CT Scan (Computed Tomography ): - What is it, Types, Procedure & Result!

• Written by Sejal Singhania

  Reviewed by Munmi Sharma

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Have you ever wondered why doctors often recommend a CT scan when they need a clearer picture of what’s happening inside your body? While X-rays and ultrasounds are helpful, they can’t always capture the level of detail needed to diagnose certain conditions accurately. 

That’s where Computed Tomography (CT), commonly known as a CT scan, comes in. This advanced imaging technology bridges the gap, providing highly detailed, cross-sectional images of the body that help doctors detect and diagnose issues with precision. Invented in the early 1970s by Sir Godfrey Hounsfield, a British engineer, and Allan Cormack, a South African physicist, the CT scan truly revolutionised modern medicine.

In this blog, we’ll explore everything you need to know about CT scans, from how they work and their types to the procedure, benefits, risks, and even how they differ from MRI scans.

What is a CT Scan?

A CT scan is a beneficial medical test that combines X-ray technology with advanced computer imaging to produce detailed pictures of what's happening inside your body. It helps us see organs, bones, and blood vessels clearly, which can be particularly helpful for doctors to diagnose health conditions accurately. The process involves a moving X-ray tube and detector that work together to capture images from different angles, then carefully piece them together to show cross-sections of your body. Unlike MRI and PET scans, which employ various methods, CT scans utilise X-rays to provide detailed images, enabling doctors to diagnose health issues more quickly and accurately.

Common Medical Conditions Diagnosed with CT Scans

CT scans are a vital part of today's medical toolkit, providing detailed insights that help doctors detect a wide range of diseases and injuries. Here are some common medical conditions that can often be diagnosed with CT imaging.

• Neurological Conditions: CT scans can also detect conditions affecting the brain. It identifies issues such as brain haemorrhage, strokes, and tumours. It can also assess the severity of neurological conditions or head injuries in an accident.
• Cancers and Tumours: A tomography scan can help identify the size, shape, and location of tumours and monitor the effectiveness of cancer treatments. It can detect liver, lung, brain, and pancreatic cancers.
• Injuries: In the event of an accident or trauma, a CT scan can diagnose internal injuries like fractures, bleeding or organ damage. They are beneficial in assessing complex bone fractures, spinal, or head injuries.
• Infections: CT scans can detect infections in the body, including abscesses in organs such as the liver or lungs, and bone infections, such as osteomyelitis.
• Lung Conditions: CT scans are also helpful for detecting lung diseases, such as tuberculosis, pneumonia, and blood clots in the lungs (pulmonary emboli). They also monitor chronic lung conditions such as chronic obstructive pulmonary disease and screen for lung cancer.
• Cardiovascular Conditions: A CT scan helps diagnose heart diseases or conditions, such as aneurysms, blood clots, and coronary artery disease. It can also detect blockages, evaluate the aorta, or detect other abnormalities in the blood vessels.
• Musculoskeletal Disorders: A computed tomography (CT) scan can detect abnormalities in muscles and soft tissues. It also diagnoses diseases and conditions affecting bones and joints, such as bone tumours, arthritis, and complex fractures.
• Stomach/Abdominal Issues: A stomach CT scan can detect abnormalities in the intestines, pancreas, and other abdominal organs. It is effective in detecting causes of urinary tract bleeding. It can also diagnose abdominal problems like kidney stones, appendicitis, and liver diseases.

CT Scan Procedure: The Step-by-Step Journey! 

A CT scan consists of a series of well-organised steps to produce detailed images of the body. Below are the specific steps involved in the CT scan procedure. 

CT Scan Preparation

A CT scan is performed by a radiographer, who is a specialist in interpreting medical images and reviewing scans. Before starting the body scan, the radiographer may ask the patient to change into a hospital gown and remove any metallic objects, such as jewellery, piercings, and watches, that could interfere with the imaging. They might use a contrast dye to highlight specific body areas in a few cases. Depending on the target area, the dye may be injected, swallowed, or administered rectally.

Positioning for the Scan

The patient must take the correct position before starting the computed tomography scan. He will be asked to lie on a motorised table that slides into the circular opening of the CT scan machine. The patient must remain still during the scan to ensure clear images for an accurate diagnosis.

X-ray Emission

The CT scanner has an X-ray tube that rotates around the patient’s body. As it spins, it emits a series of narrow X-ray beams from different angles. 

Image Capture

X-ray detectors opposite the X-ray tube capture the X-rays that pass through the patient’s body. Each rotation produces numerous cross-sectional images, or slices, of the area being examined for diagnosis.

Image Processing

After the patient’s scan, a powerful computer processes these X-ray beams and converts them into detailed, cross-sectional images of the body. These slices are then stacked together to form a three-dimensional image, providing a comprehensive view of the patient’s body’s internal structure.

Review and Analysis of the Images

Finally, the radiologist reviews and analyses the scans for abnormalities such as tumours, fractures, infections, or other medical conditions. After the review, they share a detailed report with the patient’s referring doctor. 

Types of CT Scans

Not all CT scans are the same; different types focus on various areas of the body, allowing doctors to diagnose conditions more accurately. Let’s take a closer look at the different types of CT scans:  

Contrast vs. Non-contrast CT Scans

CT scans can be done with or without contrast dye, and each type helps us see different things. Here’s a helpful table that compares these two types of CT scans, making it easier for you to understand the differences.

The use and choice between the two depend on the specific medical condition and the patient’s overall health.

Specialised CT scans: PET-CT Scan for Cancer

It is an advanced imaging technique that combines positron emission tomography (PET) and computed tomography (CT) to provide detailed information about the body’s anatomy and metabolic activities. It is often used to diagnose and manage cancer.

PET-CT scans help detect cancer early by identifying areas of increased metabolic activity. They determine the extent of the tumour and help plan an appropriate treatment. PET-CT scans also help track the efficacy of cancer treatment by comparing visuals over time and identifying cancer recurrence earlier than other methods. PET-CT scans can detect different types of cancer in the body, such as lung, head, neck, breast, thyroid, melanoma, and lymphoma.

• A PET-CT scan can also check:
• Heart attack
• Coronary artery diseases
• Heart problems Brain disorders
• Brain tumours
• Epilepsy
• Dementia
• Alzheimer’s disease

What is the Most Common Reason for a CT Scan?

CT scans are a highly valuable tool for examining the inside of your body, helping doctors to promptly and precisely identify injuries, infections, and diseases. Here's a list of some reasons and the specific body parts that your doctor might recommend for a CT scan.

• CT Scan for Chest: Performs examinations of the lungs, heart, infections, and tumours.
• CT Scan for the Brain and Head: Identifies strokes, brain injuries, tumours, and swelling.
• CT Scan for the Spine: Identifies injuries, herniated discs, and aids in surgical planning and treatment.
• CT Scan for the Stomach, Abdomen, and Pelvis: Diagnoses include appendicitis, liver or kidney problems, tumours, and bowel issues.
• CT Scan for Bones & Joints: Identifies fractures, infections, tumours, and joint problems.
• CT Scan for Neck: Examines arteries, thyroid, masses, and lymph nodes.
• CT Scan for Heart & Blood Vessels: Identifies blockages, aneurysms, and heart-related issues.
• CT Scan for Arms and Legs: Identifies fractures, soft tissue injuries, infections, and tumours.

What to Expect During the CT Scan Procedure?

CT Scans are usually performed on an outpatient basis. The procedure might depend on the medical condition and the doctor's recommendation. Here’s what you can expect during a CT scan procedure:

• You might be asked to change into the patient gown. All your piercings and jewellery will be removed so that they do not interfere with the CT Scan.
• If your scan is performed with contrast, an IV line will be started in the hand or arm for injection of the contrast media. In the case of oral contrast, you will be given a liquid contrast preparation to swallow.
• You will be asked to lie down on a scan table that slides into a large, circular opening of the scanning machine.
• The practitioner performing the scan would be in another room. However, you would be in constant contact with us through speakers and a call button.
• As the scanner starts to rotate, the X-rays pass through the body, accompanied by a clicking sound from the CT Scan machine. Keep still and hold your breath as directed.
• When the procedure is complete, you will be removed from the scanner. Drink plenty of water to help eliminate the contrast agent.
• While the CT procedure itself causes no pain, if you experience any discomfort, you should inform the doctor.

CT Scan vs. MRI and Other Imaging Techniques 

Here’s the comparison between CT scans and other types of imaging techniques in India:

What are the Side Effects of a CT Scan? 

CT scans are a safe and non-invasive way to examine the inside of the body; however, it's essential to be aware of potential side effects. 

• Contrast Dye Reaction: In rare cases, the contrast dye used in CT scans can cause allergic reactions, including mild itching and anaphylaxis. Patients may experience a warm sensation as contrast material spreads through the body.
• Radiation exposure: Ionising radiation may increase the risk of cancer. This risk is higher in pregnant women and children. 
• Discomfort: A metallic taste is a common side effect associated with IV contrast agents. There is also a possibility of nausea after receiving a contrast agent. Mobility issues can also cause physical discomfort.

How Do You Minimise CT Scan Risks?

Minimise the risks and side effects of the CT scan by following these steps:

• Inform the doctor about allergies and past medical conditions.
• Stay hydrated before and after body scans.
• Follow the pre-scan and post-scan instructions properly. 

Medical Conditions to Consider Before a CT Scan

Before undergoing a CT scan, it’s highly recommended that you consider the following medical conditions:

• Chronic or acute kidney problems
• Pregnancy
• Allergies, especially to contrast material
• Thyroid disorders
• Heart conditions
• Asthma
• Diabetes, particularly if taking metformin
• Dehydration

Inform your healthcare provider about these conditions to help plan the scan safely and effectively.

>> Read More: Health Insurance Costs and Role of Fitness Programs

Wrapping Up!

A CT scan is the most common test for diagnosing underlying medical conditions. It is a vital tool for modern medicine, providing detailed, high-resolution imaging that surpasses regular X-rays. It is versatile and accurately diagnoses most conditions, from tumours to cancers. For any treatment diagnosis, a body scan is essential; if you have health insurance coverage, your expenses can be mitigated. Therefore, choose the best health insurance to protect your financial future. 

Disclaimer: The above information is for reference purposes only. Kindly consult your general physician for verified medical advice. The health insurance benefits are subject to policy terms and conditions. Refer to your policy documents for more information.