Imaging tests — such as MRIs, X-rays, and CT scans — are one category of tools that doctors use to help diagnose pancreatic cancer.

A CT scan is often one of the first imaging tests done during the diagnostic process. While a CT scan alone isn’t enough to diagnose pancreatic cancer, it can provide images that help doctors determine the size and location of tumors.

Depending on the results, a CT scan might be followed by additional testing, such as an endoscopic ultrasound and a biopsy.

In this article, we take a closer look at computed tomography (CT) scans and how they’re used to diagnose pancreatic cancer.

Computed tomography (CT) scans are imaging tests that use computer images and X-rays to create detailed images of the inside of the body. With the addition of computer images, CT scans provide more information than X-rays alone.

Doctors use CT scans to get a look at body parts such as bones, organs, blood vessels, fat, tissues, and muscle.

The scan works by sending X-ray beams in a circle around the body. The circular motion allows images to be taken from different views.

A computer then interprets these views and puts them together to create three-dimensional images.

CT scans are an important part of the diagnostic process for many types of cancer, including pancreatic cancer. CT scans can create clear images of the pancreas, helping doctors see the exact size and location of a tumor.

A CT scan can also show whether the cancer has spread to surrounding areas such as your lymph nodes. Often, CT scans for pancreatic cancer are done with contrast dye. The dye helps create clearer images.

There are a few different types of CT scan you might have if your doctor suspects pancreatic cancer. This includes:

  • Multiphase CT: A multiphase CT involves a set of images taken over several minutes to monitor for changes.
  • Cross-sectional CT: A cross-sectional CT scan takes images at different angles of your body to get an even better idea of the size and scope of your tumor.
  • CT-guided needle biopsy: A CT-guided needle biopsy is a type of diagnostic biopsy that is done with the aid of a CT scan.

Pancreatic cancer can be seen as a mass on a CT scan. In most cases, it’s easier to see pancreatic cancer when contrast dye is used. Contrast dye helps the mass stand out from the tissue surrounding it.

You can see examples in the photos below.

A CT scan is a noninvasive procedure. It’s most often done in an outpatient setting, meaning you won’t have to stay overnight in a hospital, and you’ll be able to drive yourself to and from your appointment.

You’ll also be able to eat, drink, and take all of your standard medications on the day of your CT scan. However, if you’re having a CT scan with contrast, you’ll be asked not to eat or drink for about 3 hours before the test.

Your doctor will let you know in advance if you’ll be having a CT scan with contrast dye.

Once you arrive at your appointment, you’ll be asked to change into a patient gown. It’s important to remove all jewelry, including earrings and other piercings, before the CT scan. You’ll have a locker or other space to store your clothing during the test.

You might receive contrast liquid orally, by IV, or both ways, depending on your doctor’s recommendations. You’ll then lie back on a cushioned table that will slide into the scanning machine.

The CT technologist will go into another room, but they’ll give you a microphone that will allow you to talk with them during the test.

The machine will revolve around you as it takes X-rays. You’ll need to lie still as the machine rotates. CT scans don’t cause pain.

You might have an unpleasant taste in your mouth or feel slight nausea from the contrast solution, but for most people, these effects are mild and only last a moment or two.

CT scans typically take about 15 minutes, but they can also be longer, up to 1 hour and 15 minutes, if you’re having a scan with contrast dye.

You’ll be able to get up and get dressed after the scan. It’s important to note that some people do have reactions to contrast solutions, and some people can’t lie comfortably still on a flat surface for the test.

Talk with your doctor if you’re concerned about having a CT scan. There are ways to modify the standard procedure, and there are alternatives to a CT scan.

CT scans are an important tool for diagnosing pancreatic cancer, but they’re not 100 percent accurate. They can miss cancer in some people.

Research shows CT scans have an accuracy rate of about 83.3%. That’s less than magnetic resonance imaging (MRIs), which have an accuracy rate of 89.1%, and endoscopic ultrasounds (EUSs), which have an accuracy rate of 92.7%.

CT scans aren’t enough on their own to diagnose pancreatic cancer. You’ll likely have a variety of other tests if your doctor suspects pancreatic cancer. This will include:

  • Positron emission tomography (PET): A PET scan is an imaging test that has you swallow a sugar substance prior to the scan. Cancer cells use more sugar than normal cells and will appear brighter in images. This test is used to see if cancer has spread.
  • MRI: An MRI uses magnetic imaging to create three-dimensional images. Sometimes, a specialized type of MRI, called an MRI cholangiopancreatography, is done to view the pancreatic and bile ducts.
  • Endoscopic ultrasound (EUS): An EUS uses a thin tube called an endoscope to insert a small ultrasound probe directly into your pancreas. Sometimes, tissue and fluid samples for a biopsy are taken during an EUS.
  • Endoscopic retrograde cholangiopancreatography (ERCP): An ERCP uses dye to make the bile ducts visible. Images are then taken with an endoscope, and cells are often collected for a biopsy.
  • Percutaneous transhepatic cholangiography (PTC): A PCT test is done by placing a thin needle into the liver to inject contrast dye for bile duct imaging. This test is very invasive and isn’t done if an ERCP is possible.
  • Biopsy: During a biopsy, samples of tissue, fluid, or cells are collected so that they can be tested for cancer in a lab. Biopsies are normally done at the same time as another test, such as an EUS or ERCP.

How long does it take to get CT scan test results back?

The length of time it takes to get your CT scan results back depends on the testing facility you use and on your doctor’s office.

It can be as little as a day or two or as long as about a week. You can ask your doctor or the CT technician to get a better idea.

Many medical facilities now have online patient portals that allow you to access your results much faster than in the past.

However, your doctor may prefer to share the news with you during a clinic visit when they can more carefully explain the results, answer questions, and discuss follow-up steps and treatment options, if needed.

Can you see cancer on a CT scan without contrast dye?

It’s much easier to see cancer on a CT scan when a contrast dye is used. In most cases, doctors prefer that CT scans for pancreatic cancer are done with contrast dye.

However, since not everyone is able to tolerate contrast dye, exceptions can be made.

What are the symptoms of pancreatic cancer and when should I get tested?

It’s common for people in the early stages of pancreatic cancer to not experience any symptoms at all. Sometimes, even later stages can be easy to mistake for less serious conditions.

Once symptoms appear, they can include:

If you have any of these symptoms, it is likely they’re a condition other than pancreatic cancer. However, if you’ve had them for more than a week or two, it’s best to make a medical appointment.

Pancreatic cancer has the best treatment options and outcomes when it’s diagnosed early.

Who’s at most risk for pancreatic cancer?

There are several known risk factors for pancreatic cancer. These include:

  • a family history of pancreatic cancer
  • inheriting family cancer syndrome
  • smoking
  • diabetes
  • obesity
  • chronic or hereditary pancreatitis
  • workplace exposure to pesticides and to chemicals used in metalwork
  • being over 65
  • being a man

You can read more about the risk factors that are linked to pancreatic cancer here.

CT scans are a key piece of the pancreatic cancer diagnostic process. They create detailed images that allow doctors to see inside the pancreas and get an idea of the size and scope of tumors.

Generally, CT scans for pancreatic cancer are done with contrast dye since this creates a clearer image.

A CT scan alone isn’t enough to diagnose cancer, but it can help doctors determine if further testing is needed. Following a CT scan, you might have more precise testing, such as an EUS or a biopsy.