关键词: 乳腺肿瘤, 磁共振成像, 对比研究, 重复性

Abstract: Background and purpose: Breast cancer is one of the most common malignant tumors among women. Intravoxel incoherent motion (IVIM) is a functional imaging technique based on the theory of biexponential model developed in recent years, which can exhibit diffusion and perfusion effects. This study aimed to investigate the reproducibility of IVIM parameters and the value in the diagnosis of breast lesions, comparing with quantitative dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) parameters, to explore whether correlations exist among perfusion parameters. Methods: A prospective study was performed in 56 patients with pathologically confirmed benign lesions (n=30), malignant tumors (n=31). All patients underwent DCE-MRI and IVIM imaging. Two radiologists measured the images independently to obtain the parameters from IVIM (D, D^*, f ) and DCE-MRI (K^trans, K_ep, V_e). The data consistency between two observers was calculated with intraclass correlation coefficient (ICC). All parameters were statistically compared between benign lesions and malignant tumors using independent sample t test. The receiver operating characteristic (ROC) curve was used to evaluate the ability of the parameters in differentiation of benign and malignant breast lesions. Pearson correlation analyses were used among the IVIM and DCE-MRI parameters. Results: The agreement between 2 radiologists was good for all parameters (ICC≥0.730, P<0.05). D value was significantly lower in malignant lesions than in benign lesions, while the f , K^trans and K_ep values were higher than those in benign lesions (P<0.05). The D^* and V_e values showed no differences between benign and malignant breast lesions (P>0.05). The areas under the ROC curve for D, f, K^trans and K_ep were 0.896, 0.677, 0.796 and 0.847, respectively. There was no significant difference in the area under ROC curve between D and K^trans, neither between the D and K_ep (P>0.05). The D value showed higher specificity (86.67%) with the threshold of 1.07×10^-3 mm²/s. The K_ep value showed higher sensitivity (98.36%) with the threshold of 0.54/min. The f value exhibited a positive correlation with K^trans and K_ep value with r of 0.373 and 0.360 (P<0.05), respectively. D^* was also poorly correlated positively with Ktrans with an r of 0.294. Conclusion: The IVIM parameters showed good reproducibility between different radiologists. Both IVIM and DCE-MRI could be helpful in differentiating between benign and malignant breast lesions with positive correlation of the perfusion fraction.

Key words: Breast neoplasms, Magnetic resonance imaging, Comparative study, Reproducibility