Cranial computed tomography (synonyms: cranial CT; cranial CT; cranial CT; CCT; CT skull, cranial CT; CT head, head CT) refers to a radiologic examination procedure that primarily examines the brain, but also bony portions, vessels, cerebral ventricles with cerebrospinal fluid (cerebrospinal fluid ventricles), and the remaining soft tissues inside the skull.
Indications (areas of application)
- Cerebral hemorrhage
- Brain tumors
- Cerebral infarction (stroke)
- Meningitis (meningitis)
- Encephalitis (inflammation of the brain) or other inflammatory changes in the area of the brain and facial skull.
- Epilepsy
- Traumatic brain injury (TBI), esp. with Glasgow Coma Scale (GCS) < 15 points; persistent or multiple vomiting; anticoagulation or disorder; age greater than 60 years; dangerous accident mechanism (e.g., collision as a pedestrian or bicyclist with a motor vehicle, fall height > 5 steps or > 1 m).
- Changes in blood vessels such as atherosclerosis (arteriosclerosis; hardening of the arteries).
- Suspected impression or open skull fracture (injury in which the skull bone has been depressed or skull fracture).
- Signs of a skull base fracture (monocular or spectacle hematoma; liquorrhea (cerebrospinal fluid discharge) from the nose or ear; hematotympanum (accumulation of blood in the tympanic cavity); retroauricular hematoma (behind the ear (retroauricular) occurring hematoma / hematoma (more precisely an ecchymosis / small-area, patchy bleeding of the skin) = Battle’s sign).
- New focal neurological deficit (localized change in the brain leading to dysfunction in another part of the body).
- Diagnosis of tumorous, cystic and inflammatory dental, oral and maxillofacial diseases.
The procedure
Computed tomography is one of the non-invasive, that is, not penetrating into the body, imaging X-ray diagnostic procedures. The body or the body part to be examined is imaged layer by layer with a rapidly rotating X-ray tube. A computer measures the attenuation of the X-rays as they pass through the body and uses this to determine a detailed image of the part of the body being examined.The principle of CT (computed tomography) is to show the differences in density of different tissues. For example, water has a different density than air or bone, which is expressed in different shades of gray. For even better differentiation of the tissue types, the patient can also be administered a contrast medium. This is contrast medium containing iodine. Healthy tissue absorbs contrast medium at a different rate than diseased tissue such as cancer. With the most modern equipment, the examination takes only a few minutes, i.e. the scanning process only a few seconds, so that the patient can hold his breath during the examination and movement artifacts are impossible.The examination is performed in a lying position. The latest devices use the multislice method, i.e. several slices are taken at the same time. Modern examination devices use a 64-slice method, i.e. 64 slices are taken at the same time. This method can be compared to a Rettig, which is cut in a spiral shape. Modern devices also work with a so-called low-dose technique, i.e. only 50% of the radiation is required to produce these precise images with a layer thickness of up to 0.4 mm. New reconstruction algorithms (reconstruction calculation methods) make this precision possible.Computed tomography of the skull and brain is now routinely used for many indications, as it is a fast and very informative diagnostic procedure. NoteAfter a CT scan of the head and neck, the risk of tumors in children is increased. This is especially true for thyroid carcinomas (increased by 78%) and brain tumors (increased by 60%). The overall cancer incidence is increased by 13 %.
