What is a CT Scan? Purpose, Procedure & Results

A CT scan is a medical imaging test that takes detailed pictures of the inside of your body using X-rays and computer technology. Think of it as a more advanced version of a regular X-ray that can see your organs, bones, and tissues in thin slices, like looking through pages of a book.

This painless procedure helps doctors diagnose injuries, diseases, and monitor your health with remarkable precision. You'll lie on a table that slides through a large, doughnut-shaped machine while it quietly captures images of your body.

What is a CT scan?

A CT scan, also called a CAT scan, stands for "computed tomography." It combines multiple X-ray images taken from different angles around your body to create cross-sectional pictures of your bones, blood vessels, and soft tissues.

The machine rotates around you while you lie still, taking hundreds of detailed images in just minutes. A computer then processes these images to create clear, detailed pictures that doctors can examine on a screen.

Unlike regular X-rays that show only bones clearly, CT scans reveal soft tissues like your brain, heart, lungs, and liver with excellent detail. This makes them incredibly valuable for diagnosing a wide range of conditions.

Why is a CT scan done?

Doctors recommend CT scans to diagnose medical conditions, monitor treatment progress, and guide certain procedures. This imaging test helps them see inside your body without making any cuts or incisions.

Your doctor might order a CT scan if you're experiencing unexplained symptoms like persistent pain, unusual lumps, or concerning changes in your health. It's also commonly used after accidents to check for internal injuries.

Here are the main reasons doctors use CT scans, and understanding these can help ease any concerns you might have about why your doctor recommended this test:

• Diagnosing injuries from accidents or falls, especially head trauma and internal bleeding
• Detecting cancers, tumors, or unusual growths anywhere in your body
• Monitoring how well cancer treatments are working
• Checking for blood clots, especially in your lungs or legs
• Evaluating heart disease and blood vessel problems
• Diagnosing infections, particularly in your abdomen or chest
• Guiding biopsies and other medical procedures
• Detecting kidney stones or gallstones
• Evaluating bone fractures and joint problems
• Checking for internal bleeding or fluid buildup

Most of these conditions are treatable when caught early, which is why CT scans are such valuable diagnostic tools. Your doctor is simply gathering the information needed to provide you with the best possible care.

What is the procedure for a CT scan?

The CT scan procedure is straightforward and typically takes 10-30 minutes from start to finish. You'll change into a hospital gown and remove any metal jewelry or objects that might interfere with the imaging.

A technologist will position you on a narrow table that slides into the CT scanner, which looks like a large doughnut. The opening is wide enough that most people don't feel claustrophobic, and you can see through to the other side.

Here's what happens during your scan, step by step, so you know exactly what to expect:

1. You'll lie down on the padded table, usually on your back
2. The technologist may use pillows or straps to help you stay in the correct position
3. If you need contrast dye, it will be given through an IV or by mouth
4. The table will slowly slide you into the scanner opening
5. The machine will make whirring or clicking sounds as it takes pictures
6. You'll need to hold your breath for short periods (10-20 seconds) when instructed
7. The table may move slightly between different sets of images
8. The technologist will communicate with you through an intercom
9. You can press a call button if you need help at any time

The actual scanning takes just a few minutes, though the entire appointment may last longer if you need contrast dye or multiple scans. You'll be able to go home immediately afterward and return to your normal activities.

How to prepare for your CT scan?

Most CT scans require minimal preparation, but your doctor's office will give you specific instructions based on which part of your body is being scanned. Following these instructions helps ensure clear, accurate images.

If your scan requires contrast dye, you might need to avoid eating or drinking for several hours beforehand. This helps prevent nausea and ensures the contrast material works properly.

Your preparation might include these important steps, and taking care of them ahead of time will make your appointment go smoothly:

• Remove all jewelry, piercings, and metal objects before the scan
• Wear comfortable, loose-fitting clothing without metal zippers or buttons
• Tell your doctor about any medications you're taking
• Inform staff if you're pregnant or might be pregnant
• Mention any allergies, especially to contrast dye or iodine
• Follow fasting instructions if your scan requires contrast material
• Drink plenty of water before scans that need oral contrast
• Arrange transportation if you'll receive sedation
• Bring a list of your current medications
• Arrive 15-30 minutes early for check-in and paperwork

If you have kidney problems or diabetes, make sure to discuss this with your doctor beforehand. They may need to adjust your preparation or use different contrast materials to keep you safe.

How to read your CT scan results?

A radiologist, a doctor specially trained in reading medical images, will analyze your CT scan and write a detailed report for your doctor. You'll typically receive results within a few days of your scan.

Your doctor will explain what the results mean for your health and discuss any necessary next steps. CT scan reports can seem complex, but your healthcare provider will translate the medical terms into language you can understand.

Here's what different findings on your CT scan might indicate, though remember that your doctor is the best person to explain what these mean for your specific situation:

• Normal results mean no abnormalities were found in the scanned area
• Abnormal results might show tumors, infections, or structural problems
• Contrast enhancement can help identify areas of inflammation or unusual blood flow
• Size measurements help track changes over time
• Bone density information reveals fractures or bone diseases
• Organ shape and position show whether everything is in the right place
• Fluid collections might indicate infections or bleeding
• Blood vessel imaging can reveal blockages or abnormalities

Remember that abnormal findings don't always mean something serious is wrong. Many conditions found on CT scans are treatable, and early detection often leads to better outcomes.

What are the risks and complications of CT scans?

CT scans are generally very safe, but like any medical procedure, they do carry some small risks. The most common concern is radiation exposure, though the amount used in modern CT scanners is kept as low as possible while still producing clear images.

The radiation dose from a CT scan is higher than a regular X-ray but still relatively low. For perspective, it's similar to the natural background radiation you'd receive over several months to a few years.

Here are the potential risks to be aware of, though serious complications are quite rare:

• Radiation exposure, which slightly increases cancer risk over a lifetime
• Allergic reactions to contrast dye, ranging from mild to severe
• Kidney problems from contrast material, especially in people with existing kidney disease
• Nausea or vomiting from oral contrast material
• Injection site irritation if contrast dye leaks from the IV
• Anxiety or claustrophobia, though this is uncommon due to the open design

Pregnant women should avoid CT scans unless absolutely necessary, as radiation can potentially harm a developing baby. Always tell your doctor if you're pregnant or might be pregnant.

Your healthcare team takes every precaution to minimize risks while getting the images needed for your care. The benefits of accurate diagnosis almost always outweigh the small risks involved.

When should I see a doctor about CT scan results?

Your doctor will contact you once your CT scan results are ready, usually within a few days. They'll schedule a follow-up appointment to discuss the findings and any recommended next steps for your care.

Don't worry if your doctor wants to see you in person to discuss results. This is standard practice and doesn't necessarily mean anything is wrong. Many doctors prefer face-to-face conversations for all results, both normal and abnormal.

You should contact your doctor's office if you experience any of these situations after your CT scan:

• You haven't heard about your results within a week of your scan
• You develop new or worsening symptoms while waiting for results
• You have questions about your results or recommended treatment
• You experience delayed reactions to contrast dye, such as rash or swelling
• You need copies of your images for another doctor or second opinion
• You're feeling anxious about the results and need reassurance

Remember that your healthcare team is there to support you throughout this process. Don't hesitate to ask questions or express concerns about your CT scan or results.