Temperature Detection Patents (Class 600/412)
  • Publication number: 20110066028
    Abstract: Systems and methods are provided for detecting and responding to excessive heating of implantable medical device leads, such as leads used with pacemakers or implantable cardioverter-defibrillators (ICDs), during a magnetic resonance imaging (MRI) procedure. In one example, a critical temperature is determined for the lead that is representative, e.g., of the temperature at which tissue damage might occur or pacing/sensing might be significantly impaired. A temperature threshold is then set based on the critical temperature by subtracting a predetermined safety margin. Lead temperatures are then sensed during the MRI procedure. The lead temperatures are compared against the threshold and suitable warnings are transmitted to an external monitoring system if lead temperatures exceed their thresholds so that the attending personnel can take corrective action.
    Type: Application
    Filed: September 11, 2009
    Publication date: March 17, 2011
    Applicant: PACESETTER, INC.
    Inventors: Xiaoyi Min, Gene A. Bornzin
  • Publication number: 20110046472
    Abstract: Techniques for temperature measurement and correction in long-term MR thermometry utilize a known temperature distribution in an MR imaging area as a baseline for absolute temperature measurement. Phase shifts that arise from magnetic field drifts are detected in one or more portions of the MR imaging area, facilitating correction of temperature measurements in an area of interest.
    Type: Application
    Filed: August 19, 2009
    Publication date: February 24, 2011
    Inventors: Rita Schmidt, Hadas Ziso, Benny Assif, Osnat Dogadkin, David Freundlich, Yoav Levy, Shuki Vitek
  • Patent number: 7812604
    Abstract: A thermal management system for cooling a heat generating component of a Magnetic Resonance Imaging (MRI) apparatus includes at least one heat pipe having a portion disposed proximate the heat generating component, such as a gradient coil and/or RF coil. When heat is removed from the component, a working fluid in a relatively hotter end of the heat pipe vaporizes and travels toward a relatively colder end of the heat pipe. The colder end may be operatively coupled to a heat sink for removing the heat from the colder end and increase the overall efficiency of the system. The heat pipe may be disposed along a horizontal, a vertical direction and/or along a diagonal of the heat generating component.
    Type: Grant
    Filed: November 14, 2007
    Date of Patent: October 12, 2010
    Assignee: General Electric Company
    Inventors: Tunc Icoz, Mehmet Arik, Yogen Vishwas Utturkar, Bruce Courtney Campbell Amm
  • Publication number: 20100217115
    Abstract: A tear-away sheath is provided for use in an invasive procedure for insertion of a conductive device into a patient while the insertion is guided using Magnetic Resonance Imaging and has a peripheral wall surrounding a hollow interior through which a conductive device can be inserted. At least one and preferably two lines of weakness are formed along the length of the peripheral wall at which the sheath can be torn longitudinally so allow the peripheral wall to be opened to release engagement with a conductive device inserted therethrough. A temperature sensing device is embedded in the peripheral wall at or adjacent the distal end with an optical fiber extending longitudinally of the peripheral wall from the distal end to a position exposed form the patient for communicating the sensed temperature to a display device.
    Type: Application
    Filed: February 25, 2009
    Publication date: August 26, 2010
    Inventor: Stephen G. Hushek
  • Publication number: 20100185081
    Abstract: The in vivo measurement of tissue temperature is performed during a medical procedure using an MRI system. Fat and Water images are acquired at each temperature measurement time and corresponding phase images are produced. A temperature map is produced by subtracting the phase at each Fat image pixel from the corresponding pixel in the Water phase image to improve measurement accuracy in tissues with fat/water mixtures.
    Type: Application
    Filed: May 1, 2008
    Publication date: July 22, 2010
    Inventors: Brian J. Soher, Scott B. Reeder
  • Patent number: 7693568
    Abstract: A medical device includes a sensor for sensing for an MRI gradient magnetic field and a microprocessor for responding to the detected gradient magnetic field by switching from a first electrical signal processing mode to a second electrical signal processing mode, such that electrical signals induced by the gradient magnetic field and an associated RF burst are not counted as cardiac events.
    Type: Grant
    Filed: March 30, 2006
    Date of Patent: April 6, 2010
    Assignee: Medtronic, Inc.
    Inventor: Volkert A. Zeijlemaker
  • Patent number: 7647086
    Abstract: A magnetic resonance imaging apparatus includes an RF coil unit which generates RF pulses toward a subject, and which receives an MR signal from the subject. Gradient magnetic field coils generate a gradient magnetic field for slice selection, a gradient magnetic field for phase encoding and a gradient magnetic field for frequency encoding, respectively. An arithmetic unit generates image data on the basis of the MR signal, and a sequence controller controls phase encoding gradient magnetic field coils in order to generate flow pulses for dephasing or rephasing the MR spin of blood flow within the subject, in the same direction as that of the phase encoding gradient magnetic field.
    Type: Grant
    Filed: October 6, 2003
    Date of Patent: January 12, 2010
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Mitsue Miyazaki, Satoshi Sugiura
  • Publication number: 20090275821
    Abstract: An apparatus and method for correcting magnetic resonance temperature measurements is disclosed. In one aspect, the method identifies monitoring regions of interest outside a therapeutic region of interest. Next, a pulse sequence sensitive to changes in T1 and proton density is used to measure the temperature changes in these regions. Next, the PRFS is measured in these same regions. The PRFS in these regions will be caused both by the desired shift from temperature change, and the undesired shift from background magnetic field changes. Using the measured temperature changes from the T1-method, the component of the PRFS due to actual temperature changes is subtracted from the PRFS method, leaving only the component caused by the unwanted magnetic field changes. This analysis is performed separately for each region. At the end of this step, one has measured the change in background magnetic field within each region.
    Type: Application
    Filed: May 5, 2008
    Publication date: November 5, 2009
    Applicant: GENERAL ELECTRIC COMPANY
    Inventors: Richard Philip Mallozzi, Charles Lucian Dumoulin
  • Publication number: 20090198122
    Abstract: A method for determining a metabolic rate of a portion of a body of a patient. The method includes obtaining magnetic resonance information from the portion of the body after introduction of a fluid and determining a magnetic resonance parameter using the magnetic resonance information. The method further includes using the magnetic resonance parameter to determine a temperature differential in the portion of the body and using the temperature differential to determine a metabolic rate of the portion of the body.
    Type: Application
    Filed: January 22, 2007
    Publication date: August 6, 2009
    Inventors: John Pile-Spellman, Erwin Lin
  • Patent number: 7542793
    Abstract: An MRI system is employed to aim an ultrasonic transducer at tissues to be treated and to produce images which enable the treatment of the tissues to be monitored. A pulse sequence is used which produces both a spin-echo NMR signal and a gradient-echo NMR signal and changes in phase between these two signals is measured and used to produce a temperature map. Changes in amplitude of the spin-echo NMR signal from a reference spin-echo NMR signal is used to produce images which indicate temperature changes in both fat and water. These temperature maps may be used to aim the heat treatment device.
    Type: Grant
    Filed: August 22, 2002
    Date of Patent: June 2, 2009
    Assignee: Mayo Foundation For Medical Education and Research
    Inventors: Tao Wu, Joel P. Felmlee
  • Publication number: 20080287773
    Abstract: The apparatus 1 according to the invention comprises a computing unit 4, which is arranged to access phase images computed from the image data and representative of the target medium and the reference medium and carry out computing steps to yield temperature difference map according to the method of the invention. The operation of the computing means is preferably controlled by the computer program according to the invention, whereby the suitable computing steps are programmed as instructions to a suitable processor. The apparatus 1 further comprises a storage unit 8 arranged to store suitable image data which are accessed by the computer program during the computations. The storage unit 8 preferably stores system parameters of the magnetic resonance apparatus, like the strength of the main field B0, gyromagnetic ratio ?, and suitable parameters of the target medium, like screen constant ? in a file 3. The apparatus 1 further comprises a working memory 6, typically based on RAM.
    Type: Application
    Filed: July 29, 2005
    Publication date: November 20, 2008
    Applicant: KONINKLIJKE PHILIPS ELECTRONICS N.V.
    Inventors: Paul Royston Harvey, Andriy Shmatukha
  • Publication number: 20080275331
    Abstract: In one aspect, in general, a method is provided for detecting temperature and protein denaturation of a tissue during thermal therapy. The method includes generating a plurality of MR pulse sequences that include a first group of pulse sequences and a second group of pulse sequences, and receiving a plurality of response signals that include a first and second group of response signals in response to the first and second groups of pulse sequences, respectively. A first information associated with a degree of protein denaturation of the tissue is determined based on the first and second groups of response signals. A second information associated with a temperature of the tissue is determined based on at least some of the plurality of response signals.
    Type: Application
    Filed: May 5, 2008
    Publication date: November 6, 2008
    Applicant: National Health Research Institutes
    Inventors: Wen-Yih Isaac Tseng, Hsu-Hsia Peng, Teng-Yi Huang, Hsiao-Wen Chung
  • Publication number: 20080146913
    Abstract: A device for locating a venous structure of a patient includes a frame having a bottom surface and a top surface, an adhesive disposed on the bottom surface of the frame to allow the frame to be removably attached to skin or a patient, and one or more sections removably attached to the top surface of the frame. The sections are formed of a liquid crystal material that is sensitive to human skin temperature ranges.
    Type: Application
    Filed: December 18, 2006
    Publication date: June 19, 2008
    Applicant: MEDRAD, INC.
    Inventors: Arun Ranchod, Page Cedarholm, Kevin P. Cowan, Adrienne Fazio, David M. Griffiths
  • Patent number: 7359745
    Abstract: PRF shift MRI data is acquired. The PRF shift MRI data may include signals affected by both a desired PRF shift and an undesired PRF shift. Thus, example systems and methods describe manipulating the PRF shift MR! data to make it substantially free of the effects of the undesired PRF shift, which facilitates displaying certain MRI images based on the desired PRF shift.
    Type: Grant
    Filed: May 14, 2003
    Date of Patent: April 15, 2008
    Assignee: Case Western Reserve University
    Inventors: Jonathan S. Lewin, Jeffrey L. Duerk, Kestutis J. Barkauskas
  • Patent number: 7297907
    Abstract: The present invention discloses a novel active insulation device and method for thermally shielding an external body from temperature fluctuations of a contained body. The method comprising providing an active thermal insulation envelope between the contained body and the external body; regulating the heat transfer from the active thermal insulation envelope to the external body; and regulating the heat transfer from the contained body to the active thermal insulation envelope, thus maintaining the temperature of the external body at a constant temperature or within a narrow temperature range.
    Type: Grant
    Filed: December 8, 2005
    Date of Patent: November 20, 2007
    Inventors: Uri Rapoport, Ehud Katznelson
  • Patent number: 7251519
    Abstract: The present invention provides a method of MR investigation of a sample, said method comprising: (i) nuclear spin polarizing a high T1 MR imaging agent which contains in its molecular structure at least two hyperpolarisable nuclei within the same molecule, the frequency difference between the two resonance lines from said nuclei, ??, being dependent upon either the temperature or the pH of said sample; (ii) administering the nuclear spin polarized MR imaging agent to said sample; (iii) exposing said sample to a radiation at a frequency selected to excite nuclear spin transitions in said MR imaging agent; and (iv) detecting and manipulating magnetic resonance signals from said sample using a single-shot RARE acquisition sequence with shifted data acquisition.
    Type: Grant
    Filed: April 12, 2001
    Date of Patent: July 31, 2007
    Assignee: GE Healthcare AS
    Inventors: Oskar Axelsson, Jan Henrik Ardenkjaer-Larsen, Sven Månsson, Stefan Petersson, Ib Leunbach
  • Patent number: 7246939
    Abstract: This invention utilizes the nuclear magnetic resonance imaging and spectroscopy to experimentally measure thermal diffusivity, thermal conductivity, specific heat, specific absorption rate, thermal power, heat transfer coefficient, heat of reaction and the membrane permeability in substances and systems.
    Type: Grant
    Filed: October 23, 2004
    Date of Patent: July 24, 2007
    Inventor: David H. Gultekin
  • Patent number: 7217245
    Abstract: The systems, methods and apparatus of the present invention comprise noninvasive methods of measuring temperature changes and rates of temperature change in selected body tissues and fluids as a result of absorption and/or dissipation of externally applied heat for the purpose of detecting and monitoring disease or dysfunction, and for preparing diagnostic images of the tissues and related areas from such measurements. Some embodiments of the present invention monitor temperatures of heated tissues directly while other embodiments may measure temperatures of tissues which are heated through flow of heated fluid therethrough.
    Type: Grant
    Filed: April 14, 2000
    Date of Patent: May 15, 2007
    Assignee: University of Utah Research Foundation
    Inventors: Brent W. Snow, Patrick C. Cartwright, John T. Mansfield
  • Patent number: 7209778
    Abstract: A thermal control system having an initial bore condition and a thermal boundary condition for an MRI includes a thermal controller adapted to set at least one dynamic limit on power input into an MRI gradient coil. The dynamic limit is determined for a first commanded prescription as a function of the initial bore condition and the thermal boundary condition.
    Type: Grant
    Filed: September 27, 2002
    Date of Patent: April 24, 2007
    Assignee: General Electric Company
    Inventors: David Dean, Ariel Friedlander, David Ferguson
  • Patent number: 7123010
    Abstract: In a magnetic resonance system and operating method, antenna elements in an antenna array are disposed around an examination volume, and each antenna element has a separate transmission channel and reception channel associated therewith. The magnetic resonance apparatus is operated to obtain magnetic resonance signals, from which amplitude and phase information are derived for the individual antenna elements, and this information is used to subsequently operate the antenna elements in the array to emit RF energy with a predetermined phase and amplitude so as to generate focused RF energy for hyperthermic treatment. The magnetic resonance apparatus can also be used to obtain magnetic resonance signals in intervals which during which the hyperthermic treatment is interrupted, from which the temperature of the region being treated can be ascertained.
    Type: Grant
    Filed: June 18, 2002
    Date of Patent: October 17, 2006
    Assignee: Siemens Aktiengesellschaft
    Inventor: Horst Kröckel
  • Publication number: 20040199070
    Abstract: In a magnetic resonance system and operating method, antenna elements in an antenna array are disposed around an examination volume, and each antenna element has a separate transmission channel and reception channel associated therewith. The magnetic resonance apparatus is operated to obtain magnetic resonance signals, from which amplitude and phase information are derived for the individual antenna elements, and this information is used to subsequently operate the antenna elements in the array to emit RF energy with a predetermined phase and amplitude so as to generate focused RF energy for hyperthermic treatment. The magnetic resonance apparatus can also be used to obtain magnetic resonance signals in intervals which during which the hyperthermic treatment is interrupted, from which the temperature of the region being treated can be ascertained.
    Type: Application
    Filed: December 19, 2003
    Publication date: October 7, 2004
    Inventor: Horst Krockel
  • Publication number: 20040199069
    Abstract: An electromagnetic shield has a first patterned or apertured layer having non-conductive materials and conductive material and a second patterned or apertured layer having non-conductive materials and conductive material. The conductive material may be a metal, a carbon composite, or a polymer composite. The non-conductive materials in the first patterned or apertured layer may be randomly located or located in a predetermined segmented pattern such that the non-conductive materials in the first patterned or apertured layer are located in a predetermined segmented pattern with respect to locations of the non-conductive materials in the second patterned or apertured layer.
    Type: Application
    Filed: April 2, 2003
    Publication date: October 7, 2004
    Inventors: Patrick R. Connelly, Jeffrey L. Helfer
  • Publication number: 20040176680
    Abstract: The invention concerns an assembly for heat treatment of a region of a biological tissue (410) comprising energy-generating means (100) to supply energy to the region; means (200) for measuring and recording spatial temperature distribution in said region; a control unit (300) comprising means for point-to-point digital processing of the temperature distribution in the region. The invention is characterised in that the energy-generating means comprise means(110) for spatial and temporal distribution of the power available to them on said region, the control unit (300) comprising means (330, 350), based on the temperature distribution, for controlling the amount and distribution of energy supplied by the generating means (100).
    Type: Application
    Filed: April 27, 2004
    Publication date: September 9, 2004
    Inventors: Chretien Moonen, Bruno Quesson, Jean Jacques Vimeux
  • Patent number: 6768917
    Abstract: A method of forming a magnetic resonance image involves separate measurement of the position of a measuring site. The magnetic resonance image is corrected on the basis of the measured position of the measuring site.
    Type: Grant
    Filed: June 1, 2001
    Date of Patent: July 27, 2004
    Assignee: Koninklijke Philips Electronics N.V.
    Inventor: Johannes Jacobus Van Vaals
  • Patent number: 6757417
    Abstract: A method of defining a three-dimensional imaging section which comprises displaying a plurality of localizer images of the structure of interest, acquiring operator inputs that designate regions on the plurality of localizer images and that correspond to regions within the structure of interest, and determining a volume based on the regions designated by the operator inputs. The volume defines the three-dimensional imaging section, which is a three-dimensional section of a structure of interest.
    Type: Grant
    Filed: December 27, 2000
    Date of Patent: June 29, 2004
    Assignee: GE Medical Systems Global Technology Company, LLC
    Inventors: Paul E. Licato, James Kevin DeMarco
  • Publication number: 20040049108
    Abstract: The present invention relates to devices and method for melting solid polarised sample while retaining a high level of polarisation. In an embodiment of the present invention a sample is polarised in a sample-retaining cup (9) in a strong magnetic field in a polarising means (3a, 3b, 3c) in a cryostat (2) and then melted inside the cryostat (2) by melting means such as a laser (8) connected by an optical fibre (4) to the interior of the cryostat.
    Type: Application
    Filed: August 29, 2003
    Publication date: March 11, 2004
    Inventors: Jan Henrik Ardenkjaer-Larsen, Oskar H.E. Axelsson, Klaes Koppel Golman, Georg Hansson, H. Johannesson, Rolf Servin, Mikkel Thaning, Lennart Hansson
  • Publication number: 20040039280
    Abstract: An MRI system is employed to aim an ultrasonic transducer at tissues to be treated and to produce images which enable the treatment of the tissues to be monitored. A pulse sequence is used which produces both a spin-echo NMR signal and a gradient-echo NMR signal and changes in phase between these two signals is measured and used to produce a temperature map. Changes in amplitude of the spin-echo NMR signal from a reference spin-echo NMR signal is used to produce images which indicate temperature changes in both fat and water. These temperature maps may be used to aim the heat treatment device.
    Type: Application
    Filed: August 22, 2002
    Publication date: February 26, 2004
    Inventors: Tao Wu, Joel P. Felmlee
  • Patent number: 6640130
    Abstract: The invention is directed to imaging methods for performing real-time or near real-time assessment and monitoring. Embodiments of these methods are useful in a plurality of settings including surgery, clinical procedures, tissue assessment, diagnostic procedures, forensic, health monitoring and medical evaluations.
    Type: Grant
    Filed: July 3, 2000
    Date of Patent: October 28, 2003
    Assignee: HyperMed, Inc.
    Inventors: Jenny E. Freeman, Michael J. Hopmeier, M. Leventen, James Mansfield, Edgar Neil Lewis
  • Patent number: 6618608
    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.
    Type: Grant
    Filed: October 24, 2000
    Date of Patent: September 9, 2003
    Assignee: Txsonics, Ltd.
    Inventors: Ronald D. Watkins, Harvey E. Cline
  • Patent number: 6615069
    Abstract: An MRI apparatus and method in which image data is produced using NMR signals obtained in plural measurements performed at different times respectively. Data is calculated indicating temperature distribution within the object for image data of each measurement time and spatial discontinuity of the calculated temperature distribution data is corrected. Temperature change distribution within the object between different measurement times is calculated by subtracting the corrected temperature distribution data of each measurement time, and the calculated temperature change distribution is transformed to indicative data for supply to a display for display.
    Type: Grant
    Filed: December 18, 2000
    Date of Patent: September 2, 2003
    Assignee: Hitachi Medical Corporation
    Inventors: Kazumi Komura, Tetsuhiko Takahashi
  • Patent number: 6430429
    Abstract: A magnetic resonance imaging (MRI) system is provided with an interventional instrument with an indicator element which influences, for example locally disturbs, the magnetic resonance image. The position of the interventional instrument within the patient to be examined is derived from the local disturbances in the image as caused by the interventional instrument. The degree of influencing of the magnetic resonance image is adjustable notably by rotation of the interventional instrument with the indicator element relative to the direction of the steady magnetic field of the magnetic resonance imaging system. For example, the indicator element is a paramagnetic strip which may include several segments of different magnetic susceptibility.
    Type: Grant
    Filed: December 2, 1999
    Date of Patent: August 6, 2002
    Assignee: Koninklijke Philips Electronics, N.V.
    Inventor: Johannes J. Van Vaals
  • Patent number: 6418337
    Abstract: An MRI guided surgical apparatus includes a heat source formed by a laser and an optical fiber carrying the heat energy into a part to be coagulated by hyperthermia with an end reflector to direct the energy in a beam to one side of the fiber end. The fiber includes a reinforcing sleeve along its length to prevent bending and twisting. The sleeve is mounted in a shielded, Piezo-electric motor which causes movement of the fiber longitudinally of its axis to move the end within the part and rotation of the fiber about its axis to cause the beam to rotate about the axis. A rigid elongate cannula is arranged for insertion to a position at the part of the patient having a bore for receiving a portion of the fiber adjacent the outlet end in sliding engagement therein such that the end can pass through the cannula into engagement with the part of the patient. A part of the sleeve projecting beyond the cannula is rigid and a further part connecting to the motor is stiff but less rigid.
    Type: Grant
    Filed: June 15, 2000
    Date of Patent: July 9, 2002
    Assignee: Autolitt Inc.
    Inventors: Mark G. Torchia, Richard Tyc, Ken J. McTaggart, John S. Pacak
  • Patent number: 6377834
    Abstract: NMR images indicative of thermal changes in tissues undergoing therapy are produced using a gradient-recalled echo pulse sequence. Prior to therapy a contrast agent which shortens spin T1 relaxation time is injected into the patient and a reference phase image indicative of proton chemical shift is acquired. Temperature maps are produced in real-time as the therapy is subsequently performed by repeatedly acquiring NMR data, reconstructing measurement phase images and subtracting the reference phase image. The temporal rate at which the temperature maps are produced is increased by segmenting k-space and acquiring less than all the segments during each repetition.
    Type: Grant
    Filed: April 24, 2000
    Date of Patent: April 23, 2002
    Assignee: Wisconsin Alumni Research Foundation
    Inventors: Yong Zhou, Richard Frayne
  • Patent number: 6334846
    Abstract: An ultrasonic therapeutic apparatus consisting of a therapeutic ultrasonic wave generating source driven by a driver circuit to generate therapeutic ultrasonic waves, an in vivo imaging probe so as to obtain a tissue tomographic image in the vicinity of the focus of the therapeutic ultrasonic waves. The imaging probe is used to receive echoes of the ultrasonic pulses emitted from therapeutic ultrasonic wave generating source. The driving conditions for the therapeutic ultrasonic wave generating source is adjusted on the basis of a received echo signal. The received echo signal contains information about actual intensity of the therapeutic ultrasonic waves within a living body, thus improving the safety and reliability of therapy.
    Type: Grant
    Filed: June 18, 1999
    Date of Patent: January 1, 2002
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Yoshiharu Ishibashi, Katsuhiko Fujimoto, Mariko Shibata, Takuji Suzuki, Satoshi Aida
  • Patent number: 6280384
    Abstract: In a method for spatially resolved temperature monitoring in an examination subject, a suspension of ferromagnetic microparticles is intracorporeally introduced into the body Curie temperature of which substance corresponds to a desired temperature limit value. By means of an MR measurement, a spatially resolved representation of the body is obtained with artifacts that are caused by the substance being in the ferromagnetic state being employed as a criterion for determining that the temperature limit value has not yet been reached.
    Type: Grant
    Filed: April 15, 1999
    Date of Patent: August 28, 2001
    Assignee: Siemens Aktiengesellschaft
    Inventor: Ralf Loeffler
  • Patent number: 6246896
    Abstract: An MRI system acquires NMR tracking data from a tracking coil imbedded in an ablation device which is guided by a physician using real time anatomic images produced from image data acquired by the MRI system. The same tracking coil is energized by an RF power source to deliver energy which ablates tissue after the device is guided into proper position.
    Type: Grant
    Filed: November 24, 1998
    Date of Patent: June 12, 2001
    Assignee: General Electric Company
    Inventors: Charles Lucian Dumoulin, Robert David Darrow
  • Patent number: 6194899
    Abstract: An absolute temperature measuring pulse sequence is executed and, subsequently, a relative temperature measuring pulse sequence is repeatedly executed. Since while a relative temperature can be measured from phase information, an absolute temperature requires frequency information, a time required in the relative temperature measuring pulse can be made shorter than that required in the absolute temperature measuring pulse sequence. Since the relative temperature reveals a temperature variation, if an absolute temperature at a given time is known, an absolute temperature at a subsequent time can be calculated from the relative temperature. Thus, a local internal temperature of the subject can be measured, with a shorter temporal resolution, with the use of the absolute temperature and relative temperature.
    Type: Grant
    Filed: February 17, 1999
    Date of Patent: February 27, 2001
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Yasutoshi Ishihara, Masaaki Umeda, Hidehiro Watanabe, Kazuya Okamoto
  • Patent number: 6188923
    Abstract: A method and an apparatus for local heating and global monitoring of a tissue disposed in an imaging device, monitored by the imaging device and substantially simultaneously heated by focused ultrasound from an appropriate source. The ultrasound is generated outside the imaging device and is guided to the tissue through the use of a waveguide. In particular, the imaging device is a magnetic resonance scanner.
    Type: Grant
    Filed: September 25, 1998
    Date of Patent: February 13, 2001
    Assignee: Siemens Aktiengesellschaft
    Inventor: Mario Bechtold
  • Patent number: 6100690
    Abstract: In a magnetic resonance imaging apparatus being medical diagnostic equipment for understanding the internal structure of a human body, a radio frequency coil for a magnetic resonance imaging apparatus is provided for transmitting and receiving a magnetic resonance signal for forming a magnetic resonance image of a portion of a human body. The coil has an opening formed by splitting a portion of one turn of the coil into two. Thereby, a radio frequency coil for a vertical magnetic field provides a maximum open area. Therefore, a simple operation or an observation can be made through the opening simultaneously with taking a magnetic resonance image of the affected part. Also, a patient can feel less claustrophobic because they can see out through the opening.
    Type: Grant
    Filed: October 29, 1997
    Date of Patent: August 8, 2000
    Assignee: Samsung Electronics Co., Ltd.
    Inventors: Woan Yi, Jung-hoe Kim, Jeong-han Yi, Dong-heon Kang
  • Patent number: 6091242
    Abstract: An inversion pulse is applied to the subject in a static magnetic field. An excitation pulse is applied after a delay time depending on the time constant of the longitudinal relaxation of the spins of proton contained in fat molecule from this inversion pulse. As a result, the spins of proton contained in the fat molecule can be suppressed at high precision. On the basis of the MR signal collected after this suppression, the resonance frequency data of the spins of proton contained in water molecule which is not suppressed or the data corresponding to this resonance frequency, or the magnetic field distribution data of the static magnetic field or the data corresponding to this magnetic field distribution can be determined at high precision.
    Type: Grant
    Filed: September 9, 1998
    Date of Patent: July 18, 2000
    Assignee: Kabushiki Kaisha Toshiba
    Inventor: Masatoshi Hanawa
  • Patent number: 6032068
    Abstract: Temperature in frozen tissue can be measured from magnetic resonance signals from the frozen tissue based on spin-spin relaxation time (T2) or based on relative intensity of the magnetic resonance signals. Short echo times are required, and use of tailored RF pulses, non-Cartesian readouts, and multi-slice and 3D k-space acquisitions are preferably employed.
    Type: Grant
    Filed: February 19, 1998
    Date of Patent: February 29, 2000
    Assignee: The Board of Trustees of the Leland Stanford Junior University
    Inventors: Bruce L. Daniel, Rosemary Kim Butts
  • Patent number: 6028429
    Abstract: An antenna system for a magnetic resonance imaging apparatus has an active coil connected between a transmitter or receiver and ground and also has an isolated loop coil which is not conductively connected to ground. The isolated loop coil preferably overlies the electrically conductive pole surface of the field magnet. The isolated loop coil is inductively coupled to the active coil. The assembly has relatively low parasitic capacitance to ground and hence can be tuned to the resonant frequencies required for high field strength imaging.
    Type: Grant
    Filed: July 17, 1997
    Date of Patent: February 22, 2000
    Assignee: Fonar Corporation
    Inventors: Charles Green, Jan Votruba, Gregory Eydelman, Raymond V. Damadian
  • Patent number: 6011392
    Abstract: Fast spin echo pulse sequences are adjusted to reduce, or eliminate image artifacts caused by Maxwell terms arising from the linear imaging gradients. The waveforms of the slice selection, phase encoding and readout gradients are adjusted in shape, size or position to eliminate or reduce the phase error caused by the spatially quadratic Maxwell terms.
    Type: Grant
    Filed: January 12, 1998
    Date of Patent: January 4, 2000
    Assignee: General Electric Company
    Inventors: Xiaohong Zhou, Matthew A. Bernstein, Gousheng Tan
  • Patent number: 6008644
    Abstract: This invention relates to a method of electron spin resonance enhanced magnetic resonance imaging which relies on ex vivo dynamic nuclear polarisation of an MR imaging agent.
    Type: Grant
    Filed: July 3, 1997
    Date of Patent: December 28, 1999
    Assignees: Picker Nordstar OY, Nycomed Imaging AS
    Inventors: Ib Leunbach, Ian Young, Gosta Ehnholm, Georg Hansson, Stefan Petersson, Lars-Goran Wistrand, Klaes Golman
  • Patent number: 5998998
    Abstract: A gradient coil (1) to generate switched magnetic field gradients in an nuclear spin resonance (NMR) device consisting of one or several current paths (a, b) following windings and being arranged on the surface of a geometric body is characterized in that at least two electrical current paths (a, b) are provided for, running geometrically essentially parallel to each other and being electrically connected in parallel, which current paths cross n times per winding, wherein n is an integer with n.ltoreq.8, preferably n=1 or n=2. In this way, eddy current generation by current re-distributions on the gradient coil conductor strips and thereby a time-dependent distortion of the generated magnetic field gradient inside the volume of interest of the NMR apparatus is considerably reduced.
    Type: Grant
    Filed: July 10, 1997
    Date of Patent: December 7, 1999
    Assignee: Bruker Analytik GmbH
    Inventor: Michael Westphal
  • Patent number: 5944663
    Abstract: In an apparatus for treatment of a subject with acoustic waves, a spatial allocation, required for the treatment of the patient and a source of acoustic waves relative to each other is effected by a surgical work station using a three-dimensional navigation system on the basis of a number of images of a region to be treated, which are obtained independently of the treatment apparatus, in different coordinate systems, and are displayed on a display screen of the work station.
    Type: Grant
    Filed: October 9, 1997
    Date of Patent: August 31, 1999
    Assignee: Siemens Aktiengesellschaft
    Inventors: Rainer Kuth, Siegfried Schneider, Ulrich Schatzle
  • Patent number: 5926022
    Abstract: A bipolar, phase-encoding, pre-phaser pulse is employed in each shot of a multi-shot EPI pulse sequence to smooth the phase-encoding gradient first moment throughout the scan. The first moment of the pre-phaser pulse is calculated for each shot in the scan and is played out at the beginning of each shot after the RF excitation.
    Type: Grant
    Filed: April 9, 1997
    Date of Patent: July 20, 1999
    Assignee: Mayo Foundation For Medical Education and Research
    Inventors: Glenn S. Slavin, Stephen J. Riederer
  • Patent number: 5916161
    Abstract: A magnetic resonance imaging apparatus capable of measuring a temperature increase due to an application of RF magnetic fields for data acquisition purpose, and notifying an information on the measured temperature increase regularly to an operator, so as to secure the safety of a body to be examined. In this magnetic resonance imaging apparatus, the image data acquisition operation is controlled to acquire a phase information associated with a temperature change in an interior of the body to be examined, by displacing either an observation start timing or a radio frequency magnetic field application timing for a prescribed magnetic resonance signal in the magnetic resonance signal sequence from a normal timing for acquiring image data.
    Type: Grant
    Filed: September 13, 1996
    Date of Patent: June 29, 1999
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Yasutoshi Ishihara, Kazuya Okamoto
  • Patent number: 5906584
    Abstract: A device for invasive temperature measurements during surface and deep hyperthermia treatments. The device includes a needle-pin element and a catheter of a biocompatible material semi-rigid sheath surrounding the needle-pin element. The needle-pin element and the sheath are coupled such that the needle-pin element can be drawn out. At least one thermocouple is provided on an outer circumference of the semi-rigid sheath of the catheter. The thermocouple has an end to affect the temperature reading and is provided close to a surface of the sheath which is in contact with tissue of a human body. Positioning means are provided at the bottom of the catheter to position the catheter adjacent to a human body and for maintaining the catheter in position.
    Type: Grant
    Filed: May 21, 1997
    Date of Patent: May 25, 1999
    Assignee: Pierfrancesco Pavoni
    Inventors: Pierfrancesco Pavoni, Guglielmo Marsiglia, Gioacchino Possenti