Body CT scan is a high-speed X-ray scan that allows you to obtain minimum thickness sections of visceral organs and their three-dimensional images. The organs of the thoracic cavity (heart, lungs, main arteries and veins), abdominal cavity (pancreas, liver, gallbladder, spleen, intestines), retroperitoneal space (kidneys, urinary tract, adrenal glands), pelvis (male and female genitals) can fall into the scanning area. The study of these anatomical regions is informative for the detection of inflammatory and tumor processes, organ damage, systemic and other pathology. CT of visceral organs is often performed with contrast enhancement (intravenous, oral).
Types of CT
The anatomical region and volume of CT scans of internal organs vary depending on the goals of the diagnostic search. At the same time, it is possible both a targeted examination of a single organ and a complex computed tomography of the entire area of interest. CT of visceral organs includes:
- CT of the thoracic cavity: bone frame and soft tissues of the chest, lungs, pleura, bronchi, mediastinal organs.
- CT of the abdominal cavity: liver, pancreas, spleen, stomach, small and large intestines, gallbladder, bile ducts, mesentery, lymph nodes, arteries and veins.
- CT of retroperitoneal space: kidneys, adrenal glands, ureters, blood vessels and retroperitoneal lymph nodes.
- CT of the pelvic organs: female (vagina, uterus, appendages), male (prostate gland and seminal vesicles).
Body CT scan can be conventional, contrast-free (native) or performed using a contrast agent. Contrast computed tomography is prescribed to obtain more complete information about the condition of hollow organs: to determine their shape, size, condition of the inner shell and the size of the lumen, as well as to detect concretions. In addition, a contrast study is performed to assess the condition of blood vessels, identify vascular networks in tumors, etc.
Body CT scan is mainly a clarifying diagnostic method and is carried out at the final stage of the examination. The purpose of CT may be to clarify the nature of the pathological process or to determine indications for surgical intervention. The study is also prescribed in the process of diagnosis and differential diagnosis of acute and chronic diseases in the case when other methods do not allow obtaining enough data to make an accurate diagnosis.
CT scans of the chest and abdomen are often used to identify, determine the degree of malignancy and prevalence of volumetric processes. The technique is used in the postoperative period and in the process of conservative therapy. The aim of the study in such cases is dynamic observation and evaluation of the effectiveness of treatment. In addition, in some cases, body CT scan is prescribed in the long term, if screening methods are not informative enough to exclude a possible relapse.
CT of the biliary tract using a contrast preparation allows you to assess the size, structure, patency and mutual location of the gallbladder and bile ducts. The study is carried out after ultrasound. The indication for the diagnosis is complicated or atypically occurring cholecystitis, accompanied by a prolonged increase in body temperature, abdominal pain and impaired liver function according to biochemical blood analysis.
CT of the large intestine is a study used to assess the condition of the intestine (shape, size of the lumen, the presence of constrictions, extensions and ulcerative lesions of the mucous membranes), as well as to identify, clarify the nature and prevalence of volumetric processes. To increase the information content, a small amount of air is injected into the intestine. CT colonography is usually prescribed after irrigoscopy and/or ultrasound. In some cases, this non-invasive technique can replace an endoscopic examination of the intestine or help make a decision about the need for such a study.
Kidney CT is a technique used in the diagnosis and treatment of malformations, injuries, neoplasms, cysts, abscesses, urolithiasis and hydronephrosis. It is prescribed for ambiguous results of urography and ultrasound of the kidneys. It can be carried out with or without the use of a contrast agent. This procedure allows you to assess the size, shape and location of the kidneys, accurately localize pathological foci, determine the area for sampling material during biopsy, assess the condition of the renal bed after nephrectomy, etc.
CT of the adrenal glands is the main method of radiation diagnostics used in case of suspicion of volumetric formations of this organ. It can be contrasting or non-contrasting. This type of CT makes it possible to obtain information about the location, shape, density, contours, structure and size of the adrenal glands, the nature and localization of pathological foci (tumors, necrosis sites, areas of deposition of calcium salts, etc.). It is carried out in the process of clarifying the diagnosis, determining the possibility and tactics of surgical intervention.
The radiation load during CT does not exceed the dose of X-ray irradiation with conventional radiography. This study should not be carried out during pregnancy, since even a small dose of radiation can have a negative effect on the fetus. Among the contraindications not related to the action of X-rays are a weight of more than 120-130 kg (the tables of most CT machines are not designed for a higher load) and pronounced motor anxiety.
A relative contraindication to native body CT scan is the age of up to 14 years. For children under this age, the study is prescribed only if it is impossible to establish a final diagnosis using other methods. CT is not performed for 7 days after irrigoscopy and radiography of the stomach with barium suspension. Contraindications to CT with contrast are blood diseases, diabetes mellitus, cardiovascular pathology, renal and hepatic insufficiency, drug intolerance
Methodology of conducting
Before laying on the table, the patient removes metal objects. The table of the device moves inside a wide ring on which sensors and an X-ray tube are located, while the patient can keep in touch with the doctor in the next room. Before starting CT with contrast, the patient is injected with a contrast agent. The method of administration is chosen depending on the area of study and can be intravenous, oral or rectal.
The duration of body CT scan without the use of a contrast agent is about 15 minutes, with the use of a contrast agent – about 30 minutes. Then the radiologist examines the data obtained and draws up a conclusion. The preparation of the conclusion usually takes 1.5-2 hours. The results are either transferred to the attending physician, or given to the patient. If CT with contrast is performed during lactation, the patient is recommended to refrain from breastfeeding for 2 days.
Along with MRI and radiography, body CT scan is prescribed to detect volumetric processes, diagnose acute pathology and chronic diseases. CT differs from radiography by higher information content, therefore it is usually carried out after an X-ray examination to clarify the data obtained. Both methods involve the use of X-rays.
MRI, like CT, allows you to obtain three-dimensional images of the area under study, but is based on a different principle – the body’s response to electromagnetic radiation. The informativeness of both methods in the study of internal organs is very high. The advantage of MRI is the absence of radiation exposure, the advantages of CT are the possibility of carrying out in the presence of metal implants and implanted electronic devices, as well as the absence of a closed camera that can cause an attack of claustrophobia. Body CT scan allows to obtain more complete data on solid formations (stones, calcification foci) and fresh bleeding, MRI – on soft tissue tumors and inflammatory processes. Often both methods are used in combination.