A device and method for ablating tissue is disclosed comprising the steps of acquiring an anatomical image of a patient, correlating the image to the patient, guiding an ablating member within the patient while tracking the position of the ablating member in the patient, positioning the ablating member in a desired position to ablate tissue, emitting ablating energy from the ablating member to form an ablated tissue area and removing the ablating member from the patient.

Methods of using high intensity focused ultrasound to form an ablated tissue area containing a plurality of lesions

A device, kit and method may employ an implantable device (e.g., annuloplasty implant) and a tool to implant such. The implantable device is positionable in a cavity of a bodily organ (e.g., a heart) and operable to constrict a bodily orifice (e.g., a mitral valve). Tissue anchors are guided into precise position by an intravascularly deployed anchor guide frame and embedded in an annulus. Constriction of the orifice may be accomplished via a variety of structures, for example by cinching a flexible cable or anchored annuloplasty ring, the cable or ring attached to the tissue anchors. The annuloplasty ring may be delivered in a generally elongated configuration, and implanted in an anchored generally arch, arcuate or annular configuration. Such may move a posterior leaflet anteriorly and an anterior leaflet posteriorly, improving leaflet coaptation to eliminate mitral regurgitation.

Medical device, kit and method for constricting tissue or a bodily orifice, for example, a mitral valve

A collapsible ultrasonic reflector incorporates a gasfilled reflector balloon (50), a liquid-filled structural balloon (28) and an ultrasonic transducer (20) disposed within the structural balloon. Acoustic energy emitted by the transducer is reflected by a highly reflective interface between the balloons. In a cardiac ablation procedure, the ultrasonic energy is focused into an annular focal regions (44) to ablate cardiac tissue extending in an annular path along the wall. Devices for stabilizing the balloon structure and for facilitating collapse and withdrawal of the balloon structure are also disclosed.

Thermal treatment methods and apparatus with focused energy application

Methods and apparatus for enabling substantially bloodless surgery and for stemming hemorrhaging. High intensity focused ultrasound (“HIFU”) is used to form cauterized tissue regions prior to surgical incision, for example, forming a cauterized tissue shell around a tumor to be removed. The procedure is referred to as “presurgical volume cauterization.” In one embodiment, the method is particularly effective for use in surgical lesion removal or resection of tissue having a highly vascularized constitution, such as the liver or spleen, and thus a propensity for hemorrhaging. In further embodiments, methods and apparatus for hemostasis using HIFU is useful in both surgical, presurgical, and medical emergency situations. In an apparatus embodiment, a telescoping, acoustic coupler is provided such that depth of focus of the HIFU energy is controllable. In other embodiments, apparatus characterized by portability are demonstrated, useful for emergency medical situations.

Method and apparatus for medical procedures using high-intensity focused ultrasound

An ultrasonic system useful for providing imaging, therapy and temperature monitoring generally comprises an acoustic transducer assembly configured to enable the ultrasound system to perform the imaging, therapy and temperature monitoring functions. The acoustic transducer assembly comprises a single transducer that is operatively connected to an imaging subsystem, a therapy subsystem and a temperature monitoring subsystem. The ultrasound system may also include a display for imaging and temperature monitoring functions. An exemplary single transducer is configured such that when connected to the subsystems, the imaging subsystem can generate an image of a treatment region on the display, the therapy subsystem can generate high power acoustic energy to heat the treatment region, and the temperature monitoring subsystem can map and monitor the temperature of the treatment region and display the temperature on the display, all through the use of the single transducer. Additionally, the acoustic transducer assembly can be configured to provide three-dimensional imaging, temperature monitoring or therapeutic heating through the use of adaptive algorithms and/or rotational or translational movement. Moreover, a plurality of the exemplary single transducers can be provided to facilitate enhanced treatment capabilities.

Imaging, therapy, and temperature monitoring ultrasonic system

A High Intensity Focused Ultrasound system is provided for treatment of focal disease. The preferred embodiment includes an intracavity probe having two active ultrasound radiating surfaces with different focal geometries. Selectively energizing the first surface focuses therapeutic energy a first distance from the housing, energizing the second surface focuses therapeutic energy nearer the housing. Preferably, the probe includes a thin, flexible, inelastic membrane which is rigidized with pressure to allow blunt manipulation of tissue. Methods of use of the probe are also provided, particularly for treatment of diseases of the prostate.

Multifaceted ultrasound transducer probe system and methods for its use

This paper compares two methods for extracting room acoustic parameters from reverberated speech and music. An approach which uses statistical machine learning, previously developed for speech, is extended to work with music. For speech, reverberation time estimations are within a perceptual difference limen of the true value. For music, virtually all early decay time estimations are within a difference limen of the true value. The estimation accuracy is not good enough in other cases due to differences between the simulated data set used to develop the empirical model and real rooms. The second method carries out a maximum likelihood estimation on decay phases at the end of notes or speech utterances. This paper extends the method to estimate parameters relating to the balance of early and late energies in the impulse response. For reverberation time and speech, the method provides estimations which are within the perceptual difference limen of the true value. For other parameters such as clarity, the estimations are not sufficiently accurate due to the natural reverberance of the excitation signals. Speech is a better test signal than music because of the greater periods of silence in the signal, although music is needed for low frequency measurement.

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Monaural room acoustic parameters from music and speech

This letter proposes a new variable tap-length least-mean-square (LMS) algorithm for applications in which the unknown filter impulse response sequence has an exponential decay envelope. The algorithm is designed to minimize the mean-square deviation (MSD) between the optimal and adaptive filter weight vectors at each iteration. Simulation results show the proposed algorithm has a faster convergence rate as compared with the fixed tap-length LMS algorithm and is robust to the initial tap-length choice

/pdf/a-new-variable-tap-length-lms-algorithm-to-model-an-bj8pi1v9hd.pdf

A New Variable Tap-Length LMS Algorithm to Model an Exponential Decay Impulse Response

Reverberation time is an important objective parameter for the acoustics of enclosed spaces. Blind estimation of the reverberation time from naturally occurring sound sources alleviates the logistical constraints of traditional measurement methods, and hence enables non-invasive, in-situ measurements in occupied spaces. A maximum likelihood method using a simple exponential decay model was recently developed. It demonstrated the potential of this approach, but the decay model hinders its accuracy and usefulness in the presence of more complex decays. This paper proposes a new maximum likelihood approach that allows for the multiple decay rates found in real spaces to be more correctly modelled, and thus improves the accuracy of the estimations. Envelopes of received sound signals are segmented and suitable decay phases automatically selected. A maximum likelihood estimation is performed using a multi-decay model whose function adapts to yield the most likely reverberation parameters and decay curve estimates. Simulation, validation and real room tests confirm the improved accuracy; the estimation errors are typically below perceptual difference limens. Thus a new method for blind estimation of reverberation parameters from naturally occurring sound sources, including speech and orchestra music, is achieved.

Blind estimation of reverberation parameters for non-diffuse rooms

A new variable step-size least-mean-square (VSSLMS) algorithm is presented in this paper for applications in which the desired response contains nonstationary noise with high variance. The step size of the proposed VSSLMS algorithm is controlled by the normalized square Euclidean norm of the averaged gradient vector, and is henceforth referred to as the NSVSSLMS algorithm. As shown by the analysis and simulation results, the proposed algorithm has both fast convergence rate and robustness to high-variance noise signals, and performs better than Greenburg's sum method, which is a robust algorithm for applications with nonstationary noise.

Paul Kendrick

Papers

Multifaceted ultrasound transducer probe system and methods for its use

Monaural room acoustic parameters from music and speech

A New Variable Tap-Length LMS Algorithm to Model an Exponential Decay Impulse Response

Blind estimation of reverberation parameters for non-diffuse rooms

A New Variable Step-Size LMS Algorithm with Robustness to Nonstationary Noise