Dynamic contrast-enhanced magnetic resonance imaging features and apparent diffusion coefficient value of HER2-positive/HR-negative breast carcinoma

BACKGROUND: According to hormone receptor (HR) status, human epidermal growth factor 2 positive (HER2+) breast carcinoma can be divided into HR− and HR+, with different treatment and prognosis. We analyzed the dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) findings, apparent diffusion coefficient (ADC) value and the combination of DCE-MRI and ADC value of HER2+/HR− breast carcinoma. METHODS: Totally 259 cases (96 HR−, 163 HR+) of pathologically verified HER2+ breast carcinoma were collected. Patients underwent DCE-MRI and diffusion weighted imaging (DWI). The morphological characteristics, internal enhancement characteristics, early enhancement rate (EER), and time-signal intensity curves (TIC) were recorded, and ADC values were measured. The relationship between each feature and HER2+/HR− breast cancer was analyzed. Area under the cures (AUC) was used to compare diagnostic performance of DCE-MRI, ADC value and the combination of DCE-MRI and ADC value. RESULTS: HER2+/HR− breast cancer presented as non-mass enhancement (NME), mass with NME, whereas HER2+/HR+ breast cancer presented as mass (P<0.001). HR− cases showed a round or oval shape with circumscribed margins, whereas HR+ cases showed an irregular mass with irregular or spiculated margins (P=0.001, P=0.028). The size of the mass, the internal enhancement characteristics, EER, and TIC did not differ significantly between the two HER2+ breast carcinomas. The ADC values for HR− and HR+ breast cancers were [1.2 (1.14, 1.33)] ×10(−3) mm(2)/s and [1.0 (0.89, 1.11)] ×10(−3) mm(2)/s, respectively, which were statistically significant (Z=−9.119, P<0.001). The ADC value can be used for diagnosing HER2+/HR− breast carcinoma, with the threshold value of 1.095×10(−3) mm(2)/s [negative predictive value (NPV) of 89.8%, sensitivity of 86.5% and specificity of 70.6%]. The AUCs of ADC value, DCE-MRI, and DCE-MRI combined with ADC value were 0.839, 0.689 and 0.860, respectively. AUC of the DCE-MRI combined with ADC value was significantly higher than DCE-MRI alone (P<0.0001). CONCLUSIONS: The diagnostic performance of the DCE-MRI combined with ADC value was good in diagnosing HER2+/HR− breast cancers. MRI is an effective tool in diagnosing HER2+/HR− breast carcinoma, which will help select the clinical treatment plan and determine the prognosis.