The journey from bench to bedside is a long one in medicine, but breast MRI received a boost in March 2007 when the American Cancer Society (ACS) revised its guidelines for breast cancer screening to include annual MRI for high-risk women, a group representing about 2 percent of the US population. That same month, a report¹ on the ACR Imaging Network 6667 trial was published in the New England Journal of Medicine, recommending contralateral breast MRI for women recently diagnosed with breast cancer. In addition, the ACS recommends that women with extremely dense breasts, a personal history of breast cancer, and atypical hyperplasia receive breast MRI at their physicians’ discretion.

Another adjunct breast-imaging modality is poised to assume an even greater role in breast cancer screening and diagnosis. Ultrasound, long used to help evaluate suspicious lesions and cysts and to guide breast biopsies, has been generating a growing list of scientific citations since emerging as a hot topic at the 2006 meeting of the European Congress of Radiology (ECR) for a different reason: elastography.

Numerous studies have indicated that elastography, which uses ultrasound waves to measure the elasticity of tissue, could be a useful diagnostic tool for several cancers, including breast malignancies. Cancerous tissue is less pliant than regular breast tissue; according to the results of one British study presented at ECR 2006,² the sensitivity and specificity of breast elastography are 96 percent and 53 percent, respectively, meaning that the technique could be used to determine whether a lesion is benign or malignant without invasive biopsy. Later that year, a poster presentation³ at the annual RSNA meeting showed similar results.

An article⁴ published in the July 2008 issue of Breast Cancer, “Cost-effective Screening for Breast Cancer Worldwide: Current State and Future Directions,” provided another argument for the use of elastography in breast cancer diagnosis: its affordability. “Clinical results demonstrate that elasticity imaging, even in its simplest and least sophisticated versions, like tactile imaging, has significant diagnostic potential comparable and exceeding that of conventional imaging techniques,”⁴ the study’s authors wrote. “Tactile imaging is one method that has the potential to provide cost-effective breast cancer screening and diagnostics.”⁴

A National Cancer Institute clinical trial to validate the use of elastography in breast cancer evaluation was launched in July of 2008 and is currently recruiting participants.

Meanwhile, ultrasound guidance for breast biopsy and surgery continues to gain momentum. A recent study⁵ published in Breast looks at the use of vacuum-assisted, ultrasound-guided breast biopsy for difficult indications, including lesions with scarring or distortion, and small tumors or microcalcifications. The study indicates that the technique helped patients avoid difficult surgery in 41 of 51 cases. Another study,⁶ published in the August 2009 issue of the American Journal of Surgery, looks at using an ultrasound-guided electrosurgical loop to excise breast lesions, noting that the technique shortened procedure times and allowed incisions to be smaller.

As breast MRI proliferates around the country following the 2007 ACS revisions to its screening guidelines, research into the diagnostic potential of the modality for breast cancer continues apace. The ACS recommendation came with a caveat: The relatively low specificity of MRI could lead to false positives, resulting in unnecessary biopsies. Some hope computer-aided detection could be a solution. A study⁷ published online in September 2009 in European Radiology evaluated the accuracy of a computer-aided detection program against manual interpretation by radiologists, finding that interpretation based on computer-aided detection had a specificity of 86.4 percent. Without computer-aided detection, the specificity of MRI was found to be around 69 percent.

Another European Radiology study⁸ published online in September 2009 looks at the use of MR elastography (MRE), an experimental technique that uses MRI instead of ultrasound to look at tissue elasticity. According to the results of the study, the addition of MRE to conventional MRI of the breast resulted in sensitivity approaching 98 percent, leading the study’s authors to conclude the combination of MRE and contrast-enhanced MRI could increase the diagnostic performance of breast MRI.

References

1. Lehman CD, Gatsonis C, Kuhl CK, et al. MRI evaluation of the contralateral breast in women with recently diagnosed breast cancer. N Engl J Med. 2007;356(13):1295-1303.

2. Proceedings of the European Congress of Radiology. ECR: Vienna, Austria; 2006.

3. Thomas A, Fischer T. An advanced method of ultrasound: realtime elastography—first experience in 300 patients with breast lesions. Poster presented at: 92nd Scientific Assembly and Annual Meeting of the Radiological Society of North America; November 26–December 1, 2006; Chicago, IL.

4. Sarvazyan A, Egorov V, Son JS, Kaufman CS. Cost-effective screening for breast cancer worldwide: current state and future directions. Breast Cancer: Basic and Clinical Research. 2008;1:91-99.

5. Abbate F, Bacigalupo L, Latronico A, et al. Ultrasound-guided vacuum assisted breast biopsy in the assessment of C3 breast lesions by ultrasound-guided fine needle aspiration cytology: results and costs in comparison with surgery. Breast. 2009;18(2):73-77.

6. Fine RE, Schwalke MA, Pellicane JV, Attai DJ. A novel ultrasound-guided electrosurgical loop device for intra-operative excision of breast lesions: an improvement in surgical technique. Am J Surg. 2009;198(2):283-286.

7. Meeuwis C, van de Ven SM, Stapper G, et al. Computer-aided detection (CAD) for breast MRI: evaluation of efficacy at 3.0 T [published online ahead of print September 2, 2009]. Eur Radiol.

8. Siegmann KC, Xydeas T, Sinkus R, Kraemer B, Vogel U, Claussen CD . Diagnostic value of MR elastography in addition to contrast-enhanced MR imaging of the breast—initial clinical results [published online ahead of print September 1, 2009]. Eur Radiol.

ACS Breast MRI Recommendations

The American Cancer Society (ACS) recommends¹ an annual MRI exam for women who have the following indications:

• the BRCA1 or BRCA2 genetic mutations, or a first-degree relative with either;

• a lifetime risk for breast cancer that has been scored at 20 percent or higher;

• receipt of chest radiation between the ages of 10 and 30; and

• Li–Fraumeni syndrome, Cowden syndrome, Bannayan–Riley–Ruvalcaba syndrome, or a first-degree relative with any of these.

The ACS acknowledges that while data are insufficient to make a recommendation either for or against screening with MRI in the following risk subgroups, physicians should make individualized decisions on whether women with the following risk factors receive breast MRI exams:

• a personal history of breast cancer,

• carcinoma in situ,

• atypical hyperplasia, and

• extremely dense breasts on mammography.

Reference

1. American Cancer Society Guidelines for breast screening with MRI as an adjunct to mammography. CA Cancer J Clin. 2007;57:75-89.

At the 2008 RSNA meeting, Toshiba America Medical Systems (Tustin, Calif.) introduced two new advances for ultrasound imaging of the breast: MicroPure, an algorithm that aids in the detection of microcalcifications, and the Dynamic Micro Slice transducer for breast imaging, which enhances imaging of superficial structures and helps identify lesions.

“MicroPure is an adapted filter we put onto the image to burn out bright echoes so we can better visualize calcifications,” Erin Owen, Toshiba senior manager for clinical marketing in ultrasound, explains. “Ultrasound has never been really good at looking at microcalcifications. MicroPure puts a color on it to bring out the brighter echoes.”

Owen says the technique aids in the biopsy of microcalcifications, which can be a time-consuming and laborious process. “Calcifications are often cancerous, but there’s no way to tell without a stereotactic biopsy,” she notes. “The procedure can take up to two hours, and it’s not very pleasant. With MicroPure, we can do an ultrasound-guided biopsy and be done in 15 to 20 minutes.”

Carey Weiss, MD, medical director of the Comprehensive Breast Care Center at Mercy Hospital, Chicago, Ill., has been using MicroPure for close to a year. He notes, “We like to use ultrasound for calcifications because it’s so much easier to go after them on an ultrasound than to have the patient lie on her stomach for two hours. When we have a case that we think is a good candidate for biopsy, we’ll use ultrasound.”

In July of this year, Toshiba further enhanced its ultrasound offerings with the introduction of Precision Imaging software for the Aplio^TM XG ultrasound system. The multiresolution signal-processing technology evaluates images line by line, then incorporates information from adjacent lines to enhance the image further.

“Precision Imaging offers a much clearer signal for structure boundaries,” Owen says. “In breast imaging, we look for irregular margins for a lesion, or if it’s a cystic structure, we look to see if it’s truly fluid filled. With Precision Imaging, we can see all the variations within a cyst, which helps to differentiate between cysts and lesions and eliminates false positives for a better, more clear diagnosis.”

Weiss also uses Precision Imaging, which “cleans up the cysts well,” he notes. “With complicated cysts, Precision Imaging helps us be sure of what we’re looking at; it’s another useful tool in ultrasound evaluation of breast lesions.”

When Steinberg Diagnostic Medical Imaging (SDMI), Las Vegas, Nev., installed the Vantage Titan™ MRI system from Toshiba America Medical Systems (Tustin, Calif.) a few months ago, founder Mark Winkler, MD, was particularly looking forward to adding high-resolution breast MRI to SDMI’s capabilities. The addition of Toshiba’s Radiance Plus breast-imaging coil, available on both Vantage Atlas and Vantage Titan systems, meant SDMI could perform high-resolution breast imaging without needing a dedicated breast MRI unit.

SDMI selected the Vantage Titan MRI, a 1.5T system, because, in Winkler’s words, “It’s short, wide, and quiet.” The system features a 71-cm patient aperture and a field of view of 55 by 55 by 50 cm; it also includes Toshiba’s patented Pianissimo^TM technology, which helps to limit MRI acoustic noise. Winkler says the Vantage Titan is “more open than what is considered a conventional open system.”

The wide bore enables the Titan system to accommodate more patients while leaving ample space for the Radiance coil. “It helps make the experience nicer because it’s wider, it’s more open, and we can physically accommodate larger patients,” Winkler says. “The very short and wide bore (as well as the quietness of the system) makes it very patient friendly.”

The versatility and high image quality of the Vantage Titan have inspired SDMI to install the system in multiple facilities. “We are getting a new Titan next month and upgrading two systems to Titans, so we’ll have four within six months,” he says. “At that point, most of our breast MRI will be done on a Titan. It’s equivalent to a dedicated breast MRI, but it’s also a great open whole-body system.”

This year Toshiba’s Ultrasound (UL) and Magnetic Resonance (MR) modalities introduced new techniques and equipment dedicated to improving women’s imaging. In conjunction, Toshiba sponsored an evening event where physicians shared how Toshiba’s technology is helping women.

Pamela M. Otto, M.D., professor and director of Breast Imaging & Intervention, Department of Radiology, UT Health Science Center & University Health System, San Antonio discussed her experiences with Toshiba’s newRadiance Plus Breast Imaging Coil, which optimizes Magnetic Resonance Mammography (MRM) on the Toshiba Vantage systems. In fact, this coil enabled Dr. Otto to conduct the first contrast-free breast MRA exams. Toshiba is a pioneer in contrast-free MRA techniques, and now plans to develop a sequence that will enable contrast-free breast MR exams.

Ellen B. Mendelson, M.D., F.A.C.R., Northwestern University and Thomas Fischer, M.D., Charite Hospital, University of Berlin presented their experiences with Toshiba’s ultrasound technology. Both discussedToshiba’s new and exclusive ultrasound technique — MicroPure™, which helps physicians detect breast lesions and micro-calcifications more clearly, as well the sonoelastography suite, ElastoQ (works-in-progress), a non-invasive medical imaging technique that evaluates tumors based on their stiffness (elasticity) compared to normal tissue. Both of these Toshiba collaborators presented cases that provided insight on ultrasound’s future as an effective tool for diagnosing breast disease.

At a CT event the same evening, Frank J. Rybicki, M.D., Ph.D., director, Cardiac CT & Vascular CT/MRI, Brigham and Women’s Hospital and William W. Orrison, M.D., MBA chief of neuroradiology, Nevada Imaging Centers shared their experiences with the Aquilion® ONE 320 detector row CT.

Dr. Rybicki provided insights into key research that has been completed on the Aquilion ONE over the last year. For the first time, CT can now visualize how the cardiac vessels curve and measure flow dynamically within the vessels. He also discussed Brigham and Women’s work on the recently announced CORE 320 worldwide multicenter trial that will compare dynamic volume CT to SPECT for evaluating myocardial perfusion.

Dr. Orrison has completed more than 3,500 patient studies on the Aquilion ONE and shared the way this technology is changing his practice. Not only did Dr. Orrison showcase his whole brain perfusion studies, but he also showed advanced dynamic motion studies of musculoskeletal anatomy, which were clinically used for surgery planning and follow up.