Bydder G M, Steiner R E
Neuroradiology. 1982;23(5):231-40. doi: 10.1007/BF00339389.
The basic features of an NMR imaging system are outlined and three pulse sequences which produce images with varying dependence on proton density T1 and T2 are described. The first of these sequences, Repeated Free Induction Decay produces images which demonstrate changes in proton density as well as flow effects. The second sequence, Inversion-recovery, produces images which are dependent on T1 and show a high level of grey, white matter contrast giving considerable anatomical detail. In addition pathological processes such as infarction, haemorrhages, demyelination and malignancy, produce changes in T1 enabling lesions to be localised. The third sequence, Spin-echo, produces images which are dependent on T2. These show very little grey, white matter contrast but demonstrate acute and space occupying lesions as well as cerebral oedema. The high level of grey, white matter contrast, lack of bone artefact, variety of sequences, capacity for multiplanar imaging, sensitivity to pathological change and lack of known hazard make NMR an important addition to existing techniques of neurological diagnosis.
本文概述了核磁共振成像系统的基本特征，并描述了三种脉冲序列，它们所生成的图像对质子密度、T1和T2的依赖程度各不相同。这些序列中的第一个，即重复自由感应衰减序列，生成的图像能显示质子密度的变化以及血流效应。第二个序列，反转恢复序列，生成的图像依赖于T1，且灰质和白质对比度高，能提供相当多的解剖细节。此外，诸如梗死、出血、脱髓鞘和恶性肿瘤等病理过程会导致T1发生变化，从而使病变得以定位。第三个序列，自旋回波序列，生成的图像依赖于T2。这些图像显示的灰质和白质对比度很低，但能显示急性和占位性病变以及脑水肿。灰质和白质对比度高、无骨伪影、序列多样、多平面成像能力、对病理变化的敏感性以及无已知危害，使得核磁共振成像成为现有神经诊断技术的一项重要补充。
