Edward D. Light

Bio: Edward D. Light is an academic researcher from Duke University. The author has contributed to research in topics: Transducer & 3D ultrasound. The author has an hindex of 20, co-authored 74 publications receiving 1391 citations.

Imaging probes and catheters for volumetric intraluminal ultrasound imaging and related systems

Abstract: A real time three dimensional ultrasound imaging probe apparatus is configured to be placed inside a body. The apparatus comprises an elongated body having proximal and distal ends with an ultrasonic transducer phased array connected to and positioned on the distal end of the elongated body. The ultrasonic transducer phased array is positioned to emit and receive ultrasonic energy for volumetric forward scanning from the distal end of the elongated body. The ultrasonic transducer phased array includes a plurality of sites occupied by ultrasonic transducer elements. At least one ultrasonic transducer element is absent from at least one of the sites, thereby defining an interstitial site. A tool is positioned at the interstitial site. In particular, the tool can be a fiber optic lead, a suction tool, a guide wire, an electrophysiological electrode, or an ablation electrode. Related systems are also discussed.

Combined 3D intracardiac echo and ultrasound ablation

Abstract: We have integrated real time volumetric ultrasound imaging and ultrasound ablation in the same intracardiac catheter. This single device could be used to visualize ablation sites in three dimensions immediately prior to inducing necrosis to eliminate cardiac arrythmias. After the course of therapy, the ablated tissue could be examined ultrasonically. The 12 Fr catheter includes a 2D transducer array for imaging and a single element piston for ablation. The imaging transducer consists of 38 active elements built on a multilayer flex circuit operating at 5.2 Mhz. The ablation piston is a 4 mm by 2 mm piece of air backed PZT-4. Our real time 3D scanner (Volumetrics Medical Imaging) and the 2D array were used to image phantom targets. The spatial peak, temporal average intensity (I SPTA ) and acoustic power of the ablation beam were measured using a hydrophone. A 7 mm thick slab of beef was imaged and then ablated for 1 minute. The ultrasound ablation piston produced an I SPTA of nearly 30 W/cm 2 and a corresponding acoustic power of 2.6 W. The electrical to acoustic power efficiency of the transducer was 39%. The minute long ablation produced a transmural lesion in the beef 2mm by 4 mm by 7 mm deep.

The Ultrasound Brain Helmet: Feasibility Study of Multiple Simultaneous 3D Scans of Cerebral Vasculature

Abstract: Abtract We describe early stage experiments to test the feasibility of an ultrasound brain helmet to produce multiple simultaneous real-time three-dimensional (3D) scans of the cerebral vasculature from temporal and suboccipital acoustic windows of the skull. The transducer hardware and software of the Volumetrics Medical Imaging (Durham, NC, USA) real-time 3D scanner were modified to support dual 2.5 MHz matrix arrays of 256 transmit elements and 128 receive elements which produce two simultaneous 64° pyramidal scans. The real-time display format consists of two coronal B-mode images merged into a 128° sector, two simultaneous parasagittal images merged into a 128° x 64° C-mode plane and a simultaneous 64° axial image. Real-time 3D color Doppler scans from a skull phantom with latex blood vessel were obtained after contrast agent injection as a proof of concept. The long-term goal is to produce real-time 3D ultrasound images of the cerebral vasculature from a portable unit capable of internet transmission thus enabling interactive 3D imaging, remote diagnosis and earlier therapeutic intervention. We are motivated by the urgency for rapid diagnosis of stroke due to the short time window of effective therapeutic intervention. (E-mail: ssmith@duke.edu )

Real-time three-dimensional intracardiac echocardiography

Abstract: Using catheter-mounted 2-D array transducers, we have obtained real-time 3-D intracardiac ultrasound (US) images. We have constructed several transducers with 64 channels inside a 12 French catheter lumen operating at 5 MHz. The transducer configuration may be side-scanning or beveled, with respect to the long axis of the catheter lumen. We have also included six electrodes to acquire simultaneous electrocardiograms. Using an open-chest sheep model, we inserted the catheter into the cardiac chambers to study the utility of in vivo intracardiac 3-D scanning. Images obtained include a cardiac four-chamber view, mitral valve, pulmonic valve, tricuspid valve, interatrial septum, interventricular septum and ventricular volumes. We have also imaged two electrophysiological interventional devices in the right atrium, performed an in vitro ablation study, and viewed the pulmonary veins in vitro.

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

Abstract: 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.

Method for treating fecal incontinence

Abstract: A method for treating fecal incontinence in a body of a mammal having a rectum formed by a rectal wall extending to an anus wherein the rectal wall includes a sphincter muscle surrounding the anus. At least one nonaqueous solution is introduced into the rectal wall in the vicinity of the anus. A nonbiodegradable solid is formed in the rectal wall from the at least one nonaqueous solution.

Tuned rf energy and electrical tissue characterization for selective treatment of target tissues

Abstract: A catheter and catheter system can use energy tailored for remodeling and/or removal of target material along a body lumen, often of atherosclerotic material of a blood vessel of a patient. An elongate flexible catheter body with a radially expandable structure may have a plurality of electrodes or other electrosurgical energy delivery surfaces to radially engage atherosclerotic material when the structure expands. An atherosclerotic material detector system may measure and/or characterize the atherosclerotic material and its location, optionally using impedance monitoring.

Selectable Eccentric Remodeling and/or Ablation of Atherosclerotic Material

Abstract: A catheter and catheter system for eccentric remodeling and/or removal of atherosclerotic material of a blood vessel of a patient include an elongate flexible catheter body with a radially expandable structure. A plurality of electrodes or other electrosurgical energy delivery surfaces can radially engage atherosclerotic material when the structure expands. An atherosclerotic material detector near the distal end of the catheter body may measure circumferential atherosclerotic material distribution, and a power source selectively energizes the electrodes to eccentrically remodel the measured atherosclerotic material.

Medical ultrasound: imaging of soft tissue strain and elasticity

Abstract: After X-radiography, ultrasound is now the most common of all the medical imaging technologies. For millennia, manual palpation has been used to assist in diagnosis, but it is subjective and restricted to larger and more superficial structures. Following an introduction to the subject of elasticity, the elasticity of biological soft tissues is discussed and published data are presented. The basic physical principles of pulse-echo and Doppler ultrasonic techniques are explained. The history of ultrasonic imaging of soft tissue strain and elasticity is summarized, together with a brief critique of previously published reviews. The relevant techniques—low-frequency vibration, step, freehand and physiological displacement, and radiation force (displacement, impulse, shear wave and acoustic emission)—are described. Tissue-mimicking materials are indispensible for the assessment of these techniques and their characteristics are reported. Emerging clinical applications in breast disease, cardiology, dermatology, gastroenterology, gynaecology, minimally invasive surgery, musculoskeletal studies, radiotherapy, tissue engineering, urology and vascular disease are critically discussed. It is concluded that ultrasonic imaging of soft tissue strain and elasticity is now sufficiently well developed to have clinical utility. The potential for further research is examined and it is anticipated that the technology will become a powerful mainstream investigative tool.