Naruse S, Horikawa Y, Tanaka C, Hirakawa K, Nishikawa H, Yoshizaki K
Department of Neurosurgery, Kyoto Prefectural University of Medicine, Japan.
Magn Reson Imaging. 1986;4(4):293-304. doi: 10.1016/0730-725x(86)91039-8.
We examined the proton relaxation times in vitro in various neurological diseases using experimental and clinical materials, and consequently obtained significant results for making a fundamental analysis of magnetic resonance imaging (MRI) as followings. 1) In the brain edema and cerebral infarction, T1 prolonged and T2 separated into two components, one fast and one slow. Prolongation of T1 referred to the volume of increased water in tissue. The slow component of T2 reflects both the volume and the content of increased edema fluid in tissue. 2) In the edematous brain tissue with the damaged Blood-Brain-Barrier (BBB), the slow component of T2 became shorter after the injection of Mn-EDTA. Paramagnetic ion could be used as an indicator to demonstrate the destruction of BBB in the brain. 3) After the i.v. injection of glycerol, the slow component of T2 became shorter in the edematous brain with the concomitant decrease of water content. The effects of therapeutic drug could be evaluated by the measurement of proton relaxation times. 4) Almost all tumor tissue showed a longer T1 and T2 values than the normal rat brain, and many of them showed two components in T2. It was difficult to determine the histology of tumor tissue by the relaxation time alone because of an overlap of T1 and T2 values occurred among various types of brain tumors. 5) In vivo T1 values of various brain tumor were calculated from the data of MRIs by zero-crossing method, and they were compared with the in vitro T1 values which were measured immediately after the surgical operation. Though the absolute value did not coincide with each other due to differences in magnetic field strength, the tendency of the changes was the same among all kinds of tumors. It is concluded that the fundamental analysis of proton relaxation times is essentially important not only for the study of pathophysiology in many diseases but also for the interpretation of clinical MRI.
我们使用实验和临床材料，在体外研究了各种神经系统疾病中的质子弛豫时间，从而获得了对磁共振成像（MRI）进行基础分析的重要结果，如下所示。1）在脑水肿和脑梗死中，T1延长，T2分为两个成分，一个快成分和一个慢成分。T1延长表明组织中含水量增加。T2的慢成分反映了组织中水肿液增加的体积和含量。2）在血脑屏障（BBB）受损的脑水肿脑组织中，注射Mn-EDTA后，T2的慢成分变短。顺磁性离子可作为一种指标来证明脑中BBB的破坏。3）静脉注射甘油后，水肿脑中T2的慢成分变短，同时含水量降低。治疗药物的效果可通过测量质子弛豫时间来评估。4）几乎所有肿瘤组织的T1和T2值都比正常大鼠脑长，其中许多在T2中显示出两个成分。由于不同类型脑肿瘤之间T1和T2值存在重叠，仅通过弛豫时间很难确定肿瘤组织的组织学类型。5）采用零交叉法从MRI数据计算各种脑肿瘤的体内T1值，并与手术切除后立即测量的体外T1值进行比较。尽管由于磁场强度的差异，绝对值彼此不一致，但各种肿瘤之间变化趋势相同。结论是，质子弛豫时间的基础分析不仅对许多疾病的病理生理学研究至关重要，而且对临床MRI的解读也至关重要。
