Additional findings on Breast MRI: The added value of Second-look Digital Breast Tomosynthesis.

ABSTRACT

Additional findings on breast MRI: The added value of Second-look Digital Breast Tomosynthesis

Pr ASMA ZIDI Head of radiology department at the Salah A Zaiez Institute, Tunis, Tunisia. President of the Tunisian Society of Radiology.

Breast MRI has become an important tool in the detection and assessment of breast cancer. MRI is more accurate in the assessment of tumor extent and in the detection of multifocal, multicentric, and bilateral lesions in patients with breast cancer compared to mammography and US.
Preoperative breast MRI often generates additional suspicious findings needing further investigations and require histological confirmation, particularly lesions classified as BI-RADS 5 and 4 (in order to confirm the probability malignant ), or as BI-RADS 3 (in order to confirm the probably benign finding). In fact, additional findings (AFs)may be seen in 16 % to 48 % of breast MRI examinations.
The first step in dealing with MR-detected additional lesions is generally a second-look US examination. Indeed Second look US (SL-US) is a reliable tool for identifying these MRI AFs in 57 % to 82 % of cases. So far, second-look US has been an effective tool, but for up to 53 % of MRI-detected additional malignant lesions, a US correlate may not be found.
Importantly, the absence of an US correlate does not warrant avoiding biopsy. Hence additional MR lesions ( BIRADS 4 or 5 ) not visible with mammographic or US imaging need to be characterized by MR-guided needle biopsy. MR-guided percutaneous biopsy is essential for the correct management of suspicious lesions not otherwise identifiable.
A few retrospective studies have shown that the sensitivity of DBT to detect additional disease is higher than that of digital mammography but lower than that of breast MRI or breast US.
The literature suggests that DBT following MRI additional findings has the potential to significantly increase detection rates when compared to standard 2-D mammography and US alone.
The contribution of SL-DBT is relevant in particular for non-mass findings very difficult to detect using US. US second look can be guided by DBT images. When MR AFs  was identifiable only with DBT,  they can  be characterized by DMT -guided  biopsy and may prevent unnecessary MRI biopsy.