A preliminary study on diffusion-weighted imaging with background suppression and maximum intensity projection for screening internal mammary lymph node metastasis of breast cancer.

Abstract

Background: Internal mammary lymph node (IM) metastasis significantly affects prognosis. However, reports using imaging techniques have been limited. Diffusion-weighted imaging with background suppression and maximum intensity projection (DWIBS-MIP) is a sophisticated imaging method that emphasizes key signal areas such as tumors or lymph nodes in three-dimensional, providing a quick and comprehensive view immediately. Therefore, DWIBS-MIP can become a screening method for IM metastasis.

Purpose: To investigates the usefulness of DWIBS-MIP for screening IM metastasis in patients undergoing preoperative breast MRI.

Material and methods: Breast cancer patients with suspected IM metastasis from January 2017 to June 2024 were assessed. We evaluated the visibility and the size of IM metastasis, the long axis, short axis, and short-to-long axis (S/L) ratio of the biopsied lymph nodes at DWIBS-MIP. Patient's age, maximum diameter and hormonal status of primary cancer, breast cancer stage, the presence of axillary lymph node (Ax) metastasis, the location of the primary lesion were evaluated.

Results: This study included 31 patients with IM metastasis and eight without IM metastasis. DWIBS-MIP exhibited a predictive value of 79.5% for screening IM metastasis. Between two groups, morphological characteristics of IM lymph nodes, including the long axis, short axis, and S/L ratio, demonstrated no significant differences. A higher proportion of Ax metastasis was possible in cases with IM metastasis. Other clinical data did not indicate significant differences.

Conclusions: DWIBS-MIP provides an easy and effective assessment method for screening IM metastasis. The study indicates incorporating DWIBS-MIP into routine clinical practice can improve IM detection accuracy.