CT examination

CT is a full-featured disease detection instrument, which is short for electronic computed tomography. The CT examination is based on the difference in the absorption and transmittance of the X-rays of different tissues of the human body. The instrument with high sensitivity is used to measure the human body, and then the data obtained by the measurement is input into the computer. After the data is processed by the electronic computer, the CT examination is performed. A cross-sectional or three-dimensional image of the examined part of the human body can be taken to find small lesions in any part of the body. Basic Information Specialist classification: growth and development check classification: CT Applicable gender: whether men and women apply fasting: not fasting Tips: Patients with diabetes, multiple myeloma, dehydration, severe cerebral arteriosclerosis and cerebral vasospasm, acute pancreatitis, acute thrombophlebitis, severe cachexia, and other serious lesions should not be examined. Normal value There was no abnormality in the angiography. Clinical significance Abnormal results Middle ear cancer can be manifested as bone destruction centered on the middle ear, the small bones disappear completely, and soft tissue masses can be seen locally. Sinusitis CT manifests as mucosal thickening, increased intracavitary density, and formation of effusion or empyema. Liver cancer is mostly in a low-density area when it is flat. CT findings of cirrhosis include uneven liver surface, imbalance of leaf proportions, uneven liver parenchyma density, and splenomegaly. Acute pancreatitis is characterized by chronic enlargement of the pancreas, deformation and marginal blurring, disappearance of peripancreatic fat layer, and thickening of the renal fascia; chronic patients present with enlarged or reduced pancreas, deformation and calcification, pancreatic duct enlargement, and renal ribs The film is thickened. In patients with bronchiectasis, the bronchus on CT may be columnar, saclike or mixed. CT showed an arc-shaped shadow on the inner surface of the chest wall, which indicates the presence of pleural effusion. People who need to check: 1, neurological diseases, craniocerebral trauma, cerebral infarction, brain tumors, inflammation, degenerative diseases, congenital malformations, etc., for the application of the earliest human system, especially in the diagnosis of traumatic craniocerebral emergency is a routine and preferred method of examination, can clearly show Brain contusion, acute intracerebral hematoma, epidural and subdural hematoma, craniofacial bone fracture, intracranial metal foreign body, etc., and more sensitive than any other method. CT diagnosis of acute cerebrovascular diseases such as hypertensive cerebral hemorrhage, subarachnoid hemorrhage, cerebral aneurysm and arteriovenous malformation rupture, cerebral infarction, etc. have high value, acute bleeding can be considered as the first choice for examination, acute cerebral infarction, especially onset Within 6 hours, CT is not as sensitive as MRI. 2, cardiovascular system can be used for the diagnosis of pericardial tumor, pericardial effusion, etc., acute aortic dissection aneurysm CT has a positive diagnostic significance, especially enhanced scanning has characteristic performance, and can be qualitative diagnosis. 3, chest lesions have a very satisfactory effect on the display of lung lesions, and have a high diagnostic value for lung trauma, infectious lesions, tumors and so on. The display of masses, lymph nodes, and pleural lesions in the mediastinum is also satisfactory, and the relationship between the mass in the lung and the mediastinum can be shown. 4, abdominal organs for the organs of the liver, gallbladder, spleen, pancreas, kidney, adrenal gland and other organs show clear, for tumors, infections and trauma can clearly show the degree of anatomical accurate lesions, the disease stage, etc. have higher value, there are Helping to develop clinical treatment plans, especially for the surgical positioning of the surgical department, is of great value in the diagnosis and differential diagnosis of intra-abdominal masses. 5, pelvic organs; pelvic organs have a rich fat interval, can accurately show the invasion of the adjacent tissue, so CT has become the diagnosis of ovary, cervix and uterus, bladder, seminal vesicle, prostate and rectal tumor, clinical staging And an important means of design for radiation therapy. 6, bones and joints (1) Small lesions in bones and muscles. X-ray plain films are often covered by cortical bone and cannot be displayed. (2) Complex bones and joints, such as the spine and sterno-lock joints. (3) X-ray suspicious lesions, such as small fractures of the articular surface, soft tissue abscess, bone cortical destruction caused by intramedullary bone tumors, observation of tumor infiltration into soft tissue. (4) The display of the internal and surrounding structures of the bone destruction zone, such as dead bone, calcification, ossification and bone hyperplasia around the damaged area, soft tissue abscess, tumor showed significantly better than the conventional X-ray film. (5) For articular cartilage, ligament, meniscus, synovium, etc., MRI examination is appropriate. Precautions 1, iodine contrast agent allergy. 2, severe liver and kidney damage. 3, severe thyroid disease (hyperthyroidism). 4, renal insufficiency. 5, diabetes, multiple myeloma, dehydration, severe cerebral arteriosclerosis and cerebral vasospasm, acute pancreatitis, acute thrombophlebitis, severe cachexia and other serious lesions. 6, asthma, hay fever, urticaria, eczema and other allergic diseases. 7, heart disease: such as congestive heart failure, coronary heart disease, arrhythmia and so on. 8. Patients with previous allergies to contrast agents and other drugs. 9. Children under 1 year old and old people over 60 years old. Taboo before inspection: 1, before the abdominal CT examination, fasting for 4 hours, preferably the previous night from the fasting. 2, within 1 week, do not accept drugs containing heavy metals, do not do gastrointestinal tincture examination. Patients who have been tested for expectorant need to wait for the sputum to empty; if they are eager to have a CT examination, they should be treated with a cleansing enema or oral laxative to sputum. 3. Always remove high density or metal objects from the inspection site before inspection. 4. Patients who need to be enhanced scans should have an iodine allergy test in advance. Requirements for inspection: Actively cooperate with the doctor's work, should pay attention to the protective shielding outside the scanning inspection. Inspection process (1) Plain scan: refers to a common scan without contrast enhancement or contrast. Usually they are first cleaned. (B) contrast enhanced scan: is a method of intravenous injection of water-soluble organic iodine, such as 60% ~ 76% diatrizoate 60ml and then scan. After the concentration of iodine in the blood is increased, the concentration of iodine in the organ and the lesion may be different, and the density difference may be formed, which may make the lesion develop more clearly. Methods There are several methods of group injection, intravenous infusion and intravenous and intravenous infusion. (3) Contrast scan: It is a method of performing an angiography of an organ or structure before scanning. For example, injecting iodine to 8-10 ml or injecting air 4-6 ml into the cerebral cistern for cerebral angiography and scanning, which is called cerebral angiography CT scan, can clearly show the cerebral cistern and small tumors therein. Not suitable for the crowd Inappropriate people: The following patients should be used with caution or disabled. Adverse reactions and risks no.