Contrast mammo equals MRI for measuring tumor size

Contrast-enhanced digital mammography (CEDM) works just as well as contrast-enhanced breast MRI (CE-MRI) for measuring breast tumors before surgery, according to a study published April 24 in the British Journal of Radiology.

Preoperative breast imaging to measure tumor size helps clinicians determine the extent of disease and is a key component of surgical planning, wrote a group led by Dr. Inyoung Youn, PhD, of Sungkyunkwan University in Seoul, South Korea. MRI is the most widely used imaging modality for this application and is considered to be the most accurate.

But having another option would give surgeons a wider range of tools and address some of breast MRI's limitations.

"Breast MRI is an important imaging modality for breast cancer patients; however, the high cost of the procedure, claustrophobia, longer study time, and lesser accessibility ... compared with mammography are a few of its limitations," the team wrote.

Previous clinical research has compared the diagnostic performance of CEDM and CE-MRI and found that the two modalities are comparable in their accuracy; however, these studies haven't compared their performance in measuring tumor size before surgery. So Youn and colleagues compared the accuracy of CEDM and MRI, including maximum intensity projection (MIP) images, for measuring histologically confirmed breast tumors.

The study included 52 women with 54 cancers who had undergone contrast-enhanced MRI and contrast-enhanced digital mammography within a week before surgery for breast cancer between November 2016 and March 2017. The researchers assessed the two modalities' performance by comparing the maximum diameter of the main lesion on mediolateral oblique (MLO) and craniocaudal (CC) digital mammography and CEDM with sagittal and axial MIP images and dynamic CE-MRI before surgery. No patients experienced side effects from contrast media.

Of the 54 cancers, 41 were treated with breast-conserving surgery and 13 were treated with mastectomy. Mean lesion size was 15.5 mm. All parameters of CEDM and CE-MRI showed good agreement (kappa > 0.75), the group found.

CEDM vs. CE-MRI for measuring mean breast tumor size
	Mammography	CEDM	CE-MRI
MLO	21.1 mm	20.3 mm	--
CC	21.2 mm	20 mm	--
Sagittal MIP	--	--	19.8 mm
Axial MIP	--	--	17.7 mm

The researchers also discovered that both modalities visualized the size of the tumor more accurately in the axial plane than the sagittal, and that the CC view on CEDM was comparable or superior to that of CE-MRI.

Because CEDM and CE-MRI perform comparably when it comes to measuring breast lesions, clinicians have more options, according to the group.

"CEDM can be used as an alternative modality to CE-MRI in tumor size measurement, and the axial plane of the CEDM and CE-MRI would be the first choice for image review and surgical planning," the team concluded.