Abstract: Non-invasive quantitative in-vivo electromagnetic evaluation of bone is performed by subjecting bone to an electrical excitation waveform supplied to a single magnetic field coil near the skin of a bony member, and involving a repetitive finite duration signal consisting of plural frequencies that are in the range 0 Hz-200 MHz. Signal-processing of a bone-current response signal and a bone-voltage response signal is operative to sequentially average the most recently received given number of successive bone-current and bone-voltage response signals to obtain an averaged per-pulse bone-current signal and an averaged per-pulse bone-voltage signal, and to produce their associated Fourier transforms. These Fourier transforms are further processed to obtain the inductively determined frequency-dependent bone-admittance function.

Abstract: A method for free-hand directing of a needle towards a target located in a body volume.

Abstract: The present invention is a device localization system that uses one or more ultrasound reference catheters to establish a fixed three-dimensional coordinate system within a patient's heart using principles of triangulation. The coordinate system is represented graphically in three-dimensions on a video monitor and aids the clinician in guiding other medical devices, which are provided with ultrasound transducers, through the body to locations at which they are needed to perform clinical procedures. In one embodiment of a system according to the present invention, the system is used in the heart to help the physician guide mapping catheters for measuring electrical activity, and ablation catheters for ablating selected regions of cardiac tissue, to desired locations within the heart.

Abstract: A device to detect the location of a magnet coupled to an indwelling medical device within a patient uses three or more sets of magnetic sensors each having sensor elements arranged in a known fashion. Each sensor element senses the magnetic field strength generated by the magnet and provides data indicative of the direction of the magnet in a three-dimensional space. The device uses findamental equations for electricity and magnetism that relate measured magnetic field strength and magnetic field gradient to the location and strength of a magnetic dipole. The device uses an iterative process to determine the actual location and orientation of the magnet. An initial estimate of the location and orientation of the magnet results in the generation of predicted magnetic field values. The predicted magnetic field values are compared with the actual measured values provided by the magnetic sensors.

Abstract: Methods and apparatus for non-invasive tissue urea concentrations during or subsequent to hemodialysis using near-infrared spectroscopy are discussed. Near-infrared tissue spectra can be obtained by projecting near-infrared radiation into skin on the underside of human forearms and capturing the light reflected back and out through the tissue. An index matching medium is used to couple the tissue to the analyzer. The tissue spectrum collected preferably includes primarily diffuse reflected light reflected from the inner dermis. Multiple tissue spectra of known urea concentration are used to build a model from which the urea concentration of an unknown sample can be devised. The model is based on a partial least squares algorithm applied to multiple tissue scans and concomitant blood sample urea measurements. This model is then applied to an unknown tissue spectra.

Abstract: The present invention is capable of more accurately tracking an invasive device in a subject's body in the presence of eddy current inducing structures. Current patterns applied to the tracking system's transmit coils are modified to compensate for the effect of the eddy currents. The current supplied to the coils is a linear combination of the current needed to create the desired electromagnetic field in the region of interest; and one or more error terms. These terms are determined experimentally during system calibration and are mathematically modeled as a series of exponential functions having a given amplitude and time constant. The error terms in the current applied to the transmit coils cancel the magnetic fields created by eddy currents within the tracking region and result in an actual electromagnetic field which is close to the desired ideal electromagnetic field.

Abstract: A diagnostic imaging apparatus such as a magnetic resonance imaging (MRI) device includes a gradient coil assembly (34) and an RF coil (36) disposed proximate pole faces (30, 32). An interventional head coil assembly (40) includes a base (90), a head frame housing (96) including at least one first conductor (130) associated therewith, a first mount (94) that connects the head frame housing (96) to the base (90), a bridge housing (98) including at least one second conductor (142) associated therewith, and a second mount (100) that connects the bridge housing (98) to the head frame housing (96) thereby coupling the at least one first conductor (130) to the at least one second conductor (142) to form a surface coil for use in imaging an object attached to the head frame housing (96).

Abstract: A method and apparatus for monitoring a magnetic resonance image of a patient during administration of transcranial magnetic stimulation. The method includes the steps of applying transcranial magnetic stimulation (TMS) to a patient using a probe that is substantially constructed of non-ferromagnetic material, monitoring a magnetic resonance image (MRI) of the patient during TMS wherein application of the TMS does not need to by synchronized to monitoring of the MRI.

Abstract: Systems and methods for guiding the advancement of a guide wire through body tissue are described. In one embodiment, the guide wire has a first end, a second end, or guide wire head, a bore extending between the first and second ends, and includes an interferometric guidance system. The interferometric guidance system includes a low coherent illumination source, an optical beam splitter, a first optic fiber, a second optic fiber, and a photodetector. Each optic fiber includes a first end and a second end, and is wrapped around a piezo electric transducer (PZT). The second optic fiber has a fixed reflector on the second end. The photodetector is configured to determine interference between a first reflected light beam propagating through the first optic fiber and a second reflected light beam propagating through the second optic fiber. In one embodiment, the guide wire second end is inserted into a blood vessel so that the first optic fiber second end is inserted in the vessel.

Abstract: A dynamic MRA study is performed using a 3D fast gradient recalled echo pulse sequence. A signal strength indicator for each acquired k-space data set is calculated and these indicator values are employed to produce a contrast curve. This contrast curve is used to select data for use in forming a CONTRAST k-space data set and a MASK k-space data set. The MASK is subtracted from the CONTRAST data set and the result is used to reconstruct an image.

Abstract: An interface for association with an electrode structure deployed in contact with heart tissue generates a real image of the electrode structure acquired by an imaging device. The interface also generates an idealized image of the electrode structure based at least in part upon the real image. The interface displays either the real image, or the idealized image, or both on a display screen.

Abstract: A phase-sensitive method of inversion recovery MR imaging is provided, which is directed to a specified object. The method comprises the steps of applying an inversion-recovery MR sequence to the object to acquire a set of MR data for an initial image, wherein the initial image comprises a pixel matrix of specified size, each of the initial image pixels having an associated MR signal and a phase vector. The method further comprises generating a phase vector image from information provided by respective initial image pixels, the phase vector image having a matrix size which is substantially less than the matrix size of the initial image. A region-growing procedure is applied to the phase vector image to remove phase errors therefrom. Thereupon, the phase vector image is zoomed or expanded to a matrix of the same size as the initial image matrix. For multi-slice imaging where TI time is comparatively long, the method may employ a distributed interleave mode of data acquisition to reduce total imaging time.

Abstract: An angiography device including an endoscope designed to be inserted into a body cavity, a light source for emitting excitation light in a first wavelength range into the cavity, a digital camera for sensing an image of the body cavity in a second wave range that does not overlap the first wavelength range, and a screen for displaying the sense image, the first and second wavelength ranges lying in the infrared range.

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.

Abstract: A magnetic resonance angiogram (MRA) is acquired using a pulse sequence that samples k-space at a projection angle. The acquired NMR signal is sensitized to spin motion with a bipolar motion encoding gradient and the pulse sequence is repeated to sample k-space at a set of different projection angles. A phase image is reconstructed from the acquired NMR signals using a filtered backprojection technique. Additional sets of projections with different motion encoding directions are acquired at interleaved projection angles, and the reconstructed phase images are combined to provide a velocity image.

Abstract: A breath sensor utilizes optical fibers to detect the flow of a patients respiratory airstream. As it has no conductive or magnetic parts, it can be used on patients within the bore of a magnetic resonance imaging system for simple, safe, and rapid assessment of a patient's breathing.

Abstract: An acoustic wave therapy apparatus has an acoustic wave source such as shock wave source and an acoustic transmitter that emits such a separate acoustic signal that, during operation of the acoustic wave therapy apparatus, at least partial cancels the air-borne sound caused by the acoustic wave source.

Abstract: A device and method for imaging an object that is situated within a fluid environment having suspended particles uses infrared illumination. In a representative application, a catheter having fiber optics is inserted into the vasculature of a patient. The fiber optics transmits infrared light to an optical head at a distal end of the catheter, which transmits the light into a bloody environment to an object to be imaged. Light reflecting from the object is collected and transmitted throughout the fiber optic to an infrared camera, so that an image is formed. Proper selection of the wavelength of infrared illumination allows objects to be imaged through what would otherwise be an opaque liquid. The invention has particular utility in the field of medical imaging.

Abstract: Methods and computer executable instructions are disclosed for ultimately developing a dosimetry plan for a treatment volume targeted for irradiation during cancer therapy. The dosimetry plan is available in “real-time” which especially enhances clinical use for in vivo applications. The real-time is achieved because of the novel geometric model constructed for the planned treatment volume which, in turn, allows for rapid calculations to be performed for simulated movements of particles along particle tracks there through. The particles are exemplary representations of neutrons emanating from a neutron source during BNCT. In a preferred embodiment, a medical image having a plurality of pixels of information representative of a treatment volume is obtained. The pixels are: (i) converted into a plurality of substantially uniform volume elements having substantially the same shape and volume of the pixels; and (ii) arranged into a geometric model of the treatment volume.

Abstract: An apparatus and method for marking the location for excising a bone lesion by surgery. A localizing needle containing radioactive source of radiation at its tip, is received in a guide needle, with sharp ends of both needles juxtaposed. A cable extends from the opposite end of the localizing needle through the guide needle lumen and out the proximal end of the guide needle. With the bone lesion visualized on a monitor in real time, the needle combination is inserted, tip-first, through the skin and advanced toward the lesion. The radiation from the localizing needle tip assists the surgeon to manipulate the guide needle tip to a marker site on the bone immediately adjacent the lesion. The guide needle tip is pushed into and securely held in the bone. In one embodiment, a handle secured to the cable outside the proximal end of the guide needle is rotated a quarter turn to anchor hooked tips of the localizing needle in the bone.