CT brain is a technique for visualizing intracranial and extracranial vessels using a directed beam of X-rays, combining angiography with computer data processing. Scanning the vessels of the cerebral pool gives an idea of the blood supply to the brain and allows you to detect blood flow disorders at any level. Vascular CT is performed for head and neck injuries, before neurosurgical intervention, in the diagnosis of aneurysms, atherosclerosis, vascular thrombosis and other vascular pathology. The study may include only cerebral vessels or vessels of the neck, or a full complex, carried out natively or with contrast.
Indications for CT of the vessels of the brain and neck are signs of cerebral circulatory insufficiency. Clinically, this may be indicated by symptoms such as:
- intense headache of a permanent nature
- deterioration or loss of memory and speech
- gratuitous dizziness
- loss of acuity or blurred vision
- disturbance of balance, coordination of movements
- epileptiform seizures
- signs of increased intracranial pressure.
To confirm the preliminary diagnosis and differential diagnosis, CT brain is used for strokes, cerebral artery aneurysms, meningitis and encephalitis, venous sinus thrombosis, benign and malignant tumors, hemorrhages of traumatic and organic genesis, ischemic attacks on the background of atherosclerosis, etc. Also, this technique can be used at the stage of preoperative preparation or to control the treatment.
The main contraindications to CT are pregnancy at any time and younger childhood. This is due to the harmful effects of radiation exposure on the child’s body and teratogenic effect on the fetus. Relative contraindications are considered lactation, mental illness (schizophrenia, psychosis), claustrophobia, the inability of the patient to maintain a static position throughout the study (severe pain, hyperkinesis, etc.).
CT brain of the head and neck with the use of radiopaque drugs is contraindicated for people with allergies to iodine-containing drugs, with severe renal dysfunction, diabetes mellitus, iodine-dependent thyroid diseases, thyrotoxicosis, multiple myeloma. If the examinee has heart failure, bronchial asthma or other conditions that require constant monitoring, it is mandatory to notify the radiologist and have with you the medicines necessary for first aid.
Native CT brain does not involve special training. The need to use intravenous contrast requires an assessment of the excretory function of the kidneys and a test for sensitivity to the drug used. In most clinics, CT brain with contrast is performed on an empty stomach.
Immediately before placement in the tomograph, the patient must remove all metal objects (jewelry, piercings, external hearing aids, hairpins), because they can “layer” the images and distort the results obtained. Some clinics may also ask you to change into a special robe. If it is impossible to stay in a static position for a long time (people suffering from severe somatic pain or having mental disorders), a full-time anesthesiologist can perform drug sedation.
Methodology of conducting
CT brain is performed in a specially equipped room divided into several rooms. As a rule, this is a room with a medical device, a locker room for a patient and a room for a radiologist with equipment controls. Most of the tomographs used visually resemble a large semicircle with a hole inside. After preparation and a short briefing, the patient lies down on the platform of the device and moves inside. The radiologist goes to the control room, from where he starts scanning.
If necessary, after receiving the first native images, an intravenous radiopaque substance is injected. The examination time is from 20 to 40 minutes, depending on the capabilities of the tomograph and the thickness of the slices. During the study, the radiologist monitors the quality of the images obtained, observes the patient and communicates with him. The patient should lie still during CT angiography of the brain.
Most people do not feel any changes during the scan, when contrast is introduced, there may be a feeling of warmth, slight nausea, dizziness or general weakness. Also, during the study, you can hear clicking or clacking produced by the device. With proper preparation, CT of extra- and intracranial vessels does not cause any complications or undesirable consequences.
Interpretation of results
The result of CT brain in most medical institutions can be obtained already 40-60 minutes after the end of the study. Depending on the clinic, the patient may be given a written or printed conclusion with or without a detailed description, a CD with images or a 3D model, copies printed on X-ray film. Some diagnostic centers also provide the opportunity to upload the results of the procedure to the patient’s personal account on the clinic’s website.
CT scans of the vessels of the brain and neck can reveal vascular malformations, the presence of aneurysms and their stratification, hematomas, kinking syndrome, signs of vasculitis, ischemic or hemorrhagic stroke, hemodynamically significant atherosclerosis, the presence of malignant or benign tumors. Despite the high informative value of cerebral CT angiography, the final diagnosis is established by the attending physician when comparing the clinical picture, data from all analyses and studies.
Like any other method, CT brain has its advantages and disadvantages. Compared with radiography, it allows you to get more detailed images and study the area in layers, exposes the patient to a lower dose of radiation. MRI is a more expensive procedure, mainly aimed at the study of soft tissues and is contraindicated in patients with metallic foreign bodies in the body (cochlear implants, traumatological and orthopedic structures).
Unlike ultrasound, the result of computed tomography of blood vessels does not depend on the professionalism of the radiologist and the individual characteristics of the patient. With regard to the diagnosis of vascular pathologies of the brain, the possibilities of ultrasound are very limited. However, ultrasound and MRI do not have a radiation load on the patient, and there is such a load during CT of the vascular bed of the brain.