Sugahara T, Korogi Y, Shigematsu Y, Liang L, Yoshizumi K, Kitajima M, Takahashi M
Department of Radiology, Kumamoto University School of Medicine, Japan.
Top Magn Reson Imaging. 1999 Apr;10(2):114-24. doi: 10.1097/00002142-199904000-00004.
The degree of tumor malignancy generally correlates to tumor grade, and the direct measurement of tumor vasculature is desired. Dynamic susceptibility contrast magnetic resonance imaging can provide relative cerebral blood volume and, therefore, is one of the most reliable methods to evaluate tumor vasculature in vivo. Tumor vessel size is extremely variable due to complex tumor angiogenesis, and the gradient-echo echo-planar imaging (GE-EPI) technique, which is sensitive to the total vascular bed, is well suited for this purpose. As many studies have shown, dynamic susceptibility contrast magnetic resonance imaging is more useful for grading glioma than conventional magnetic resonance imaging. We found that this technique can also provide supplementary information to differentiate between malignant lymphoma and glioma because the absence of tumor neovascularization of malignant lymphoma leads to low rCBV, which is in contrast to those of malignant gliomas. Indeed, this technique can be used for the differentiation of extra-axial tumors such as between meningioma and neurinoma. Recently, this technique has been focused toward determining the stereotactic biopsy site, monitoring the embolization of effect in meningioma, or evaluation of treatment effects after radiation therapy. However, the value of tumor rCBV is affected by many conditions such as the T1 relaxivity effects of gadolinium in the extravascular space. To establish the usefulness of this technique, further examination will be needed.
肿瘤恶性程度通常与肿瘤分级相关,因此需要直接测量肿瘤血管系统。动态磁敏感对比增强磁共振成像能够提供相对脑血容量,所以它是体内评估肿瘤血管系统最可靠的方法之一。由于肿瘤血管生成复杂,肿瘤血管大小变化极大,而对整个血管床敏感的梯度回波平面回波成像(GE-EPI)技术非常适合此目的。正如许多研究表明的那样,动态磁敏感对比增强磁共振成像在胶质瘤分级方面比传统磁共振成像更有用。我们发现该技术还能为鉴别恶性淋巴瘤和胶质瘤提供补充信息,因为恶性淋巴瘤缺乏肿瘤新生血管会导致相对脑血容量较低,这与恶性胶质瘤不同。实际上,该技术可用于鉴别轴外肿瘤,如脑膜瘤和神经鞘瘤。最近,该技术已集中用于确定立体定向活检部位、监测脑膜瘤栓塞效果或评估放射治疗后的治疗效果。然而,肿瘤相对脑血容量的值受许多因素影响,如血管外间隙钆的T1弛豫效应。为确定该技术的实用性,还需要进一步研究。