Advances in Breast Imaging: Beyond Mammography

When most people think of breast imaging, they think only of mammography. While mammography remains the mainstay of breast imaging, this subspecialty area of radiology has evolved rapidly and substantially during the last several decades to include several other advanced technologies that aid in the detection and diagnoses of breast diseases. Ultrasound and MRI have also become standard components of breast imaging practices, along with breast interventional radiology. I recently discussed breast imaging beyond mammography in San Francisco Medicine.

With this evolving technology, comes the evolving role of the breast imaging radiologist. In the past, breast imaging radiologists solely interpreted imaging and provided reports to referring physicians. Today, breast imaging radiologists play an integral part of a multidisciplinary team caring for patients with breast cancer and other breast health issues.

Breast Ultrasound

Last week we discussed the vital role of mammography and its evolution through the decades. However, mammography is not the only tool breast imaging radiologists use to detect and diagnose breast diseases. Breast ultrasound is often performed contemporaneously with mammography in the diagnostic setting to evaluate breast lesions. Adding ultrasound to mammography for better characterization of breast masses improves diagnostic specificity and reduces the number of benign biopsies.

The modality has also been used for whole-breast screening and has the demonstrated ability to detect small cancers that are clinically and mammographically occult in women with dense breasts. However, several challenges limit the adoption of ultrasound as a common screening method, including operator dependence, physician time to perform the study, and a high rate of false-positive biopsies.

MRI

In addition to ultrasound, MRI is used by breast imaging radiologists to detect abnormalities in breast tissue. Breast MRI is considered the most sensitive imaging technique for detecting breast cancer. As a result, the technique is being used increasingly on patients who are at high risk for the disease. Breast MRI is also frequently used to monitor treatment response to neoadjuvent chemotherapy, as studies have shown that breast MRI has clinical utility for predicting recurrence-free survival and pathologic complete response.

While breast MRI is a highly sensitive technique, it is supplemental screening and should not be used alone. Rather, it should be used in addition to mammography, as some cancers are undetectable by MRI, yet visible with mammography. Breast MRI is not recommended for screening women who have an average risk for breast cancer, due to a high rate of false-positive biopsies. Advances in MRI technology and the addition of newer techniques, such as diffusion weighted imaging, may help improve the specificity of breast MRI.

Breast Interventions

In the past, management of a mammographically detected, but clinically occult suspicious lesion was problematic because it was difficult to excise a nonpalpable lesion. Often the surgeon would resect a large portion of the breast quadrant to ensure removal of the lesion. But the development of mammographically guided needle-localization techniques has allowed more precise excisions, with more conservation of normal breast tissue. This localization can be performed under mammography, ultrasound, or MRI guidance.

The development of image-guided percutaneous breast biopsy has expanded the role of the radiologist in managing breast imaging patients further. Rather than localize a suspicious mammographic finding for a breast surgeon to excise, the radiologist can now obtain a sample directly and provide a tissue diagnosis. Expediting the diagnosis in this way decreases morbidity and improves cosmesis for the patient, plus decreases heath care costs for society.

Given its benefits, image-guided percutaneous breast biopsy is currently considered the “first-line” approach for tissue diagnosis, while breast surgical excision is reserved for cases not amenable to an image-guided biopsy or for cases where additional tissue is warranted to ensure adequate sampling after initial image-guided biopsy.

A Critical Practice

Breast imaging has come a long way from the days of direct-exposure films and rampant quality concerns. Breast imaging radiologists now have more tools at their disposal and are more integrated into patient care than ever before. As additional technological innovations are achieved and breast imaging radiologists continue to advance in their expertise, mammography and other imaging techniques, like MRI, ultrasound, and breast intervention, are expected to remain central to early detection efforts.

Early detection remains a key to reducing mortality. Breast screening is the most effective and affordable tool for detecting breast cancer and we continue to advocate for annual mammography screening starting at age 40.

Read my full article in San Francisco Medicine.