Iodine maps derived from contrast-enhanced dual-energy computed tomography for operable breast cancer: Correlation of tumoral iodine concentration and visual pattern with pathological features

Abstract Background: Contrast-enhanced dual-energy computed tomography produces iodine maps (i-maps) based on tissue iodine concentration (IC). We analyzed the features of i-maps in operable breast cancer. Methods: I-maps made from patients with operable breast cancer were retrospectively reviewed. The mean IC of the whole tumor and visual patterns (sharp/obscure) were analyzed with respect to pathological features. The tumor extent was retrospectively verified with dynamic contrast-enhanced magnetic resonance of mammary gland (MRM) and pathological specimens. Results: The median IC of 858 cases was 4.3 (interquartile range [IQR]: 4.0–5.1) mg/mL. The IC of the luminal A-like subtype of invasive breast cancer was significantly higher than that of the human epidermal growth factor 2 (HER2) and triple-negative (TN) subtypes (luminal A-like: 4.5 [IQR: 4.3–5.5] mg/mL vs. HER2: 3.9 [IQR: 3.5–4.4] mg/mL and TN: 3.8 [IQR: 3.6–4.2] mg/mL; both p < 0.05). The IC was significantly correlated with the histological grade and Ki-67 labeling index. Sharp visual patterns correlated with the estrogen receptor and Ki-67 labeling index, while obscure patterns correlated with the HER2 subtype. I-maps underestimated tumor extent in 84 (9.8%) of the 532 partial resection cases, especially in lobular carcinoma and mucinous carcinoma. Conclusions: The IC and visual patterns correlated with the pathological features of operable breast cancer. Most breast cancers are identifiable on i-maps; however, the adjunction of MRM is preferred for tumors with low IC on i-maps to evaluate tumor extent.