Medical research and diagnostics

Computed tomography (CT) of the foot

The foot is the distal extremity of the stop-flow living organisms. The body is a vault, which is in contact with the surface of the earth and serves as a support when moving or fixing on one point. Pathologies of the foot can significantly impair the quality of movement and human life. For quick and informative diagnosis using computed tomography. What you need to know about the method, exactly how the study goes and what diseases the human foot is susceptible to?

How does computed tomography work?

The principle of operation of a computer tomograph is based on X-rays. After placing a person inside the apparatus of CT, X-rays pass through his body. The degree of absorption of rays depends on the location, density, specificity of tissues, so it is heterogeneous. The device records the degree of absorption of rays by certain tissues, and transmits this information to a special computer. The computer calculates the location of the tissues and, based on the information received, creates an image of the scanned area in three-dimensional format. For comparison, with a standard X-ray, we get a two-dimensional image of the shadows of the organs. Computed tomography can improve visualization and examine each section at a different angle to get as much information about the organ as possible.

Modern equipment receives an image of even the smallest elements. The thickness of the slice can reach 0.5 millimeters in various planes. Computed tomography, like any other method based on X-rays, separates 5 structural components: bones, fat, air, soft tissues and water. The greatest difficulties arise in the diagnosis of soft tissue structures. For this, doctors advise the patient to undergo several types of diagnostics, which work on the opposite principle. For example, computed tomography is often combined with ultrasound. To increase the information content of the method, radiopaque substances are used. After ingesting the body, they literally “highlight” organs and vessels, which has a positive effect on visualization.

What you need to know about contrast tomography?

Radiocontrast agents are used to enhance the visualization of an organ / vessel. What does this give? The substance is administered to the human body orally or intracutaneously. In the first case, it spreads through the gastrointestinal tract, in the second - through the bloodstream. The fluid literally stains the vessels or organs through which it “travels.” The CT apparatus fixes the dark areas of the body much better, so on the final image the tinted organs will be seen as clearly as possible. This greatly facilitates the work of the radiologist and other specialized specialists, as well as increases the information content of the procedure.

The composition of most radiopaque drugs includes iodine. Coloring liquids are absolutely safe and independently derived from the human body with the assistance of the kidneys. The only caveat - the contrast is contraindicated in case of individual intolerance to the drug and serious impairment of renal function. In the first case, the patient may develop a severe allergic reaction, in the second - the removal of the substance from the body becomes more complicated.

Is CT scan safe?

Tomography, like X-rays, is based on the study of X-rays. In this case, X-rays are allowed to do only a few times a year due to high radiation exposure. What is the situation with computed tomography?

Absolutely all CT equipment operates with reduced radiation exposure. Scientists managed to minimize the degree of exposure, but to remove it completely impossible. The time frame between computed tomography is much less than between x-ray procedures. But using CT for multiple diagnostics, during pregnancy or in childhood is not recommended. For this, ultrasound diagnostics or magnetic resonance imaging, which are absolutely safe for the human body, is more suitable.

CT is used in almost all areas of medicine - from neurosurgery to urology. The information content of the method is much more valuable than the possible minimal risks. Moreover, modern equipment is constantly being improved. Scientists reduce the time of diagnosis, for which it is possible to obtain a full range of information, and thus reduce the radiation load.

Important: CT scan is carried out only on prescription. For the purpose of prevention, it is better to use non-treating methods of examination (ultrasound or MRI).

Indications / contraindications for

Mechanical damage to the foot - dislocations, subluxations, fracturesPregnancy (due to the pathogenic effect of X-rays on the baby)
Infectious and inflammatory diseasesAge limit (tomography is allowed from 14 years old; in severe cases it is possible to have a diagnosis at the age of seven)
Congenital or acquired defects of developmentOverweight (modern equipment designed for patients weighing up to 200 kilograms)
Arthrosis (chronic pathology of the joints, which is associated with their deformity and limitations in mobility)The patient’s overall serious condition (notify the doctor even of a slight deterioration. You may have to postpone the diagnosis or even cancel it)
Gout (pathology of the joints / tissues, which occurs due to failure of metabolic processes in the body)Hepatic insufficiency, diabetes mellitus, thyroid abnormalities, renal failure (during the contrast study)
Myositis (inflammation of skeletal muscles)Mental deviations, fear of confined space (the patient will not be able to adequately respond to the requests of the radiologist, which will affect the effectiveness of the method)
Arthritis (inflammatory process in the joint)
Defects in the bone structure
Damage to blood vessels of various etiologies
Cancer neoplasms regardless of the nature of the tumor
General diagnosis of the foot before or after surgery


During tomography, no specific preparation is required. Immediately before the procedure, the laboratory technician will ask you to remove all metallic jewelry and clothing with metallic elements. The only caveat - before the contrast diagnosis, the patient should refrain from eating 6 hours before CT.

Computed tomography of the foot is no different from the study of any other zone. Before scanning, the patient must provide medical records. It includes the direction of the attending physician for diagnosis, the necessary list of tests, specific instructions to the laboratory assistant. The laboratory assistant studies the medical documentation, determines the type and features of the procedure (the area under study, with or without contrast). If it is necessary to improve the visualization of the soft tissues and vessels of the foot, the contrast is injected intracutaneously just before the procedure. Contrast MRI is performed on an empty stomach (the patient must discard the food for 6 hours before the introduction of contrast).

A medical officer helps the patient to sit on the retractable table. At will, he can fix the body with soft straps. At the time of scanning, the patient must remain stationary. Even a slight reflex movement can spoil the scan, and hence the final three-dimensional image. The medical officer selects the optimal location of the scanning ring, and covers the rest of the body with a special apron that protects the tissue from X-rays. As soon as the patient has taken a comfortable position, the technician sets up a scanning ring above the foot, reports a possible means of communication, and leaves for the next room. From there, the medical officer monitors the scan and the patient's condition.

Important: If you feel pain, discomfort or want to stop the diagnosis for any other reason - immediately inform the technician. It will help eliminate the problem, identify the root cause and conduct a re-study.

As soon as the device is started, the ring begins to rotate rapidly around the area under investigation, fixing the intensity of X-rays and foot sections. Diagnosis lasts about five minutes. When using contrast, the time frame increases to 20 minutes. As soon as all the information is collected, the CT ring stops, the technician returns to the office and helps the patient to get up / get out of the straps.

No adaptation or recovery procedures after tomography are required. The patient can immediately return to the usual rhythm of life. The tomography results are given 30–60 minutes after the end of the diagnosis (the time frame may vary, depending on the workload of the medical staff).

The result of a CT scan is assessed by at least 2 specialists - a laboratory technician and diagnostic physician. The laboratory assistant gives an overall assessment of the condition of the foot, and the attending physician compares the information obtained with the current history. Based on the tomogram, a therapeutic course and specific recommendations for foot care are compiled. Follow medical instructions and stay healthy!

Watch the video: CT Computed Tomography Scan: What to expect (January 2020).