Who wouldn’t go to the hospital for the rest of their lives? When you go to the hospital, you will often be prescribed a variety of imaging tests, such as ultrasound, CT, MRI, and so on. You may be confused, of all the different types of tests, why do I have to choose this one? Is it just that the more expensive ones are better? Because many people may have such doubts, so I am here to talk about common sense, I hope you will also be helpful. Imaging examination how to choose, first to a concise version, not to go into the fine reasoning, but for practical: traumatic bone: coarse look at the X-ray film, look at the CT, MRI can not see; cervical spine, lumbar spine: the best MRI, the second choice CT; brain, spinal cord: brain infarction to see MRI, bleeding to see CT, the rest, including brain tumors mostly MRI best; chest: a general understanding of the X-ray film, detailed analysis to choose CT, look at the lungs do not choose MRI, heart the following single said Abdominal and pelvic cavity: except for the intestine, the organs can be generally ultrasound, CT and MRI have their own advantages; Heart: patients with high risk chest pain can choose CT to exclude coronary heart disease, look at the heart itself with ultrasound can be, MRI is better. After reading these lines, I believe that some of the doubts you may have during your consultation can be answered by yourself. First of all, I would like to give a “boring” introduction to what these tests are. The most common X-ray, similar to the “chest X-ray” often used in the past during medical examinations, is an image obtained by using X-rays to penetrate the human body. This is why they are still widely used in clinical practice today. PET/CT is a new technique that combines positron emission tomography with conventional CT, and it can evaluate the metabolic function of cells while examining the structure, combining the evaluation of structure and function. advantages. Ultrasound and MRI are much less effective than X-ray based X-ray and CT for the bone cortex and medulla. For intervertebral disc disease (cervical spondylosis, lumbar disc herniation, etc.), the intervertebral discs and corresponding nerve roots need to be observed, and for the best observation of these soft tissues, the best choice is MRI. Similarly, MRI is also preferred for the examination of joints, muscles, and fatty tissues. For brain and spinal cord diseases, MRI has the strongest soft tissue resolution and can directly obtain clear three-dimensional images, using different sequences to obtain more comprehensive diagnostic information. However, for hemorrhagic stroke (e.g., “cerebral hemorrhage”), CT examination can be performed in emergency conditions to detect abnormalities at the earliest and obtain early diagnosis. In the case of ischemic stroke (infarction), MRI can detect abnormalities earlier than CT, so early CT alone without detecting abnormalities often cannot rule out an infarction. X-ray chest radiographs can cursorily examine the heart, aorta, lungs, pleura, and ribs, and can see, for example, enlarged heart shadow, increased lung texture, calcified spots in the lungs, and calcified aortic nodes. Compared with X-ray, CT chest examination shows clearer structures, and the sensitivity of detecting chest lesions and the accuracy of showing lesions are better than conventional X-ray chest films, especially for the confirmation of early lung cancer diagnosis. High-resolution CT further increases the resolution of lung observation, which is significant for certain diseases (e.g. interstitial lung disease). However, the radiation dose of CT examinations is significantly higher than that of X-rays, and MRI has very limited application for the diagnosis of lung diseases. The diagnosis of gallbladder diseases is very dependent on ultrasound, which is superior to CT and MRI. This is mainly because the abdominal organs are affected by respiration and have greater motion, which affects CT and MRI imaging, whereas ultrasound is not affected by this. The diagnostic accuracy of ultrasound for the liver, spleen, pancreas, kidney, pelvic organs, etc. is high and is as accurate as CT and MRI with an experienced ultrasonographer, but ultrasound is greatly disturbed by gas, so the diagnostic accuracy of ultrasound for areas containing more gas, such as the intestine, is greatly reduced. Imaging of the heart is mainly to examine the coronary arteries, with the myocardium, pericardium and other structures. Coronary artery stenosis up to a certain limit is what we usually call “coronary heart disease”. The gold standard for coronary artery examination is inpatient arteriography, but for reasons of convenience and feasibility, CT can sometimes be used instead. evaluation. Finally, it is important to mention that coronary CT is not suitable as a routine physical examination because of its high radiation exposure. MRI is the “gold standard” for evaluating the structure and function of the heart, although there is no electromagnetic radiation, but the observation of coronary arteries is far less than CT. When myocardial infarction occurs, cardiac MRI can not only accurately display the size of the atrioventricular cavity and the thickness of the ventricular wall, but can also comprehensively show the motion changes in each segment of the ventricular wall and identify post-infarction scar tissue. It is also uniquely superior to cardiac ultrasound for the diagnosis of various cardiomyopathies, such as dilated cardiomyopathy, hypertrophic cardiomyopathy, arrhythmogenic right ventricular cardiomyopathy, and left ventricular myocardial densification insufficiency. For restrictive cardiomyopathy and constrictive pericarditis, which have similar clinical features and pathophysiological changes, the “one-stop” scan can provide relevant signs for diagnosis and differential diagnosis in terms of anatomy, function and histological characterization. For congenital heart disease, especially complex or compound malformations, cardiac MRI can effectively complement cardiovascular imaging, such as atrioventricular junction, ventricular aortic junction, and extracardiac malformations, and play an important role in postoperative follow-up. However, as a routine examination of cardiac structure and function, cardiac ultrasound is more commonly used because it already provides more adequate information and is simple and easy to perform.