Computed tomography, also known as a CT scan, is a medical imaging technique that combines X-rays and computer processing to create detailed cross-sectional images of the body. CT scans provide more detailed and precise images compared to conventional X-rays, allowing healthcare professionals to diagnose and evaluate a wide range of medical conditions. Here’s some important information about CT scans:
CT scans are used to visualise and evaluate various structures within the body, including organs, bones, blood vessels and soft tissues. They are commonly used to diagnose conditions such as tumours, infections, fractures, internal injuries, blood clots and to monitor the response to treatment. CT scans can provide detailed information about the size, shape and density of structures, assisting in accurate diagnosis and treatment planning.
During a CT scan, the patient lies on a table that moves through a circular opening in the CT scanner. The scanner consists of an X-ray tube that rotates around the body, emitting a series of narrow X-ray beams. Detectors on the opposite side of the scanner measure the X-ray beams that pass through the body. A computer processes the collected data to create cross-sectional images, which can be viewed on a monitor.
In some cases, a contrast agent may be used to enhance the visibility of certain structures or abnormalities during a CT scan. Contrast agents can be administered orally, intravenously, or rectally, depending on the area being examined. These agents contain substances that highlight specific tissues or blood vessels, improving the clarity of the images.
Safety and Radiation
CT scans involve exposure to ionising radiation, although the amount of radiation used is generally considered safe. The benefits of obtaining necessary diagnostic information usually outweigh the risks associated with the radiation exposure. However, radiation dose optimisation and appropriate usage guidelines are followed to minimise radiation exposure, especially in sensitive populations such as children and pregnant women.
Types of CT Scans
CT scans can be performed on different areas of the body based on the specific clinical question. Some common types include:
- Chest CT: Used to evaluate the lungs, heart, blood vessels and chest cavity.
- Abdominal CT: Provides detailed images of the organs in the abdomen, such as the liver, pancreas, kidneys, spleen and intestines.
- Head CT: Examines the brain, skull and sinuses to diagnose conditions like stroke, brain tumours and head trauma.
- Pelvic CT: Evaluates the pelvic organs, including the uterus, ovaries, prostate gland and bladder.
- Virtual Colonoscopy: A special type of CT scan used to visualise the colon and detect abnormalities, such as polyps or tumours.
CT technology has advanced over the years, leading to improvements in image quality and reduced scanning times. Multidetector CT (MDCT) scanners, which have multiple rows of detectors, can acquire images faster and produce higher-resolution images. This allows for quicker and more accurate diagnoses, as well as the ability to perform more complex imaging tasks.
CT scans are powerful diagnostic tools that provide detailed images for the evaluation and management of various medical conditions. They are widely used in hospitals and healthcare facilities to aid in diagnosis, treatment planning and monitoring of patients.