From the reproductive years to menopause to post-menopause, ultrasound could be dubbed the singular imaging modality that is “a girl’s best friend.”
“Ultrasound is so wonderful for all areas of the female anatomy because it offers little or no potential to do harm and you get an evaluation in real time,” said Pat Whitworth, MD, director of the Nashville Breast Center and immediate past chairman of the board and chairman of the research committee of the American Society of Breast Surgeons.
Today, ultrasound is being utilized effectively and safely for a host of health challenges across the entire scope of female anatomy—breast, vaginal, abdominal—and at every stage of a woman’s life. Recent breakthroughs with the modality include exciting findings that validate the value of breast ultrasound for women at high risk for breast cancer as well as inroads in infertility diagnostics and treatment. Here is a look at some of the latest ultrasound innovations.
FIBROID TUMORS: MR-GUIDED FOCUSED ULTRASOUND
Studies show that about 25% of women aged 30 to 50 have uterine fibroids large enough to cause symptoms, and 30% to 50% of women have fibroid tumors that are asymptomatic. In the United States, approximately 2 million women seek care for their fibroids every year. While non cancerous, fibroids are hardly a nonissue to the women who suffer from them. In addition to causing abnormal bleeding and pelvic and back pain, fibroids can interfere with fertility. Surgery for fibroids includes myomectomy and hysterectomy. But women today want options.
That’s what MR-guided focused ultrasound (MRgFUS) is all about. “This technology is an alternative to surgery,” said Phyllis Gee, MD, FACOG, medical director, North Texas Uterine Fibroid Institute. “Even for women who are not planning to have children in the future, if they don’t want to have surgery, it offers another option.”
In 2004, the FDA approved MR-guided focused ultrasound for the treatment of fibroid tumors. Essentially, the procedure offers a uterine fibroid ablation therapy—a very precise method of shrinking the tumors. However, the fibroids do not disappear altogether and may indeed eventually grow back. Nonetheless, it’s a noninvasive alternative; that means an outpatient procedure with no anesthesia.
The treatment uses a high-intensity focused ultrasound beam to heat and destroy targeted tissue coupled with MRI to visualize patient anatomy and control the treatment by monitoring the tissue effect in real time.
Explaining the process, Gee says it’s all about focusing energy on the tumor. The MR allows the clinician to see into the body and evaluate what needs to be treated. “You get 3D pictures of pelvic organs—hundreds of cuts,” Gee said. The transducer—which Gee calls “key”—is built into the MR table and directs a target of energy at the tumor(s). Once it is targeted, the MR equipment provides “real-time feedback of the treatment. Within 3 to 5 seconds, we get a temperature curve and know when we’ve reached a critical temperature to destroy the tumor,” Gee said .
“It is very precise. You can visualize the anatomy and monitor what’s going on with the tissue,” Gee said . “So you are able to control the treatment.”
Gee is a big proponent of MRgFUS. “It’s very exciting and very rewarding work,” said Gee. “A woman walks in the door and walks out 60 to 90 minutes later. Typically, within 3 months, she experiences significant symptom improvement.” That’s a lot faster—and easier—than surgery. But does the procedure work efficiently … and on whom?
According to experts, the ideal candidate for MR-guided focused ultrasound is a woman with one to four moderately sized fibroids, ranging from 4 to 6 cm. For the treatment to work, the tumors must be of a specific type. Subserosal fibroids, which are located on the outer surface of the uterus, do respond to MRgFUS. But MRgFUS cannot treat pedunculated tumors—which Gee likens to “a piece of broccoli, where the fibroid is the flower part.”
NEW TRIAL TO ASSESS MRgFUS FOR INFERTILITY TREATMENT
The big news concerns a recently approved worldwide fertility enhancement trial. In May 2008, the FDA gave InSightec Ltd, an Israel-based company, approval to conduct a clinical trial to evaluate the efficacy and safety of its ExAblate 2000 system utilizing MR-guided focused ultrasound surgery for the enhancement of fertility in women with non-hysteroscopically resectable uterine fibroids who are diagnosed with unexplained infertility.
Some 20 US and international sites will enroll a total of 650 women with uterine fibroids who are diagnosed with unexplained infertility. Half the women will undergo treatment with the ExAblate system, while the other half will have their fibroids surgically removed.
“The hope is that MR-guided focused ultrasound will prove as good as myomectomy in select patients, thereby providing an alternative to surgery for women hoping to conceive,” Gee said. The trial will assess how quickly the study participants conceive, as well as look at miscarriage rates and delivery complications. “At the completion of the trial, we hope to have better data about the safety of each procedure for women who have difficulty conceiving,” Gee said .
THE FUTURE OF MRgFUS
Gee notes multiple benefits to the use of MRgFUS for the treatment of fibroids, including a low rate of complications. However, the cost of the equipment is far from low. “It is pretty expensive technology, and most clinicians are not going to invest in new technology until they know they can treat several patients,” said Gee, who is hoping the new data from the ExAblate trial will help address this concern.
The procedure is not routinely covered by insurance, though some payors are beginning to approve it. Gee says the lack of reimbursement is most likely due to the fact that MRgFUS for fibroids is still “considered experimental”—despite the fact that there are more than 35 published articles regarding the procedure in peer-review journals and more than 4,000 treatments have been done to date worldwide.
But Gee is optimistic. “MRgFUS is a robust treatment for uterine fibroids. It changes the nature or characteristic of the tumor,” Gee said . “It’s like turning a rock into silly putty.”
BREAST ULTRASOUND
Breast cancer incidence in women has increased from one in 20 in 1960 to one in eight today. When it comes to combating these dire statistics, experts say breast ultrasound is a tool of growing importance, both as a screening method and in assisting surgical procedures.
“At Montclair Breast Center, we’ve been believers in breast ultrasound for a long time now,” said Rose Heller-Savoy, director of mammography services, Montclair Breast Center in Montclair, NJ. “But it should not be used with every woman. Rather, the key is to use it with a subset of the population, specifically those with dense breasts as well as high-risk patients.”
Heller-Savoy, who calls breast ultrasound “one of the most exciting things in the field since I finished my training,” notes that the results of the American College of Radiology Image Network (ACRIN) trial published in May 2008 offer some of the most relevant data to date on breast ultrasound.
The ACRIN trial found that in women at increased risk for breast ultrasound, adding a screening ultrasound exam to routine mammography revealed 28% more cancers than mammography alone. However, the additional ultrasound exam substantially increased the rates of false-positive findings and unnecessary biopsies.
According to the ACRIN study results, mammography alone prompted an unnecessary biopsy for one in 40 women in the study. The combination of mammography and ultrasound screening prompted an unnecessary biopsy for one in 10 women—that means four times more women having an unnecessary biopsy.
“A lot of clinicians don’t believe in screening ultrasounds because of the false positives,” said Heller-Savoy. “But that’s a price I’m willing to pay to find some of these small breast cancers we are finding with ultrasound.”
The study’s principal investigator, Wendie Berg, MD, PhD, a radiologist specializing in breast imaging with American Radiology Services at Johns Hopkins Green Spring, Lutherville, Md, advises, “The study results confirm that screening ultrasound in combination with mammography detects more cancers than mammography alone in women at increased risk for breast cancer. However, this benefit comes with the added risk of a false-positive result. If we are going to offer screening ultrasound, we need to inform women of the substantial risk of receiving an unnecessary biopsy.”
SURGICAL APPLICATIONS
Ultrasound for screening is one matter, but surgical applications are another. “We believe surgeons should be using ultrasound to enhance the evaluation of masses and abnormalities found in the breast, but also in the OR, to better target the removal of tissue and help guide the surgeon,” said Whitworth.
According to Whitworth, there exists something of a turf battle between surgeons and radiologists. “There is some controversy among surgeons and radiologists about who should be using breast ultrasound,” said Whitworth.
“Our position is that surgeons don’t need to be using it so much for screening, but certainly breast surgeons should have superb ultrasound skills for aiding surgical procedures.”
Whitworth calls breast ultrasound “a wonderful problem-solving tool.” He points to several benefits: Its ability to provide more information about abnormalities found through a mammography or MRI; the ability to evaluate other ultrasound scans from other physicians; and its ability to help guide biopsies and surgeries.
WHAT’S NEXT FOR BREAST ULTRASOUND?
There appears to be growing interest in the use of ultrasound-guided cryoablation for certain breast cancers. In May 2007, radiologists at the University of Wisconsin Hospital & Clinics in Madison, presented a case report concluding that ultrasound-guided cryoablation of small breast cancer may be a safe procedure associated with minimal morbidity and high patient satisfaction.
The case concerned an 85-year-old woman with two small biopsy-proven invasive ductal carcinomas that were treated solely with the technique. Authors of the report have stated that the patient was without known progressive disease after 1 year based on mammography and ultrasound follow-up.
Most recently, the National Cancer Institute is conducting a trial to determine the rate of complete tumor ablation in patients with invasive ductal breast carcinoma treated with cryoablation. Launched in January 2008, the multicenter study is looking at approximately 99 women. The trial is expected to be completed in September 2009.
In addition to new studies, we can anticipate new breast ultrasound product features, says Heller-Savoy. “Manufacturers are working to make breast ultrasound more specific,” said Heller-Savoy. “So that in the future, the modality will be able to identify lesions that have been categorized as ‘probably benign’ as ‘benign.’ ” Heller-Savoy anticipates exciting new breast ultrasound technology at this year’s RSNA.
FETAL HEART MONITORING
More than 4 million babies were born in the United States in 2007. But congenital heart disease is one of the most serious conditions affecting new infants, resulting in the largest number of infant deaths within the first year of life.
GE Healthcare is doing something about that sad fact. The company has licensed a technique patented by a respected obstetrician that can automate the acquisition of ultrasound images used by physicians to diagnose fetal heart defects. GE has licensed the software for exclusive use in its 3D/4D ultrasound systems.
Alfred Abuhamad, MD, professor and chairman of the Department of Obstetrics and Gynecology at Eastern Virginia Medical School (EVMS), says that screening the heart in the first year of life is not typically done very well. “This is due to two facts. First, the heart is tiny,” said Abuhamad. “But in addition, ultrasound relies on the skill of the technician. An infant’s heart is a difficult organ to look at and the experience of the operator matters a great deal.”
Recognizing this fact, Abuhamad developed the automation protocol, called Sonography-based Volume Computer Aided Diagnosis or SonoVCAD—which is now licensed by GE and incorporated into the company’s Voluson EB, the next generation of the GE Voluson ultrasound platform for women’s health care. This still new 3D/4D ultrasound system includes a number of new tools to help improve clinical workflow.
On the market for less than 1 year, SonoVCAD automates the acquisition of images to display the planes that are needed for a complete ultrasound of the fetal heart. “It makes everything much simpler for the technician,” said Abuhamad. “It automates the examination of the heart prenatally, ensuring better detection of congenital heart problems.”
With the software, an ultrasound technician identifies a standard starting point, for the four-chamber view of the fetal heart. Abuhamad has created algorithms that allow the other planes to be generated from that four-chamber view. Those views let physicians identify the type and severity of fetal heart defects.
ASSISTED REPRODUCTIVE MEDICINE
About 12% of women (7.3 million) in the United States aged 15 to 44 had difficulty getting pregnant or carrying a baby to term in 2002, according to the National Center for Health Statistics of the Centers for Disease Control and Prevention.
GE Healthcare is on the front lines with technology that helps fight the heartbreaking problem of infertility. In March, the company launched enhancements to its premier ultrasound system for obstetrics and gynecology, the Voluson E8 Breakthrough 2008. These include improved probe imaging capabilities, enabling clinicians to see more anatomical detail. Equally important, GE debuted its proprietary software program, Sonography-based Automated Volume Count (SonoAVC), which delivers an efficient method of calculating the number and volume of ovarian follicles. This is an important initial step in assisted reproductive medicine.
In assisted reproductive medicine, ultrasound is part of a baseline evaluation of the patient. Often it includes an assessment of the anatomy such as the uterus, fallopian tubes, ovaries, and endometrium. Ultrasound can help in surgery planning, as well as help to detect abnormalities and cysts. GE’s SonoAVC automatically measures and calculates the number and volume of hypoechoic structures, such as ovarian follicles, in a volume sweep. This is a critical diagnostic step in assisted reproductive medicine, because each fluid-filled follicle contains hormone-producing cells and a maturing egg.
Abuhamad, who tested the software, sees it as a breakthrough. “Most doctors measure the follicles one at a time,” said Abuhamad. “SonoAVC allows you to obtain automated measurement from the ovary, increasing efficiency, reducing time, and enhancing accuracy.”
According to GE, bringing automation to the exam can significantly reduce a clinician’s time for follicular assessment and reporting, as much as 7.6 minutes per patient. Moreover, the standardization of the exam increases efficiency and consistency between physicians across locations. SonoAVC also generates instant results a patient can see in an easy-to-view report format. “It’s user-friendly,” said Abuhamad. “Displaying ovarian follicles in a 3-D mode allows for an easy visual depiction of the geometric shape of individual follicles and thus enhances the optimal evaluation of the stimulated ovary.”