Picker International, Inc.

University of Minnesota

Leland Stanford Junior University

Image-guided Drug Delivery System, Inc.

Haiying Liu

Charles Loeb Truwit

Ravi Srinivasan

Rao P Gullapalli

Robert A Elek

Gordon D DeMeester

Mark J Loncar

Kamil Ugurbil

Paul M Margosian

Wei Chen

Yansun Xu

Wayne R Dannels

Joseph Vilmos Hajnal

John Kucharczyk

David A Molyneaux

David A Lampman

James M McNally

Michael E Moseley

Francis H Bearden

Larry Kasuboski

Debra F Bauer

A catheter is used for medical treatments within an organism. The catheter comprises at least one lumen. Within the at least one lumen are at least two microcatheters, with at least one of the at least two microcatheters being connected to a source of liquid material to be delivered to the organism and another of the at least two microcatheters being connected to a system capable of effecting a medical treatment other than delivery of the liquid.

MR-compatible devices

There is disclosed a method of positioning an interventional device in a body using a guide pivoting about a pivot point, performed by locating the spatial coordinates of a target and the pivot point, determining a third point outside of the body lying along or proximate a line extending through the target and pivot point, and aligning the axis of the guide with the third point using an imaging system. There is also disclosed a medical imaging system including a processing unit and computer software operative on the processing unit to permit an operator of the system to locate the spatial coordinates of a target point and a pivot point of a guide, and determine a third point outside of the body lying along or proximate a line extending through the target and pivot point. This medical imaging system may further include computer software operative on the processing unit to assist an operator in obtaining an image by which the axis of the guide can be aligned with the third point using an imaging system. There is also disclosed an article of manufacture formed by a computer program encoded in a carrier, wherein the program is operative on a processing unit of a medical imaging system to permit an operator of the system to locate the spatial coordinates of a target point and a pivot point of a guide, and determine a third point outside of the body lying along or proximate a line extending through the target and pivot point.

Method and apparatus for positioning a device in a body

NMR spectroscopy data recovery methods and apparatus for improving the quality of an NMR spectrum are disclosed. The NMR spectrum is improved by acquiring more than the half spin-echo data signal and using an iterative numerical method to reconstruct the missing data points of the corresponding full symmetrical spin-echo data signal. The method includes filtering the initial data signal to extract a low-resolution phase term. The low-resolution phase term is used to form a phase-constrained initial data signal, which is Fourier-transformed to obtain a reconstructed data signal. The reconstructed data signal is modified to include the original spin-echo signal data. The formation of the reconstructed spin-echo data signal and subsequent modification is iterated until convergence is obtained. The reconstructed data signal is then Fourier-transformed to form a reconstructed NMR spectrum.

NMR spectroscopy data recovery method and apparatus

An alegebraic reconstruction matrix generator (90) generates an algebraic reconstruction matrix P. A gradient trajectory memory (94) contains elements k.sub.n which describe the k-space trajectory of a time-varying read gradient wave form. An A-matrix generator (96) generates a coefficient matrix A from the elements k.sub.n. A D-matrix generator (100) generates a diagonal matrix D having elements d.sub.n. Using the elements of matrices A and D, an H-matrix generator creates a matrix H. An inverter (110) inverts the matrix to obtain H.sup.-1. A transposer (112) transposes matrix A to obtain A.sup.T. A multiplication processor (114) combines H.sup.-1, A.sup.T, and D to obtain the algebraic reconstruction matrix P. A multiplication processor (122) then combines the matrix P and an array of image data lines b to generate an image matrix array X which is stored in an image memory (124). A one-dimensional column Fourier transform processor and associated memory (125) transforms and stores the image matrix array. A video processor (126) converts the image matrix array into an appropriate format for display on a video monitor (130). The image data sampling can be performed at previously unused portions of a read gradient wave form, thus reducing image acquisition time.

Alternative reconstruction method for non-equidistant k-space data

A less-claustrophobic, quadrature, radio-frequency head coil (42) includes first and second broken end rings (90, 92) connected to each other in parallel by a plurality of leg conductors (94). At least two of the leg conductors are interconnected by a third arcuate conductor segment (98) axially displaced from planes of the first and second end rings to provide an opening (44) over a subject's face. The opening reduces patient claustrophobia and permits access to the patient for life-support devices or the practice of interventional medicine. The end rings have a fixed capacitance (C.sub.1, C.sub.2) between each pair of leg conductors. The fixed capacitance C.sub.1 between at least one pair of leg conductors and the fixed capacitance C.sub.2 between at least the pair of leg conductors adjacent the opening, where C.sub.2 &gt;C.sub.1. A two-port feed (66, 68) circumferentially attached to the coil generally opposite the opening matches the individual linear modes. Thus, the radio frequency coil is able to maintain two preferred principal linear modes (A, B) across the open area of the coil.

Less-claustrophobic, quadrature, radio-frequency head coil for nuclear

The use of devices in procedures, especially medical procedures where the events take place under view of Magnetic Resonance Imaging (MRI) systems is becoming more important. Although some general and specific structures have been discussed in the literature and commercialized, little has been done effectively to design devices for MRI procedures for specific tasks. The present invention describes a device for use within an organism, said device comprising an element having at least one pair of opposed RF receiver microcoils having a space between each microcoil of said pair of microcoils, the coils of said microcoils may have diameters of less than 2.4 mm. The device may also comprise an element having at least one pair of opposed RF receiver microcoils having a space between each microcoil of said pair of microcoils, said RF receiver microcoils each comprising at least three individual coils, said at least three individual coils of said microcoils having spacing between adjacent microcoils so that spacing between at least two pairs of individual coils within said microcoils differ by at least 10%. Circuitry may be insulated within the device by providing the wires and circuits within different layers in a coaxial layering of components within the catheter. The device may also comprise device an element having at least one pair of opposed RF receiver microcoils having a space between each microcoil of said pair of microcoils, the RF receiver microcoils each comprising at least three individual windings, the at least three individual windings of said microcoils having spacing between adjacent windings so that spacing between at least two pairs of individual windings within the microcoils differ by at least 10%.

MR-compatible medical devices

A single-circuit quadrature surface coil is formed from two ladder resonator coils and includes a first mode circuit path for detecting or generating magnetic flux in a vertical axis from a body under investigation and a second mode circuit path for detecting or generating magnetic flux in a parallel axis, with the first mode and second mode currents 90 degrees out of phase. The surface coil, which supports two resonance current modes for quadrature operation on only one single coil conductor structure, provides a high signal-to-noise ratio (SNR) and a good B.sub.1 homogeneity over the imaging volume. This coil alone may be used either for both transmitting and receiving RF signals or for detecting RF signals as 'receive only.' This coil is well suited for imaging the human neck, spine and heart.

Single circuit ladder resonator quadrature surface RF coil

Within a selected slice or slab, diffusion sensitizing gradients (54, 56) and read gradients (66, 68) are induced along each of a pair of orthogonal axes (G.sub.x, G.sub.y). The motion sensitizing gradient pulses sensitize excited magnetic resonance to diffusion in a preselected diffusion direction (D) which is orthogonal to a selected read gradient direction. The diffusion sensitizing gradients are rotated by sin(.theta.+.pi./2) and cos(.theta.+.pi./2) and the read gradients are rotated by sin.theta. and cos.theta. to generate a plurality of angularly displaced data lines. The diffusion sensitivity direction remains perpendicular to the read direction in each of the angularly displaced data lines. The phase of each data line is determined (90) and shifted (94) to compensate for linear translations. The data values within each data line are shifted (86) to center the peak amplitude of the data line at a preselected position to compensate for higher order motion. The set of angularly incremented data lines are reconstructed (96) into an image representation (98). In one embodiment, a plurality of the images are generated, each from data lines with their peak value shifted to a location which is offset by a fraction of a sample relative to the data lines which constructed the other images. Corresponding patches of these corresponding images are examined (110) for phase. Based on the examination, the one of the corresponding patches with the best image quality is transferred to a final image memory (114). In this manner, the final image is made up of the best patches of a plurality of corresponding images.

Rotating diffusion MR imaging reduced motion artifacts

A transmitter (24) and gradient amplifiers (20) transmit radio frequency excitation and other pulses to induce magnetic resonance in selected magnetic dipoles and cause the magnetic resonance to be focused into a series of echoes (66) at each of a plurality of preselected echo positions following each excitation. A receiver (38) converts each echo into a data line. Calibration data lines having a close to zero phase-encoding are collected and used to generate correction parameters (102) for each of the echo positions. These parameters include relative echo center positions (96) and unitary complex correction vectors (106). The calibration data lines for each of the preselected positions are one-dimensionally Fourier transformed (82) and multiplied (90) by the same complex conjugate reference echo (80). These data lines are then inverse Fourier transformed (92) to generate an auxiliary data array (94). A relative echo center position is computed (96) which represents a fractional shift of the true center relative to the reference echo. A complex sum is computed (104) from the relative echo center position and normalized (106) to generate a unitary correction vector. The phase-correction parameters are used to phase-correct (116) imaging data lines. The phase-corrected imaging data lines are sorted (122) to build an image plane which is one-dimensionally Fourier transformed (128) in the phase-encoding direction to produce a final corrected image (130) for display on a monitor (134).

Method for magnetic resonance spin echo scan calibration and

A sequence control (40) causes a transmitter (24) and gradient amplifiers (20) to transmit radio frequency excitation and other pulses to induce magnetic resonance in selected dipoles and cause the magnetic resonance to be focused into a series of echoes in each of a plurality of data collection intervals following each excitation. A receiver (38) converts each echo into a data line. Calibration data lines having a close to zero phase-encoding are collected during each of the data collection intervals. The calibration data lines in each data collection interval are zero-filled (86) to generate a complete data set and Fourier transformed (88) into a series of low resolution complex images (90.sub.1, 90.sub.2, . . . 90.sub.n), each corresponding to one of the data collection intervals. The low resolution images are normalized (92) and their complex conjugates taken (94). Imaging data lines are sorted by a data collection interval and zero-filled (104) to create full data sets. The full data set corresponding to each data sampling interval is Fourier transformed into partial image representations (106.sub.1, 106.sub.2, 106.sub.n). Each partial image is multiplied (108) by a complex conjugate of the normalized phase correction map (96) to create corrected partial images which are summed (112) to generate a composite image (114). The composite images are density corrected (120).

Magnetic resonance scan calibration and reconstruction technique for

A magnetic resonance system is used to excite high .gamma. dipoles, such as hydrogen, and lower .gamma. dipoles, such as phosphorous, to resonate concurrently. A multiply-tuned radio frequency coil (40) is disposed around the region of interest. The multiply-tuned radio frequency coil is tuned to the resonance frequency of the high .gamma. dipoles and the resonance frequency of the low .gamma. dipoles. The coil has an inner coil section, defined by a first leg or ring (92) and a second leg or ring (94), which is tuned by added capacitance substantially to the resonance frequency of the low .gamma. dipole. A first outer coil section which is defined by a third leg or ring (90) and the first leg or ring. A second outer coil section defined by the second leg or ring (94) and a fourth leg or ring (96). The first and second outer sections, together with the inner coil section define a coil which has a co-rotating mode and a counter-rotating mode. Added capacitance is sized such that one of the co-rotating and counter-rotating modes is at the high .gamma. resonance frequencies. In this manner, a multiply-tuned radio frequency coil is defined which is simultaneously tuned to at least two resonance frequencies. Separate pick-ups (130, 132) for the high and low resonance frequencies enable both signals to be received (66, 70) simultaneously for reconstruction (74) into image representations.

Multipl-tuned radio frequency coil for simultaneous magnetic resonance

When a magnetic resonance imaging sequence is retrieved from memory (58), one of the slice select, phase-encode to read gradient profiles are retrieved for one of the slice select, phase-encode, read gradients. The two gradient profiles have a common field of view if a read gradient or slice thickness if a slice select gradient, but have different motion sensitizations. The reference gradient profile G.sub.1 stored in a memory (52) and the motion sensitized gradient profile G.sub.2 stored in a memory (56) are weighted (60, 62) by weighting functions .alpha..sub.1, .alpha..sub.2 which are selected in accordance with the selected motion sensitivity and a selected one of the field of view or slice thickness. The weighted profiles are combined (64) to generate a motion sensitized gradient with the selected motion sensitivity, field of view or slice thickness. The combined weighted gradient profile and the reference gradient profile are used in imaging sequences to generate reference and motion sensitized data lines (82, 84) which are reconstructed (86) into a reference image representation and a motion sensitized image representation. A moving tissue only image representation can be obtained (88) as well.

Phase sensitive magnetic resonance technique with integrated gradient

A sequence control (40) causes a transmitter (24) and gradient amplifiers (20) to transmit appropriate radio frequency excitation and other pulses to induce magnetic resonance in selected dipoles and cause the magnetic resonance to be refocused into a series of echoes following each excitation. A receiver (38) converts each echo into a digital data line. Each data line is regridded (70) for uniformity in k-space (FIG. 4). The data lines are one-dimensionally Fourier transformed (72) in a frequency encode direction. The one-dimensionally Fourier transformed data lines are multiplied (80) with a phase correction vector. A phase correction vector determining system (82) determines a corresponding phase correction vector for each echo number or position following excitation from a series of calibration echoes. To compensate for a decrease in magnitude with echo position following excitation, the intensity of each data line is scaled (90) to a common magnitude. The intensity corrected data lines are stored in a memory (96) and one-dimensionally Fourier transformed in a phase encode direction into an image memory (100). A monitor (104) converts the image memory representation into a human-readable display.

Growing community of inventors

Euclid, OH, United States of America

Haiying Liu