CT scan of the sinuses
CT nose and paranasal sinuses is a noninvasive examination method that enables the diagnosis of many diseases of this localization. Formed on the screen of the image is due to the different penetrating ability of the tissues with respect to x-rays. A series of images taken in parallel planes but at different levels, enables the physician to obtain the most complete picture of the nature of the pathological process.
Indications for diagnostic
CT nose and paranasal sinuses is performed for certain indications (they carefully weigh and since the method is associated with radiation exposure). These include:
CT scan of nose and sinuses do not in the following cases:
- pregnancy (MSv is quite high and therefore may cause the development of abnormalities in the fetus);
- allergic reactions to iodine-containing medications used in CT with contrast (taken into account any allergies and intolerance);
- children’s age (computed x-ray examination of can be done from 14 years of age);
- obesity patient (body weight greater than 150 kg);
- fear of closed spaces.
Safety and radiation exposure on human
Performing a CT scan of the nose and sinuses associated with a certain degree of radiation. It is measured in millisieverts (mSv). This dose is different depending on which area is examined. So, as a person gets when mSv CT scan of the nose and paranasal sinuses?
In the study of the head and its structures, the radiation dose is about 2 mSv. If it’s the neck, the load is 3 mSv, the abdomen is 10 mSv, etc.
The question arises, how many mSv for man are acceptable? Scientists determined that in the year people can get up to 150 mSv. It also includes the radiation exposure that is emitted by the rays from space, a man constantly receives it.
If you compare the x-ray and CT scan, the load from computed tomography more. When x-ray study is performed from 1 to 3 shots. CT always involves a series of scans that take place at different levels. Therefore, the minimum number of shots is 5, maximum – 15. With this data, just to calculate how much radiation a person receives when he make a computer tomography of the nose and paranasal sinuses, based on x-ray radiation. The radiation dose in this case will be from 10 to 30 mSv. In this regard, CT is not often possible to do, for example, to assess the dynamics of pathological process. To solve this problem, the patient receives target x-ray or MRI depending on the indications.
The efficacy and diagnostic value
Computed tomography of nose and paranasal sinuses shows signs of the following diseases:
- sinusitis – inflammation of the maxillary (maxillary) sinuses;
- sphenoidal inflammation of the sinus, which is located in the thickness of the sphenoid bone;
- etmoidit — inflammation of the ethmoid sinuses;
- sinusitis – inflammation of the frontal sinus;
- geocenosis – accumulation of blood in the sinuses that is most often associated with their injury;
- injuries of the facial skull;
- various anomalies of the maxillofacial region.
Computed tomography of the nose and sinuses shows the following anatomical structures and their mutual arrangement:
- sinus wall;
- nasal septum;
- the bones of the nose;
- of the orbit;
- some parts of the brain;
- upper jaw.
The preparation of the study and its description
Imaging of the nasal bones and paranasal sinuses do without special training. However, there are some nuances that will be described in the form of questions.
- How to study you cannot eat? The minimum time is 3 hours.
- How to study last time to use the liquid? 3 hours.
- How long is the scan? Normally, the study of the maxillary sinus and other paranasal sinuses is half an hour.
- How goes the research? Man was placed on a special table-a couch, which moves relative to the scanner. At this time, the emitted x-ray beams, which produce a scan of a layer.
- How much time is required to reach a conclusion? Usually the result is given on the same day, after analyzing the images is a radiologist.
The disadvantages of the method
If you notice signs of plus tissue of the maxillary (maxillary) sinuses sinuses or other required MRI. Magnetic resonance imaging allows to distinguish the malignant tumors from the polyps, as it uses the electromagnetic field, not x-rays. This gives a good opportunity to consider the nature of the abnormal tissue, allowing you to establish an accurate diagnosis.
Basic rule – if the CT showed something different from simple anatomical education, there is shown an MRI so as to detect tumors in x-rays is not very informative.
Consider the informative value of CT for the diagnosis of sphenoiditis – as one of the most difficult to detect diseases. Often this pathology is clinically includes the following symptoms:
- pus from the nose (this is not a pathognomonic symptom of sphenoiditis, it can be observed for other ENT-diseases, for example, inflammation of maxillary sinus);
- pain in the parietal area (more specific sphenoiditis);
- often when sphenoiditis suffers from the sense of smell (to detect this symptom can bring different flavors to the nose, a man is not defined);
- diplopia, that is, the dichotomy of visual images (if sphenoidale not always defined);
- fever is characteristic of the acute sphenoiditis.
Steroidit can be definitively diagnosed only after a series of x-ray images with their subsequent computer analysis. Taken into account the following characteristics:
- the blurred outlines of the sphenoid sinus;
- the presence of a determined fluid level;
- the reduction in the airiness of the sinus.