英语翻译FunctionalMRI(fMRI)istheuseofMRItodetectlocalizedchangesinbrainactivity,usuallyintheformofchangesincerebralmetabolism,bloodflow,volume,oroxygenationinresponsetotaskactivation.Thesechangesareinterrelatedandm

Question

英语翻译
Functional MRI (fMRI) is the use of MRI to detect localized changes in brain activity,
usually in the form of changes in cerebral metabolism,blood flow,volume,or
oxygenation in response to task activation.These changes are interrelated and
may have opposite effects.For example,an increase in blood flow increases blood
oxygenation,whereas an increase in metabolism decreases it.The most common
means of detection is measuring the changes in the magnetic susceptibility of
hemoglobin.Oxygenated blood is dimagnetic and deoxygenated blood is para-
magnetic.These differences lead to a detection method called blood oxygen level
dependent contrast (BOLD).Changes in blood oxygenation can be seen as differences
in the T2 decay constant,so T2 weighted images are used.Because these changes
are very small,images before and after task initiation are subtracted from each
other and the resultant difference image is overlaid on a standard image.
Special care must be taken when obtaining these images because the effect is
small and can be corrupted by several sources of noise.Typically,hundreds of images
are taken for each slice plane position and statistical analysis is used to produce
the final image.Sources of noise errors are thermal noise,head movement,
and respiratory and cardiac cycles.An example of an fMRI image is shown in
Figure 16.52.

Answer 1

呼.终于译完了.因为是手译的,很多专业术语要一个个查.
有一两个句子很长,很罗嗦,我把它断开了,会更容易理解.
功能磁共振成像 是用磁共振成像来检测大脑的本地活动（这个就是大脑的某个部分的活动的意思）,一般是检测由大脑任务所激活的脑代谢、血流量、容量和血液含氧量的变化.
这些变化都有着关联而且可能作用相反.例如,血流量的增加会促使血液含氧量的增加,而生陈代谢的增加则会减少血液含氧量.
最普遍的检测是 测量血红蛋白的磁化率.氧化的血液是抗磁的,而无氧化血液是顺磁的.
这些不同能创造一个检测方法（意思就是因为有这些不同,所以这些检测方法才有可能实现）叫做血氧水平依赖对比（简称BOLD）（网上查的专业术语）.
血氧度的不同 可以从“T2衰变常数的变化”（专业术语）看出来.因此,T2加权像被使用.（就是这个T2常数一变,就证明血氧度变了）.
因为这些变化很微小,任务启动前后的影片要相减,这个差在覆盖在标准图片上.
在采取这些图片时必须非常小心,因为效果很小,很容易被其他音源给干扰到.
通常,每个切片平面位置都要照上上百张图片,然后用统计学分析来制成最后的图片.
音源可能来自热噪音,头的移动,呼吸或者心跳周期.
figure16.52 是功能磁共振成像图片的例图