31 results about "Mri techniques" patented technology

A method and apparatus are provided for measuring a parameter such as capillary pressure in porous media such as rock samples. The method comprises mounting a sample in a centrifuge such that different portions of the sample are spaced at different distances from the centrifuge axis, rotating the sample about the axis, measuring a first parameter in the different portions of the sample, and determining the value of a second parameter related to the force to which each portion is subjected due to rotation of the sample. In one embodiment, the first parameter is relative saturation of the sample as measured by MRI techniques, and the second parameter is capillary pressure.

The invention is directed techniques for coordinating telemetry of medical devices with magnetic resonance imaging (MRI) techniques. By coordinating telemetry of a medical device with the performance of MRI techniques with, the use of telemetry during MRI may be facilitated. In one example, information indicative of electromagnetic radiation bursts in MRI techniques can be communicated to the medical device prior to execution. In another example, the medical device may identify the electromagnetic radiation bursts, e.g., by measuring for the presence of such bursts. In either case, the medical device can adjust its telemetry to improve communication during MRI.

The invention is directed techniques for coordinating telemetry of medical devices with magnetic resonance imaging (MRI) techniques. By coordinating telemetry of a medical device with the performance of MRI techniques with, the use of telemetry during MRI may be facilitated. In one example, information indicative of electromagnetic radiation bursts in MRI techniques can be communicated to the medical device prior to execution. In another example, the medical device may identify the electromagnetic radiation bursts, e.g., by measuring for the presence of such bursts. In either case, the medical device can adjust its telemetry to improve communication during MRI.

The disclosed innovation is a method for acquiring spatial frequency spectra from specific locations in a 3D sample using modifications of the current MRI techniques for localized NMR spectroscopy. The innovation in its simplest abstraction is to add the use of a read out gradient to the current NMR spectroscopy pulse sequences and record the resultant echo. These techniques generate spectra from a selected region or generate an image of the results over a region of the sample. These methods can be applied to analyzing the structure of trabecular bone as well as for analyzing or diagnosing disease in cases where there is a difference in the spatial frequency power spectrum due to physiologic or disease processes. Various embodiments are disclosed.

The disclosed embodiments provide a method for acquiring MR data at resolutions down to tens of microns for application in in-vivo diagnosis and monitoring of pathology for which changes in fine tissue textures can be used as markers of disease onset and progression. Bone diseases, tumors, neurologic diseases, and diseases involving fibrotic growth and / or destruction are all target pathologies. Further the technique can be used in any biologic or physical system for which very high-resolution characterization of fine scale morphology is needed. The method provides rapid acquisition of selected values in k-space, with multiple successive acquisitions of individual k-values taken on a time scale on the order of microseconds, within a defined tissue volume, and subsequent combination of the multiple measurements in such a way as to maximize SNR. The reduced acquisition volume, and acquisition of only select values in k-space along selected directions, enables much higher in-vivo resolution than is obtainable with current MRI techniques.

Methods for correcting inhomogeneities of magnetic resonance (MR) images and for evaluating the performance of the inhomogeneity correction. The contribution of both transmit field and receiver sensitivity to signal inhomogeneity have been separately considered and quantified. As a result, their negative contributions can be fully corrected. The correction method can greatly enhance the accuracy and precision of MRI techniques and improve the detection sensitivity of pathophysiological changes. The performance of signal inhomogeneity correction methods has been evaluated and confirmed using phantom and in vivo human brain experiments. The present methodologies are readily applicable to correct signal intensity inhomogeneity artifacts produced in different imaging modalities, such as computer tomography, X-ray, ultrasound, and transmission electron microscopy.

The disclosed embodiments provide a method for acquiring MR data at resolutions down to tens of microns for application in in-vivo diagnosis and monitoring of pathology for which changes in fine tissue textures can be used as markers of disease onset and progression. Bone diseases, tumors, neurologic diseases, and diseases involving fibrotic growth and / or destruction are all target pathologies. Further the technique can be used in any biologic or physical system for which very high-resolution characterization of fine scale morphology is needed. The method provides rapid acquisition of selected values in k-space, with multiple successive acquisitions of individual k-values taken on a time scale on the order of microseconds, within a defined tissue volume, and subsequent combination of the multiple measurements in such a way as to maximize SNR. The reduced acquisition volume, and acquisition of only select values in k-space along selected directions, enables much higher in-vivo resolution than is obtainable with current MRI techniques.

The present invention describes methods and compositions for non-invasively assessing the molecular structure of biocompatible hydrogels using MRI analysis. It is shown that biocompatible hydrogels prepared from polymerizing macromolecules that are attached to a paramagnetic, superparamagnetic or ferromagnetic contrast agents form reporter gels wherein monitoring of the changes in the structure of the hydrogels by MRI is facilitated by the presence of such paramagnetic, superparamagnetic or ferromagnetic agents in the biocompatible hydrogel.

The disclosed embodiments provide a method for acquiring MR data at resolutions down to tens of microns for application in in vivo diagnosis and monitoring of pathology for which changes in fine tissue textures can be used as markers of disease onset and progression. Bone diseases, tumors, neurologic diseases, and diseases involving fibrotic growth and / or destruction are all target pathologies. Further the technique can be used in any biologic or physical system for which very high-resolution characterization of fine scale morphology is needed. The method provides rapid acquisition of signal at selected values in k-space, with multiple successive acquisitions at individual k-values taken on a time scale on the order of microseconds, within a defined tissue volume, and subsequent combination of the multiple measurements in such a way as to maximize SNR. The reduced acquisition volume, and acquisition of only signal values at select places in k-space, along selected directions, enables much higher in vivo resolution than is obtainable with current MRI techniques.

Disclosed are methods, compositions, reagents, systems, and kits to prepare nitroxide-functionalized brush-arm star polymer organic radical contrast agent (BASP-ORCA) as well as compositions and uses thereof. Various embodiments show that BASP-ORCA display unprecedented per-nitroxide and per-molecule transverse relaxivities for organic radical contrast agents, exceptional stability, high water solubility, low in vitro and in vivo toxicity, and long blood compartment half-life. These materials have the potential to be adopted for tumor imaging using clinical high-field 1H MRI techniques.

The disclosed embodiments provide a method for acquiring MR data at resolutions down to tens of microns for application in in-vivo diagnosis and monitoring of pathology for which changes in fine tissue textures can be used as markers of disease onset and progression. Bone diseases, tumors, neurologic diseases, and diseases involving fibrotic growth and / or destruction are all target pathologies. Further the technique can be used in any biologic or physical system for which very high-resolution characterization of fine scale morphology is needed. The method provides rapid acquisition of selected values in k-space, with multiple successive acquisitions of individual k-values taken on a time scale on the order of microseconds, within a defined tissue volume, and subsequent combination of the multiple measurements in such a way as to maximize SNR. The reduced acquisition volume, and acquisition of only select values in k-space along selected directions, enables much higher in-vivo resolution than is obtainable with current MRI techniques.

Methods for correcting inhomogeneities of magnetic resonance (MR) images and for evaluating the performance of the inhomogeneity correction. The contribution of both transmit field and receiver sensitivity to signal inhomogeneity have been separately considered and quantified. As a result, their negative contributions can be fully corrected. The correction method can greatly enhance the accuracy and precision of MRI techniques and improve the detection sensitivity of pathophysiological changes. The performance of signal inhomogeneity correction methods has been evaluated and confirmed using phantom and in vivo human brain experiments. The present methodologies are readily applicable to correct signal intensity inhomogeneity artifacts produced in different imaging modalities, such as computer tomography, X-ray, ultrasound, and transmission electron microscopy.

MRI techniques provide robust imaging in the presence of inhomogeneity in the B1 (RF) and / or B0 magnetic fields. The techniques include using a magnetization prep sequence that includes an adiabatic half passage (AHP) followed by a spin-lock pulse, followed by a reverse AHP, after which a data acquisition sequence can be applied. The AHP and reverse AHP can have amplitude and frequency modulated to sweep through a region of frequency space. The RF amplitude of the AHP and reverse AHP can be designed to be equal to the spin-lock amplitude. Quantification of a magnetization relaxation parameter(e.g., T1rho) can use a modified relaxation model that accounts for relaxation effects during the reverse AHP. A dual-acquisition technique in which the reverse AHP of the second magnetization prep sequence has opposite frequency modulation to the reverse AHP of the first magnetization prep sequence can also be used.

The present invention refers to a process for preparing a compound of formula (I) through a carboxymethylation reaction occurring in the presence of a suitable alkylating agent and of a base, without the need of monitoring the pH of the reaction environment. The compound of formula (I) is a useful intermediate in the preparation of diagnostic contrast agents for MRI techniques.

In magnetic resonance imaging (MRI), selected magnetic dipoles in a subject are aligned with a main magnetic field for later manipulation, and signals received after such manipulations are used to create image representations of the subject. One drawback is that even powerful magnetic fields can only align a very small percentage of dipoles in the region of the field. Electromagnetic radiation endowed with orbital angular momentum (OAM) aligns dipoles along the direction of travel of the radiation, but at a much higher percentage; as high as 100% of the dipoles in the region can be aligned. Resultantly, resonance signals emanating from the region are several orders of magnitude stronger than signals emanated using traditional MRI techniques. All electromagnetic radiation, including visible light can be endowed with OAM and used to hyperpolarize a region of interest.

The present invention refers to a process for preparing a compound of formula (I) through a carboxymethylation reaction occurring in the presence of a suitable alkylating agent and of a base, without the need of monitoring the pH of the reaction environment. The compound of formula (I) is a useful intermediate in the preparation of diagnostic contrast agents for MRI techniques.

Vasculature or parenchyma is imaged using upright MRI techniques, on patients who may have conditions such as congestive heart failure, or otherwise be healthy. When an individual is horizontal, venous drainage is minimized, causing the vessels to remain engorged, also referred to herein as vascular congestion. Vascular congestion results in an enlarging of the vessels and surrounding tissue causing the vessels to be more visible on MRIs. The decrease in vascular visibility in upright subjects is in part, due to an increase in venous drainage. Patients suffering from coronary and / or pulmonary deficiencies (e.g. CHF) experience decreased rates and degrees of venous drainage. In one embodiment, the present invention uses upright imaging to visualize these enlarged vessels.

In magnetic resonance imaging (MRI), selected magnetic dipoles in a subject are aligned with a main magnetic field for later manipulation, and signals received after such manipulations are used to create image representations of the subject. One drawback is that even powerful magnetic fields can only align a very small percentage of dipoles in the region of the field. Electromagnetic radiation endowed with orbital angular momentum (OAM) aligns dipoles along the direction of travel of the radiation, but at a much higher percentage; as high as 100% of the dipoles in the region can be aligned. Resultantly, resonance signals emanating from the region are several orders of magnitude stronger than signals emanated using traditional MRI techniques. All electromagnetic radiation, including visible light can be endowed with OAM and used to hyperpolarize a region of interest.

The present invention relates to improved methods for determining metabolic function in tissues of an animal. In particular, the invention relates to methods for determining the penumbra in ischaemic tissues using MRI techniques in association with hyperoxic conditions and an oxygen carrier. The invention also relates to systems adapted to perform the methods.