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Computed tomography of the thyroid gland is one of the most effective tools for recognizing diseases of this organ even in the early stages of development.
The gland itself is located on the front surface of the neck, opposite the laryngeal cartilage. It is rather problematic to visualize it using standard methods due to the peculiarities of the location, as well as the fact that the organ does not consist of bone tissue. Because of this, a conventional x-ray is not able to provide a detailed picture of the state of the organ.
The main task of the thyroid gland, which has the shape of a butterfly, is to secrete hormones necessary for normal functioning. As soon as its functionality goes astray, this affects the general well-being, including a sharp weight gain.
If, however, diseases of the gland are detected at the initial stage of development, then it will be possible to prevent negative consequences for the body and maintain health without significant complications.
Why do you need a CT scan?
The main hormones that iron produces are thyroxine (T4) and triiodothyronine (T3). They contribute to the successful metabolism of proteins, carbohydrates, fats and the process of glycogen breakdown. If the patient loses the rhythm of their production, then this results in increased excitability and increased heart rate, provoking many other deviations.
But if there are not enough hormones, this is also bad, since a person is diagnosed with developmental delay, which is especially serious for children and adolescents.
In addition, the thyroid gland produces thyrocalcitonin, which helps to cope with the distribution of calcium and phosphorus throughout the tissues. At the moment, it has been established that it is mainly a marker of tumor diseases of the thyroid gland, although it was previously believed that it takes an active part in calcium metabolism and is necessary for the proper formation of the bone skeleton.
Using an innovative research technique, which is a modernized X-ray irradiation, doctors can examine the structural changes in the thyroid gland and make a verdict on its condition in a couple of hours.
The standard ultrasound examination, to which sometimes doctors prefer to send patients to diagnose possible deviations, does not lose its relevance today. Unlike computed tomography, which is called CT for short, the results of ultrasound may be less informative regarding some points. Thanks to the CT technique, it is possible to visualize not only the organ itself, but also the tissues surrounding it, which makes it possible to assess the picture of changes on a larger scale.
You should not ignore the scheduled examination, since, in combination with blood tests for thyroid hormones, it will help to diagnose in time and prevent the further development of thyroid diseases such as thyrotoxicosis – excessive production of hormones due to various reasons, or, conversely, reduced hormonal activity – hypothyroidism.
Almost always, the reason for the change in the size of the gland is a problem with the supply of iodine. It is either not enough and the thyroid gland has to increase in size in order to have time to cover the deficiency of the mineral, or too much.
Such deviations will externally be expressed in the following symptoms:
- increased irritability;
- constant fatigue;
- muscle pain;
- dryness of the skin;
- delayed menstruation in women.
If a patient has at least a few signs from the list, and it is impossible to explain them in some way, then this is a reason to contact an endocrinologist to get a referral for a CT scan or ultrasound of the thyroid gland.
The technique helps to conduct a thorough assessment of not only possible morphological changes in tissues and organs, but at the same time clarify the diagnosis in case of suspicion of an erroneous verdict. The price of a tomography will be slightly higher than for a classic ultrasound, but the picture may turn out to be more detailed, which is especially important when searching for diseases at the initial stages of development.
Some people mistakenly believe that only those who are suspected of having a malignant neoplasm are sent to undergo such testing. But in fact, the list of ailments that the modern method is able to catch is much longer. These are both congenital anomalies and benign tumors.
Another stereotype associated with computer diagnostics is the opinion that it is harmful. In reality, the examination of the thyroid gland using such X-ray detectors is indeed slightly worse tolerated by the body than CT scans of other internal organs. But this does not mean that the technique is unsafe. Compared to X-rays, the harmfulness of radiation here is an order of magnitude lower, just the thyroid gland is the organ that is hypersensitive to radiation effects.
Tomographs are divided into two types: spiral and multispiral. They are similar to each other: a person lies down on a medical table, which is rolled into a tunnel with a scanner, and it starts to rotate around. In the second case, a larger number of rays is simply directed to the area chosen for study.
The procedures are identical in time, only with a multispiral study it turns out to visualize a more accurate picture. This is necessary for situations where it is required to additionally examine the condition of nearby blood vessels.
In addition to the size and structure of the thyroid gland, the examination is designed to provide information on:
- about the possible presence of neoplasms;
- about detected pathological nodes;
- about the state of the parathyroid glands;
- evaluation of the lymph nodes.
But often traditional approaches are not enough for a full-fledged detailed clinical picture. Therefore, the thyroid gland is more often examined with the involvement of an additional contrast phase.
How does a multispiral procedure with contrast work?
The onset of computed tomography remains the same for any variety, be it spiral or multispiral, supplemented by a contrast phase.
First, the patient is placed on a medical couch. Since he will have to be in a horizontal position for about ten to fifteen minutes motionless, in some cases the laboratory assistant suggests fixing his head with auxiliary straps.
Previously, the patient is asked to remove all jewelry and other things that contain metal elements. If the examination is carried out in the inpatient department of the hospital, then he will be offered to change into hospital pajamas at all. In private clinics, people are given disposable gowns.
With multi-scanning, the doctor will receive a detailed picture of the internal organ, which allows you to identify hidden congenital anomalies that cannot be detected by other alternative analyzes.
The information in the conclusion will affect the indicators:
- extent of inflammation;
- hearth depth.
Despite the increased cost of such testing, some diseases cannot be defined differently. And although CT is not able to track even significant fluctuations in hormonal levels, it perfectly monitors the overall dynamics. This is necessary to mark the progress in therapy at intermediate stages in order to confirm the correctness of the prescribed course of treatment.
An additional stage – contrasting is prescribed only by the attending physician on the basis of primary tests, as well as the current state of health, complaints and anamnesis.
If contrast is needed, then after the first phase, a special drug is injected intravenously into a person. To speed up the procedure, an automatic dispenser is used, which injects the agent into the cubital vein. The technique is called bolus.
But it is not suitable for all patients. Those patients who belong to the group of allergic people are at risk of worsening the condition. To exclude the chances of anaphylactic shock, the specialist must first clarify whether the ward has an allergic reaction to the components of the drug, and conduct an allergic test to identify a possible reaction to the drug.
Usually, iodine is taken as the basis of the contrast, and with some types of thyroid ailments, its increased content in the body can provoke an attack of deterioration in well-being even without allergies. Because of this, such patients are sometimes prescribed alternative drugs. They are also used for those people whose allergy test turned out to be positive.
Then the situation repeats itself:
- The person is laid on the couch and fixed with straps.
- Launch the scanner, which begins to rotate around the head. It will occasionally beep and click, but this is completely normal so don’t panic.
- The results of the projection are given either on the hands within an hour after the test, or sent the next day to the attending doctor.
Contrasting, despite the use of iodine, is considered more informative, if only because it determines even the slightest changes, nodules in the thyroid gland. He is able to detect minor pathologies of glandular tissues, which conventional multiscanning cannot provide.
You should prepare in advance for the fact that the introduction of the solution may be accompanied by various side effects. Within the framework of the norm, they are called:
- nausea;
- headache;
- metallic taste;
- temperature rise.
But usually all this passes in an hour or two.
Reasons for appointment
Usually, an endocrinologist sends an endocrinologist to the diagnostic room to check the thyroid gland. And first, he will offer the applicant to pass a series of classic tests like a general and biochemical blood test, as well as blood tests for hormones, in order to have precise grounds for serious suspicions.
Also, the following complaints from the victim testify in favor of the need to check the condition of this important organ:
- change of voice;
- problems with swallowing;
- sensation of a lump in the throat;
- squeezing the esophagus;
- swelling in the neck or salivary glands;
- pathology of the trachea;
- enlarged lymph nodes.
In some cases, two CT scans are required. This applies to situations where the picture is blurred due to random movement of the patient. Also, with rare anomalies, one has to return to the diagnostic room in order to cover the examination of nearby organs together with the thyroid gland itself and neighboring tissues. This will also help in order to exclude the spread of metastases when confirming a malignant disease.
A detailed projection based on multiple slice images helps to define the area of the lesion and further adjust the treatment program.
Ultrasound cannot always detect metastases.
Also, if necessary, the patient can be sent for an additional CT scan of the cervical vessels and MRI of the specified area. This is necessary to compile a comprehensive information picture.
The visualization itself is a black-and-white image, which clearly shows not only bones, as happens with X-rays, but also blood vessels and lymph nodes. The final image is obtained by adding up the set of layered tomograms received by the main computer.
They are obtained by scanning the selected area with beams of radioactive radiation. Moreover, each subsequent fixation will be done at a certain distance from the previous point of “photography”. The smallest step is 1 mm, which is typical for the most modern equipment models. But here it is worth considering the fact that the smaller the step, the longer you have to lie under the detectors. But the result will be with increased clarity.
The resulting projections are collected by the software application to line up in a three-dimensional spatial model. With its help, it turns out to highlight a holistic anatomical picture.
Ready visualized information on the thyroid gland gives an idea not only about its condition, but also about:
- possible damage to the cervical spine;
- lesions of the tissues of the cervical region;
- changes in the vascular structure;
- developing atherosclerosis;
- the presence of pathological nodes.
The same data determine the incorrect location of the gland itself. Most often, instead of the normal position in problem patients, its location is fixed in the retrosternal region.
Contraindications for appointment
All contraindications for the appointment of the procedure belong to the relative camp. This means that if the benefit of the test outweighs it, it is still carried out. But the final decision should still be made only by the attending physician, taking into account all the risks.
The only exception is pregnancy. Despite the minimal doses of radiation, sometimes they can adversely affect the development of the fetus. Because of this, doctors prefer to postpone the examination until the end of the pregnancy.
A little easier with the lactation period. If the procedure needs to be carried out immediately, then the woman must agree for the sake of her own health. And after the contrast manipulation, it is necessary to abandon breastfeeding for at least a couple of days. During the specified time, the components of the contrast agent will have time to be excreted naturally in the urine.
Other relative contraindications include:
- childhood;
- weight over 150 kg;
- claustrophobia.
You also need to understand that even doses of radiation that are safe for the body are still radiation. If in a short period of time several identical or similar analyzes are carried out at once with the involvement of radioactive impulses, then one should not be surprised at the deterioration in well-being. But here is one procedure as a control cut – a completely safe solution.
To get a really accurate result the first time, it is recommended to refuse food with a high content of iodine or preparations based on them for some time before the procedure. But first, you still need to consult with a treating specialist on a given issue. Otherwise, the interrupted course of treatment will not be worth such sacrifices.
But to control the absence of the use of iodine from the outside is quite within the power of the patient himself. Various iodine nets, which are still used by people of the old school for the speedy healing of injection sites, should be excluded in advance.
Deciphering norms and deviations
Usually the attending doctor himself will decipher the conclusion of the diagnostician to the patient. But sometimes the results are given to the patient in his hands, and he hurries to deal with him on his own, waiting for his turn for an appointment in the corridor.
The normal state is called a homogeneous parenchyma. In this case, the transverse size of both lobes should be about three centimeters, and the anterior-posterior indicator should vary from 1 cm to 2 cm. The average statistical parameters for the upper-lower size are 4-7 cm.
If an adult undergoes a CT scan, then for him the normal volume of the thyroid gland should fit into a radius of 18 to 25 cubic centimeters. For children, the requirements are reduced and are calculated for each year of life individually.
But even the most high-precision tomography should not become the only type of examination for making a diagnosis. An experienced doctor is obliged to take note of the old data from the medical record, complaints of the ward and other related test results.