A few years ago, the abbreviation of CT and MRI by people far from medicine was perceived as something very scary and terrifying. Today, each of us knows that these studies are extremely important for making a correct diagnosis. We propose to go a little deeper into the essence of the work of these diagnostic methods and find out what is better - a CT scan or MRI of the brain.
Computer diagnostic capabilities
A CT scanner is essentially the same x-ray machine, but only an advanced one. But unlike the usual radiographs, the doctor receives not just a static photo of the brain, but sees on the screen an organ captured from each side and from a different viewing angle.
At the same time, a very dry assessment is supplemented with the necessary mathematical and statistical data, for example, the distance between the bones or the density of tissues. An additional function of a tomograph is the construction of a three-dimensional image of the brain, which is analyzed in detail layer by layer. Judging by what CT of the brain shows, the doctor can clarify the diagnosis and find the location of a particular problem.
Sometimes for this x-ray examination should be carried out with contrast. Thus, for the diagnosis of cerebral vascular diseases, iodine-containing drugs are injected intravenously into the human body. When a patient is placed in a CT scanner, the substance on the screen begins to glow, and thus it is possible to determine the location of blood clots or other vascular defects.
However, it should be understood that the radiation load on the body during CT is not lower than the X-ray diagnostics, and sometimes even higher, therefore, examination by this method is never prescribed to pregnant women. And if this introduces a special contrast, then doctors need to make sure additionally that the patient is not allergic to iodine.
MRI, in turn, is based on the action of the magnetic field and the properties of the hydrogen atoms that are part of our body. The operation of the magnetic field causes the hydrogen atoms to become active, allowing them to interact with the signals of the apparatus at different frequencies. Each atom has its own density and responds to these signals differently. It is these slightest fluctuations that the special detector picks up, after which the obtained data are processed and displayed on the screen. Then they are stored on electronic media and, if necessary, reproduced on film.
The procedure for magnetic resonance imaging is practically no different from computer diagnostics. The patient is placed on a special conveyor table, which drives into the tunnel of the scanning device. But at the same time, he is in it with his whole body, while with CT, only the diagnosable part falls into the device. This is the main, but not the only factor in how CT differs from MRI.
No special preparation for the procedure is required. The only thing that doctors strongly recommend is to remove all gold or silver jewelry and clothing with metal parts. Moreover, it is best to do this before entering a special room, as a strong magnet of the device can damage them. In addition, metal objects significantly affect the quality of the picture.
What is better - an MRI or CT scan of the brain and neck vessels cannot be answered unambiguously, since these are not always alternative or interchangeable methods of examination. Both methods are prescribed if you suspect the presence of such diseases, defects and pathologies, such as:
- cerebral hemorrhage;
- injury or contusion of the skull;
- hematomas of the soft tissue of the brain;
- disorders of the pituitary gland;
- the presence of foreign bodies;
- tumors and other neoplasms.
At the same time, the MRI will better see the organs themselves, which the skeleton carefully hides:
- internal organs of the lower abdomen;
- intervertebral discs;
- cerebrospinal fluid;
- articular parts of the skeleton.
In turn, the CT scanner will be much more effective when you need to investigate such parameters:
- the structure of the skeleton and the skull;
- the size, shape and location of blood vessels;
- foreign bodies, neoplasms or signs of infection.
It should be borne in mind that when diagnosing diseases of the brain, the significance of CT and MRI is equivalent. It is better to listen to the opinion of the attending physician who prescribed the procedure. Based on the data already available, the specialist will know better which of the methods will bring more additional information.
The choice between CT and MRI can be made conditionally when considering contraindications or the principle of operation of the apparatus. So, if a patient has a pacemaker, an insulin pump, and implants sewn into the leg or arm, it is forbidden to perform an MRI. And computed tomography is categorically contraindicated in such categories of persons:
- pregnant women;
- patients with diabetes;
- patients who have already undergone an x-ray a few months ago;
- nursing mothers, if the diagnosis requires the introduction of contrast.
To judge the safety of a diagnostic method is impossible. Of course, CT creates a radiation load on the body, but at the same time the work of the magnetic field itself is not fully understood.
To make a specific choice between CT and MRI can not, and even more so to require the doctor to conduct a specific diagnostic method. Of course, only a doctor can make a final decision based on certain indications. As a patient, your task is to help a specialist make the right choice: to provide reliable information about the presence of certain symptoms, point out contraindications and then follow the instructions clearly.