Contrast-enhanced mammo on par with breast MR

Bilateral dual-energy contrast agent-enhanced (DE CE) digital mammography detected known primary tumors at a rate comparable to breast MR and a higher rate than digital mammography, according to a study published online Dec. 6 in Radiology. The authors suggested DE CE may offer a potential staging tool if it is able to depict breast cancers in a fashion similar to MR.

Both mammography and MRI are plagued by shortcomings. Mammography has limited specificity and its positive predictive value for biopsy recommendation hovers in the 25 to 45 percent range. MR is sensitive for breast cancer, but its specificity is limited.

“The advantage of MR imaging in staging needs to be balanced with its disadvantages: greater expense, lack of accessibility and the frequency of false-positive examinations. False-positive examinations lead to an increased number of biopsies and of patients choosing mastectomies and [to] delay the time to definitive treatment,” wrote Maxine S. Jochelson, MD, from the department of radiology at Memorial Sloan-Kettering Cancer Center in New York City, and colleagues.

One option that might address some shortcomings of existing modalities is DE CE, which brings the capability to map blood flow to the mammography platform.

Jochelson and colleagues sought to determine the feasibility of bilateral DE CE digital mammography and compare it with digital mammography and breast MR in women with known breast cancer.

The researchers demonstrated the feasibility of DE CE mammography in 10 women between March 2010 and August 2011. An additional 52 women were enrolled in the comparison study and underwent DE CE mammography and breast MR.

DE CE mammography did not detect any suspicious lesions that were not visible at either conventional mammography or MR imaging. DE CE mammography and breast MR each depicted 50 of the 52 index lesions, while conventional mammography showed 42 of the 52 lesions.

The size of lesions depicted via DE CE mammography was 4 mm to 67 mm, and size approximated pathologic size in all but two patients. In these women, DE CE mammography overestimated lesion size by 1 cm and 1.7 cm, respectively. MR imaging was accurate in both of these patients.

The size range of cancers missed by DE CE was 1 mm to 20 mm. “It appears that the usefulness of this test was not a function of size, but rather, a function of histologic characteristics of individual tumors and contrast agent pharmacology,” wrote Jochelson et al.

The researchers reported that MR imaging surpassed DE CE digital mammography in its capability to depict additional malignancies. MR showed 15 of 16 additional sites, while DE CE mammography showed nine of these sites. MR depicted 22 of 25 additional lesions in these sites, while DE CE mammography depicted 14 of the 25 additional lesions.