For millennia, physicians have used palpation as a part of the physical examination to detect pathology. The ubiquitous presence of "stiffer" tissue associated with pathology often represents an early warning sign for disease, as in the cases of breast or prostate cancer. Very often tumors are found at surgery that were occult even with modern imaging instruments. This implies that methods for estimating "hardness" of tissues would add a weapon to the medical armamentarium. To this end, this review discusses several methods of estimating tissue hardness using internal or external means of applying stress (force per unit area) and several associated methods of detecting the resulting strain (fractional length change) in an effort to image a tissue mechanical property, such as Young's modulus (ratio of stress to strain). Some investigators have developed methods of estimating stiffness or modulus, but most methods result in qualitative images of stiffness. Nevertheless, such estimates may add a great deal of information not currently available to the current field of medical imaging.

Selected methods for imaging elastic properties of biological tissues.

Devices and methods for treating heart valves include members that assist the valve in closing during at least a portion of the cardiac cycle. Such devices include members configured to alter the shape of a valve annulus, reposition at least one papillary muscle, and/or plug an orifice of the valve so as to provide a coaptation surface for the valve leaflets.

Devices and methods for heart valve treatment

An apparatus for treatment of a failing heart by reducing the wall tension therein. In one embodiment, the apparatus includes a tension member for drawing at least two walls of a heart chamber toward each other. Methods for placing the apparatus on the heart are also provided.

Heart wall tension reduction apparatus and method

A device for heart valve repair including at least one tension member having a first end and second end. A basal anchor is disposed at the first end of the tension member and a secondary anchor at the second end. The method includes the steps of anchoring the basal anchor proximate a heart valve and anchoring the secondary anchor at a location spaced from the valve such that the chamber geometry is altered to reduce heart wall tension and/or stress on the valve leaflets.

Valve to myocardium tension members device and method

Various methods and devices are disclosed for improving cardiac function in hearts having zones of infarcted (akinetic) and aneurysmal (dyskinetic) tissue regions. The methods and devices reduce the radius of curvature in walls of the heart proximal infarcted and aneurysmal regions to reduce wall stress and improve pumping efficiency. The inventive methods and related devices include splinting of the chamber wall proximal the infarcted region and various other devices and methods including suture and patch techniques.

Methods and devices for improving cardiac function in hearts

An non-contacting measurement apparatus for measuring distances, angles and related geometric quantities, and for computing other quantities based on the measurements, is provided. A visible light beam or ultrasonic beam allows a user to point the device at one or more points to which the distance is measured, and angular rotation between the various points of interest can be measured and recorded. Then, geometric and trigonometric relationships are used to compute and display lengths, areas, volumes or other facts derived from the measurements. Various input and output features are provided in the present embodiments.

Method and Apparatus for Dimensional Measurement

Similar to other therapeutic methods, ultrasound surgery requires an imaging modality to monitor the extent of tissue damage during treatment. In this paper, we have considered the method of ultrasound-stimulated acoustic emission (USAE) that uses two ultrasonic beams at high frequency (1.7 MHz) (same as that used for ablation) to locally excite the tissue by generating a low-frequency (1–50 kHz) radiation force. Recording of the tissue response at several locations yields an image. The amplitude of the tissue response depends on the mechanical and acoustic tissue properties, namely its stiffness and absorption. These two properties were initially hypothesized to have counteractive effects on the response amplitude, i.e., the amplitude should increase with absorption and decrease with stiffness. To check this hypothesis as well as the degree to which these properties influence the response, finite-element simulations of a uniform lesion formed inside a homogeneous medium were used. The results show that, as expected, the displacement amplitude decreased with increasing lesion stiffness at lower frequencies (except at resonance) while, contrary to our initial hypothesis, it increased with stiffness at relatively higher frequencies (>22 kHz). At resonance, a frequency upshift occurred with increasing stiffness but was found to be highly spatially variant and system dependent, i.e., not yielding a uniform lesion response when imaged. On the other hand, the absorption increase led to a uniform linear increase of the mechanical response amplitude of the lesion. Therefore, at higher frequencies, increase of the two parameters had a synergistic effect on the tissue response to the applied radiation force. This study showed that relatively higher frequencies constitute the optimal range in the use of USAE for coagulation monitoring. A preliminary experimental verification in vitro is also provided.

https://iopscience.iop.org/article/10.1088/0031-9155/46/11/314/pdf

A focused ultrasound method for simultaneous diagnostic and therapeutic applications--a simulation study.

Surgical probe for use in minimally invasive surgery. The probe includes an elastic membrane tip portion which deforms upon contact with an object. The elastic membrane forms an enclosure containing fluid and an inside surface of the membrane includes a plurality of visible markings such as dots. A CCD camera forms an image of the dots and the image of the dots or a representation of the image of the dots is displayed on a video monitor. The probe also includes an ultrasound transducer which responds to frequency shifts to indicate motion of an object reflecting ultrasound energy. A speaker generates sounds related to the frequency shift as an indication of motion. The probe thus provides information about the surface of an object encountered during a minimally invasive procedure and also about motion of structures within the body.

Surgical probe comprising visible markings on an elastic membrane

The present disclosure provides systems and methods for imaging and display of features of a region of interest such as a portion of a body of a patient. A first imaging portion of the system is used to cause an interaction of an imaging beam with an underlying feature of a region of interest. A reflected or returned portion of said imaging beam is detected by a detector which then provides an output to control a display portion of the system for displaying an image corresponding to that which was detected. The system can be used for guiding or assisting clinical or industrial operations or for diagnosis of medical conditions and other uses within medicine, industry and others.

Compact feature location and display system

A method and system including an applicator for treating dermatological conditions such as warts is presented for applying ultrasonic energy from a specially-designed ultrasonic energy applicator designed for use with localized dermatological conditions to heat an affected localized region sufficiently to achieve a desired therapeutic result. Specific embodiments include temperature measurement and/or sensing and/or actuation by way of a temperature sensor coupled to the ultrasonic energy applicator. Also, a medicated ultrasound-compatible patch is disclosed for applying to a region of tissue to be treated and includes substances known to aid in the treatment of a condition and adapted for transmitting the ultrasound energy into the region of tissue.

Jonathan S. Thierman

Papers

Method and Apparatus for Dimensional Measurement

A focused ultrasound method for simultaneous diagnostic and therapeutic applications--a simulation study.

Surgical probe comprising visible markings on an elastic membrane

Compact feature location and display system

Treatment of warts and other dermatological conditions using topical ultrasonic applicator