River J N, Lewis M Z, Lubich L M, Karczmar G S
Department of Radiology, University of Chicago, Illinois 60637, USA.
Magn Reson Med. 1995 Mar;33(3):318-25. doi: 10.1002/mrm.1910330306.
Experiments were performed to determine whether changes in T2*-weighted MR images during and after hyperoxia differentiate tumors from normal tissue. Mammary adenocarcinomas implanted in the right hind limbs of rats were studied. Gradient echo images were obtained at 2 Tesla with an evolution time of 20 ms and a recycle time of 1 s. Breathing gas was either air or 100% O2. Significant increases in image intensity were observed in tumor centers and rims during hyperoxia while much smaller changes were detected in the surrounding muscle. The relaxation rate (1/T2*) in tumors decreased during hyperoxia by an average of 2.5 +/- 1.0 s-1, while in muscle the average change was an increase of 0.6 +/- 2.1 s-1. The largest decreases in relaxation rate were detected in non-necrotic tumor regions with relatively low density of blood vessels. Immediately following hyperoxia significant decreases in intensity were detected in tumors while much smaller decreases were detected in the surrounding muscle.
进行实验以确定高氧期间及之后T2加权磁共振图像的变化是否能区分肿瘤与正常组织。对植入大鼠右后肢的乳腺腺癌进行了研究。在2特斯拉磁场下获得梯度回波图像，回波时间为20毫秒，重复时间为1秒。呼吸气体为空气或100%氧气。高氧期间，肿瘤中心和边缘的图像强度显著增加，而周围肌肉的变化则小得多。高氧期间肿瘤的弛豫率（1/T2）平均降低2.5±1.0 s-1，而肌肉中的平均变化是增加0.6±2.1 s-1。在血管密度相对较低的非坏死肿瘤区域检测到最大的弛豫率降低。高氧后立即检测到肿瘤强度显著降低，而周围肌肉的降低则小得多。
