The Johns Hopkins University

National Institutes of Health, a Component of the US Dept. of Health & Human Services

Surgi-vision Inc.

Ge Medical Systems Global Technology Company, LLC

The United States of America As Represented by the Department of Health

Elliot R McVeigh

Ergin Atalar

Albert Clark Lardo

Henry R Halperin

Ronald David Berger

Hugh Calkins

Joao Lima

Peter Kellman

Paul Arthur Bottomley

Reza Nezafat

Daniel Alfredo Herzka

John Andrew Derbyshire

Michael Guttman

Amir Pourmorteza

Parag V Karmarkar

Yiping Du

Matthias Stuber

Christine McNamara

Ronald Ouwerkerk

Xiaoming Yang

Richard Thompson

Steve Tulley

Fady Dawoud

J Andrew Derbyshire

Elias Zerhouin

Anthony Z Faranesh

Scott B Reeder

Karl H Schuleri

Bradley D Bolster, Jr

The present invention is directed to a method for combining assessment of different factors of dyssynchrony into a comprehensive, non-invasive toolbox for treating patients with a CRT therapy device. The toolbox provides high spatial resolution, enabling assessment of regional function, as well as enabling derivation of global metrics to improve patient response and selection for CRT therapy. The method allows for quantitative assessment and estimation of mechanical contraction patterns, tissue viability, and venous anatomy from CT scans combined with electrical activation patterns from Body Surface Potential Mapping (BSPM). This multi-modal method is therefore capable of integrating electrical, mechanical, and structural information about cardiac structure and function in order to guide lead placement of CRT therapy devices. The method generates regional electro-mechanical properties overlaid with cardiac venous distribution and scar tissue. The fusion algorithm for combining all of the data suggests cardiac segments and routes for implantation of epicardial pacing leads.

Imaging toolbox for guiding cardiac resynchronization therapy implantation from patient-specific imaging and body surface potential mapping data

An embodiment in accordance with the present invention provides a method and system for evaluating regional cardiac function and dyssynchrony from an imaging modality using the motion of endocardial features of the heart. In the method and system, an imaging modality such as a CT scanner is used to obtain an image sequence that is then processed using a computer program. The computer program is configured to create an endocardial mesh formed from triangular components that represents at least the region of interest of the subject's heart. From tracking the motion of conserved topological features on this endocardial mesh at least two time points a displacement map can be modeled. The displacement map can be further analyzed to determine metrics of regional cardiac function such as SQUEEZ, myocardial strain, torsion etc., and the displacement map can also be used to create visual representations of the function of the subject's heart.

Methods for evaluating regional cardiac function and dyssynchrony from a dynamic imaging modality using endocardial motion

A method of producing volume renderings from magnetic resonance image data in real time with user interactivity. The method comprises collecting raw magnetic resonance image (MRI) data representative of shapes within an image volume; transferring the raw MRI data to a computer; and continuously producing volume renderings from the raw MRI data in real time with respect to the act of collecting raw MRI data representative of shapes within the image volume.

Real time, interactive volumetric magnetic resonance imaging

A system and method for using magnetic resonance imaging to increase the accuracy of electrophysiologic procedures includes an invasive combined electrophysiology and imaging antenna catheter which includes an RF antenna for receiving magnetic resonance signals and diagnostic electrodes for receiving electrical potentials. The combined electrophysiology and imaging antenna catheter is used in combination with a magnetic resonance imaging scanner to guide and provide visualization during electrophysiologic diagnostic or therapeutic procedures, such as ablation of cardiac arrhythmias. The combined electrophysiology and imaging antenna catheter may further include an ablation tip, and be used as an intracardiac device to deliver energy to selected areas of tissue and visualize the resulting ablation lesions. The antenna utilized in the combined electrophysiology and imaging catheter for receiving MR signals is preferably of the coaxial or 'loopless' type. High-resolution images from the antenna may be combined with low-resolution images from surface coils of the MR scanner to produce a composite image. A system for eliminating the pickup of RF energy in which intracardiac wires are detuned by filtering so that they become very inefficient antennas. An RF filtering system is provided for suppressing the MR imaging signal while not attenuating the RF ablative current. Steering means may be provided for steering the invasive catheter under MR guidance. Other ablative methods can be used such as laser, ultrasound, and low temperatures.

System and method for magnetic-resonance-guided electrophysiologic and ablation procedures

Real-time, interactive volumetric magnetic resonance imaging

A method for fat-suppressed imaging is disclosed. Such a method may include storing a first spectral component of an echo signal formed at TR/2 from a sample, suppressing a second spectral component of the echo signal at TR/2, re-exciting the stored spectral component after suppressing the second spectral component, and producing an image of the sample based on the re-excited stored spectral component.

Spectrally selective suppression with steady-state free precession

Herein is disclosed a magnetic resonance imaging probe, having a probe shaft including a magnetic resonance antenna, and a spring tip attached to a distal end of the antenna.

Magnetic resonance imaging probe

A system and method for using magnetic resonance imaging to increase the accuracy of electrophysiologic procedures is disclosed. The system in its preferred embodiment provides an invasive combined electrophysiology and imaging antenna catheter which includes an RF antenna for receiving magnetic resonance signals and diagnostic electrodes for receiving electrical potentials. The combined electrophysiology and imaging antenna catheter is used in combination with a magnetic resonance imaging scanner to guide and provide visualization during electrophysiologic diagnostic or therapeutic procedures. The invention further provides a system for eliminating the pickup of RF energy in which intracardiac wires are detuned by filtering so that they become very inefficient antennas. An RF filtering system is provided for suppressing the MR imaging signal while not attenuating the RF ablative current. Steering means may be provided for steering the invasive catheter under MR guidance.

MRI-guided therapy methods and related systems

A method of performing brain therapy may include placing a subject in a main magnetic field, introducing into the subject's brain a combination imaging and therapeutic probe, the probe including a magnetic resonance imaging antenna and an electrical energy application element, acquiring a first magnetic resonance image from the antenna of the combination probe, acquiring a second magnetic resonance image from a surface coil, combining the first and second magnetic resonance images to produce a composite image, positioning the combination probe within the brain with guidance from at least one of the images, and delivering electrical energy to the brain from the electrical energy application element of the combination probe thus positioned.

Brain therapy

A Tpreparation sequence uses a segmented BIR-4 adiabatic pulse with two substantially equal delays and is insensitive to Bfield variations and can simultaneously suppress fat signals with low specific absorption rate (SAR). An adiabatic reverse half passage pulse is applied followed by a predetermined delay. An adiabatic full passage pulse is applied followed by a substantially equal delay, followed by an adiabatic half passage pulse. Fat signal suppression is achieved by increasing or decreasing either the first delay or the second delay.

Method for spectrally selective B1 insensitive T2 preparation contrast enhancement for high field magnetic resonance imaging

Phase contrast magnetic resonance images are produced using interleaved spiral k-space scanning with a bipolar phase contrast gradient. Spiral scanning is configured so that acquisition impulse response defines a central alias free portion in a partial field of view, and signal acquisition is arranged so that moving spins are contained with this central alias free portion. First and second signals are acquired with alternate phase encodings, and a complex difference of the acquired signals is obtained. The complex difference is substantially free of aliasing artifacts within the central portion.

Imaging and reconstruction of partial field of view in phase contrast MRI

A method that exploits the intrinsic selectivity of steady-state free precession (SSFP) to perform spectral suppression is disclosed. Such a method avoids the need to incorporate additional spectrally selective pulse sequence elements. The scheme is based on breaking the FISP imaging sequence into short trains having, for example, 8&#x2013;64 RF pulses. At the moment of echo formation (i.e., TE=TR/2) after the last full RF pulse of the train, water signal is z-stored. Residual transverse magnetization, which include isochromats phase-opposed to the on-resonance water, is gradient crushed and RF spoiled. The stored magnetization is subsequently re-excited with little disturbance to the on-resonance steady-state water signal. The additional time required to perform the steady-state interruption is typically as little as a single TR, minimally affecting the efficiency of the imaging process. The sequence can be employed repetitively, greatly reducing the amplitude of fat signals throughout a real-time or cine imaging process.

An MRI imaging system includes at least one processor and a plurality of coils to acquire a plurality of k-space samples of a target to image. The system includes a machine-readable media comprising instructions which, when executed by the processor, result in determining a plurality of different regularization matrices for a plurality of different regions of an image of the target. The regularization matrices are applied in the determination of a plurality of unmixing matrices for the regions. The unmixing matrices are applied to produce the image without ghost artifacts, from a plurality of MRI images produced from the plurality of k-space samples and each comprising ghost artifacts.

Method and apparatus to improve an MRI image using regularization

A system and method for using magnetic resonance imaging to increase the accuracy of electrophysiologic procedures is disclosed. The system in its preferred embodiment provides an invasive combined electrophysiology and imaging antenna catheter which includes an RF antenna for receiving magnetic resonance signals and diagnostic electrodes for receiving electrical potentials. The combined electrophysiology and imaging antenna catheter is used in combination with a magnetic resonance imaging scanner to guide and provide visualization during electrophysiologic diagnostic or therapeutic procedures. The invention is particularly applicable to catheter ablation, e.g., ablation of atrial fibrillation. In embodiments which are useful for catheter ablation, the combined electrophysiology and imaging antenna catheter may further include an ablation tip, and such embodiment may be used as an intracardiac device to both deliver energy to selected areas of tissue and visualize the resulting ablation lesions, thereby greatly simplifying production of continuous linear lesions. The invention further includes embodiments useful for guiding electrophysiologic diagnostic and therapeutic procedures other than ablation. Imaging of ablation lesions may be further enhanced by use of MR contrast agents. The antenna utilized in the combined electrophysiology and imaging catheter for receiving MR signals is preferably of the coaxial or 'loopless' type. High-resolution images from the antenna may be combined with low-resolution images from surface coils of the MR scanner to produce a composite image. The invention further provides a system for eliminating the pickup of RF energy in which intracardiac wires are detuned by filtering so that they become very inefficient antennas. An RF filtering system is provided for suppressing the MR imaging signal while not attenuating the RF ablative current. Steering means may be provided for steering the invasive catheter under MR guidance. Other ablative methods can be used such as laser, ultrasound, and low temperatures.

A ghost artifact cancellation technique is disclosed. Phased array combining is used to cancel ghosts caused by a variety of distortion mechanisms, including space-variant distortions, such as local flow or off-resonance. The technique uses a constrained optimization that optimizes signal-to-noise ratio (SNR) subject to the constraint of nulling ghost artifacts at known locations. In one aspect multi-coil, k-space data is passed through a converter to convert the k-space data to image domain. After the conversion, the images contain ghost artifacts. The images are then passed through one or more phased array combiners. Each phased array combiner separates the superimposed ghosts to produce an image without ghosts. These images may then be aligned by means of shifting and combined by a variety of means to improve the final image quality. In another aspect, the phase encode order is varied in time to produce ghosts with time varying phase. The series of images are then used to adaptively compute the phased array combiner and output combiner coefficients. The developed technique may be used with phase encode orders which reduce image distortion.

Growing community of inventors

Phoenix, MD, United States of America

Elliot R McVeigh