Abstract: Diffusion-weighted data are acquired with an MRI system. From the diffusion-weighted data, a comprehensive diffusion tensor distribution (CDTD) is generated. The provides a proportional weighting, at the voxel level, of different diffusion tensors that could describe the water diffusion occurring in the voxel. The CDTD provides insight into tissue microstructure without making assumptions about the structure of a diffusion tensor used to characterize diffusion occurring in tissues of interest. Water pool images, corresponding to different subsets of diffusion tensors in the CDTD, may be generated to assess different components of water diffusion in tissue. Classification images can also be generated from the CDTD to depict different clusters of voxels having similar distributions of diffusion tensors.

Abstract: A system may transform sensor data from a sensor domain to an image domain using data-driven manifold learning techniques which may, for example, be implemented using neural networks. The sensor data may be generated by an image sensor, which may be part of an imaging system. Fully connected layers of a neural network in the system may be applied to the sensor data to apply an activation function to the sensor data. The activation function may be a hyperbolic tangent activation function. Convolutional layers may then be applied that convolve the output of the fully connected layers for high level feature extraction. An output layer may be applied to the output of the convolutional layers to deconvolve the output and produce image data in the image domain.

Abstract: A system may transform sensor data from a sensor domain to an image domain using data-driven manifold learning techniques which may, for example, be implemented using neural networks. The sensor data may be generated by an image sensor, which may be part of an imaging system. Fully connected layers of a neural network in the system may be applied to the sensor data to apply an activation function to the sensor data. The activation function may be a hyperbolic tangent activation function. Convolutional layers may then be applied that convolve the output of the fully connected layers for high level feature extraction. An output layer may be applied to the output of the convolutional layers to deconvolve the output and produce image data in the image domain.

Abstract: A system may transform sensor data from a sensor domain to an image domain using data-driven manifold learning techniques which may, for example, be implemented using neural networks. The sensor data may be generated by an image sensor, which may be part of an imaging system. Fully connected layers of a neural network in the system may be applied to the sensor data to apply an activation function to the sensor data. The activation function may be a hyperbolic tangent activation function. Convolutional layers may then be applied that convolve the output of the fully connected layers for high level feature extraction. An output layer may be applied to the output of the convolutional layers to deconvolve the output and produce image data in the image domain.

Abstract: Spin-lock T1?-weighted images of a subject are acquired and processed to produce an image that is indicative of bioelectromagnetic activity in the subject. A spin-lock RF field B1? is produced such that the Larmor frequency in the rotating frame corresponds to the expected frequency of the bioelectromagnetic activity. As a result, the magnetic field fluctuations generated by the bioelectromagnetic currents shorten the T1? of the surrounding tissue, creating a contrast mechanism that is seen as a reduced MR signal in the T1?-weighted image that is produced.

Abstract: A method includes administering to a subject (i) a pharmacological agent that binds to receptors in a subject, and (ii) a radiotracer to alter a functional state and occupancy of the receptors in the subject. The method also includes acquiring imaging data of brain tissue in the subject comprising the receptors. The imaging data include positron emission tomography (PET) imaging data and functional magnetic resonance (fMR) imaging data. The method further includes calculating (i) a dynamic response of the functional state to the pharmacological agent and the radiotracer based on the fMR imaging data, and (ii) a dynamic response of the receptor occupancy to the pharmacological agent and the radiotracer based on the PET imaging data.

Abstract: A system and method for generating a report regarding a vascular health status of a subject being imaged using a magnetic resonance imaging (MRI) system includes receiving a plurality of MRI datasets, each MRI dataset acquired from the a portion of the subject including a vascular structure. The process also includes analyzing the MRI datasets to identify at least one of a temporal shift and a MR signal variation between the MRI datasets, correlating the at least one of the temporal shift and the MR signal variation to a vascular health status, and generating a report indicating the vascular health status of the subject.

Abstract: A system and method for producing an image of a subject with a magnetic resonance imaging system, in which the image depicts an image contrast indicative of rotary saturation produced in response to magnetic particles administered to the subject, are provided. An agent that includes magnetic particles is administered to the subject. An electromagnetic drive field is applied to the subject at a drive frequency so that the magnetic particles produce magnetic fields that oscillate at the drive frequency and harmonics thereof. A spin-lock field is then established at a spin-lock frequency that is a harmonic of the drive frequency in order to produce rotary saturation of nuclear spins affected by the magnetic fields produced by the magnetic particles. Image data is then acquired from the subject using the MRI system, from which an image of the subject that depicts an image contrast indicative of the produced rotary saturation is reconstructed.

Abstract: A system and method for accurately producing MR images of selected vascular compartments includes employing a control scan and a tag scan, each including velocity selective modules that suppress signal from blood flowing faster than a given cutoff velocity, to acquire control and tag sets of NMR data that may be subtracted to produce a compartment-specific MR image that is substantially free of information from stationary tissues and blood outside the selective vascular compartments. Accordingly, physiological parameters, such as oxygen saturation (SaO2), oxygen extraction fraction (OEF), and cerebral metabolic rate of oxygen (CMRO2), can be generated from the compartment-specific images. Further still, kinetic curves of oxygen exchange can be created, thus providing detailed insight into oxygen exchange dynamics.

Abstract: A method and system for producing an image of a subject with a magnetic resonance imaging (MRI) system, in which the presence of a contrast agent is detected using a spin-lock pulse sequence, is described. More specifically, a contrast agent that induces saturation of magnetic resonance signals responsive to a spin-lock condition is administered to a subject. A spin-lock condition is subsequently established to saturate spins in proximity to the contrast agent. Image data is then acquired with an imaging pulse sequence and images indicative of the presence of the contrast agent are reconstructed.

Abstract: A system and method for producing an image of a subject with a magnetic resonance imaging system, in which the image depicts an image contrast indicative of rotary saturation produced in response to magnetic particles administered to the subject, are provided. An agent that includes magnetic particles is administered to the subject. An electromagnetic drive field is applied to the subject at a drive frequency so that the magnetic particles produce magnetic fields that oscillate at the drive frequency and harmonics thereof. A spin-lock field is then established at a spin-lock frequency that is a harmonic of the drive frequency in order to produce rotary saturation of nuclear spins affected by the magnetic fields produced by the magnetic particles. Image data is then acquired from the subject using the MRI system, from which an image of the subject that depicts an image contrast indicative of the produced rotary saturation is reconstructed.

Abstract: A method for correcting subject motion in positron emission tomography (PET) imaging includes acquiring navigator signals from the subject with a magnetic resonance (MR) imaging system. The navigator signals are used to determine subject motion during a PET scan relative to a reference position and corrective values therefrom. Sinogram data acquired during the PET scan can then be corrected using the corrective values. PET images are then reconstructed from the corrected sinogram data.

Abstract: This invention relates to novel magnetic resonance imaging contrast agents, and methods of making and use thereof.

Abstract: A system and method for accurately producing MR images of selected vascular compartments includes employing a control scan and a tag scan, each including velocity selective modules that suppress signal from blood flowing faster than a given cutoff velocity, to acquire control and tag sets of NMR data that may be subtracted to produce a compartment-specific MR image that is substantially free of information from stationary tissues and blood outside the selective vascular compartments. Accordingly, physiological parameters, such as oxygen saturation (SaO2), oxygen extraction fraction (OEF), and cerebral metabolic rate of oxygen (CMRO2), can be generated from the compartment-specific images. Further still, kinetic curves of oxygen exchange can be created, thus providing detailed insight into oxygen exchange dynamics.

Abstract: A method and system for producing an image of a subject with a magnetic resonance imaging (MRI) system, in which the presence of a contrast agent is detected using a spin-lock pulse sequence, is described. More specifically, a contrast agent that induces saturation of magnetic resonance signals responsive to a spin-lock condition is administered to a subject. A spin-lock condition is subsequently established to saturate spins in proximity to the contrast agent. Image data is then acquired with an imaging pulse sequence and images indicative of the presence of the contrast agent are reconstructed.

Abstract: Spin-lock T1?-weighted images of a subject are acquired and processed to produce an image that is indicative of bioelectromagnetic activity in the subject. A spin-lock RF field B1? is produced such that the Larmor frequency in the rotating frame corresponds to the expected frequency of the bioelectromagnetic activity. As a result, the magnetic field fluctuations generated by the bioelectromagnetic currents shorten the T1? of the surrounding tissue, creating a contrast mechanism that is seen as a reduced MR signal in the T1?-weighted image that is produced.

Abstract: A method for correcting subject motion in positron emission tomography (PET) imaging includes acquiring navigator signals from the subject with a magnetic resonance (MR) imaging system. The navigator signals are used to determine subject motion during a PET scan relative to a reference position and corrective values therefrom. Sinogram data acquired during the PET scan can then be corrected using the corrective values. PET images are then reconstructed from the corrected sinogram data.

Abstract: A method for correcting attenuation in a positron emission tomography (PET) image includes acquiring images of tissue using a magnetic resonance imaging (MRI) system. The images of tissue are acquired by the MRI system at substantially the same time that sinogram data are acquired from the PET scanner. An attenuation correction sinogram is produced from the MR images and employed to correct the acquired sinogram data. PET images are then reconstructed from the corrected sinogram data.

Abstract: A reporter conjugate for non-invasive imaging of gene expression in vivo is disclosed. The conjugate includes a targeting nucleic acid linked to a contrast agent, such as a paramagnetic label that can be used with magnetic resonance imaging (MRI). The targeting nucleic acid can be an anti-sense strand that hybridizes to a portion of a messenger RNA encoded by the gene whose expression is to be imaged. In some embodiments, the contrast agent is a chelated metal such as gadolinium or dysprosium. The invention also features methods to image gene expression in various tissues, including the brain.

Abstract: The invention provides methods for inhibiting psychostimulant-induced or nicotine-induced craving of additional psychostimulants (e.g., cocaine or amphetamine) or nicotine. In these methods, D1-like antagonists or D1-like agonists are administered to a patient dependent on psychostimulant drugs or nicotine and therefore susceptible to, or suffering from, such a craving. Also disclosed is an animal model system useful for measuring the ability of test compounds to inhibit psychostimulant-induced or nicotine-induced cravings in humans.