Medical imaging examinations mainly include ordinary X-ray, CT, MRI, B-ultrasound, etc. Many people may have done these examinations in hospitals, but the differences and functions of these imaging examinations are not clear. below, Compare the body to food. How do these examinations play different roles?
X-ray : Flatten the bread. The X-ray will pass through the human body and leave a black and white image on the negative. If the blocked part cannot be penetrated by the bone, it will be displayed as white on the negative, otherwise it will be displayed as black. This is like a piece of bread or cotton ball. The fiber structure inside cannot be seen on the surface, but it will be much clearer if it is flattened. The advantages of X-ray are simple, fast and low cost. The biggest disadvantage is that due to the thickness and overlap of the deep and shallow tissues, it is impossible to clearly show the details of a certain area.
CT Cut the watermelon into slices. CT is to make X-ray of multiple layers pass through the human body, and the obtained data are processed twice by the computer to obtain the cross-sectional image of the human body. It's like cutting a whole watermelon into pieces, so you can clearly see the internal structure of the watermelon. The advantage of CT is that it can be seen in layers, and the information of each layer can be clearly displayed.
nuclear magnetic resonance Shake the egg and look again. In short, it is like shaking an egg hard to make the egg white vibrate in the direction of shaking, and then suddenly stop shaking to feel the vibration inside the egg. Therefore, NMR is also known as "shake check". Its greatest advantage is that it has a good discrimination between the central nervous system and soft tissues.
B-mode ultrasonography : Knock before picking watermelon. B ultrasound is like picking watermelons. Some people will knock on the surface of watermelons while listening, reflecting the internal structure of watermelons through the sound. The biggest disadvantage of B-ultrasound is that it is greatly affected by bone and gas, and the display of bone system and air containing cavity organs is not ideal.
