Introduction of Computed Tomography

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Computed tomography (CT) is a safe, non-invasive and high diagnostic rate. CT uses a narrow X-ray beam to scan a certain plane of the body, and uses a highly sensitive detector to measure the amount of X-rays passing through various points of the object. After computer processing, the results show different densities of colors according to the different X-ray absorption coefficients of different tissues or lesions. For example, the tissues that absorb the most X-rays (bones) are white, and the tissues that absorb the least X-rays (such as air and fat) are black, and the shades are gray. Therefore, according to the displayed images, we can determine various structures in the body layer and the location, scope and nature of the lesions in them.

The CT process requires strict braking, otherwise "action illusion" will affect the image display. Generally speaking, children must be calm and restrained. Sometimes, in order to strengthen the contrast effect and make the focus clearer, a dose of water-soluble iodide (Hypaque 4ml/kg, at most once.

CT has been widely used in clinic, especially in children with brain diseases such as hydrocephalus, intracranial tumor, cerebrovascular disease and brain abscess. (see the article "children's brain computed tomography").

Abdominal CT has positive value in the diagnosis and localization of the following diseases: ① Liver and biliary tract masses such as intrahepatic tumors, abscesses, cysts or hematomas, choledochal cysts, hydrocele of gallbladder sheath, etc. ② Etiology of obstructive jaundice. ③ Renal tumors, such as nephroblastomas, renal cysts, hydronephrosis, adrenal cortical tumors, neuroblastoma, etc. Follow-up of renal injury, renal function and complications after renal transplantation. ④ Retroperitoneal cavity and pancreatic mass. ⑤ Abdominal Hodgkin's disease and other lymphomas.