What if physicians could see more than an ultrasound examination currently allows? What if they could look into a tumor to determine its consistency, thereby determining noninvasively if it is cancerous or benign?
For the last 16 years, Jonathan Ophir, Ph.D., professor and director of the Ultrasonics Laboratory in the Department of Diagnostic and Interventional Imaging at The University of Texas Medical School at Houston, and his research team, have been perfecting the technique that they invented in 1991, when they found that it was possible to noninvasively measure and image the local elastic changes inside soft objects, such as tissues. This work has received ongoing support through a major program project grant from the National Cancer Institute, and a portfolio of patents has been produced as a result of these groundbreaking efforts.
Using the existing technology of diagnostic ultrasound, elastography involves a before and after picture – after a 1 percent compression – of the tissue in question. From these two images, a new image, an elastogram, is generated, which displays the hardness or softness of all tissue elements in the field of view with high resolution. Since it is known that tissue hardness is related to the presence of pathology, the technique is able to image the elastic manifestations of pathological changes that may not be visible by other imaging methods.
The modern technique recalls traditional palpation methods with a visual and measurable result. Initial work has shown that elastography may be able to differentiate between benign and malignant breast tumors.
"Most cancerous tissues are much harder than normal tissues, and malignant breast tumors are at least 5-10 times stiffer than other breast tissues. If you have a lump in your breast, it will be biopsied – yet only 1 in 5 will end up being cancer. These numbers mean that there are many unnecessary biopsies," Dr. Ophir explains.
With the national annual cost of unnecessary biopsies of breast tumors approaching $2 billion a year, elastography has the opportunity to make a difference in not only easing the minds of patients but impacting health care costs by reducing these numbers.
Elastography recently took a giant leap from the labs of the sixth floor of the Medical School Building to the scientific and medical instrumentation showrooms worldwide with the debut of the newest ultrasound machine produced by Siemens.
"Their new machine, which was introduced in November at the national radiology conference, RSNA, contains software that can produce elastograms," Dr. Ophir explains.
Dr. Ophir says that several major medical imaging companies have taken licenses to produce the patented elastography technology.
"As a researcher in the Medical School, I see our role to prove principles and to develop prototype instruments to help drive technology," Dr. Ophir says.
Dr. Ophir knows firsthand the benefits of new technologies on health care. A young man of 23 studying electrical engineering at the University of Kansas in Lawrence in 1968, Ophir was diagnosed with an advanced stage of Hodgkin's disease, a cancer of the lymphatic system.
"I was given one year to live," he recalls.
Fortunately, Dr. Vincent DeVita Jr., who was working at the National Cancer Institute (and who later became the director of the NCI) had been developing combination chemotherapy programs that ultimately led to an effective regimen of curative chemotherapy for Hodgkin's disease. Ophir did not qualify for an NCI-sponsored experimental drug study because he had received prior radiation therapy. Nevertheless, his physician arranged for him to receive the treatments outside the study on a compassionate basis, which saved his life.
"I was a guinea pig, but in a few weeks, the cancer was gone and never came back," he says. During his prolonged hospital stay, he became exposed to the early medical ultrasound techniques ("they kept the machine in the broom closet"), which defined his subsequent career choice.
Will Dr. Ophir continue to use the modified ultrasound machines that he and his colleagues cobbled together to debut elastography many years ago?
"Of course, those are our workhorses," Dr. Ophir says. "But one of the companies promised to send us a new elastography package to try out soon."
When that software arrives, Dr. Ophir and his team will begin using it on a clinical trial looking at kidney rejection with Barry Kahan, Ph.D., M.D., in the Division of Immunology and Organ Transplantation, and Alan Cohen, M.D., in the Department of Diagnostic and Interventional Imaging.
"The possibilities for elastography are vast and include the classification of breast lesions, detection of prostate cancer, on which we have worked with collaborators in France, the thyroid, cervical cancer, and classifying intravascular plaque. There are therapy-monitoring applications as well," Dr. Ophir says.
Dr. Ophir's group is continuing to explore the limits of elastography. In the past several years they have expanded the technology to allow the imaging of the compressibility of soft tissues, thus following the slow movement of clear fluids in healthy and diseased tissues, and imaging the bonding characteristics of tumor margins to their surrounding tissues, allowing detection of differences in such bonding between benign and malignant breast tumors.
With Dr. Ophir's support, this technology will remain in front of the patients and physicians – and not in the closet.
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