Molecular imaging in small animals - Roles for micro-CT
Molecular imaging in small animals - Roles for micro-CT
复制标题
DOI：
10.1002/jcb.10415
复制
发表时间：
2002-01-01
影响因子：
4
通讯作者：
Ritman, EL
中科院分区：
文献类型：
--
作者：
Ritman, EL
X 射线微型 CT 目前主要用于生成微结构（以及可以从中推断出的功能）的 3D 图像以及完整的啮齿动物器官或大型动物和人类活组织检查中所施用的不透射线指示剂的区域分布。目前 X 射线显微 CT 的使用可以通过三种方式进行扩展，以增加此类样本内分子传输和积累的定量成像。 (1) 通过使用除常用碘之外的重元素，将其附着到感兴趣的分子或这些分子的替代物上。指示剂在生理区室中的积累以及往返于这些区室的运输可以根据这些造影剂的成像空间分布来定量。 (2) 传统基于 X 射线衰减的 CT 图像的高空间分辨率可用于改善基于放射性核素的断层摄影图像 (SPECT 和 PET) 的定量性质，方法是对发射的伽马射线的衰减进行校正，并精确描绘已知选择性累积这些指标的生理空间。同样，其他也在 2D 图像中定位功能的成像模式（例如随后从同一标本获得的组织切片）可以提供与基于 CT 的 3D 微观结构的协同组合。 (3)通过使用K边缘减影成像、X射线荧光成像、各种类型的散射X射线的成像以及X射线穿过不同组织的速度变化的后果(例如折射和相移)等方法来提高X射线CT图像对比度的灵敏度和特异性。由于传统使用的 X 射线衰减，这些其他 X 射线成像方法可以将对比度提高一个数量级以上。为了充分发挥其潜力，需要大力开发不透射线指示器、扫描仪硬件以及图像重建和分析软件。
X-ray micro-CT is currently used primarily to generate 3D images of micro-architecture (and the function that can be deduced from it) and the regional distribution of administered radiopaque indicators, within intact rodent organs or biopsies from large animals and humans. Current use of X-ray micro-CT can be extended in three ways to increase the quantitative imaging of molecular transport and accumulation within such specimens. (1) By use of heavy elements, other than the usual iodine, attached to molecules of interest or to surrogates for those molecules. The accumulation of the indicator in the physiological compartments, and the transport to and from such compartments, can be quantitated from the imaged spatial distribution of these contrast agents. (2) The high spatial resolution of conventional X-ray attenuation-based CT images can be used to improve the quantitative nature of radionuclide-based tomographic images (SPECT & PET) by providing correction for attenuation of the emitted gamma rays and the accurate delineation of physiological spaces known to selectively accumulate those indicators. Similarly, other imaging modalities which also localize functions in 2D images (such as histological sections subsequently obtained from the same specimen), can provide a synergistic combination with CT-based 3D microstructure. (3) By increasing the sensitivity and specificity of X-ray CT image contrast by use of methods such as: K-edge subtraction imaging, X-ray fluorescence imaging, imaging of the various types of scattered X-ray and the consequences of the change in the speed of X-rays through different tissues, such as refraction and phase shift. These other methods of X-ray imaging can increase contrast by more than an order of magnitude over that due to conventionally-Used attenuation of X-ray. To fully exploit their potentials, much development of radiopaque indicators, scanner hardware and image reconstruction and analysis software will be needed.