Cerebral CT

Cerebral Computed Tomography (CT)

Cerebral computed tomography (CT) is a radiographic procedure that uses X-rays to produce medical images of the head, including the brain, skull, sinuses, and eye sockets⁽¹⁾.

Through cerebral CT, radiographers see the patient’s brain without the need for surgery. The procedure creates medical images of certain parts of the brain, including the cerebrum, brainstem, and cerebellum.

Cerebrum

The cerebrum has two parts: the right and left hemispheres. The cerebrum is responsible for several body functions, including initiation and coordination of movement, touch, vision, hearing, temperature, judgment, problem-solving, emotions, reasoning, and learning⁽²⁾.

Brainstem

The brainstem may be found in the middle of the brain. Its parts include the midbrain, the pons, and the medulla.

The brainstem functions include the eye and mouth movement, hunger, respiration, relay of sensory messages, consciousness, body temperature, swallowing, involuntary muscle movement, cardiac function, sneezing, coughing, and vomiting⁽³⁾.

Cerebellum

The cerebellum (back of the brain) is located at the back of the head. The cerebellum coordinates voluntary muscle movements and maintains equilibrium, posture, and balance⁽⁴⁾.

Indications of Cerebral CT

A physician may prescribe a brain CT scan for a patient to look for the following⁽⁵⁾:

• Brain mass or tumor
• Hydrocephalus (fluid buildup in the deep cavities of the brain)
• Bone abnormalities
• Abscess in the brain
• Hemorrhage or internal bleeding
• Stroke
• Trauma or skull fracture

Doctors may also order a cerebral CT scan to determine the cause of⁽⁶⁾:

• Abnormal head size in children
• Hearing loss 
• Changes in thinking or behavior
• Fainting
• Headache, when accompanied by other symptoms
• Symptoms of brain damage, such as muscle weakness,  vision problems, numbness and tingling, speaking difficulties, or problems in swallowing

If a patient does not want to undergo brain CT, they may opt for other imaging procedures to address the medical issues mentioned above. 

Instead of recommending a brain CT, the doctor may order a magnetic resonance imaging (MRI) or a positron emission tomography (PET) scan of the head⁽⁷⁾.

What to Expect From a Cerebral CT

Some CT scans require a contrast dye, which the doctors administer to patients before the test starts. Radiologists recommend the dye for better image quality.

If the procedure requires a contrast dye, the patient may not eat or drink anything for four to six hours before the exam⁽⁸⁾.

The contrast dye may cause a slight burning sensation and a metallic taste in the mouth. However, these effects are normal and may dissolve after a few seconds⁽⁹⁾.

Before the patient receives the dye, they must inform their doctor if they are taking the diabetes medicine metformin Glucophage. They must also disclose if they have kidney function problems as the contrast dye may affect their condition⁽¹⁰⁾.

Contrast agents may raise the chances of metformin causing lactic acidosis (lactate buildup) in patients with decreased kidney function⁽¹¹⁾.

If the patient weighs over 135kg, they must ask the attending radiologic technologist if the CT machine has a weight limit. 

Before the procedure, the radiologic technologist may ask the patient to remove their jewelry and change into a hospital gown.

Once the patient is ready, they may lie down on a narrow slate that slides into the center of the CT machine. They must remain still during the procedure because movements may cause blurred images. 

The radiologic technologist may also ask the patient to hold their breath for a couple of seconds to let the machine take clear images.

The machine’s X-ray beam rotates to take images of the head’s internal structures at various angles. A computer produces separate images of the body, called slices. 

The images developed by the CT machine may be stored, viewed on a monitor, or saved to a disc. Radiologists may create three-dimensional models of the head by stacking the slices together.

A cerebral CT scan usually takes only 30 seconds to a few minutes to complete⁽¹²⁾.

Risks of Cerebral CT

A cerebral CT comes with certain risks, including radiation exposure, allergic reaction to contrast dye, and kidney damage from the contrast dye⁽¹³⁾.

CT scans expose individuals to more radiation than regular X-rays. Frequent X-ray and CT exams may increase an individual’s risk of cancer over time⁽¹⁴⁾.

The patient and their doctor should consider the risk of radiation exposure against the benefits of doing the procedure.

Individuals undergoing CT scan procedures may also have allergic reactions to the contrast agent. Common contrast dyes contain the mineral iodine. 

Those with iodine allergy may experience itching, nausea or vomiting, sneezing, or hives if they receive this type of contrast agent⁽¹⁵⁾.

In rare cases, the contrast agent may cause individuals to go into anaphylactic shock, a life-threatening allergic reaction⁽¹⁶⁾. If the patient feels any trouble breathing during the CT scan, they must immediately tell their attending radiologic technologist.

To address the issue mentioned above, a physician may prescribe an antihistamine (anti-allergy) before the procedure. 

After the procedure, the kidneys work to flush the dye from the body’s system. A doctor may advise individuals, especially those who have kidney disease or diabetes, to drink extra fluids after a CT scan. The extra fluids help flush the iodine out of the body.

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