Abstract: A system and method is provided for classifying voxels of first and second images generated using first and second echoes of a dual MRI scan, the first and second echoes corresponding to respective first and second sets of image acquisition parameters.

Abstract: A system and method is provided for classifying voxels of first and second images generated using first and second echoes of a dual MRI scan, the first and second echoes corresponding to respective first and second sets of image acquisition parameters.

Abstract: A method for magnetic resonance imaging includes applying a first two echo gradient echo sequence to a tissue region, the first two echo sequence generating a first echo and a subsequent second echo. A second two echo gradient echo sequence is applied after heating the tissue region, the second two echo sequence generating a third echo and a subsequent fourth echo. A magnitude difference between the third echo and the first echo is measured and correlated to a temperature shift for fat tissue, and a phase difference between the fourth echo and the second echo is measured and correlated to a temperature shift for water-based tissue. A thermal image is generated of the tissue region based upon the temperature shift for both fat and water-based tissue.

Abstract: A multi-channel phased array coil for use in a magnetic resonance (MR) system is disclosed herein. The phased array coil includes N coils configured in an array, each of the N coils having a geometric shape and overlapping with (N−1) coils to form an overlap area within the array. The geometric shape of each of the coils and the overlap area are configured to cause a mutual inductance between every pair of the coils to be less than 10 percent of the self-inductance of each of the N coils. At least four coils are provided in the phased array coil.

Abstract: A method and an apparatus for three-dimensional imaging of ultrasound data by reducing speckle artifact data before the acquired data from a volume of interest is projected onto an image plane. An ultrasound scanner collects B-mode or color flow mode images in a cine memory, i.e., for a multiplicity of slices. The data from a respective region of interest for each slice is sent to a master controller, such data forming a volume of interest. The master controller performs an algorithm that iteratively projects the pixel data in the volume of interest onto a plurality of rotated image planes using a ray-casting technique. Prior to projection, the master controller smooths the speckle contained in the pixel data filtering using a convolution filter having a nine-point kernel.

Abstract: A magnetic resonance (MR) active invasive device system employs a small, high-field polarizing magnet, and a large magnetic resonance (MR) imaging magnet for the purpose of generating MR images of selected body cavities. A subject is positioned in a large low-field MR imaging magnet. A substance, intended to be used as a contrast agent is first cooled, and then passed through the small high-field polarizing magnet where it becomes highly polarized. The substance is then heated to physiologic temperatures, vaporized, and introduced into the subject through a transfer conduit as a vapor. Radiofrequency (RF) pulses and magnetic field gradients are then applied to the patient as in conventional MR imaging. Since the vapor is highly polarized, it can be imaged even though it has a much lower density than the surrounding tissue.

Abstract: An automatically positioned focussed energy transducer system facilitates medical procedures by allowing a physician to interactively view the position the focal point of a focussed energy transducer superimposed upon a medical image and computer generated model of internal structures of a patient. A tracking device tracks the position and orientation of the ultrasound transducer. A medical imaging system creates an image of internal structures of the patient near the location of the energy transducer. A general purpose computer either receives a model of internal structures constructed in advance, or employs a medical imaging device to create the model. The general purpose computer displays selected surfaces of the model in an orientation and view which coincides with the medical image acquired.

Abstract: Three-dimensional (3D) image data is acquired from a subject with a medical imaging device and stored. The stored 3D image data is processed by a model workstation to segment the model into discrete structures and produce a segmented computer graphic model. An operator interacts with the model workstation to cause it to display desired structures of the the segmented model in a desired view and orientation. The operator also selects a position and orientation of a cutting plane passing through the segmented model. Once selected, the position and orientation information is provided to a pulse sequencer of a magnetic resonance (MR) imaging system. The pulse sequencer controls an RF transmitter and gradient amplifiers to cause an MR image of the subject at an imaging plane, corresponding to the cutting plane of the model workstation, to be acquired.

Abstract: Thermal drug treatment of tumor tissue is obtained by attaching a thermally active drug to carrier molecules which have an affinity to tumor tissue. Localized heating is performed on the tumor tissue, thereby activating the drug in the tumor tissue. The end result may be concentrated delivery of a drug to a chosen tissue, or, in the case where the drug creates a toxin when heated, selective tissue destruction of a selected locations heated. The localized heat may be applied by focused ultrasound heating.

Abstract: A non-invasive imaging device obtains a four dimensional (4D) image data set of a living subject representing three dimensions and time in relation to the subject's cardiac cycle. In order to determine various vascular parameters, it is useful to segment the image data set into internal structures defined as having the same tissue types contiguous locations. To accomplish this, a gradient calculation unit constructs a gradient data set from the image data set indicating the magnitude of spatial changes in the image data set. A plurality of locations are selected by an operator with a pointing device during `training` along with corresponding data values in the image and gradient data sets. These data values are plotted by a scatter generator against each other to construct a scatter plot then processed to determine a bivariate statistical probability distribution. The remaining data values are then assigned a tissue type based upon their plot on the bivariate statistical probability distribution.

Abstract: A positioner for a magnetic resonance (MR) surgery system which positions a focal point of an ultrasound transducer to selectively destroys tissue in a region within a patient. The positioning means moves an ultrasound transducer under the control of an operator. Mechanical threaded shafts and slides act as screw drives causing several connected slides to move the ultrasound transducer in three dimensions. Expanding shafts are connected between a fixed point on a housing and the actuating point of the threaded shafts. Two of the expanding shafts employ universal joints allowing the shafts to rotate as they follow the slides. The third expanding shaft need only expand but the relative angle between its attachment points does not change, thereby eliminating the need for universal joints.

Abstract: A 4D image data set of a living subject is obtained by non-invasive imaging means representing three dimensions and time in relation to the subject's cardiac cycle. In order to determine various vascular parameters, it is useful to segment the image data set into internal structures defined as having the same tissue types contiguous locations. To accomplish this, a gradient data set is constructed from the image data set indicating the magnitude of spatial changes in the image data set. A plurality of locations are selected in `training` along with corresponding data values in the image and gradient data sets. These data values are plotted against each other to construct a scatter plot then processed to determine a bivariate statistical probability distribution. The remaining data values are then assigned a tissue type based upon their plot on the bivariate statistical probability distribution. Contiguous locations having the same tissue type assignment are identified as a solid structure.

Abstract: In order to display the surfaces of internal structures within a solid body from non-intrusively acquired data sets, it is useful to segment the data sets into the internal structures of interest before searching for the surfaces of such structures. To accomplish this, a data segmentation system uses a plurality of sample data points to construct a statistical probability distribution for a plurality of internal structures. Using these probability distributions, each data point is labeled with the most likely structure identification. Searching the thus-segmented data points for surfaces is considerably faster than is possible with the entire data set and produces surface renditions with fewer anomalies and errors. A non-intrusive imaging means is used to obtain a 3D data set. The probability distribution is bivariate and the two data sets are plotted against each other to assist in identifying tissue types.

Abstract: A manually positioned focussed energy transducer system facilitates medical procedures by allowing a physician to manually position the focal point of the focussed energy transducer to a selected tissue. The focal point of the focussed energy transducer is the location which tissue is destroyed when the energy transducer is activated. A tracking device tracks the position and orientation of the ultrasound transducer. An MR imaging system creates an image of internal structures of the patient near the location of the energy transducer. A superposition device receives the position and orientation of the ultrasound transducer from the tracking device and superimposes a symbol on the image corresponding to the position of the energy transducer relative to the patient. This allows the physician to adjust the position of the energy transducer to the appropriate location without the need for energizing the energy transducer.

Abstract: Surgery is performed with pulsed heat means that selectively destroys tissue in a region within a patient. The size of the region destroyed is dependent upon the frequency of the pulses of the pulsed heat means and thermal conductivity of the tissue of the patient. The pulsed heat means can be a coherent optical source that is guided by laser fiber to the tissue to be destroyed. In another embodiment the pulsed heat means is a focussed ultrasound transducer that dissipates ultrasonic energy at a focal point within the region of tissue to be destroyed. A magnetic resonance imaging system employing a temperature sensitive pulse sequence creates an image of the tissue and the region being heated to allow a surgeon to alter the position of the pulsed heat means or vary the pulse frequency.

Abstract: A magnetic resonance (MR) imaging system for use in a medical procedure employs an open main magnet allowing access to a portion of a patient within an imaging volume, for producing a main magnetic field over the imaging volume; a set of open gradient coils which provide magnetic fields gradients over the imaging volume without restricting access to the imaging volume; a radiofrequency coil set for transmitting RF energy into the imaging volume to nutate nuclear spins within the imaging volume and receive an MR response signal from the nuclear spins; and a pointing device for indicating the position and orientation of a plane in which an image is to be acquired; an image control means for operating power supplies for the gradient coils and the RF coils to acquire an MR signal from the desired imaging plane; and a computation unit for constructing an image of the desired imaging plane.

Abstract: Surgery is performed with a pulsed heat-producing device that selectively heats a region in a specific tissue within a patient destroying the tissue. The pulsed heat-producing device may be a coherent optical source that is guided by laser fiber to the tissue to be destroyed. In another embodiment, the pulsed heat-producing device is a focussed ultrasound transducer which concentrates ultrasonic energy at a focal point within the specific tissue. A magnetic resonance imaging system employing a real-time temperature-sensitive pulse sequence monitors the heated region of the tissue to provide temperature profiles allowing an operator to alter the position and size of the heated region.

Abstract: Surgery is performed with a pulsed heat-producing device that selectively heats a region in a specific tissue within a patient destroying the tissue. The pulsed heat-producing device may be a coherent optical source that is guided by laser fiber to the tissue to be destroyed. In another embodiment, the pulsed heat-producing device is a focussed ultrasound transducer which concentrates ultrasonic energy at a focal point within the specific tissue. A magnetic resonance imaging system employing a real-time temperature-sensitive pulse sequence monitors the heated region of the tissue to provide temperature profiles allowing an operator to alter the position and size of the heated region.

Abstract: Surgery is performed with a pulsed heat-producing device that selectively heats a region in a specific tissue within a patient destroying the tissue. The pulsed heat-producing device may be a coherent optical source that is guided by laser fiber to the tissue to be destroyed. In another embodiment, the pulsed heat-producing device is a focussed ultrasound transducer which concentrates ultrasonic energy at a focal point within the specific tissue. A magnetic resonance imaging system employing a real-time temperature-sensitive pulse sequence monitors the heated region of the tissue to provide temperature profiles allowing an operator to alter the position and size of the heated region.

Abstract: Surgery is performed with pulsed heat means that selectively destroys tissue in a region within a patient. The size of the region destroyed is dependent upon the frequency of the pulses of the pulsed heat means and thermal conductivity of the tissue of the patient. The pulsed heat means can be a coherent optical source that is guided by laser fiber to the tissue to be destroyed. In another embodiment the pulsed heat means is a focussed ultrasound transducer that dissipates ultrasonic energy at a focal point within the region of tissue to be destroyed. A magnetic resonance imaging system employing a temperature sensitive pulse sequence creates an image of the tissue and the region being heated to allow a surgeon to alter the position of the pulsed heat means or vary the pulse frequency.