MRI of pituitary gland: indications, preparation, how to do, normal results

A diagnostic radiological method, which includes magnetic resonance imaging, is one of the most informative ways to determine even small changes in tissue structure. Often, it is not possible to determine pathology visually or using X-ray examination - for example, with disorders in the pituitary gland. In such a situation, doctors resort to tomography: MRI of the pituitary gland will allow you to specify the problem and even find its cause.

What does an MRI of the pituitary gland show?

The MRI procedure of the pituitary gland is a diagnostic method that helps to detect all kinds of large and small painful formations, localized in the pituitary gland area:

• birth defects;
• tumor processes;
• cystic formations;
• changes in blood vessels;
• inflammatory processes in the hypothalamus-pituitary ligament.

During a standard MRI of the brain, the sella turcica area is assessed simultaneously. However, the information obtained during the examination may often be insufficient. For example, if it is necessary to diagnose a painful area at the initial stage of pathology development and assess structural changes, an MRI of the pituitary gland is additionally performed - in this case, the sella turcica area is scanned specifically, sometimes with the use of contrast.

To ensure that the resulting image is clear and distinct, the voltage used in the tomographic apparatus is no less than 1.5 Tesla.

Indications for the procedure

The MRI procedure 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 for almost any disorder of the brain function.

In most cases, the MRI procedure of the pituitary gland is relevant when there is a suspicion of an adenoma of this organ, and especially if such a tumor is rapidly progressing. Pituitary adenoma is one of the types of benign neoplasms that develops from glandular cells. Adenoma is considered a rather dangerous disease that can lead to the development of severe brain pathologies. However, MRI of the pituitary gland is performed not only for adenoma.

Indications for the study may include:

• suspected Cushing's syndrome;
• an unspecified cause of overactivity of certain hormones;
• increased prolactin release;
• other disorders of the endocrine system in the body;
• unspecified cause of migraine, persistent headache;
• increasing functional disorders of the brain;
• sudden deterioration of vision without apparent cause;
• unspecified causes of menstrual cycle irregularities in women;
• drastic, unexplained weight fluctuations (the patient rapidly loses weight, or, on the contrary, gains weight rapidly);
• unspecified cause of erectile dysfunction in men;
• suspected dysfunction of the pituitary gland (phenomena of gigantism or dwarfism).

MRI of the pituitary gland with elevated prolactin

Pathological causes that influence the increased release of prolactin into the blood are considered to be:

• tumor process (pituitary adenoma);
• pressure on the pituitary gland (SPTS - syndrome of invagination of the subarachnoid space into the intrasellar region, insufficiency of the diaphragm of the sella turcica);
• diseases of the hypothalamus caused by CNS disorders;
• primary hypothyroidism;
• long-term chronic pathologies in the body.

In order to accurately determine the cause of increased secretion of prolactin, MRI of the pituitary gland is often prescribed - primarily 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, a violation of its production is primarily associated with a violation of the function of the pituitary system.

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Preparation

• The patient must promptly warn the doctor that he has dental implants, joint implants, artificial heart valves, pacemakers and other devices, as well as piercings, which may interfere with the MRI of the pituitary gland.
• If an MRI of the pituitary gland is performed without contrast, the patient does not need to undergo any specific preparation for the examination. It is only necessary to follow the general rules for preparing for an MRI of the pituitary gland: remove outerwear and all metal accessories.
• If an MRI of the pituitary gland with contrast is to be performed, then before the procedure one should not eat for at least 5-6 hours. If the patient has an allergy to any medications, then before the administration of the contrast agent he must inform the doctor about it.
• Pregnant patients are prescribed MRI of the pituitary gland 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 mental disorders, then it is preferable to perform MRI of the pituitary gland on an open device, or to use sedatives as prescribed by the doctor beforehand.
• If it is necessary to perform an MRI of the pituitary gland on a child, then such a procedure can be prescribed from the age of 5. The fact is that the child can move during the procedure, which will significantly affect the quality of the images.

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The device for carrying out the procedure

What should you pay attention to when choosing a machine for MRI of the pituitary gland?

• The tomograph must be powerful enough – preferably 1-1.5 Tesla, no less. The fact is that less powerful tomographs will not be able to provide information about formations with dimensions up to 5 mm.
• The more powerful the device, the faster the MRI procedure will be.
• Some high-power machines can evaluate vascular abnormalities without the use of contrast.
• The MRI machine must be able to assess not only structural but also functional changes in the brain.
• The device can be open or closed. The open version is used to diagnose the pituitary gland in children, patients with obesity or claustrophobia, and patients with mental disorders. For other cases, the closed version is preferable, as it produces improved image quality and better identifies pathological inclusions.

When choosing a quality device for MRI of the pituitary gland, it is necessary to pay special attention to the length of time the tomograph has been used and the brand of the manufacturer. Siemens, Philips and some other well-known brands are rightfully recognized as the best brands.

Technique MRI of the pituitary gland

During the MRI of the pituitary gland, the patient is in a lying position, face up. To ensure complete immobility of the patient, his head is fixed with a specially designed fastener - this is necessary to obtain a clear and high-quality MRI image.

The surface with the patient lying on it is loaded into the tomograph capsule, and the magnetic frame should be in the location of the projection of the area being examined.

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 patient via a speakerphone. If the diagnostics is performed on a child, then it is allowed for one of the relatives to be in close proximity at the same time.

An MRI of the pituitary gland can take an average of 45 minutes. However, this time may vary depending on the number of images required, the class of the machine, and whether contrast enhancement was used.

MRI of the pituitary gland with contrast

The doctor can make the images obtained during MRI of the pituitary gland more informative if he uses the introduction of contrast - a special substance that is injected into the circulatory system. What does this give? When contrasting, the substance injected into the bloodstream allows the doctor to visualize the entire network of vessels in the required area. In almost all cases, this allows you to assess the location and size of the painful focus, determine the presence of a connection with nearby organs, and determine the intensity of the blood flow.

MRI of the pituitary gland with contrast is often prescribed to patients who are scheduled to undergo surgery to remove tumors in this part of the brain. The contrast agent 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 allows you to see a tumor even of a small size.

Among the most common contrast agents are those based on gadolinium salts (Magnevist, Omniscan, etc.); less frequently, and mainly for CT, drugs with iodine are used (Omnipaque, Hexabrix, etc.).

MRI of the pituitary gland with or without contrast?

The doctor may prescribe a simple MRI of the pituitary gland or an MRI with contrast enhancement. As a rule, paramagnetic substances are used for this, which are administered by intravenous injection immediately before the procedure. The amount of the drug administered is determined individually, based on the patient's weight.

Is contrast enhancement really necessary? This is determined on an individual basis. If it is necessary to determine the clear boundaries of the tumor, its structure, the condition of healthy tissues near the tumor, then the use of contrast is quite justified. Most often, contrast is used in patients who are being prepared for surgery to remove pituitary tumors.

MRI of the pituitary gland sella turcica

During the MRI of the pituitary gland, the doctor must differentiate pathological foci, taking into account their location. If the pathological inclusion is located in the sella turcica, then a pituitary adenoma can be diagnosed, and if localized above the sella - craniopharyngioma, meningioma, astrocytoma, aneurysm.

Empty sella syndrome, which is characterized by a defect in the diaphragm and degenerative changes in the pituitary gland, may also be detected.

The listed diseases are considered very serious. They manifest themselves with symptoms such as severe constant headaches, thyroid dysfunction, adrenal and cardiac disorders, and autonomic nervous system failures.

No other type of examination will provide such information about the disease as MRI of the pituitary gland provides. Therefore, if there are indications for the procedure, there is no need to delay. Even if any pathologies are detected, the chances of recovery are always very high.

MRI of the pituitary gland in a child

If a doctor prescribes an MRI of the pituitary gland to a child, this usually happens no earlier than 5-6 years of age. In order to obtain a high-quality image from the tomograph, the patient must remain motionless while inside the device. It is very difficult to ensure a motionless state for a small child. In addition, he may get scared when in a closed space.

To avoid the above difficulties, children can undergo MRI using an open-access device. However, even during such a study, the child must be as still as possible.

Often, when examining children, parents or other close people of the child are asked 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.

If the child is restless or capricious, then in some cases before the procedure it is recommended to administer special sedatives to calm the baby and ensure normal quality of the images.

Contraindications to the procedure

The MRI procedure of the pituitary gland is considered to be quite safe for human health. However, this diagnostic method also has a number of contraindications.

• Absolute (strong) contraindications:
  • the presence of metal implants in the patient's body;
  • the presence of non-removable pacemakers or insulin devices (pumps);
  • the presence of ferrimagnetic implants.
• Relative contraindications, the presence of which is discussed with the doctor:
  • the presence of non-metallic implants in the body;
  • presence of nervous system stimulants;
  • cardiac insufficiency;
  • critically large body mass;
  • episodes of claustrophobia and panic attacks, mental illness.

It is also not recommended to perform MRI of the pituitary gland on pregnant women, especially in the first months of pregnancy.

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Normal performance

In a normal healthy person, the pituitary gland has a rectangular configuration (if the diagnosis is made from the frontal angle). The lower borders are similar to the outlines of the sella turcica (that is why this part is called accordingly). The upper edge can be either horizontal, convex, or slightly concave - all of the listed options are normal.

The image should clearly show the lobes of the organ in the sagittal plane. In 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 classified as a glandular organ, since it produces hormones: this process is controlled by releasing factors of the hypothalamus.

In tomographic images, the normal height of the pituitary gland is no more than eight millimeters, but gender and age norms for the pituitary gland in MRI may differ. For example, in female patients of childbearing age, the height of the organ can fluctuate from 9 to 10 mm - this is especially noticeable by the slightly elevated diaphragm of the sella. During pregnancy, the diaphragm rises even higher, so the height can increase to 10-12 mm.

Normal pituitary gland size on 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 generally accepted that with a microadenoma, any of the pituitary gland size indicators should not be higher than 10 mm; larger sizes indicate a macroadenoma.

Pituitary tumor on MRI

During the MRI procedure of the pituitary gland, the doctor must notice any pathological formations, as well as record their location and growth dynamics.

As a rule, the main signs of tumor processes are:

• heterogeneous tissue structure;
• asymmetrical outlines of the organ and its convexity.

• A pituitary adenoma on MRI is a benign formation growing from pituitary cells. The tumor can be up to 10 mm or larger than 10 mm. In the first case, we speak of a microadenoma, and in the second, of a pituitary macroadenoma.

Macroadenoma may exhibit hormonal activity and have a rounded and dense capsule shell. Most often, macroadenoma is a prolactinoma.

Microadenoma of the pituitary gland on MRI lacks distinct outlines and capsule. Therefore, its presence can be guessed by the convexity of the diaphragm of the sella, or by the beveled stalk of the organ.

• A pituitary cyst MRI looks like a round formation in the sella turcica. Rarely, there may be a lack of intense blood flow. In order to determine the affiliation of such a tumor, it is recommended to conduct an MRI with contrast. In this case, the 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. This tumor is characterized by rapid infiltrative growth and rapid damage to the organ and nearby tissues. Adenocarcinoma is capable of quickly spreading metastases, both hematogenously and lymphogenously.

Often, adenocarcinomas form from a hormonally 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 gland structure - these can be adenomas, cysts, tumor processes. That is, heterogeneity indicates the presence of individual compacted areas of gland tissues.

The MRI picture of an additional inclusion of the left lobe of the pituitary gland, as well as the right one, can be different, depending on the nature of this inclusion. For example, the main sign of a tumor formation in the pituitary gland is the detection of inclusions of increased and decreased density, in T1 and T2 modes in the projection of the pituitary gland. If a small adenoma is detected, then considerable importance is attached to specific indirect signs: displacement of the diaphragm of the sella upward, deformation of the pituitary funnel, etc.

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Dental implants and MRI of the pituitary gland

Any patient who goes for an MRI of the pituitary gland is worried about the diagnostic results being clear and informative. Therefore, it is very important to warn the doctor about any nuances that may interfere with high-quality diagnostics.

Indeed, metal implants are a contraindication for this examination. But: if the dentures are made using the latest technology, from modern dental material - not metal - then MRI of the pituitary gland is quite possible. Before the diagnostic procedure begins, the patient must warn the doctor about the presence of dentures, and also provide him with X-ray images: the doctor must clearly understand the location of the implants, since on this basis he will be able to adjust the device accordingly.

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Complications after the procedure

The MRI procedure of the pituitary gland is considered absolutely painless and harmless. However, some patients note certain symptoms that are often associated with the passage of magnetic resonance imaging:

• nausea;
• weakness;
• dizziness;
• headache;
• heartbeat;
• a feeling of anxiety and worry.

However, to date there is no direct evidence that these symptoms have any relationship with pituitary MRI.

When performing an MRI of the pituitary gland with contrast, such a complication as an allergic reaction to the contrast agent may occur. It is worth noting right away that gadolinium salts rarely cause allergies in patients, unlike iodine-containing drugs.

Allergy to contrast is manifested by skin rashes, allergic conjunctivitis, skin itching, swelling. To prevent the development of an allergic process, it is necessary to conduct an allergy test before the procedure to ensure the absolute safety of the drug being administered.

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Care after the procedure

After the MRI of the pituitary gland, no special care is required for the patient. The patient leaves the MRI room and waits for the results in the corridor for some time: it usually takes about half an hour to receive the images. 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 minimal size - even 4-5 mm, as well as in specifying their location, describing the boundaries and assessing the condition of the surrounding tissues. This procedure is quite expensive. But today there is no alternative procedure that would be as informative as MRI. But a correct diagnosis is the key to the success of further treatment of the patient.

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