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How accurate is a CT scan for cancer? Should you get one?

Key takeaways:

  • A CT scan is a fast, painless, and non-invasive medical imaging test used to screen for cancer.
  • While this is a good test to detect some tumors in certain parts of the body, it is not as effective for other cancers.
  • A CT scan uses ionizing radiation that may increase the risk of developing cancer. An MRI scan does not have harmful ionizing radiation.
  • An MRI scan may be a good alternative where CT scanning is not ideal.

Cancer is the second leading cause of death in the U.S., and its financial and social impact on American lives is considerable. Thankfully, early detection of this disease can help improve prognosis. Medical imaging tests have become more popular recently for cancer detection. CT (computed tomography) scan is one such imaging test. But how accurate is CT scan for cancer? Let’s try to understand. 

How accurate is a CT scan for cancer? A research-based answer.

How accurate is CT scan for cancer: doctor talking to a patient

No single imaging test is 100% accurate in detecting abnormalities. There may be a misdiagnosis due to the quality of the scan or due to the expert reading the scan.

The answer to the question, “How accurate is CT scan for cancer?” lies in a combination of the equipment, quality of the scan, and the radiologist reviewing the images.

A CT scan, or CAT scan, is useful for staging cancer. It can help one find out how cancer is present in a patient’s body and its location and is usually the first choice imaging test. A CT scan is a better alternative to scan areas of the body where there is motion. It is thus better suited for screening for cancer in the lungs and the bowel (colon), where it can detect even very small tumors. 

In case of screening lungs for cancer, a CT scan can produce better images than an MRI. It has the ability to detect calcification.

A CT scan can image a potential tumor’s shape, size, and location. It also helps healthcare practitioners understand how the tumor is responding to a treatment regimen.

CT scans can also be good at scanning blood vessels and may help find blockages and other abnormalities. They may also be used to guide certain medical procedures, like biopsies.

A CT scan is not ideal for imaging all kinds of tissues. In such cases, an MRI (magnetic resonance imaging) test is often helpful. 

At Ezra, we understand the benefits of both these tests and use them accordingly to screen for cancer in up to 14 organs. An MRI scan has a high degree of sensitivity, enabling us to see potential abnormalities smaller than 2 mm.

How does a CT scan work?

A CT (computerized tomography) scan is usually performed as an outpatient procedure. The CT scanner is a doughnut-shaped machine with a sliding table that moves back and forth. The patient lies on the table, and it slides through the center of the hole of the scanner. 

Inside the round scanner, an X-ray tube rotates and emits a thin beam of X-rays at different angles that quickly pass through the patient’s body and are received at the opposite end. The signals are then passed to a computer where special software creates detailed images of the inside of the body. 

The CT images seem like “slices” of the body part being scanned. These sliced images help the radiologist observe the inside of your body. 

The CT scan is a painless and non-invasive procedure. All you need to do is lie as still as possible while the scanning is being done. Depending upon the part of the body being scanned, it may take anywhere from 10 to 30 minutes. During the scan, you may be asked to hold your breath for a few seconds.

CT scan with contrast.

In some cases, you may be given a contrast agent before scanning. This chemical dye helps create better images that help the radiologist see a problem clearly. The contrast agent is usually a chemical derivative of barium or iodine and can be given either orally, as an enema, or through an IV drip.

Some people may experience mild allergic reactions to a contrast dye, such as rash, nausea, or itching. These side effects usually subside after a while. If you have kidney issues, the contrast material can cause serious problems. 

If you suffer from a liver or kidney disease or have allergies, let your care team know before they give you a contrast. They will then evaluate the need to give you a contrast.

Drawbacks of a CT scan.

While a CT scan is a good imaging test to screen for cancer, it does have some limitations. It’s not the best test to screen for different types of cancers in all areas of the body. Another limitation of CT scanning is that there is a high rate of nodule detection. In a study, a benign nodule was detected in over 50% participants, leading to follow-up scans. This increased the risk of radiation as well as cost.

Secondly, a CT scan uses ionizing radiation. While the amount of radiation from a single CT scan may not pose much danger, every subsequent CT scan will increase the risk of radiation exposure in a patient. This should be weighed against the benefits of getting a CT scan, such as identifying abnormalities in different parts of the body.

One example of a situation that may need regular CT scans is undergoing cancer treatment. If the cancer is in an area such as the lungs, regular CT scans can help practitioners see how the treatment is working. In this case, the patient’s cumulative radiation dose increases.

At Ezra, we use a low-dose CT (LDCT) scan as part of our cancer screening service to scan the chest for lung cancer. As the name implies, this scan uses a very low dose of ionizing radiation and also leverages the advantage CT scanning has over other imaging tests in scanning the chest for signs of cancer.

Is an MRI scan a better alternative to a CT scan alone?

Happy couple sitting on their sofa

Due to the risk of radiation with CT scan, a safer alternative is an MRI (magnetic resonance imaging) scan. 

Along with being painless and non-invasive, it does not use any harmful ionizing radiation that may increase the risk of cancer. This imaging method uses a combination of radio waves and a strong magnetic field to create sharp, clear images of the inside of the body.

In some cases, an MRI is much better at showing certain cancers than a CT scan. 

For instance, prostate and uterus cancers and certain liver cancers are difficult to detect by a CT scan, and an MRI scan is often a better option. For example, a multiparametric MRI, which is used by Ezra, is usually recommended for screening for prostate cancer. Similarly, bone and brain metastases are usually better observed by an MRI scan.

How Ezra uses MRIs.

At Ezra, we leverage the advantages of MRI scans using state-of-the-art equipment and the expertise and experience of our dedicated healthcare team to make cancer screening fast, accurate, and affordable.

Our MRI protocol is in it’s sixth generation, has been validated through over 400 test scans that were verified for standard of cancer from 5 radiologists. We use 3T strength magnets and multiparametric MRI for our imaging to increase specificity and minimize false positives of cancer findings. 

The Ezra Scan.

The Ezra Scan is a full-body scan service designed to screen for cancer in up to 14 internal organs. Our full body imaging provides a holistic approach to screening for early cancer— as we’re able to look at findings across the body to detect abnormalities. It is a 60-minute MRI-based scan and a 5-minute low-dose CT of the chest that includes an optional follow-up consultation with a Medical Provider to walk through your results.  

So far, 72% of our members have had clinically significant findings from our scan1. Throughout your entire Ezra experience, you’ll be guided by a personal Care Advisor. Your Ezra Report includes recommendations on your findings, including lifestyle and dietary changes as well as follow up steps for any signs of possible cancer.

The Ezra MRI Protocol.

Our full body MRI protocol has been optimized to find cancer early while being relatively fast—at 60 minutes. Our protocol is in its 6th generation and combines 40 different series and thousands of MR images to cover most major vital organs. 

We’ve run over 400 test scans that have been reviewed by 5 radiologists and a data science team for ensuring high quality care.  We use multiparametric MRI (multiple sequences in multiple planes) to increase the specificity of our findings and minimize false positives of cancer findings. MRIs have a high degree of sensitivity, making it possible to catch early cancer as small as 2 mm (or 4 pixels wide).

The Ezra Full Body.

At $1,950 or $180 a month, the Ezra Full Body screens for potential cancers in the head, neck, abdomen, and pelvis. Here is a list of the organs covered from our Full Body:

  • Brain
  • Spine
  • Thyroid
  • Liver
  • Gallbladder
  • Pancreas
  • Spleen
  • Kidney
  • Adrenal glands
  • Bladder
  • Ovaries
  • Uterus
  • Prostate

The Ezra Full Body Plus.

At $2,350 or $220 a month, the Ezra Full Body Plus is our most advanced service that scans up to 14 organs by including a 5-minute low-dose chest CT for those who medically qualify, coronary calcium scoring of the heart, and a Prostate MRI with IV contrast to screen for prostate cancer.

The Ezra Mammogram.

The Ezra Mammogram is a 3D mammogram that screens for breast cancer. This 20-minute procedure is simple to book and offers results within 48 hours of the scan.

Which scan is better?

The answer to this question is “It depends.” As discussed earlier, no single imaging test is confirmatory and medical practitioners may go back and forth as needed. For instance, they may order a CT scan and if they see something and are unsure about it, they may order an MRI, and vice versa. Medical imaging is all about deciding whether the benefits of a particular test outweighs its risks. The final diagnosis that the experts reach is often done using a combination of tests and the sound judgment and experience of the medical team.  

Early detection may save your life.

Early cancer diagnosis has been found to offer a good prognosis and increase survival rates

To keep a step ahead of cancer, Ezra helps put time and knowledge on your side. With our state-of-the-art cancer screening service, we help you take control of your health.

While a CT scan is faster and more affordable than an MRI scan, it isn’t always the best test for screening for all possible cancers. 

The Ezra Scan is an elective full body scan service that is accurate, sensitive, and better at identifying potential cancer than a CT or ultrasound alone. You can also use your FSA/HSA dollars to pay for the Ezra Scan. While you wait to decide on when to book your first scan, take our 5-minute quiz to assess your risk of cancer.