Ogawa S, Lee T M, Nayak A S, Glynn P
AT&T Bell Laboratories, Murray Hill, New Jersey 07974.
Magn Reson Med. 1990 Apr;14(1):68-78. doi: 10.1002/mrm.1910140108.
At high magnetic fields (7 and 8.4 T), water proton magnetic resonance images of brains of live mice and rats under pentobarbital anesthetization have been measured by a gradient echo pulse sequence with a spatial resolution of 65 x 65-microns pixel size and 700-microns slice thickness. The contrast in these images depicts anatomical details of the brain by numerous dark lines of various sizes. These lines are absent in the image taken by the usual spin echo sequence. They represent the blood vessels in the image slice and appear when the deoxyhemoglobin content in the red cells increases. This contrast is most pronounced in an anoxy brain but not present in a brain with diamagnetic oxy or carbon monoxide hemoglobin. The local field induced by the magnetic susceptibility change in the blood due to the paramagnetic deoxyhemoglobin causes the intra voxel dephasing of the water signals of the blood and the surrounding tissue. This oxygenation-dependent contrast is appreciable in high field images with high spatial resolution.
在高磁场（7和8.4特斯拉）下，通过梯度回波脉冲序列测量了戊巴比妥麻醉下活小鼠和大鼠大脑的水质子磁共振图像，空间分辨率为65×65微米像素大小，切片厚度为700微米。这些图像中的对比度通过各种大小的众多暗线描绘了大脑的解剖细节。在通常的自旋回波序列拍摄的图像中没有这些线。它们代表图像切片中的血管，当红细胞中的脱氧血红蛋白含量增加时出现。这种对比度在缺氧大脑中最为明显，但在含有抗磁性氧合血红蛋白或一氧化碳血红蛋白的大脑中不存在。由于顺磁性脱氧血红蛋白导致血液中磁化率变化而产生的局部场，会引起血液和周围组织水信号的体素内失相。这种依赖于氧合作用的对比度在具有高空间分辨率的高场图像中很明显。
