乳腺MRI技术进展及面临的挑战

Advances and challenges of MRI in breast

随着我国乳腺癌发病率的迅速增长,乳腺癌的早期诊断愈发受到重视。近年来,MR功能成像技术不断发展,为乳腺癌的早期诊断及预后判断带来新的思路。动态增强MRI(dynamic contrast-enhanced magnetic resonance imaging,DCE-MRI)可借助对比剂定量分析肿瘤组织病变特征;弥散加权成像(diffusion weighted imaging,DWI)无需注射对比剂,即可显示组织内水分子运动特点,反映病变组织微观结构变化。体素内不相干运动(intravoxel incoherent motion,IVIM)作为一种非高斯、双指数DWI模型,将组织内水分子扩散与微循环灌注效应分开,能更为真实地反映病变血流灌注等信息;扩散峰度成像(diffusion kurtosis imaging,DKI)则通过评价水分子弥散位移分布偏离高斯函数的程度,更真实地反映病变组织复杂程度。越来越多的研究表明,MRI技术通过多元化地反映病变微环境(如血流灌注、组织成分及代谢变化等),有可能在乳腺癌的诊断、新辅助化疗疗效判断中发挥重要作用。

With the rapid increase of the incidence of breast cancer in China, the early diagnosis of breast cancer becomes more and more important. In recent years, MRI functional imaging technology develop rapidly, bringing about new ideas for the early diagnosis and predicting the prognosis of breast cancer. Dynamic contrast-enhanced MRI（DCE-MRI） could quantitatively analyze features of tumor tissue with injection of contrast agent. Diffusion-weighted imaging（DWI） could detect the characteristics of water molecules movement without contrast agent, reflecting the microstructure of the lesion. As a non-Gaussian, biexponential model, intravoxel incoherent motion（IVIM） model separates the diffusion of water molecules from microcirculation more accurately, which could reflect the information of blood flow perfusion. Diffusion kurtosis imaging（DKI） depicts the complexity of abnormal tissue more accurately by evaluating the degree of diffusion non-Gaussianity. More and more studies have shown that MRI technique may play an important role in the diagnosis of breast cancer and predicting the response of neoadjuvant chemotherapy by reflecting the microenvironment（such as blood perfusion, tissue composition and metabolic changes）.