Computer tomography of the brain

CT, or X-ray CT, is the first method of intravital imaging of the brain structure (in the English literature this method is also often called "computer axial tomography"). Computed tomography of the brain is based on an X-ray study with computerized analysis of the results, which makes it possible to detect subtle differences in the absorption of X-rays in different (normal and altered) brain tissues. Using computer graphics, layered images of "slices" of the brain (3-10 mm thick) are obtained.

Many CT studies of the brain are carried out without the introduction of a contrast agent. For example, in the differential diagnosis of intracranial hemorrhages and strokes in patients with acute neurological disorders, the introduction of contrast agents is not required. Nevertheless, it is necessary to detect a violation of the blood-brain barrier (BBB), which is observed in tumors, metastases and inflammatory processes.

[1], [2], [3], [4], [5], [6],

Purpose of computer tomography of the brain

The purpose of CT of the brain is to identify and determine the shape, size and location of various brain lesions [posttraumatic, atrophic, ischemic (day after day)) and hemorrhagic (from the first hours) stroke, meningiomas and glial tumors], brain structures, edema of the brain, the state of liquor-containing spaces to exclude possible "organic" causes of psychopathological symptoms.

Indications for computer tomography of the brain

Indications for CT of the brain: a suspicion of the presence of "organic" causes of psychopathological symptoms (the presence of atrophic, degenerative or demyelinating process, epileptic focus, cerebral circulation disorders, brain tumor).

• Diagnosis of brain lesions in neuroinfections.
• Differential diagnosis of neuroinfections with volumetric processes in the brain.
• Monitoring the effectiveness of treatment for encephalitis, toxoplasmosis, brain tumors.

How is CT of the brain performed?

When the CT of the brain is performed, the patient is lying on a precisely positioned table. By successive gradual displacement of the patient's body, a series of X-ray "images" are performed using rotating sources arranged around each other (X-ray tube) and an X-ray detector. 

To improve the visualization of brain lesions associated with a violation of the blood-brain barrier (recent stroke, growing tumors, infectious and inflammatory processes), with CT, iodine-containing radiopaque preparations injected into the bloodstream are used.

Method of computer tomography of the head

Alternative methods

MRI can be used as an alternative to conducting CT of the brain . Partly replace CT, although with less information, can Echo.

[7], [8], [9], [10], [11], [12], [13], [14], [15], [16]

Contraindications to computer tomography of the brain

Allergic reactions to iodine or contrast agent, I trimester of pregnancy, since the introduction of an iodine-containing solution can have a damaging effect on the fetus.

• the impossibility of maintaining the patient's motionless posture during the study;
• presence in the skull of the patient of foreign objects (bone or metal fragments, bullets, etc.);
• previously high total doses of ionizing radiation received by the patient; risk of allergic reactions of the patient to radiopaque materials (if necessary contrasting).

[17], [18], [19], [20], [21]

Interpretation of results

In the psychiatric clinic, along with the visualization of atrophic brain lesions with "organic" mental disorders, the CT scan of the brain made it possible to identify a number of features of structural disorders in schizophrenia and a number of other "functional" disorders. For example, in patients with schizophrenia, the expansion of the lateral and third cerebral ventricles is often detected (which is combined with the presence of "negative" symptoms and the worst efficacy of therapy with neuroleptics), the presence of cerebellar atrophy and more pronounced lesions of the prefrontal cortex compared with other cortical areas, an increase in volume or partial atrophy corpus callosum, morphological asymmetry of the brain with predominance of the right hemisphere, which is not noted in other mentally ill and healthy subjects.

• Analysis of CT images of the head
• Computer tomography of the head is normal
• Head pathology on computed tomography

Factors affecting the outcome

A certain limitation of CT of the brain is a weak separation of the gray and white matter of the brain due to the close absorption coefficients of X-ray radiation by these tissues. If there are foreign objects (bone or metal fragments, bullets, etc.) in the skull, they give powerful "shadows" and distortions on the CT images. In addition, when CT is performed (as well as all other neuroimaging methods), the patient should maintain a fixed posture for a sufficiently long time. Therefore, when carrying out CT of the brain, restless psychiatric patients (especially young children) need to use general anesthesia. It is important to correlate the diagnostic information of CT and the risk of complications of anesthesia.

[22], [23], [24], [25], [26], [27], [28],

Complications

The limitations of the CT scan of the brain include the effect of X-ray radiation, comparable in doses to the doses obtained with fluorography or radiography of the skull, as well as problems associated with the use of radiopaque preparations (the need for intravenous injections and the risk of allergic reactions to iodine-containing drugs).

[29], [30], [31], [32], [33], [34], [35]