CT, also known as computed tomography, can be scanned out of the internal structure of the human body in layers, the body of all tissues and organs are applicable to the positive lesions that have been found CT examination can also be more detailed description of the location of the lesion, the scope of the accuracy of the X-ray is higher. (It is especially important in the diagnosis of tumors.)
MRI, also known as nuclear magnetic **** vibration, is different from CT's cross-sectional scanning, he is a longitudinal scanning to check the brain, spine, nerves are more common. In the brain hemorrhage, cerebral infarction, as well as spinal deformity, disc herniation and other checks are more commonly used.
DR, CR is a kind of X-ray examination
DSA is digital subtraction angiography, through the injection of contrast medium to make blood vessels imaging, such as interventional examination will use this technology, in the cerebral blood vessels, coronary blood vessels (nutrient cardiac blood vessels) and so on, more use, you can avoid the influence of the bones, organs, more intuitive judgment of the blood vessels of the alignment and changes in the situation.
What kind of bottom line are you asking about? There is lightning protection, safety, signaling, etc. Medical devices in order not to interfere with each other, the ground is to be separated.