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When a CT Scan or Other Imaging Test Finds an Unexpected Abnormality

Date: January 1, 2017      Publication: Bottom Line Health      Source:  Stella K. Kang, MD, MS, NYU Langone Medical Center      Print:

You’re having abdominal pain and visit your primary care physician. As part of the workup, your doctor orders a CT scan of your abdomen and pelvis to rule out possible causes, such as an infection. The results arrive two days later, and there’s nothing obviously wrong with your bowels. But…

In the report accompanying the scan, the radiologist noted an incidental finding (IF)—a spot on your kidney that was “too small to characterize.”

Is it a harmless cyst…or a tumor that might grow and spread if left untreated? Should your doctor ignore it for now…or order more tests, possibly opening a medical Pandora’s box that could perhaps entail a biopsy and raise radiation exposure? More and more patients and doctors are facing such questions.

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Incidental findings—when a physician investigating a specific problem finds another possible problem (known in doctor-speak as an “incidentaloma”)—are on the rise, in part because scanning technology is more precise than ever before.

Eye-opening statistics: On average, about 40% of all scans reveal an incidental finding. For two common imaging tests—CT of the abdomen and pelvis…and CT of the thorax (below the neck and above the abdomen)—IFs are now detected 61% and 55% of the time, respectively. Basic types of IFs… 

  • High risk. This type could cause real harm, even death, if it’s not discovered and dealt with. Example: A large cancerous kidney tumor.
  • Intermediate risk. This type has some potential to cause future harm, with a need for medication or other treatment. Example: A kidney stone that is asymptomatic.
  • Low risk. This type has a greater than 99% chance of never causing harm. Example: A benign kidney cyst, which does not interfere with kidney function.

Why it gets tricky: Even though the discovery of an abnormality can sometimes be lifesaving (when an asymptomatic malignancy is found, for example), there are few medical standards for reporting and managing IFs—often leading to unnecessary testing and treatment of low- and intermediate-risk IFs.

BEST STRATEGIES

Here are ways to increase the likelihood that IFs are responded to safely and effectively—but unnecessary follow-up is avoided…

If your doctor orders any type of imaging test (X-ray, CT, PET or MRI scan, for example), ask about the likelihood of an IF. You should know before the test whether or not it’s likely to uncover an IF—so you’re less apt to be surprised and frightened if an IF is found. Helpful: Before the test, ask your doctor to give you a quick overview of high-, intermediate- and low-risk IFs commonly produced by the test.

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To ensure that you are made aware of any IFs from an imaging test, ask to receive a copy of the radiologist’s report so that you can discuss it with your doctor.

Partner with your primary care doctor. With its array of specialists and subspecialists, medical care is increasingly fractured—making it more likely that specialist-ordered testing will follow the discovery of any IF, including those that are intermediate- and low-risk.

Best: Even if a specialist ordered the test, talk over the results with your primary care physician. He/she is likely to have a sense of your overall health and preferences regarding medical interventions such as testing.

If there’s an IF, get an accurate description of the risk. Sometimes a doctor will talk in vague terms about the risk from an IF—for example, “It’s probably not going to hurt you.” But that’s not enough information to effectively partner with your doctor in deciding if more testing is appropriate.

Best: Ask for a statistical estimation of risk. Is the likelihood of harm (such as cancer that could metastasize or an enlarged blood vessel that could rupture) from the IF one out of 10? One out of 1,000? If the numerical level of risk is hard to understand, ask the doctor to explain it another way.

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Ask if the American College of Radiology (ACR) recommends further imaging for this type of IF. The ACR, the professional organization for radiologists, has guidelines for further investigation of some of the most common IFs, such as thyroid nodules, ovarian nodules and IFs discovered during abdominal CTs.

Best: Ask your physician if there are ACR guidelines for your IF and if he is following them.*

Ask your doctor to consult with the radiologist. When certain IFs don’t fall under ACR guidelines, radiologists don’t always agree about their significance or management. One radiologist might recommend further testing. Another might say no additional testing is necessary. A third might not make a recommendation, letting the primary care physician decide what to do next.

Best: If your test has an IF with unclear implications for management, your doctor might schedule a joint consultation with the radiologist so the three of you can talk through your options—a strategy that is effective but underutilized.

Get a second opinion. When a lesion is indeterminate (unclear in importance), consider asking your doctor to have another radiologist take a look at the result.

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Best: Ask your doctor to recommend a consultation with a subspecialist—for instance, if the IF is on the kidney, talk to a radiologist who is expert in examining the kidney.

WHEN FOLLOW-UP IS NEEDED

Some IFs require follow-up testing and medical care. Discuss follow-up options with your doctor for… 

  • Lung nodules—a risk factor for lung cancer—found during a CT of the thorax.
  • Coronary artery calcification—a risk factor for a heart attack—detected during a CT of the chest or a CT of the abdomen and pelvis.
  • A solid lesion on an ovary, which could be a tumor, revealed by an abdominal and pelvic CT.
  • Enlarged lymph nodes, which may be related to infection or malignancy, found during a pelvic MRI.
  • Enlarged aorta (aneurysm) found by an abdominal CT. If this major blood vessel is enlarged, you could be at increased risk for it to break open and cause severe bleeding that could be fatal.

*To read the American College of Radiology’s guidelines on incidental findings, go to Nucradshare.com.

Source: Stella K. Kang, MD, MS, an assistant professor of radiology and population health at NYU Langone Medical Center in New York City. She is the author or coauthor of more than two dozen scientific papers that have been published in the Journal of the American College of Radiology, Clinical Oncology and other leading medical journals.