MRI of the pituitary: evidence, preparation, how to do, normal results
The diagnostic radial method, to which magnetic resonance imaging belongs, is one of the most informative methods for determining even small changes in the structure of tissues. Often to determine the pathology visually or with the help of X-ray research is not possible - for example, in cases of abnormalities in the pituitary gland. In this situation, doctors resort to the help of tomography: MRI of the pituitary gland will allow to specify the problem and even find its cause.
What is the MRI of the pituitary gland?
The procedure of MRI of the pituitary gland is a diagnostic technique that helps to detect all kinds of large and small painful formations, with localization in the pituitary zone:
- birth defects;
- tumor processes;
- cystic formations;
- changes in blood vessels;
- inflammatory processes in the ligament of the hypothalamus-pituitary.
During the usual procedure of MRI of the brain, the assessment of the area of the Turkish saddle is simultaneously carried out. However, often the information obtained during the research may not be enough. For example, if it is necessary to diagnose a painful area at the initial stage of the development of pathology and to evaluate structural changes, an additional MRT of the pituitary gland is performed. At the same time, the area of the Turkish saddle is scanned, sometimes with the use of contrast.
In order to obtain a clear and clear image, apply a voltage in the tomographic apparatus of at least 1.5 Tesla.
Indications for the procedure
The procedure for MRI of the pituitary gland can be performed already at the first suspicion of the presence of painful processes in this area. In general, MRI is prescribed in almost all disorders of brain function.
In most cases, the procedure of the pituitary MRT is relevant for the suspected adenoma of this organ, and especially if such a tumor progresses rapidly. Pituitary adenoma is one of the types of benign neoplasms that develops from glandular cells. Adenoma is considered quite a dangerous disease, which can lead to the development of severe brain pathologies. Nevertheless, MRI of the pituitary gland is carried out not only with adenoma.
Indications for the study can be:
- suspected Cushing's syndrome;
- unidentified cause of hyperactivity of certain hormones;
- increased release of prolactin;
- other disorders of the endocrine system in the body;
- unidentified cause of migraine, constant pain in the head;
- increasing functional disorders of the brain;
- sharp deterioration of vision for no apparent reason;
- unidentified causes of the malfunction in the menstrual cycle in women;
- cardinal causeless weight jumps (the patient rapidly loses weight, or vice versa - abruptly gets better);
- Unidentified cause of erectile dysfunction in men;
- alleged impaired function of the pituitary gland (the phenomenon of gigantism or dwarfism).
MRI of the pituitary gland with increased prolactin
Pathological causes that affect the increased release of prolactin into the blood are:
- tumor process (pituitary adenoma);
- pressure on the pituitary gland (SPTS - a syndrome of invagination of the subarachnoid space into the intrasellar region, insufficiency of the diaphragm of the Turkish saddle);
- Hypothalamic disease due to CNS disorder;
- primary hypothyroidism;
- long-term chronic pathologies in the body.
In order to pinpoint the cause of increased prolactin secretion, it is often the MRI of the pituitary gland that is primarily used because benign prolactinoma is considered the most common and at the same time the most dangerous cause of this phenomenon. Prolactin is a hormone produced by the anterior pituitary gland. Therefore, the violation of its production is first associated with a dysfunction of the pituitary system.
Preparation
- The patient should warn the doctor in a timely manner that he has implants of teeth, joints, IV, artificial heart valves, stimulants and other devices, as well as elements of piercing, which can interfere with MRI of the pituitary gland.
- If a pituitary MR is performed without contrast, the patient does not need to undergo any specific preparation for the examination. It is only necessary to observe the general rules of preparation for MRI of the pituitary: remove the outer clothing and all the accessories from the metal.
- If an MRI of the pituitary gland is to be performed with contrast, then the procedure should not be taken at least 5-6 hours before the procedure. If the patient is allergic to any medication, then before the introduction of a contrast agent, he must necessarily inform the doctor about it.
- Pregnant patients with pituitary MR imaging are prescribed only in extreme cases, and in the first trimester such a procedure is not performed at all.
- If the patient suffers from claustrophobia or any psychic abnormalities, the pituitary MRT is preferable to be performed on an open device, or to prescribe sedatives as prescribed by the doctor.
- If it is necessary to carry out an MRI of the pituitary gland to a child, then this procedure can be prescribed from the age of 5. The fact that the child during the procedure can be rotated, which will significantly affect the quality of images.
The device for carrying out the procedure
What should I look for when choosing a device for MRI of the pituitary gland?
- The tomograph should be powerful enough - preferably 1-1,5 Tesla, not less. The fact is that less powerful tomographs can not provide information on formations with dimensions up to 5 mm.
- The more power the device, the faster the MRI procedure is.
- Some super-powerful devices can evaluate vascular disorders without using contrast.
- The MRI device should be able to evaluate not only structural, but also functional changes in the brain.
- The device is open or closed type. The open version is used to diagnose the pituitary gland in children, patients with obesity or claustrophobia, in patients with mental disorders. For other cases, the closed variant is preferable, since it provides improved image quality and better recognizes pathological inclusions.
When choosing a quality apparatus for MRI of the pituitary gland, it is necessary to pay special attention to the prescription of the use of a tomograph and to the manufacturer's brand. The best brands are rightly recognized as Siemens, Philips and some other well-known brands.
Technique of the mRI of the pituitary gland
During the MRI of the pituitary gland the patient is lying down, face up. To ensure complete immobility of the patient, his head is fixed by means of specially designed fasteners - this is necessary to obtain a clear and qualitative MRI image.
The surface with the patient lying on it is loaded into the capsule of the tomograph, while the magnetic frame should be at the site of the projection of the investigated area.
During the procedure, the patient is completely alone: the doctor performs manipulations behind the wall, in front of the monitor, but can talk to the subject through a "hands-free" connection. If the diagnosis is carried out by the child, it is allowed to simultaneously find in the immediate vicinity of one of the relatives.
The procedure of MRI of the pituitary gland can last an average of 45 minutes. However, this time can vary, depending on the number of required images, the class of the device, and also whether the contrast gain was applied.
MRI of the pituitary gland with contrast
The doctor can make images obtained with MRI of the pituitary gland more informative if he uses the introduction of contrast - a special substance that is injected into the circulatory system by injection. What does it give? When contrasting, the substance injected into the bloodstream allows the doctor to visualize the entire vascular network at the desired site. Practically in all cases, this makes it possible to assess the location and size of the lesion, to determine the presence of a connection with nearby organs, and to determine the intensity of the blood flow.
MRI of the pituitary gland with contrast is often prescribed to patients who are undergoing surgery to remove tumor formations in this part of the brain. Contrast substance accumulates in areas with increased blood supply - for example, in tissues in which the tumor process is actively developing. As a result, the necessary visual contrast is created, which makes it possible to see a tumor even of a small size.
Of the most common contrast substances, one can name preparations based on gadolinium salts (Magnevist, Omniskan and others), less often - mainly with CT, iodine preparations (Omnipak, Hexabrix, etc.) are used.
MRI of the pituitary gland without contrast or contrast?
The doctor can prescribe to the patient a simple procedure for the pituitary MRT, or MRI using contrast enhancement. As a rule, paramagnetic substances are used for this, which are introduced by intravenous injection immediately before the procedure. The amount of the drug administered is determined individually, based on the weight of the patient.
Is it necessary to use contrast enhancement? This is determined on an individual basis. If you want to define clear boundaries of the tumor, its structure, the state of healthy tissue near the tumor, then the use of contrasting is fully justified. Most often, contrast is used in patients who are being prepared for an operation to remove tumors of the pituitary gland.
MRI of the pituitary gland of the Turkish saddle
During the MRI of the pituitary gland, the doctor must differentiate pathological foci, given their location. If the pathological inclusion is located in the area of the Turkish saddle, then the adenoma of the pituitary gland can be diagnosed, and for localization over the saddle, craniopharyngioma, meningioma, astrocytoma, aneurysm.
Also, the "empty Turkish saddle" syndrome, which is characterized by a defect in the diaphragm and degenerative changes in the pituitary gland, can be identified.
The listed diseases are considered very serious. They manifest themselves by such symptoms as severe persistent headaches, thyroid dysfunction, adrenal and cardiac disorders, and autonomic nervous system failures.
No other type of study will allow to obtain such information about the disease, which is provided by the MRI of the pituitary gland. Therefore, if there are indications for the procedure, then do not delay. Even if any pathologies are found, the chances of recovery are always very high.
MRI of the pituitary gland to the child
If a doctor prescribes a pituitary MRT to a child, it usually does not occur before 5-6 years of age. To obtain a high-quality image from a tomograph, the patient should remain stationary while inside the device. Provide a steady state to a small child is very difficult. In addition, he may be frightened while in an enclosed space.
To avoid these difficulties, children can use an open access device to carry out MRI. However, even with such an investigation, the child should be as immovable as possible.
Often, when examining children to parents or other close people, the baby is offered to be present during the procedure. To do this, the person who will be next to the child must remove all metal accessories and clothing from himself.
If the child is restless or moody, then in some cases, before the procedure, it is recommended that special sedatives be introduced to calm the baby and ensure the normal quality of the pictures.
Contraindications to the procedure
The procedure of MRI of the pituitary gland is considered quite safe for human health. However, this diagnostic method also has a number of contraindications.
- Absolute (weighty) contraindications:
- presence in the patient's body of metal implants;
- presence of non-removable pacemakers or an insulin device (pump);
- presence of ferrimagnetic implants.
- Relative contraindications, the presence of which is discussed with the doctor:
- presence of nonmetallic implants in the body;
- presence of stimulants of the nervous system;
- insufficiency of cardiac activity;
- Critically large body weight;
- episodes of claustrophobia and panic attacks, mental illness.
It is also not recommended to carry out an MRI of the pituitary gland to pregnant women, especially in the first months of pregnancy.
Normal performance
In a normal healthy person, the pituitary gland has a rectangular configuration (if the diagnosis is carried out from the front view). The lower borders are similar to the outlines of the Turkish saddle (therefore this part is called respectively). The upper edge can be either horizontal, or convex, or slightly concave - all of the above options are normal.
The image of the body should clearly differ in the sagittal plane. On the frontal plane, the organ has a symmetrical shape.
The pituitary gland is a very small structural formation. Its mass is no more than 1 g. The pituitary gland is referred to the glandular organs, since it produces hormones: this process is controlled by releasing factors of the hypothalamus.
On tomographic images, the normal height of the pituitary gland is no more than eight millimeters, but the sex and age norms of the pituitary gland according to MRI may differ. For example, in women of childbearing age, the height of the organ can vary from 9 to 10 mm - this is especially noticeable in the slightly elevated diaphragm of the saddle. During pregnancy, the diaphragm rises even higher, so the height can increase to 10-12 mm.
The size of the pituitary gland on an MRI:
- width from 3 to 10 mm;
- length from 5 to 8 mm;
- height from 3 to 8 mm.
These indicators are individual and variable, since fluctuations in size can be observed during periods of active sexual development, during pregnancy or in childhood.
It is also believed that with a microadenoma, any of the dimensions of the pituitary gland should not be higher than 10 mm - larger dimensions indicate a macroadenoma.
Pituitary tumor on MRI
During the procedure of MRI of the pituitary gland, the doctor should notice any pathological formations, and also fix their location and dynamics of growth.
As a rule, the main signs of tumor processes are:
- heterogeneous structure of tissues;
- asymmetrical outlines of the organ and its convexity.
- The adenoma of the pituitary gland on MRI is a benign formation that grows from the pituitary cells. The tumor can have dimensions up to 10 mm or more than 10 mm. In the first case, they speak of a microadenoma, and in the second case, a macroadenoma of the pituitary gland.
Macro-adenoma can manifest hormonal activity, have a rounded and denser capsular membrane. Most often, the macroadenoma is prolactin.
Microadenoma of the pituitary gland on MRI is devoid of distinct outlines and capsules. Therefore, its presence can be guessed by the convexity of the diaphragm of the saddle, or by the beveled leg of the organ.
- The pituitary cyst MRI looks like a round shaped formation in the area of the Turkish saddle. There is rarely a lack of intensive blood flow. In order to determine the affiliation of such a tumor, it is recommended to perform MRI with contrast. In this malignant formation will accumulate a marker in the tissues.
- Adenocarcinoma of the pituitary gland on MRI has a glandular structure and is most often found in the anterior lobe, or adenohypophysis. Such a tumor is characterized by rapid infiltrative growth and rapid damage to the organ and nearby tissues. Adenocarcinoma is able to rapidly spread metastases, both hematogenous and lymphogenous.
Often, adenocarcinomas are formed from the hormone-active pituitary adenoma.
- The heterogeneous structure of the pituitary gland on MRI means different reflective abilities of the organ tissues. This happens with additional pathological inclusions in the structure of the gland - it can be adenomas, cysts, tumor processes. That is, heterogeneity indicates the presence of separate densified sections of the gland tissues.
MRI picture of the additional inclusion of the left lobe of the pituitary gland, as well as the right one, may be different, depending on the nature of this inclusion. For example, the main sign of tumor formation in the pituitary gland is the detection of inclusions of high and low density, in T1 and T2 regimens in the projection of the pituitary gland. If a small size of the adenoma is found, considerable importance is attached to specific indirect signs: displacement of the diaphragm of the saddle upwards, deformation of the pituitary funnel,
Dental implants and MRI of the pituitary gland
Any patient who is sent to the procedure of a pituitary MRT is going through, so that the results of the diagnosis are clear and informative. Therefore, it is very important to warn the doctor about any nuances that may interfere with the qualitative diagnosis.
Indeed, metal implants are a contraindication for carrying out this study. But: if dental prostheses are made according to the latest technologies, from a modern dental material - not from metal, then carrying out an MRI of the pituitary gland is quite possible. Before the diagnostic procedure begins, the patient should warn the doctor about the presence of the prosthesis, and also provide him with X-ray pictures: the doctor should clearly represent the location of the implants, because on this basis he can adjust the device accordingly.
Complications after the procedure
The procedure of MRI of the pituitary gland is considered absolutely painless and harmless. However, some patients note individual symptoms, which are often associated with the passage of magnetic resonance imaging:
- nausea;
- weakness;
- dizziness;
- headache;
- palpitation;
- a feeling of anxiety and anxiety.
However, to date, there is no direct evidence that these symptoms have any connection with the MRI of the pituitary gland.
When carrying out the MRI procedure of the pituitary gland with contrast, a complication such as an allergic reaction to a contrast agent may occur. It should be noted right away that gadolinium salts rarely cause allergy in patients, in contrast to iodine-containing drugs.
An allergy to contrast is manifested by skin rashes, allergic conjunctivitis, skin itch, swelling. In order to prevent the development of an allergic process, it is necessary to perform an allergy test before the procedure in order to make sure of the absolute safety of the injected drug.
Care after the procedure
After the MRI of the pituitary gland, no special care is required for the patient. The examinee leaves the MRI office and awaits some results in the corridor for some time: usually it takes about half an hour to take pictures. Then the patient can go home: MRI of the pituitary gland does not threaten the human body with any negative consequences.
MRI of the pituitary gland is the most optimal method for diagnosing diseases of the gland. It helps in detecting inclusions of a minimum size - even 4-5 mm, as well as in clarifying their location, describing the boundaries and assessing the condition of surrounding tissues. This procedure is quite expensive. But to date there is no alternative procedure that would be as informative as MRI. But a correctly diagnosed diagnosis is the key to the success of further treatment of the patient.
Medical expert editor
Portnov Alexey Alexandrovich
Education: Kiev National Medical University. A.A. Bogomolets, Specialty - "General Medicine"
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