What is a CT Scan? A Guide to Computed Tomography Scans

January 9, 2024

patient going into ct scanA CT scan, or a computed tomography scan, is a common diagnostic tool used in the medical field. These scans produce cross-sectional images of the body, allowing healthcare professionals to identify and diagnose a variety of medical conditions and injuries. While CT scans are a widely used medical technology, many people are still unsure about what they are and how they work. In this article, we'll take a closer look at what CT scans are, how they are used, and what patients can expect during the scan process.  

Understanding CT Scans

A CT scan is a medical imaging procedure that utilizes X-ray technology to produce cross-sectional images of the body. These images, also known as slices, are compiled by a computer to create a comprehensive view of internal structures, providing detailed information that can help healthcare professionals in diagnosing and monitoring various medical conditions. 

Different types of CT scans are tailored to specific medical needs. Whether it's a CT angiography focusing on blood vessels or a CT urogram examining the urinary tract, each type serves a unique purpose. The choice of a specific type of scan depends on the medical condition and the targeted area for examination.

CT Scanners

CT scanners are intricate machines that include an X-ray tube and a detector. During a scan, the patient is positioned on a table that slides into the scanner. The scanner rotates around the body, capturing X-ray images from multiple angles. This data is then processed to generate detailed cross-sectional images, providing a three-dimensional view of the targeted area. 

The CT scan experience involves lying on a table that smoothly slides into the scanner. This adjustable table ensures optimal positioning for imaging while prioritizing patient comfort. The sliding table minimizes the need for repositioning, contributing to the efficiency of the procedure. 

Benefits of CT Scans

There are several different types of diagnostic scans used in healthcare settings, including CT, MRI, and traditional X-ray. MRI uses a powerful magnetic field and radio frequencies to produce detailed images of your internal structures, while CT scans rely on X-rays and computer processing. CT scans are often preferred in emergency settings, where speed is critical.  

While both utilize X-rays, CT scans differ from traditional X-ray scans because they show detailed cross-sectional information of a specific area without overlapping images, which is a significant improvement over basic films. As a result, CT scans offer an excellent correlation between clinical symptoms and pathology for suspected illnesses. 

CT scans are also particularly adept at visualizing blood vessels and soft tissues within the body. The ability to examine vascular structures and soft tissues in high detail makes these scans indispensable in the diagnosis of cardiovascular conditions, cancer, and various internal organ abnormalities.

Why Do I Need to Hold My Breath During a CT Scan?

To optimize image quality and minimize motion artifacts, patients undergoing a CT scan may be instructed to hold their breath for short periods of time during the procedure. This simple act ensures that the captured images are clear and accurate, enabling healthcare professionals to make precise diagnoses. 

IV Contrast for CT Scans 

Some scans involve the use of contrast agents to enhance visibility. CT scans with contrast, or contrast-enhanced CT scans, utilize intravenous (IV) contrast material to highlight blood vessels and soft tissues. This contrast material, often iodine-based, is administered through an IV line, allowing for a more detailed examination of the targeted areas. 

While IV contrast is safe, there is a minimal risk of allergic reactions. It is crucial for patients to communicate any history of allergies to healthcare providers before the administration of contrast material. In rare instances, individuals may experience an allergic reaction, ranging from mild skin irritation to more severe symptoms.  

Before receiving IV contrast, healthcare providers may assess kidney function, as the contrast material is excreted through the kidneys. Impaired kidney function can affect the body's ability to eliminate the contrast agent, potentially leading to complications. Patients with pre-existing kidney conditions or those at risk may undergo additional assessments to ensure the safe use of contrast material. 

Oral Contrast for CT Scans

In certain CT scans focusing on the gastrointestinal tract, oral contrast may be administered. This contrast material is ingested to highlight the digestive system's structures, aiding in the detection of abnormalities such as tumors, inflammation, or blockages. It's a crucial component of specific CT scans that provide valuable information about the digestive organs. 

Following the administration of contrast material, some patients may experience a temporary metallic taste in the mouth. This side effect is normal and typically subsides shortly after the procedure. It's essential for patients to communicate any side effects to their healthcare providers. 

Radiation Exposure and Safety

Concerns about radiation exposure are common when discussing medical imaging procedures. CT scans do involve X-rays, and while the amount of radiation is carefully controlled, it is essential to consider the balance between the diagnostic benefits and potential risks. Healthcare providers should prioritize minimizing radiation exposure while obtaining the necessary information for an accurate diagnosis. This involves monitoring radiation levels, limiting exposure time, and using protective equipment

CT scans provide detailed and accurate information for the diagnosis and monitoring of various medical conditions. Understanding the basics, from the use of contrast agents to the significance of patient cooperation, can help ensure the success of this advanced diagnostic test. If you have questions or concerns about CT scans, consult with your healthcare provider, who can offer personalized guidance based on your medical history and specific needs. 


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