From breast exams to childbirth, ultrasound is gaining momentum
July 13, 2016
by Lauren Dubinsky
, Senior Reporter
Since about three-fourths of premenopausal women and about 40 percent of postmenopausal women have dense breasts, 27 states have enacted laws that require physicians to inform their patients if they fall into that population. But the question is, what should be done after the patient receives the letter? Many experts believe that ultrasound should be the next step, since it involves no radiation, is less expensive than MR, and has been shown to find additional cancers. But ultimately, it comes down to what the physician and patient decide is the best option.
“The kinds of cancers you detect on breast ultrasound are tiny cancers,” says Dr. Marcela Böhm-Vélez, radiologist at Weinstein Imaging Associates. “Those are the kinds of cancers we want to find because we want to be able to give that woman options for treatment. The earlier you treat breast cancer, the more likely that it will be cured.” In her practice, Böhm-Vélez uses Philips Healthcare’s EPIQ ultrasound system on patients with dense breasts. She chose this system because it’s equipped with technology that improves the characterization of masses, differentiates between normal fat lobule and hypoechoic masses and detects calcifications seen by mammography.
However, with the advent of tomosynthesis, many of her patients are questioning why they need an ultrasound exam anymore. It has been proven many times that if you add ultrasound to a mammogram, you will find more cancers, but the same results have not been found with tomosynthesis yet.
The University of Pittsburgh has a study underway that is having patients with heterogeneous or very dense breasts undergo a tomosynthesis exam and then an additional ultrasound exam to determine if it adds any value. Böhm-Vélez is confident that ultrasound will be found to be useful, because the American College of Radiology Imaging Network (ACRIN) study and other earlier studies have already shown that if you perform an ultrasound exam on dense breasts, you will find cancers that could not be detected by mammography alone.
Ultrasound is often criticized for its false positives and the anxiety it creates. But at Böhm-Vélez’s practice, she is able to perform the mammogram, ultrasound exam and ultrasound core biopsy, which can usually take up to two weeks, on the same day. “If it was a false positive and it wasn’t cancer, the patient is relieved that everything was done as soon as possible,” she says.
Automating the exam
“Automated breast ultrasound is essentially going to replace handheld ultrasound scanning of the entire breast,” says Sankar Suryanarayanan, general manager of GE Healthcare ABUS. It’s a bold statement, but he says the industry is realizing the importance of automated breast ultrasound (ABUS) because of dense breast tissue. The challenge with handheld ultrasound is that it’s manual, so it’s not a practical method to screen or assess women on a population basis.
“Handheld is very operator-dependent, so depending on the skill of the ultrasound technician, you may get a very good image or some may not be good,” he adds. “Also, there is a risk of missing tissue, which is a huge concern.” For an ABUS exam, the clinician just has to press a button, which is similar to a mammography exam. It takes away a lot of the variability of the operator in order to get consistent, quality images on a population basis.
GE’s Invenia ABUS system, which received FDA approval in 2012, is the only ABUS system approved as an adjunct screening tool for dense breasts. There are other ABUS systems on the market, but they are mostly used in the diagnostic setting. Siemens Healthcare’s ACUSON S2000 Automated Breast Volume Scanner was introduced in 2008 and several software advancements have been made for it over the last few years. It acquires a 3-D volumetric view of the breast.
A study published in the American Journal of Roentgenology in May compared how well radiologists can detect breast cancer using full-field digital mammography alone and then using it along with 3-D ABUS. For the cancers that were originally missed with mammography, ABUS improved sensitivity from 38.5 percent to 62.4 percent. For cancers that were missed by mammography that had no prior interventions, sensitivity improved from 32.4 percent to 68.1 percent.
The researchers concluded that, “The addition of ABUS to screening mammography showed a significant increase in cancer detection with a nominal insignificant decrease in specificity. Although these findings were in a research environment, one might expect a similar impact of screening ABUS in clinical practice.”
Prior studies showed that ABUS increases sensitivity, but that it impacts specificity. This new study shows that there was a substantial increase in sensitivity and that the impact on specificity was very low and not statistically significant. “That tells us that the technology continues to be very promising and it could play a very pivotal role in the way we personalize screening, especially for dense breast women,” says Suryanarayanan.
Breast microcalcifications are small calcium deposits that are usually not a result of cancer, but can be a sign of precancerous cells or early breast cancer if they appear in certain patterns. They appear as white specks on mammography, but with gray-scale ultrasound imaging they can barely be seen. In 2012, Thomas Jefferson University in Philadelphia conducted a pilot study that compared Toshiba America Medical Systems, Inc.’s MicroPure imaging processing technique with gray-scale ultrasound imaging for detecting breast microcalcifications. The researchers found that MicroPure significantly improved the identification of microcalcifications compared with gray-scale imaging.
“Microcalcifications are usually very, very tiny and sometimes you are looking a little bit for a needle in the haystack,” says Tina Hodgson, ultrasound marketing manager at Toshiba. “You may find them in the end, but you will spend longer, probably, looking for them. The MicroPure can help them pop out at you and make them more visible.” Ultrasound shouldn’t be used as a substitute for mammography, but when additional screening is needed the MicroPure technology makes ultrasound a good option. It uses a filter technique called Constant False Alarm Rate, which makes the calcifications appear brighter.
Thomas Jefferson University has recently started another study to investigate how useful MicroPure is for biopsies. When patients need a biopsy for microcalcifications, it’s usually guided by mammography, but ultrasound might be more ideal. “[Mammography] is uncomfortable for the patient because you put her belly on the machine and then you compress her breast and it takes a little while,” says Dr. Priscilla Machado, one of the lead researchers. So far they have performed four biopsies using MicroPure and have found that it works well. They are now trying to see if they can reproduce those same findings with a larger number of patients.
“We still have a lot of things to study. The next step will be doing more biopsies using MicroPure, trying to see if we are in the right location,” says Machado.
Shear wave elastography
Shear wave elastography has been used to image the liver for many years, but it’s starting to be used more for breast imaging now. In 2013, Siemens received FDA clearance for its Virtual Touch technology, and in November 2015, Toshiba’s shear wave technology for breast imaging received clearance. Shear wave technology provides information on stiffness in breast tissue. It generates a color-coded map, so clinicians can see what they might have missed on ultrasound, and it gives them a quantifiable number on how stiff a certain area is.
Other options on the market are GE’s LOGIQ E9 ultrasound system with shear wave elastography software, which received FDA clearance in December 2014, and SuperSonic Imagine’s Aixplorer ultrasound system, which received clearance in August 2009.
New player in the OB/GYN market
In June 2015, Carestream took its plunge into the ultrasound market with the introduction of its Touch Prime and Touch Prime XE ultrasound systems. North Fulton Hospital in Georgia is one of the first facilities in the U.S. to purchase the Touch Prime XE. This system is especially helpful when assessing the venous and arterial flow through the umbilical cord. When clinicians are looking at color flow, they typically can only see red and blue to indicate the venous and arterial blood flow, but this system has arrows that show the direction of the flow.
“If there is a problem, you can see that the blood is flowing in the wrong direction very clearly. It’s not a question of [whether] there’s a problem, but it’s more of an absolute ‘this is where the problem is,’” says Tracy Wilkinson, director of imaging services at North Fulton Hospital. The monitor, angle of the keyboard, height of the system and prop for the feet can be adjusted, which is very important for the sonographers. Musculoskeletal pain and discomfort due to work exposure is experienced by 90 percent of sonographers, according to a 2013 study published in the journal, Work. The previous ultrasound systems at the hospital couldn’t be adjusted significantly. The height was fixed and the monitors couldn’t be moved up and down and at an angle.
Ultrasound during labor
The Norfolk and Norwich University Hospital (NNUH) in England received a grant in March to use handheld ultrasound to identify breech births. They will deploy 25 scanners to find babies that are positioned incorrectly during labor. Clinicians usually rely on palpation to determine if the baby is in a breeched position, but that is only accurate about 70 percent of the time. Once the midwives are trained to use the handheld ultrasounds, they are confident that the prognosis rate for breech issues will jump to 100 percent.
“What the use of ultrasound during labor allows you to do is have objective measurements on the progression of labor,” says Barbara Del Prince, director of global product and clinical management for GE Healthcare women’s health ultrasound. GE has tools, including its SonoL&D, to provide the physician with objective evidence and help the patient better understand what is happening during labor. It can automatically measure the angle of progression during childbirth and those images can be shown to the patient.
If it’s a long labor and the patient is getting tired, the images can provide encouragement that things are moving along. If things aren’t progressing and a Cesarean section is required, the tool helps the patient understand that the baby is in the wrong position and that’s why the intervention is needed. “It’s still a very new thing, but we are starting to see more and more in the literature about it,” says Del Prince. “I think in the next year, we’ll start to see more research coming out, talking about the effectiveness.”