Computed tomography (CT tomography ), X-ray - Causes, Symptoms and Treatment .MF .
Computed tomography (CT) - a modern method of beam diagnostics, allowing to obtain layer-image of any human field slice thickness from 0.5mm to 10mm, to assess the state of the studied organ and tissue localization and prevalence of pathological process.
operating principle of the X-ray CT based on circumferential transillumination study area with a thin beam of x-rays perpendicular to the axis of the body, registration attenuated radiation from the opposite side of the detector system and converting it into electrical signals: passing through a human body, the X-rays are absorbed by different tissues in varying degrees.Then the X-rays hit a special sensitivity matrix, the data which are read computer.MRI provides a clear picture of several body sections and the computer processes the images in very high quality three-dimensional, three-dimensional image, which allows you to see in detail the topography of the organs of the patient, location, extent and nature of the disease foci, their relationshi
discovery of X-ray computed tomography (CT) gave impetus to the development of all digital fibrewise research techniques: magnetic resonance imaging (MRI), single photon emission (radionuclide), computed tomography (SPECT), positron emission (PET), computed tomography, digital radiography.Computed tomography (CT) today - stantarny leading method of diagnosis of many diseases of the brain, spine and spinal cord, lungs and mediastinum, liver, kidney, pancreas, adrenal, aorta and pulmonary artery, and several other organs.Usually
" X-ray computed tomography " is simply called " CT ".
Advantages computed tomography (CT)
advantages of X-ray computed tomography (CT):
- high tissue resolution - to evaluate the change of the radiation attenuation coefficient in the range of 0.5% (in conventional radiography - 10-20%);
- no imposition of organs and tissues - no closed areas;
- allows us to estimate the ratio of organ study area
- software package for processing the received digital image allows you to get more information.
harm computed tomography (CT)
There is always a small risk of developing cancer from excessive exposure.However, the possibility of an accurate diagnosis outweighs the minimal risk.
effective load beam computed tomography (CT) is from 2 to 10 mSv, which is the same, which, on average, a person receives from background radiation in 3-5 years.Women should always inform your doctor or radiologist, if there is any possibility that they are pregnant.Computed tomography (CT study), in general, are not recommended for pregnant women because of the potential risk to the child.
Lactating mothers after contrast injection should take a break from breastfeeding within 24 hours.
risk of a serious allergic reaction to contrast materials that contain iodine is extremely rare.But the radiology department are well-equipped to deal with them.
Because children are more sensitive to radiation, then assign a computer tomography (CT study) children can be used only when absolutely necessary.
absolute contraindications to the computed tomography (CT) is not.Relative contraindications to computed tomography (CT) scan: pregnancy and the younger children's age, which is associated with radiation exposure.
Indications for computed tomography (CT) determined by the attending physician in conjunction with a physician-radiologist conducting the study.The study of internal organs on the screening program (preclinical detection of latent diseases) can take place without the direction of the treating physician.In this case, the radiologist determines contraindications, if any.
In some cases, a CT scan is performed
Computer tomography do now more and more often.This method is non-invasive (no surgery, safe and is used in many diseases can be studied virtually any body using computed tomography -.. From the brain to the bone often CT scans are used to clarify the abnormalities detected by other methods for example in the sinus, a deviated septum.often first make a radiography of the paranasal sinuses, and then to refine the diagnosis - conducted a CT scan of the nose and paranasal sinuses
Unlike conventional x-rays, which are best seen bones and pneumatic structures (light), computed tomography (CT) is excellent.visible and soft tissues (brain, liver, etc.), it makes it possible to diagnose the disease in its early stages, for example, detect the tumor while it is still small size and amenable to surgical treatment.
With the advent of spiral and multislice CT scanners have the opportunity to carry outCT scans of the heart, blood vessels, bronchi, intestines.
Computed tomography (CT) is used in dentistry for detailed research and accurate diagnosis of dentition and departments of the maxillofacial region, and is necessary when planning surgical interventions for the treatment of dental and dental implantation operations.High resolution and contrast computed tomography versus conventional X-rays make this method is the most valuable and highly informative in dentistry.
How is the procedure of computer tomography (CT)
In preparation for X-ray computed tomography (CT) is recommended approximately four hours prior to the study to stop the use of food and water (if you want to take medicine, you can drink a small amount of water).
Computed tomography takes time span of 15-20 minutes per study area.In preparation for the doctor gives some recommendations which will make a survey of the most effective and informative.
Computed tomography (CT) scan is performed in the supine position.You will be positioned on a movable table for study, which moves through the tunnel.Straps and pillows may be used to help you preserve and maintain the correct position during computed tomography (CT).
images by computed tomography (CT) is obtained by rotating a narrow X-ray beam and the sensor system, arranged in a circle, called the gantry.Computer station that processes the image, is located in a separate room, where the technologist operates the scanner and monitors the progress of the study.
If carried out a study of the abdominal cavity and small pelvis, the patient is advised to take a contrast agent under the special scheme.Drip installed in the cubital vein, for a contrast agent administered indications.Recommended during the tomographic study lie still, in some cases, the doctor may be asked to hold your breath for a few seconds.Any movement - breathing or body movements, can lead to defects in the CT scans.These defects are like blurred photographs, which can be obtained when shooting a moving subject.
For CT studies table moves, creating conditions for a better scan of organs and systems.New modification tomography, spiral computed tomography (CT), gives the opportunity to explore the anatomy of a period of delay of breath and a step change in the subsequent reconstruction of the data processing.You will be alone in the room during a computed tomography (CT).However, the technologist or radiologist will see, hear and speak with you during the entire study.When computed tomography (CT) may allow parents of children in special lead apron, present in the room where the study is conducted.
Then you can go back to their normal way of life computed tomography (CT).If you injected contrast material, you will be given specific recommendations.The results will be sent to your doctor for further examination, diagnosis and staging of drawing up a treatment plan.The procedure for computing the X-ray and magnetic resonance imaging painless, minimally invasive.
CT scan is painless.The only drawback - the need to lie without moving from a few minutes to half an hour.Some patients (children, excited patients) can not do this, then they are administered sedatives.Computed tomography (CT) is considered to be a safe method.The dose of X-rays is relatively small.There is also a very small risk, if you want the introduction of soothing drugs and contrast agents.Patients should tell your doctor, if they have allergies to medications, iodine, seafood, if he suffers from diabetes, asthma, heart disease and thyroid.
Computed tomography (CT) is contraindicated in pregnancy.Especially in the first trimester of pregnancy.In the rare case when the CT can not do without (for serious injury, for example), it still do, but cover the lead shield the uterus as possible.If you are pregnant, be sure to tell the doctor conducting the scan.
MRI study in contrast to the X-ray computed tomography (CT) is completely harmless.Unlike other methods have no MRI radiation (X-ray) hazard.However, there are some contraindications to its implementation.First of all, this applies to patients who are implanted pacemaker, ferromagnetic implants and / or grafts, and patients weighing more than 130 kg.
results computed tomography (CT)
In the process of computed tomography (CT) will get a detailed image of the examined organ.The radiologist who trained implementation and interpretation of radiological examinations, will analyze the acquired images and sends the results to your doctor.Your doctor will inform you about the results.
main symptoms of diseases revealed by computed tomography.
signs of the disease, detected by computed tomography, are different depending on the organs that are investigated.Thus, when examination of the liver, spleen, pancreas, the main features of the defeat of these bodies are the heterogeneity of structure, the presence of pockets of change, their number, size, location.Changing contours of organs, they become irregular, fuzzy, bumpy.Some combination of these features allows for liver with high confidence to recognize the smallest tumor size, cysts, abscesses.Computed tomography helps with high confidence to diagnose fatty liver.Stones with a diameter of 1 mm are clearly defined in the study of the gall bladder.Computed tomography is a leading method for the detection of pancreatic diseases such as chronic pancreatitis and cancer of the body.If brain research has major importance increase or decrease in brain tissue density.Reducing density in restricted areas characteristic of infarcts, cysts, abscesses.Increased density observed in fresh hemorrhage.Well recognized focal and diffuse brain changes in inflammatory diseases, developmental disabilities, brain injury.Clearly recorded brain changes, developing as a result of the processes that lead to a reduction in brain tissue volume (Huntington's chorea, Wilson's disease, Pick's disease, Alzheimer's).
Spiral X-ray computed tomography (CT)
In the conventional X-ray computed tomography (CT) scan creates a single image of a single layer, the scan cycle is repeated after the next move of the table as many times as necessary to get the image of bundle.The TCS provides continuous motion around the tube at the investigated area promoting uniform parallel with the patient table in the longitudinal direction.X-ray tube movement trajectory to the longitudinal axis of the test object takes the form of a spiral.
Fast rotation emitting tube, no interval between the emission cycles to advance to the next position of the table significantly reduce the time of the study.This facilitates the study of patients who can not hold their breath for a long time, long time to be in the unit (trauma patients, patients in serious condition, sick children), and also increases the capacity of rooms.
High-speed scanning produces sharper images with less artifacts from the physiological movements.New technology has also improved the quality of the image moving organs of the chest, the abdominal cavity.Reduced exposure time makes the method of spiral computed tomography (CT) is safer for patients.When helical computed tomography (CT) scans the entire object, which allows to obtain an image of any fixed layer of the scanned volume.Spiral computed tomography (CT), which allows to explore all the given object at a single breath-hold, eliminates the possibility of release ( "escape") pathological focus of the scanned layer that provides better detection of small focal lesions in parenchymal organs.
Helical CT - angiography - the latest achievement of the X-ray computed tomography.In contrast to conventional computed tomography (CT), a study conducted at the time of intravenous administration of the water soluble nonionic contrast agents.The contrast agent is injected into the vein without complicated surgical procedures related to the intra-arterial catheter to the test body.This makes it possible to conduct research on an outpatient basis for 40-50 minutes and eliminate the risk of complications from surgical procedures.Sharply reduced radiation exposure to the patient, and significantly reduces the cost of the study. CT - Angiography completely replaces screening (diagnostic) angiography and vastly superior US - research vessels.
MSCT (multislice computed tomography) with two sources of X-rays - a new kind of computer tomography , which allows to carry out research at a high speed and high spatial resolution (0.5 mm) and small movingstructures such as the coronary artery.
multislice computed tomography method allows you to quickly assess the health center in a state of the coronary arteries in patients with various diseases of the cardiovascular system, including after surgical interventions on the heart vessels (stenting and bypass surgery), with the identification of the level and degree of narrowing of the lumen of blood vessels.The quality of the images is not dependent on the heart rate, and therefore, do not need to take additional medication during the preparation of the study.A study carried out with the introduction of a non-ionic iodinated contrast agent into a vein.
survey carried out in two phases - before the administration of contrast medium (estimated degree of calcification of the coronary arteries) and during the administration of contrast medium (estimates lumen of the coronary arteries, the degree of damage the walls of the coronary arteries, stent patency and functionality shunts).
method multislice CT has practically no contraindications.The limitation for the study is the presence of allergy to iodinated contrast.
advantages of multislice CT scanners over conventional spiral CT:
- improved temporal resolution;
- improved spatial resolution along the longitudinal axis z;
- increase in scanning speed;
- improved contrast resolution;
- increase the signal / noise ratio;