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Advances in Cardiovascular MRI Imaging

Robert Herfkins, MD (Stanford Medical Center)

Dr. Robert Herfkens will be the featured speaker at the January 15 meeting of the Santa Clara Valley Engineering in Medicine & Biology Society. Dr. Herfkens has extensively studied the in-vivo mechanical properties of arteries using magnetic resonance imaging as a non-invasive measurement method. He and his colleagues have published many articles in this area in recent years.

Noninvasive measurement of arterial wall properties are difficult to measure, and have wide application in the theoretical modeling of dynamic motion of arterial wall during the cardiac cycle, as well as in the development of new medical devices such as stents. These recent publications illustrate the range of applications of this method.

"Quantification of vessel wall cyclic strain using cine phase contrast magnetic resonance imaging."

In vivo quantification of vessel wall cyclic strain has important applications in physiology and disease research and the design of intravascular devices. Methods are described to calculate vessel wall strain from cine PC-MRI velocity data. Forward-backward time integration is used to calculate displacement fields from the velocities, and cyclic Green-Lagrange strain is computed in segments defined by the displacements. Results demonstrated nonuniform deformation and circumferential variation in cyclic strain.

"In vivo quantification of blood flow and wall shear stress in the human abdominal aorta during lower limb exercise."

Magnetic resonance (MR) imaging techniques and a custom MR-compatible exercise bicycle were used to measure, in vivo, the effects of exercise on hemodynamic conditions in the abdominal aorta of eleven young, healthy subjects.

"Measurement of vessel wall strain using cine phase contrast MRI."

The objective was to determine the feasibility of using magnetic resonance imaging (MRI) to non-invasively measure strain in the aortic wall. Cine phase contrast MRI was used to measure the velocity of the aortic wall and calculate changes in circumferential strain over the cardiac cycle. Results of in vivo studies and measurement of cyclic strain in human thoracic and abdominal aortas demonstrate the feasibility of the technique.

Dr. Herfkins will discuss these publications as well as other recent advances in Cardiovascular MRI Imaging.

Dr. Robert Herfkens is a Professor of Radiology and Director of Magnetic Resonance Imaging at Stanford University. His background includes training in internal medicine, nuclear medicine and radiology. He has published over 200 papers, most in relationship to Magnetic Resonance Imaging. He is past president of the International Society for Magnetic Resonance Imaging. His current research interests include cardiovascular magnetic resonance imaging, fast imaging techniques and development of techniques for image-guided therapies, as well as cardiovascular and Body CT.


Cooling: The Emergence of a Promising Therapy

Andrew Cleeland (Radient Medical, Inc.)

Mild hypothermia has been shown to protect and preserve heart and brain tissue in the event of an ischemic insult such as a heart attack, stroke or cardiac arrest. The pre-clinical and clinical evidence is compelling and therapeutic cooling is emerging as a promising new therapy.

Hypothermia has been utilized in surgery to provide tissue protection, decrease metabolism and to allow a bloodless operative field since the 1950s. However, the cumbersome and invasive nature of the technology has, until now, limited its therapeutic application.

Radiant Medical has developed an innovative catheter-based system to rapidly, precisely and reliably manage patient temperature. The Reprieve Endovascular Temperature Therapy System consists of a proprietary heat exchange catheter, a heat exchange cassette and an external controller. The catheter is placed in the inferior vena cava via the femoral vein. Warm or cool sterile saline is then continuously circulated through the catheter thereby adding heat to or removing heat from the passing blood by means of counter current heat exchange. The heat exchange is achieved without direct contact of the saline with blood. As this exchange takes place, the saline is returned from the catheter through insulated extension lines to the cassette (mounted in the controller) that contains a second heat exchange surface and a pump head that drives the circulation of the saline between the cassette and catheter.

As the saline is returned to the cassette, heat is exchanged with the thermoelectric plate integral to the Controller. The temperature of the thermoelectric plate, which governs the degree and rate of heat exchange, is controlled based on the patient's temperature that is being independently monitored through two separate temperature sensors.

Clinical studies have been initiated in cardiac surgery, neurosurgery, heart attack and stroke. The studies have demonstrated that the technology effectively manages patient temperature, is readily integrated within existing treatment pathways and is generally safe. The initial clinical results in heart attack and stroke are very promising. This presentation charts the development and early clinical application of this novel technology and the emergence of this promising (and cool!) therapy.

Andrew Cleeland, speaker for the February 19 meeting of the Santa Clara Valley Engineering in Medicine & Biology Society, is a senior vice president at Radiant Medical Inc., a private, venture-funded medical technology company based in Redwood City. In this role Andrew has responsibility for Radiant's research & development (Controller Platform), clinical, regulatory and quality programs. Prior to joining Radiant, Andrew has held various positions of increasing responsibility in the medical device field. He began his career in 1988 with the Therapeutic Goods Administration, the Australian Government Agency empowered with the task of regulating therapeutic medical products. He has a BS in biophysics from Swinburne Institute of Technology in Melbourne, Australia.


Optical measurements of biological tissue:
From Bench to Bedside

Mohamed Elmandjra (Photonify)

Optical Diffusion Imaging and Spectroscopy (ODIS) is a non-invasive tissue characterization method based on measurement of scattering and absorption of photons.

In biological tissue, near infrared light is highly scattered and minimally absorbed. This allows photons to travel up to one meter, in a random walk fashion, before being absorbed. ODIS uses statistical methods to describe photon transportation inside turbid medium such as the photon diffusion or transportation equations. Diffuse optical imaging is achieved by sending various format of optical signal (continuous wave, pulse, or intensity modulated wave) to various location of tissue and measuring the corresponding diffuse reflectance or transmittance on tissue surface and then inversely solving those equations.

Mohamed Elmandjra will discuss this topic at the March 19 meeting of the Santa Clara Valley Engineering in Medicine & Biology Society. In his talk, Dr. Elmandrja will cover the scientific basis of optical tissue imaging, but then expand on clinical applications of the technology ranging from the diagnosis of peripheral vascular disease and plastic surgery to breast imaging. Finally, he will expand on the commercial potential of the technology.

Dr Elmandjra began his career at General Electric Medical Systems where he held scientific, product development, marketing and business management positions in Europe and the U.S. In January 1998, he joined ADAC Laboratories, the world leader in nuclear medicine and a Malcolm Baldrige Award winner, as vice president of marketing.

In September 1999, ADAC acquired UGM Medical Systems and expanded its presence in the Positron Emission Tomography (PET) market, the fastest growing area of medical imaging and Dr. Elmandjra was named vice president and general manager of the PET division. In September 2000, he was given the responsibility over all of the company's activities outside the U.S. and named senior vice president of international operations. In December 2000, ADAC was acquired by Philips and he continued as senior vice president until he joined Photonify in December 2001.

Dr. Elmandjra holds a PhD in bioengineering from the University of Pennsylvania and an MBA from the University of Chicago.


Nanomechanics in the Cochlea:
How the inner ear works and what happens when it doesn't

Dr. John S. Oghalai (UCSF)

Our normal activities require hearing, yet we take hearing for granted. This is largely because the ear does its job so well without our having to pay attention to it. Hearing is the only sensory system that allows us to know what is going on everywhere in our environment - we don't have to be looking at the twig that is snapping to know there is something behind us in the dark. This ability imparts tremendous survival advantages for all animals.

In addition, human social structures rely on speech communication that requires the sensitive, rapid processing of acoustic energy that the normal inner ear provides. This is done by two types of receptor cells: inner hair cells, that passively transduce mechanical energy into nerve impulses; and outer hair cells, providing an active electro-mechanical transduction.

Changes in outer hair cell shape at the nanometer level function as a positive feedback mechanism to amplify the sound waves within the cochlea. Sensorineural hearing loss is a common clinical problem, and can be caused by many different etiologies including noise exposure, ototoxic drugs, and age-related hearing loss.

Dr. John Oghalai will discuss this topic at the April 16 meeting of the Santa Clara Valley Engineering in Medicine & Biology Society. The common site of pathology for all of these conditions is the outer hair cell. New potential therapeutic strategies for hearing loss will be discussed.

John S. Oghalai is a clinical instructor in the Department of Otolaryngology - Head and Neck Surgery at the University of California. San Francisco. He is based in the Division of Otology, Neurotology, and Skull Base Surgery.

He received his BS in electrical engineering and as well as his MD from the University of Wisconsin. Madison. Currently, 75 percent of his time is clinical practice, caring for patients with hearing loss, chronic ear infections, and tumors of the ear and skull base. The rest of his time is dedicated to basic science research on hearing. The ultimate goals of these efforts are to understand force transmission within the cochlea and to develop therapeutic interventions for noise-induced and age-related hearing loss.


Recent Advances in Diagnostic and Therapeutic Laser Techniques in Medicine

John Black, PhD (Lightwave Electronics)

The introduction of the laser as a therapeutic tool has had a profound effect on certain fields of medicine, principally in dermatology, ophthalmology and some surgical disciplines such as urology. Definitive clinical endpoints for some procedures are often lacking, though, leading to subjective parameter usage, variable patient outcome, and an intrinsic barrier to the communication of good technique.

The use of lasers as diagnostic tools, both as stand-alone devices and coupled to other devices has lagged behind their more glamorous therapeutic counterparts despite many enabling features. These include the ability to use fiber-optics, sometimes with diameters as small as 50 microns as delivery devices for the energy, and the possibility of combining the spectral and coherence properties of laser light to yield simultaneously both molecular level functional information and tissue/organ level structural imaging.

Motivated by a desire to bridge the gap between diagnostic and therapeutic applications in some of the above areas, there has been study on the interaction between lasers and a favorite chromophore, hemoglobin, using newly developed time-resolved spectroscopic and imaging techniques, including high-speed Optical Coherence Tomography (OCT). It has been shown that the laser-blood interaction is an extraordinarily complicated process involving structural changes in the red blood cells, thermal denaturation of proteins, and the generation of new chemical derivatives of hemoglobin.

Using these results, two new techniques have been developed, one therapeutic and one diagnostic that offer the potential to open up new areas of laser medicine.

John Black, PhD, will discuss this research at the May 21 meeting of the Santa Clara Valley Engineering in Medicine & Biology Society.

He will first describe the development of a two-photon laser technique for the treatment of cutaneous vascular lesions such as Port Wine Stains. He will then show what is believed to be the possibility for the first direct in-situ generation of intravascular MRI contrast using a laser.

Generating MRI contrast in-situ offers substantial advantages over exogenous agent injection, including the possibility of time-domain tissue perfusion measurements and vessel flow rate analysis, a relative absence of significant toxicity worries, and potentially a simplified regulatory pathway to approval. Applications for the two-photon dermatology technique and the in-situ MRI contrast agent technology will be discussed.

John Black received a BSc degree in chemistry from Nottingham University (UK) in 1984, and a PhD in physical chemistry from the same institution in 1987. He subsequently did post-doctoral research at Stanford University and Columbia University, developing new lasers and laser techniques for the study of molecular photochemistry and dynamics. He rejoined the laser industry in Silicon Valley in 1994, first at Continuum, and then from 1996 at Coherent Medical Group where this work was performed. He is currently at Lightwave Electronics in Mountain View.


Advances and new technology in the treatment of Male Urological Disorders

Harchi Gill, MD
Associate Professor / Department of Urology
Stanford School of Medicine

Benign prostatic hyperplasia is one of the most common problems a urologist sees in his or her office. Over the past 15 years, there have been major advances in our understanding of the epidemiology, etiology, natural history, and treatment of BPH. Probably no one area in urology has experienced as much innovation and evolution as treatment of patients with BPH. The common goal of all the newer surgical therapies have been to avoid the morbidity of transurethral resection. The focus has been to develop procedures that can be done as outpatient preferably in the office with local or no anesthesia, the limited need for catheter drainage, minimal or no morbidity such as incontinence and impotence, maximal improvement of symptoms and durability of results. I will discuss the new techniques and share some of the early results. One of the more significant changes in urologic oncology over the past decade has been the introduction of laparoscopic techniques. Marked improvements in the imaging systems and the development of new instruments have expanded the role of laparoscopy in kidney, adrenal and prostate cancer. I will present an update on the accepted laparoscopic techniques and also discuss some of the controversies of urologic laparoscopy.

Harcharan Gill received his M.D. from the University of Nairobi, Kenya, in 1977. He completed his general surgery residency at the Royal College of Surgeons in Dublin, Ireland, in 1982 following which he did a urology residency at the British Institute of Urology in London. He joined the University of Pennsylvania in 1986 for fellowship and residency in urology. Dr Gill joined the department of Urology at Stanford in 1991 and is currently an associate professor.Dr Gill is a fellow of the Royal College of Surgeons and also The American College of Surgeons. His research interests include BPH and minimally invasive surgery.


Automated Cell Biology in Drug Discovery and Development

Jay K. Trautman, Ph.D.
Vice President, Technologies

The research paradigm that has developed in the pharmaceutical industry, focused on modifying the activity of individual isolated proteins, has not proven productive for the discovery of new therapeutics. This failure is rooted in the complexity of in vivo biology, as evidenced by the fact that the majority of candidate drugs that fail in the clinic do so not from lack of potency toward the target protein, but from adverse effects deriving from off-target activity.

Cytokinetics has adopted a cell-biology-centric approach to the discovery and development of novel therapeutics, with a particular focus on cytoskeletal targets. The cell, while lacking the complexity of an organism, nevertheless represents an integrated, dynamic, non-equilibrium system within which the biological activity of candidate drugs can be effectively tested. We have developed a suite of cellular phenotyping technologies, consisting of high-resolution microscopy, image analysis, automation, and multivariate data analysis, which constitute an integral component of our small molecule discovery and development programs. Profiles are generated in a panel of cell-based assays that are compiled into fingerprints representative of phenotypes associated with diverse molecular mechanisms of drug action. These fingerprints contain not only information on the potency and specificity of a compound against a biological target, thereby ensuring drug candidates have the desired on-target effects in cells, but also incorporate off-target features, so as to thoroughly filter away compounds with non-specific effects that may subsequently give rise to side effects or toxicities.

Jay K. Trautman, Ph.D., Vice President, Technologies, joined Cytokinetics in June 2002. Dr. Trautman's career has centered on the development of new approaches to address problems in physics, chemistry and biology. Prior to joining the company, he had served as CEO of Praelux Incorporated from the time of its acquisition by Amersham Biosciences in 2000. From 1996 to 2000, Dr. Trautman held a variety of positions at Praelux and its predecessor company, SEQ Ltd., directing the research and development of a single-molecule DNA-sequencing technology and a novel confocal imaging system specifically designed for high-throughput cell-based fluorescence assays. From 1989 to 1996, Dr. Trautman was at AT&T Bell Laboratories, where he co-invented a method of high-resolution optical imaging, the tapered-fiber Near-field Scanning Optical Microscope and pioneered single-molecule spectroscopy. Dr. Trautman holds a B.S. in Chemistry from the University of Washington and a Ph.D. in Chemistry from Cornell University.


A Novel System for Cardiac Surgical Ablation

Michael Nasab
CIRCUIT MENTOR, Boulder Creek, CA.

Eric K. Y. Chan
VP of Product Development
CARDIMA, Inc., Fremont, CA.

The CARDIMA INTELLITEMP is a radiofrequency (RF) Energy Management Device that takes as input the RF energy from a commercially available RF generator such as a Valleylab electrosurgical unit, and channels it through 8 ablation electrodes on the Surgical Probe. The deflectable electrode section permits excellent electrode-tissue contact, resulting in efficient RF-coupling to form linear lesions. Thermocouples situated on the probe provide temperature feedback that regulates energy delivery to the electrodes. These electrodes emit at high current densities, ensuring creation of deep lesions with minimal power requirements. The resulting cardiac lesions replicate those of the highly successful surgical Maze procedure for the treatment of atrial fibrillation (AF).

The first procedure with the Surgical Ablation System was performed in August at the prestigious Lenox Hill Hospital in New York. In the aftermath of the procedure to treat a patient with a long history of chronic AF, Dr. Didier Loulmet, who heads up the Lenox Hill Hospital Atrial Fibrillation Program, commented that the "unique technology behind the CARDIMA Ablation System proved to be a critical and powerful tool for this especially difficult case. The ease of use, the power, and the depth of penetration given the small size of the catheter is impressive."

This talk will discuss the functionality of the ablation system as well as include narratives of real world open heart surgery experiences.

Michael Nasab is the Principal of Circuit Mentor, an electronics consulting business based in Boulder Creek, CA. He received his engineering degrees from international as well as U.S. institutions. He was the R&D Project Manager and primary engineer of the INTELLITEMP Energy Management Device at CARDIMA. His expertise is in R&D and product development in the fields of electromagnetics, power supply design, LabVIEW instrumentation development and system integration. He has held several engineering management and technical positions in Silicon Valley since 1986.

Eric Chan is VP of Product Development at CARDIMA, Inc. in Fremont, CA. He received his BSEE from Purdue University, MSE & PhD in BME from Univ. of Texas at Austin. He served as a past co-chairman of the Central Texas IEEE-EMBS. He has spent the last 12 years in the development of many commercially released medical products in the cardiology and cardiac electrophysiology (EP) field. He was recently elected a Fellow of the European Society of Cardiology.


Road to a New Medical Device: a Tortuous Path

John B. Simpson, MD, Ph.D.

I believe that there are two fundamentally different approaches, either of which can lead to the invention of a new medical device. The first and surely the most remarkable method occurs when a person of clearly superior intellect is placed in just the right setting, and that person working alone through some almost mystical event (never to be disclosed to the common man) invents a new medical device. I have as yet not had any experience with this approach.

The second approach occurs when a very curious, persistent, and perhaps desperate inventor of average intellect, surrounds him or herself with talented engineers and business people. Over a period of year, an enormous number of designs are tried and money is spent demonstrating all the most promising designs of the initial inventor are clever, but unmanufacturable. Then a recently hired junior engineer with no experience in medicine makes a ridiculous proposal, which fortunately provides the required breakthrough. The original inventor gets all the credit and his previously flawed concepts and designs are forgotten. I personally have extensive experience with this approach.

What evidence confirms that I best fit the second model? Average intellect is a certainty, having graduated in the middle of every class from kindergarten through medical school, without having once receiving an academic honor or being named to any honor society. Although I am of average intellect, I am very curious, can recognize medical problems that are desperate for solution, and have an insatiable appetite for help. I am willing to listen to almost any design proposal, without being seduced to the exotic. In addition, I can admit when I am wrong, although not too easily or quickly.

The trait of dogged persistence make it possible for me to raise money, find polymers, hire engineers, participate in device design, supervise clinical trials, and aid in the federal regulatory process without any formal training in these areas. Success comes from the commitment of countless people. The issue for Advanced Cardiovascular Systems (ACS) is a movable guidewire through the balloon catheter; for Devices for Vascular Intervention (DVI) is a plaque removal from the coronary arteries; for PerClose is remote suturing of femoral artery puncture sites; and for LocalMed is delivery of medication and stents in diseased coronary arteries.

In this talk, I hope to cover the design, clinical, regulatory, financial, and business issues to justify my perspective on the inventive process.

John Simpson is internationally recognized as a pioneer, innovator, and authority on interventional cardiology. His invention of the over the wire balloon angioplasty catheter led to the founding of Advanced Cardiovascular Systems (ACS) in 1978. In 1984, Dr. Simpson invented the concept of directional atherectomy (the removal of atheroma from the coronary artery) and founded Devices for Vascular Intervention (DVI). ACS and DVI are now divisions of Guidant, Inc.

Dr. Simpson is the founder of Perclose, (an Abbott Laboratories company). In addition, he serves as Chairman of both Fox Hollow Technologies and Lumend, Inc. He also serves as Professor of Clinical Medicine at Stanford University and a Staff Cardiologist at Sequoia Hospital (Redwood City, California). He completed his undergraduate education at Ohio State University and received his Masters and Doctorate degrees in Biomedical Science at the University of Texas. He is a graduate of the Duke University Medical School and completed his fellowship in interventional cardiology at Stanford University. He is a fellow of the American College of Cardiology and a member of the American College of Physicians.

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