Most of the disorders are diagnosed by X-ray. The technique has found its true purpose in many branches of medicine. Sometimes, due to relatively low sensitivity, radiography is not able to detect signs of the disease, often they are not enough.
Therefore, patients are often referred for tomography. It is all about the same x-ray method. But spend it on more advanced equipment. The complex structure of the device includes several conventional ray tubes, special sensitive sensors and a computer monitor, where direct data processing is carried out, and ready-made images of the structures of the studied area are created.
In addition, according to the pictures of the affected area, it is possible to study the knee, ankle structures as thoroughly as possible.
This is a highly accurate diagnostic technique. It allows you to see layers of the body on the X-ray images. The procedure is ideal for diagnosing inflammatory, tumor, destructive processes, injuries, foreign bodies. In particular, the technique perfectly visualizes the bones of the leg. This determines the popularity of the method for examining this part of the body.
CT scan is more suitable for examining bone elements. If you need to inspect additional soft tissue - the technique is complemented by contrast enhancement. Such a solution allows to get clearer, high-quality images of loose elements.
Often CT is the only method of examination that allows you to make an accurate diagnosis. Regular x-ray allows you to see only the superficial part of the bone, CT gives the opportunity to consider pathological changes throughout the thickness of the bones. The procedure eliminates any kind of inaccuracy due to an incorrectly selected projection.
Today, the technique is a leader in the accuracy of detecting pathological changes in bones. The principle of operation is based on all the same x-rays. They pass through the fabric, shining through them. The intensity of the image depends on the density of the structures. So, the denser the elements studied, the longer the rays stay in them, and the brighter they are in the pictures. That is why the bone structures, salt deposits have a whitish color, and empty areas, liquid structures - black. Physical capabilities of CT are required in cases with fractures and bone diseases. If the lower limb is injured with the likelihood of muscle damage or ligament rupture, then it is better to use in the diagnosis of MRI.
Indications for CT
Mostly diagnostics prescribed for:
- severe arthritis of the articular elements;
- to control the degree of bone accretion after a fracture;
- for planning further implants;
- abnormal bone development;
- suspected myeloma
Despite the harmlessness of the procedure, a survey of such a plan is carried out in children only after 14 years. It is better to avoid the adverse effects of radiation on the physical health of children.
Features of the procedure
The technique is absolutely painless, not accompanied by discomfort. When the slightest sign of discomfort appears, there is a constant two-way communication with the technologist. According to the rules in the office, the patient is left alone. Control over the process is carried out through the glass from the neighboring room.
Scanning takes place in the supine position of the patient in the annular part of the apparatus. During the procedure, the table on which the patient is located moves somewhat. In this case, the patient must be motionless. This is the key to image clarity.
Contrast enhancement technique
Contrast is a special iodine substance. It is necessary for maximum clarity of visualization of the examined elements. Injected parenterally a few minutes before diagnosis. Owns neutrality, low toxicity on the body. Therefore, no effect on the patient's condition.
In the lower leg, neoplasms are much more common. Therefore, due to contrasting, it is possible to more clearly and accurately visualize any kind of structural changes.
When injected into the bloodstream, the contrasting element stains the blood vessels, gradually accumulating in them. This allows a closer look at the area under study. So, it is those areas that have enhanced blood flow and a dense network of blood vessels that are best visualized. We are talking about inflammatory elements, malignant neoplasms. The dosage of the contrast element is always selected individually. It all depends on the age and weight of the patient. The substance is removed for several days.
Contraindications for examination
The technique is based on x-ray irradiation. But this does not prevent repeating it repeatedly. The load on the body of radiation is minimal, so there will be no harm from the procedure. CT scan is entirely safe if there are no contraindications for it. The main of them include severe pain, which is accompanied by disruptions of motor reflexes. In this case, there may be an obstacle to the preservation of immobility. It is strictly forbidden to perform CT at all stages of pregnancy. Rays can have an unpredictable effect on the intrauterine development of the baby.
The device according to its technical characteristics is not able to diagnose patients weighing more than 180-200 kg.
In the case of contrast, contraindications increase. The procedure is not performed in the presence of renal failure. After all, problems with the allocation of delayed contrast element in the body. This provokes severe poisoning. Contrasting cannot be used if there is any kind of non-perception of the iodine element. Allergy sufferers should take the same procedure as a precaution. The study is not intended for patients with severe thyroid disease.
Lactation is a serious contraindication for contrast CT. The fact is that the iodine element easily penetrates into breast milk and is capable of harming the baby. In extreme cases, if necessary, the procedure is carried out, but the woman refuses breastfeeding for the next 48 hours.
Preparation for diagnostics
The study is carried out exclusively in the direction. Therefore, each patient should have with him a medical referral, an extract from the ambulatory card, the results of previous studies. For conventional CT training is not required.
If necessary, a contrast examination, before the procedure, it is important not to eat at least 6 hours.
All received images are processed and evaluated by a special program under medical supervision. This treatment is often not more than a quarter of an hour. The patient on his hands receives several large images and their detailed decoding.
It is important to show the results to the doctor or specialist, whose work is associated with the identified pathology. Only by bringing together all the studies and evaluating the clinical picture, the doctor makes a final diagnosis.