Tien R D, Felsberg G J, Friedman H, Brown M, MacFall J
Department of Radiology, Duke University Medical Center, Durham, NC 27710.
AJR Am J Roentgenol. 1994 Mar;162(3):671-7. doi: 10.2214/ajr.162.3.8109520.
The purpose of this study was to evaluate the usefulness of diffusion-weighted echoplanar MR imaging in the examination of high-grade brain gliomas compared with that of conventional spin-echo (SE) or fast spin-echo (FSE) MR imaging. We hypothesize that diffusion-weighted MR imaging may enable us to differentiate various tumor components on the basis of differences in the diffusion of water.
Conventional SE and FSE MR images were obtained in 10 patients with high-grade brain glioma. Diffusion-weighted echoplanar MR images were obtained with a head gradient coil capable of providing diffusion-weighted imaging along the cephalocaudal axis. Using SE and FSE MR images as a baseline, we evaluated the diffusion-weighted MR images for usefulness in distinguishing tumor components on the basis of differences in diffusion.
Areas of tumor that showed significant enhancement on T1-weighted SE MR images obtained after injection of contrast material were markedly hyperintense on diffusion-weighted images and had a lower apparent diffusion coefficient (ADC) than the ADCs for nonenhancing tumor and peritumoral edema. Cystic or necrotic portions of tumor showed the most signal suppression on diffusion-weighted images and were associated with the highest ADCs. On T2-weighted FSE MR images, areas of hyperintensity observed in white matter oriented parallel to the direction of the diffusion gradient could be differentiated into two patterns on the basis of findings on diffusion-weighted images: areas that showed marked signal suppression with a higher ADC, most likely representing areas of predominantly peritumoral edema, and areas that showed a lesser degree of signal suppression with similar but slightly lower ADCs than those of edema, most likely representing areas of predominantly nonenhancing tumor.
Diffusion-weighted echoplanar MR imaging is a useful technique for examining high-grade cerebral gliomas. It enabled us to differentiate various components of the tumor (e.g., enhancing, nonenhancing, cystic, or necrotic) and to distinguish areas of predominantly nonenhancing tumor from areas of predominantly peritumoral edema when the abnormality was located in the white matter aligned in the direction of the diffusion-weighted gradient. Diffusion-weighted echoplanar MR imaging appears to be a powerful tool in the characterization of brain neoplasms.
本研究旨在评估扩散加权回波平面磁共振成像在高级别脑胶质瘤检查中的实用性，并与传统自旋回波（SE）或快速自旋回波（FSE）磁共振成像进行比较。我们假设扩散加权磁共振成像或许能使我们根据水分子扩散的差异来区分各种肿瘤成分。
对10例高级别脑胶质瘤患者进行了传统SE和FSE磁共振成像检查。使用能够沿头足轴提供扩散加权成像的头部梯度线圈获取扩散加权回波平面磁共振图像。以SE和FSE磁共振图像作为基线，我们根据扩散差异评估扩散加权磁共振图像在区分肿瘤成分方面的实用性。
注射造影剂后获得的T1加权SE磁共振图像上显示明显强化的肿瘤区域在扩散加权图像上显著高信号，且其表观扩散系数（ADC）低于未强化肿瘤和瘤周水肿的ADC。肿瘤的囊性或坏死部分在扩散加权图像上信号抑制最明显，且ADC最高。在T2加权FSE磁共振图像上，在与扩散梯度方向平行的白质中观察到的高信号区域，根据扩散加权图像的表现可分为两种模式：信号明显抑制且ADC较高的区域，最可能代表主要为瘤周水肿的区域；信号抑制程度较轻且ADC与水肿相似但略低的区域，最可能代表主要为未强化肿瘤的区域。
扩散加权回波平面磁共振成像是检查高级别脑胶质瘤的一种有用技术。当异常位于与扩散加权梯度方向一致的白质中时，它能使我们区分肿瘤的各种成分（如强化、未强化、囊性或坏死），并区分主要为未强化肿瘤的区域和主要为瘤周水肿的区域。扩散加权回波平面磁共振成像似乎是脑肿瘤特征性诊断的有力工具。
