Department of Radiology, Yonsei University College of Medicine, Seoul, Republic of Korea.
Magn Reson Med. 2010 Mar;63(3):553-61. doi: 10.1002/mrm.22261.
Contrast-enhanced three-dimensional T(1)-weighted imaging based on magnetization-prepared rapid-gradient recalled echo is widely used for detecting small brain metastases. However, since contrast materials remain in both blood and the tumor parenchyma and thus increase the signal intensity of both regions, it is often challenging to distinguish brain tumors from blood. In this work, we develop a T(1)-weighted, black-blood version of single-slab three-dimensional turbo/fast spin echo whole-brain imaging, in which the signal intensity of the brain tumor is selectively enhanced while that of blood is suppressed. For blood suppression, variable refocusing flip angles with flow-sensitizing gradients are employed. To avoid a signal loss resulting from the flow-sensitizing scheme, the first refocusing flip angle is forced to 180 degrees. Composite restore pulses at the end of refocusing pulse train are applied to achieve partial inversion recovery for the T(1)-weighted contrast. Simulations and in vivo volunteer and patient experiments are performed, demonstrating that this approach is highly efficient in detecting small brain metastases.
基于磁化准备快速梯度回波的对比增强三维 T1 加权成像广泛用于检测小的脑转移瘤。然而，由于对比剂仍存在于血液和肿瘤实质中，从而增加了这两个区域的信号强度，因此通常很难区分脑瘤和血液。在这项工作中，我们开发了一种 T1 加权、黑血单层面三维涡轮/快速自旋回波全脑成像技术，其中脑肿瘤的信号强度被选择性增强，而血液的信号强度被抑制。为了抑制血液信号，采用了带有流敏感梯度的可变重聚焦翻转角。为了避免由于流敏感方案导致的信号丢失，第一个重聚焦翻转角被强制设置为 180 度。在聚焦脉冲序列的末端应用复合恢复脉冲，以实现 T1 加权对比的部分反转恢复。进行了模拟以及志愿者和患者的体内实验，结果表明，这种方法在检测小的脑转移瘤方面非常有效。
