(Head CT Scan, Intracranial CT Scan)
What is a CT or CAT scan of the brain?
Computed tomography (CT or CAT scan) is a noninvasive diagnostic imaging procedure that uses a combination of X-rays and computer technology to produce horizontal or axial images (often called slices) of the body. A CT scan shows detailed images of any part of the body, including the bones, muscles, fat, and organs. CT scans are more detailed than standard X-rays.
In standard X-rays, a beam of energy is aimed at the body part being studied. A plate behind the body part captures the variations of the energy beam after it passes through skin, bone, muscle, and other tissue. While much information can be obtained from a standard X-ray, a lot of detail about internal organs and other structures is not available.
In computed tomography, the X-ray beam moves in a circle around the body. This allows many different views of the same organ or structure. The X-ray information is sent to a computer that interprets the X-ray data and displays it in a two-dimensional (2D) form on a monitor.
CT scans may be done with or without "contrast." Contrast refers to a substance taken by mouth or injected into an intravenous (IV) line that causes the particular organ or tissue under study to be seen more clearly. Contrast examinations may require you to fast for a certain period of time before the procedure. Your physician will notify you of this prior to the procedure.
CT scans of the brain can provide more detailed information about brain tissue and brain structures than standard X-rays of the head, thus providing more information related to injuries and/or diseases of the brain.
Other related procedures that may be used to diagnose brain disorders include X-rays, magnetic resonance imaging (MRI) of the brain, positron emission tomography (PET) scan of the brain, and cerebral arteriogram. Please see these procedures for additional information.
Anatomy of the brain
The central nervous system (CNS) consists of the brain and spinal cord. The brain is an important organ that controls thought, memory, emotion, touch, motor skills, vision, respirations, temperature, hunger, and every process that regulates our body.
What are the different parts of the brain?
The brain can be divided into the cerebrum, brainstem, and cerebellum:
Cerebrum. The cerebrum (supratentorial or front of brain) is composed of the right and left hemispheres. Functions of the cerebrum include: initiation of movement, coordination of movement, temperature, touch, vision, hearing, judgment, reasoning, problem solving, emotions, and learning.
Brainstem. The brainstem (midline or middle of brain) includes the midbrain, the pons, and the medulla. Functions of this area include: movement of the eyes and mouth, relaying sensory messages (hot, pain, loud, etc.), hunger, respirations, consciousness, cardiac function, body temperature, involuntary muscle movements, sneezing, coughing, vomiting, and swallowing.
Cerebellum. The cerebellum (infratentorial or back of brain) is located at the back of the head. Its function is to coordinate voluntary muscle movements and to maintain posture, balance, and equilibrium.
More specifically, other parts of the brain include the following:
Pons. A deep part of the brain, located in the brainstem, the pons contains many of the control areas for eye and face movements, facial sensation, hearing, and equilibrium.
Medulla. The lowest part of the brainstem, the medulla is the most vital part of the entire brain and contains important control centers for the heart and lungs.
Spinal cord. A large bundle of nerve fibers located in the back that extends from the base of the brain to the lower back, the spinal cord carries messages to and from the brain and the rest of the body.
Frontal lobe. The largest section of the brain located in the front of the head, the frontal lobe is involved in personality characteristics and movement.
Parietal lobe. The middle part of the brain, the parietal lobe helps a person to identify objects and understand spatial relationships (where one's body is compared to objects around the person). The parietal lobe is also involved in interpreting pain and touch in the body.
Occipital lobe. The occipital lobe is the back part of the brain that is involved with vision.
Temporal lobe. The sides of the brain, these temporal lobes are involved in memory, speech, and sense of smell.