Iima Mami, Le Bihan Denis
Department of Diagnostic Imaging and Nuclear Medicine, Kyoto University Graduate School of Medicine, Kyoto, Japan.
Department of Clinical Innovative Medicine, Institute for Advancement of Clinical and Translational Science, Kyoto University Hospital, Kyoto, Japan.
Front Oncol. 2023 Feb 21;13:993540. doi: 10.3389/fonc.2023.993540. eCollection 2023.
Breast cancer is the leading cause of cancer in women with a huge medical, social and economic impact. Mammography (MMG) has been the gold standard method until now because it is relatively inexpensive and widely available. However, MMG suffers from certain limitations, such as exposure to X-rays and difficulty of interpretation in dense breasts. Among other imaging methods, MRI has clearly the highest sensitivity and specificity, and breast MRI is the gold standard for the investigation and management of suspicious lesions revealed by MMG. Despite this performance, MRI, which does not rely on X-rays, is not used for screening except for a well-defined category of women at risk, because of its high cost and limited availability. In addition, the standard approach to breast MRI relies on Dynamic Contrast Enhanced (DCE) MRI with the injection of Gadolinium based contrast agents (GBCA), which have their own contraindications and can lead to deposit of gadolinium in tissues, including the brain, when examinations are repeated. On the other hand, diffusion MRI of breast, which provides information on tissue microstructure and tumor perfusion without the use of contrast agents, has been shown to offer higher specificity than DCE MRI with similar sensitivity, superior to MMG. Diffusion MRI thus appears to be a promising alternative approach to breast cancer screening, with the primary goal of eliminating with a very high probability the existence of a life-threatening lesion. To achieve this goal, it is first necessary to standardize the protocols for acquisition and analysis of diffusion MRI data, which have been found to vary largely in the literature. Second, the accessibility and cost-effectiveness of MRI examinations must be significantly improved, which may become possible with the development of dedicated low-field MRI units for breast cancer screening. In this article, we will first review the principles and current status of diffusion MRI, comparing its clinical performance with MMG and DCE MRI. We will then look at how breast diffusion MRI could be implemented and standardized to optimize accuracy of results. Finally, we will discuss how a dedicated, low-cost prototype of breast MRI system could be implemented and introduced to the healthcare market.
乳腺癌是女性癌症的主要病因，具有巨大的医学、社会和经济影响。迄今为止，乳腺钼靶摄影（MMG）一直是金标准方法，因为它相对便宜且广泛可用。然而，MMG存在某些局限性，例如暴露于X射线下以及在致密乳腺中解读困难。在其他成像方法中，MRI的敏感性和特异性显然最高，乳腺MRI是对MMG发现的可疑病变进行检查和管理的金标准。尽管有这种性能，但不依赖X射线的MRI除了针对明确界定的高危女性类别外，未用于筛查，原因是其成本高且可用性有限。此外，乳腺MRI的标准方法依赖于动态对比增强（DCE）MRI并注射钆基造影剂（GBCA），这些造影剂有其自身的禁忌证，并且在重复检查时可能导致钆在包括大脑在内的组织中沉积。另一方面，乳腺扩散MRI在不使用造影剂的情况下提供有关组织微观结构和肿瘤灌注的信息，已显示出与DCE MRI具有相似的敏感性但特异性更高，优于MMG。因此，扩散MRI似乎是一种有前景的乳腺癌筛查替代方法，其主要目标是以非常高的概率消除存在危及生命病变的可能性。为实现这一目标，首先必须规范扩散MRI数据采集和分析的方案，而这些方案在文献中差异很大。其次，必须显著提高MRI检查的可及性和成本效益，随着用于乳腺癌筛查的专用低场MRI设备的开发，这可能成为现实。在本文中，我们将首先回顾扩散MRI的原理和现状，将其临床性能与MMG和DCE MRI进行比较。然后我们将探讨如何实施和规范乳腺扩散MRI以优化结果的准确性。最后，我们将讨论如何实施一种专用的低成本乳腺MRI系统原型并将其引入医疗保健市场。
