What Is Computed Tomography (CT)? How Is CT Scan performed?
Radiological examinations, which are used in the diagnosis of many diseases, are performed by a radiologist or radiology specialist. CT, short for computed tomography, is an imaging technique commonly used in the field of radiology. First, let’s look at the dictionary meaning of tomography. Tomography is derived from the Greek words “Tomos,” meaning slice or section, and “Graphein,” meaning to record or write. When your doctor requests a CT scan, a radiologist or radiology technician takes the tomography of the body region to be examined and prepares a detailed report of the captured images to be sent to the relevant physician. CT, which is frequently used as a diagnostic tool, scans the relevant area or areas of the body in detail using X-ray beams, creating a detailed and layered image. During the scan, it scans the images of bones, soft tissues, organs, and blood vessels in the body from different angles and allows them to be visualized in sections. Unlike conventional X-rays, CT provides much more detailed, three-dimensional, and sectional images, providing doctors with detailed information about the treatment and intervention process. The images obtained using X-ray beams, which are moved around the patient who lies motionless, are merged by a computer, enabling detailed visualization of the sections. The obtained image is examined by a radiologist who then interprets and creates a report. The CT machine is a ring-shaped device with a hollow center, in which the patient lies down on a table. Due to its rapid imaging capabilities, CT is frequently used for emergency diagnoses.
How is a CT Scan performed?
The patient who needs a CT scan is directed to the area where the CT machine is located within the radiology department. The patient, who has not eaten for approximately 6 hours before the scan and has not consumed any liquids for at least 4 hours prior, enters a cabin, removes their clothing or all garments, and puts on a hospital gown in the area to be imaged. At this point, all metal objects such as rings, glasses, dentures, and hair clips need to be removed. After the necessary information and instructions are provided by the doctor, the patient is positioned on the CT scan table. Depending on the location to be imaged, the patient may be asked to lie on their back or on their stomach. The movable parts during imaging may vary depending on the model of the CT machine. In most cases, the patient lies on a fixed table while the machine moves around them, but in some machine models, the machine remains stationary while the table moves. The patient is informed about this situation in advance by the doctor who will perform the CT scan. Pillows and straps are used to ensure the patient’s comfort and proper imaging. During the scan, the patient is alone in the room with the machine. However, the radiologist performing the scan can see, hear, and communicate with the patient if necessary. It is important for the patient not to move during the CT scan to ensure accurate imaging, clear image quality, and to avoid repetition. In some cases, the patient may be asked to hold their breath for a short period during the scan. When the CT scan starts, there may be sounds related to movement, mechanical noises, and sounds associated with the imaging process. This is quite normal and should not cause concern. During the scan, the X-ray tube rotates around the patient on the table, capturing a series of images. These images are then merged by the computer to create a three-dimensional image, which the radiologist can view on their computer. The duration of a CT scan can vary depending on the size of the area being scanned but typically lasts between a few minutes to half an hour. After the scan, the patient can resume their daily activities without any restrictions. Some scans may be performed with the use of contrast agents, which is known as contrast-enhanced CT.
What is contrast-enhanced CT?
Contrast-enhanced CT, also known as CT with contrast, is a technique used to obtain more detailed and clear images. It involves administering a contrast agent to the patient, depending on the region to be imaged and the type of examination. Before the procedure, the patient’s allergy history is thoroughly assessed. The contrast agent can be given to the patient through injection or orally. The administered contrast agent is a substance that enhances the visibility of the images and is typically iodine- or barium-based. The process of performing a contrast-enhanced CT scan is the same as a regular CT scan, using the same equipment, so there is no difference in what the patient experiences. However, due to the contrast agent, the patient may experience a metallic taste or a warm sensation in their mouth. After the contrast-enhanced CT scan, the patient may be observed by a radiologist for a period of time. In rare cases, the barium or iodine given during the scan may cause allergic reactions in some individuals, which can manifest as rash, itching, nausea, or redness. The contrast agent used in contrast-enhanced CT helps produce clearer images during the imaging process and enables rapid visualization of any obstructions or leaks in the area being examined. The results of the contrast-enhanced CT scan are reported by a radiologist and sent to the referring physician.
Why is a CT scan performed?
A CT scan is not a treatment but a diagnostic and imaging method. After listening to the patient’s history and performing a physical examination, a doctor may request a CT scan to aid in diagnosis. CT scans are used to visualize potential damage caused by sudden traumas such as accidents or falls, both in the brain and other parts of the body. CT scans are commonly performed in the following situations:
- To visualize internal organs and assess the risk of internal bleeding in cases of injuries
- To detect bone fractures and tumors
- To image the paranasal sinuses (sinus cavities around the nose) when necessary
- To diagnose diseases in organs such as the heart, brain, lungs, and liver
- To precisely locate blood clots or tumors
- To measure bone density
- To detect bone pathologies and image the skeletal system
- To determine the stage of cancer and monitor its treatment progress
- To detect metastasis
- To assess the effectiveness of other treatment methods
- CT scans provide three-dimensional cross-sectional images, unlike magnetic resonance imaging (MRI), which is why they are often preferred. Brain and lung CT scans are among the most commonly used medical imaging techniques.
How is a brain tomography performed?
Brain tomography, also known as a brain CT scan, is a commonly used rapid and effective imaging method for diagnosing brain-related conditions such as tumors, head injuries, stroke, brain hemorrhage, and other brain diseases. Brain tomography can be performed with or without contrast. In contrast-enhanced tomography, a contrast agent is injected into the patient’s bloodstream through a vein to obtain more detailed images for a thorough examination. During the scan, the patient may be asked to hold their breath at certain intervals.
What are the advantages of computerized tomography (CT)?
The advantages of CT can be listed as follows:
- Obtaining detailed images in sections or slices
- Short duration of the imaging process
- Rapid differentiation between damaged and healthy tissues
- Preventing unnecessary interventions and enabling accurate treatment planning
- Three-dimensional visualization of blood vessels, tissues, bones, and organs
When deemed necessary by the physician, computerized tomography can be used to clarify the diagnosis and determine the course of treatment.
Do not neglect to regularly undergo check-ups for a healthy life.
