Peritumoral Fat Content Correlates with Histological Prognostic Factors in Breast Carcinoma: A Study Using Iterative Decomposition of Water and Fat with Echo Asymmetry and Least-squares Estimation (IDEAL)

Purpose: To correlate peritumoral fat content using iterative decomposition of water and fat with echo asymmetry and least-squares estimation (IDEAL) with histologic prognostic factors in breast carcinoma. Methods: This study consisted of 100 patients who were diagnosed with invasive carcinoma of breast and underwent breast MRI including IDEAL before surgery. The scan time of IDEAL fat fraction (FF) map imaging was 33 s. Four regions of interests (ROIs), which are a distance of 5 mm from the tumor edge, and one ROI in the mammary fat of the healthy side were set on the FF map. Then average peritumoral FF values (FFt), average FF values in the healthy side (FFh), and peritumoral fat ratio (pTFR: defined as FFt/FFh) were calculated. Histologically, the presence of lymph node metastasis and the MIB-1 index were evaluated. Results: FFt and pTFR for breast carcinoma with lymph node metastasis (79.27 +/- 10.36 and 0.897 +/- 0.078) were significantly lower than those without (86.23 +/- 4.53 and 0.945 +/- 0.032) (P < 0.001 and P = 0.005). Spearman rank correlation suggested that the FFt correlated with the MIB-1 index (r = -340, P = 0.001). Conclusion: Quantification of peritumoral fat using IDEAL-iron quantification is associated with the histologic prognostic factors, and may be a practical tool for therapeutic strategy of breast carcinoma.