

There is disclosed an image processing, pattern recognition and computer graphics system and method for the noninvasive identification and evaluation of female breast cancer including the characteristic of the boundary thereof using multidimensional Magnetic Resonance Imaging (MRI). The system and method classifies the tissue using a Fisher linear classifier followed by a refinement to show the boundary shape and whether the surface of the carcinoma is lobulated or spiculated. The results are a high information content display which aids in the diagnosis and analysis of breast cancer and to assist in any surgical or other remedial planning. The high information content display also assists in the assessment of the effectiveness of therapies showing any reduction or increase in the size of the carcinoma.

System and method for the noninvasive identification and display of

There is disclosed an image processing, pattern recognition and computer graphics system and method for the noninvasive identification and evaluation of atheroscelerosis using multidimensional Magnetic Resonance Imaging (MRI). Functional information, such as plaque tissue type, is combined with structure information, represented by the 3-D vessel and plaque structure, into a single composite 3-D display. The system and method is performed with the application of unsupervised pattern recognition techniques and rapid 3-D display methods appropriate to the simultaneous display of multiple data classes. The results are a high information content display which aids in the diagnosis and analysis of the atherosclerotic disease process, and permits detailed and quantitative studies to assess the effectiveness of therapies, such as drug, exercise and dietary regimens.

Growing community of inventors

Charlottesville, VA, United States of America

James R Brookeman