An Incidental Finding on Your Scan: What Happens Next?

Here's a statistic that surprises almost everyone who hears it: incidental findings — those unexpected "by the way" discoveries on medical imaging — turn up in roughly 15–30% of all diagnostic imaging tests, and in 20–40% of CT and MRI scans, according to a 2024 analysis published in the Medical Journal of Australia. In other words, if you and three friends each had a CT scan tomorrow for four completely unrelated reasons, statistically at least one of you would walk out with something on the report nobody went looking for.

Now layer that over how much scanning Australians actually do. The Australian Institute of Health and Welfare reports that almost 2 in 5 Australians — over 10 million people — received more than 27 million Medicare-subsidised diagnostic imaging services in a single year. Multiply those numbers together and you get a very Australian phenomenon: hundreds of thousands of people every year opening a radiology report that mentions a nodule, a cyst, a lesion or a "focus of uncertain significance" that has absolutely nothing to do with the ankle, headache or cough that sent them for the scan in the first place.

If that's just happened to you, your heart rate is probably up. You may have already typed the words into Google at 11pm and found yourself three clicks deep into a forum thread from 2013. Take a breath. This article is here to walk you calmly through what an incidental finding on a scan actually is, why they're becoming so common, how doctors decide whether one matters, what follow-up imaging involves, and what your realistic next steps look like inside the Australian health system.

We're NextClinic, an Australian telehealth service, and we help people around the country every day with the practical side of this: getting a GP consultation quickly, organising a specialist referral, or sorting a medical certificate when appointments and procedures collide with work. We've seen how often the anxiety around an incidental finding comes not from the finding itself, but from not understanding the process. Let's fix that.

First, what exactly is an "incidental finding"?

An incidental finding — sometimes called an incidentaloma — is a lesion or abnormality that's discovered by chance on imaging performed for an entirely different reason. As the Medical Journal of Australia puts it, incidentalomas are lesions, usually without symptoms, that are serendipitously detected in patients undergoing imaging for an unrelated purpose.

Some real-world examples of how this plays out:

• You have a CT of your abdomen after a bout of severe pain, and the report mentions a small cyst on your kidney.
• You have a chest X-ray or CT for a persistent cough, and a 5 mm nodule shows up in your lung.
• You have a CT of your neck after a car accident, and a thyroid nodule is spotted at the edge of the images.
• You have an MRI of your brain for migraines, and there's a small area described as a "nonspecific white matter hyperintensity".
• You have a pelvic ultrasound for period pain, and an ovarian cyst is noted.
• You have a lumbar spine MRI for back pain, and the report lists disc bulges, facet joint arthropathy and a "Schmorl's node" — none of which anyone had mentioned before.

The crucial word is unrelated. The finding wasn't the question being asked. It was in the frame anyway, because modern scanners photograph everything in their field of view — in exquisite detail.

Why incidental findings are more common than ever

Three forces have collided, and the MJA analysis names them clearly: increasing use of imaging tests, an ageing population, and the enhanced image resolution of modern machines are all driving a surge in incidentalomas.

Think about what higher resolution really means. A scanner that can resolve a 2 mm structure will find 2 mm things. Twenty years ago, that same person would have had a scan, been told everything was fine, and lived a long and happy life never knowing about the 4 mm speck in their liver. The speck was always there. We just couldn't see it.

Then there's the sheer volume. The AIHW notes that in 2024–25, 18.3 million Australians (67%) received at least one Medicare-subsidised pathology, imaging or other diagnostic service. More scans mean more chances of an incidental discovery.

Emergency departments are a particular hotspot. A systematic review and meta-analysis published in Annals of Emergency Medicine00237-2/abstract), covering nearly 148,000 encounters across 16 countries, found the pooled prevalence of any incidental finding on ED CT scans was 31.3%. That's roughly one in three.

Even in healthy, asymptomatic adults, findings crop up. A systematic review in The BMJ of MRI in apparently asymptomatic adults found the pooled prevalence of potentially serious incidental findings was 3.9% across brain and body MRI — rising to 12.8% once findings of uncertain seriousness were included. So the majority of scans in well people are clear, but a meaningful minority are not.

What actually happens between your scan and your result

Understanding the workflow removes a lot of the mystery — and a lot of the dread.

Step 1: The images are taken. As healthdirect explains, radiographers are allied health professionals trained to take medical images. They are not permitted to interpret your scan or tell you what it shows, which is why the friendly person operating the machine goes quiet when you ask "does it look okay?" It's not bad news. It's their scope of practice.

Step 2: A radiologist reads them. The images go to a radiologist — a specialist doctor who interprets the findings and provides a written report to your referring doctor. The radiologist reads systematically: they answer the clinical question that was asked, then review everything else in the field of view.

Step 3: The report is written. It typically has a "Findings" section (everything seen) and an "Impression" or "Conclusion" (what the radiologist thinks it means, plus any recommendations). The Impression is the part your GP will focus on.

Step 4: The report goes to your referring doctor, and in most cases is also uploaded to My Health Record unless you've asked for it not to be.

*Step 5: Your doctor interprets it in the context of you.* This is the step people skip when they read their own report first — and it's the most important one. A radiologist sees pixels and a one-line clinical history. Your GP sees your age, family history, smoking status, medications, previous scans, examination findings and what you're actually experiencing.

Decoding radiology language (so it stops sounding terrifying)

Radiology reports are written doctor-to-doctor, not doctor-to-patient. A few translations that help:

• "Lesion" simply means an area that looks different from surrounding tissue. It is not a synonym for cancer. A freckle is a lesion.
• "Nodule" means a small rounded density. Extremely common in lungs and thyroids, and overwhelmingly benign.
• "Cannot be excluded" means the scan can't definitively rule something out — not that it's likely.
• "Clinical correlation is advised" means: doctor, please match this against the actual patient in front of you.
• "Of uncertain significance" means the radiologist genuinely doesn't know yet, and is flagging it honestly.
• "Nonspecific" means it doesn't have features pointing to a particular diagnosis, which is usually reassuring.
• "Unchanged from prior imaging" is one of the best phrases in medicine. Stability over time is powerful evidence of a benign process.

How clinicians decide whether an incidental finding matters

This is the heart of it. When a radiology report incidental finding lands on your GP's desk, they're weighing several factors at once.

1. Size

Size is the single most-used trigger in most guidelines. For lung nodules, the widely adopted Fleischner Society criteria stratify follow-up by nodule size and patient risk, with the explicit aim of reducing unnecessary CT scans for small indeterminate nodules while still catching what matters.

2. Imaging characteristics

Radiologists look at density, borders, internal contents and how a lesion behaves with contrast. In adrenal glands, for example, density measured in Hounsfield units helps distinguish a benign lipid-rich adenoma from something needing further work-up. The NSW Agency for Clinical Innovation sets out how assessment of an adrenal incidentaloma involves imaging, functional (hormone) testing and assessment of malignancy risk.

3. Which organ it's in

This matters enormously. The MJA review notes that fewer than 5% of incidental lesions involving the brain, parotid gland and adrenal gland prove malignant, whereas renal, thyroid, ovarian, pancreatic and breast incidentalomas are classified as malignant in 25–40% of cases — though the authors also stress that many of these cancers are indolent and may never cause harm.

4. Whether it's functional

Some incidentalomas are harmless in size but active hormonally. An adrenal nodule quietly producing excess cortisol or aldosterone can drive high blood pressure or metabolic problems, which is why blood and urine tests sometimes follow an imaging finding.

5. Your personal risk profile

Age, smoking history, family history, occupational exposures, previous cancers and immune status all shift the probability. An 8 mm lung nodule in a 32-year-old lifelong non-smoker is a very different conversation from the same nodule in a 68-year-old with a 40 pack-year smoking history.

6. Whether it explains your symptoms

Sometimes an incidental finding turns out to be the answer to a question nobody had asked yet. More often, it's genuinely unrelated — and part of your GP's job is making sure it doesn't distract from the original problem.

7. What action would realistically follow

Good clinicians ask a quietly powerful question: if we investigate this and find something, would it change what we do? For a frail 90-year-old with multiple conditions, chasing a slow-growing incidental lesion may cause more harm than benefit. This is core to shared decision-making.

The four possible pathways after an incidental finding

Once your doctor has weighed all that up, the outcome is almost always one of four things.

Pathway 1: No action at all

The most common outcome. Simple kidney cysts, tiny liver haemangiomas, degenerative spine changes and small benign-appearing nodules frequently need nothing beyond a note in your file. Your GP should tell you explicitly that no follow-up is needed, and it's worth asking for that in writing so a future doctor doesn't restart the process.

Pathway 2: Watchful waiting with follow-up imaging

Here you'll be booked for a repeat scan at a defined interval — 3, 6, 12 or 24 months is typical, depending on the guideline. The logic is elegant: rather than performing a biopsy on something with a low probability of being harmful, we let time act as the diagnostic test. If it hasn't changed, it's very likely benign. If it grows, we reassess.

If you're placed on a follow-up imaging pathway, the single most valuable thing you can do is diarise it. Follow-up recommendations get lost when people change GPs, move interstate or simply forget. Put it in your phone calendar with an alert a month before it's due.

Pathway 3: A different test

Sometimes the next step isn't another scan but a blood test, hormone panel, urine test, ultrasound or a dedicated targeted scan with a specific protocol. For thyroid nodules, Australian Prescriber outlines the standard investigative pathway including thyroid function testing and ultrasound characterisation.

Pathway 4: Specialist referral

If a finding meets criteria for specialist input, you'll be referred to a respiratory physician, endocrinologist, urologist, gynaecologist, gastroenterologist, neurologist or surgeon. Occasionally a biopsy follows. Referral does not mean bad news — it usually means the finding needs someone with a narrower, deeper expertise to characterise it properly.

If you know which specialist you need and you're just chasing the paperwork, our post on navigating specialist referrals in 5 minutes explains how an online GP referral can bridge the gap quickly.

The part nobody tells you: findings can cause harm too

It feels intuitive that finding more is always better. The evidence says otherwise, and Australian clinicians have been unusually vocal about it.

The MJA piece is titled "First do no harm in responding to incidental imaging findings" for good reason. Investigating an incidentaloma carries real costs: additional radiation from repeat CTs, procedural risks from biopsies, out-of-pocket expenses, time off work, and significant psychological burden. Being labelled a "patient with a nodule" changes how people feel in their own bodies, sometimes for years.

Then there's overdiagnosis — detecting a condition that was never going to cause symptoms or shorten your life. The thyroid is the textbook Australian case study. Australian Prescriber reports an estimate that 73% of thyroid cancer diagnoses in Australia in 2012 represented overdiagnosis — people who would never have developed symptomatic thyroid cancer in their lifetime, but who may still have had surgery and lifelong medication.

This is precisely why Choosing Wisely Australia, with the Royal Australian and New Zealand College of Radiologists among its founding partners, encourages conversations between doctors and patients about avoiding tests that don't add value. Not all tests help, and some can be costly or harmful.

None of this means findings should be ignored. It means the right response is proportionate — and that a recommendation of "no further action" is a legitimate, evidence-based clinical decision, not laziness.

What to do when you get an incidental finding: a practical checklist

1. Read the Impression, not just the scary word. Skim-reading a Findings section out of context is how people spiral. The Impression is where the radiologist tells you what they actually think.

2. Resist the 11pm search binge. If you're going to read, read Australian, evidence-based sources: healthdirect, InsideRadiology (run by RANZCR for consumers), and your relevant condition-specific national body.

3. Book a proper conversation. Not a hurried two-minute call. Ask for a standard or long consultation so there's time to discuss it.

4. Bring your questions written down. healthdirect's Question Builder is a genuinely useful free tool for this. Good questions include:

• What exactly was found, and how big is it?
• How likely is it that this is serious, in someone like me?
• What guideline are you using to decide the next step?
• What happens if we do nothing?
• When is the follow-up due, and who is responsible for booking it?
• What symptoms should prompt me to come back sooner?

5. Track down your old scans. If you've had imaging before — even years ago, even interstate — comparison images are gold. "Unchanged since 2019" can end an investigation in one sentence.

6. Write the plan down. Date, finding, size, plan, review date. Store it with your other health records.

7. Ask about cost upfront. Medicare rebates vary by item and provider, and follow-up MRI in particular can carry substantial out-of-pocket costs. Ask the imaging practice for a quote before you book, and ask your GP whether a bulk-billing provider is available in your area.

8. Don't let it derail the original problem. If you went in for knee pain, the knee still needs sorting.

Where telehealth fits into all of this

An incidental finding creates admin as much as anxiety — and that's a space where online care is genuinely useful for Australians, particularly outside the major cities.

Here's how we help at NextClinic:

Talking it through. Our telehealth consultations let you speak with an Australian-registered doctor about your scan results without waiting weeks for an in-person appointment. That's especially valuable in the anxious gap between receiving a report and seeing your usual GP.

Specialist referrals. If your finding warrants specialist assessment, we can issue a referral where clinically appropriate, so you can get onto a waiting list sooner rather than later.

Medical certificates. Follow-up scans, biopsies and specialist appointments happen during business hours. If you need documentation for time off, we can issue an online medical certificate — and if you're wondering whether employers accept them, our article on whether online medical certificates are legal in Australia covers the regulatory detail.

Prescriptions. If your investigation results in ongoing medication, our online prescription service can keep you supplied without a trip to the clinic each time.

A quick note on scope: telehealth is excellent for interpretation, planning, referrals and documentation. It is not a substitute for emergency care. If you develop severe chest pain, breathlessness, sudden severe headache, coughing up blood, or any symptom that frightens you, call 000 or go to your nearest emergency department. You can also call the healthdirect helpline on 1800 022 222 to speak with a registered nurse, 24 hours a day.

A word on "just get everything scanned" health checks

Whole-body screening scans marketed directly to consumers are increasingly available. They sound sensible — why not check everything? — but the evidence above explains the catch. Scanning asymptomatic people generates a substantial crop of findings of uncertain significance, most of which are harmless, but each of which can launch a cascade of tests, costs and worry.

There are excellent, evidence-based screening programs in Australia that are worth participating in: BreastScreen, the National Bowel Cancer Screening Program, the National Cervical Screening Program and, for eligible people, the National Lung Cancer Screening Program. These have been assessed for benefit versus harm at a population level. Speculative whole-body imaging has not. If you're considering one, talk it through with a GP first — including what you'd do with an ambiguous result.

Recapping the essentials

Let's pull the threads together.

Incidental findings are common, not freakish. They appear in 15–30% of diagnostic imaging tests and up to 40% of CT and MRI scans. You are firmly in the majority.

They're a by-product of better technology, not worsening health. Higher resolution finds smaller things — most of which were always there and always harmless.

Context is everything. Size, imaging characteristics, organ, your age, your risk factors and your symptoms all feed into the decision, and no single number decides it.

Most findings need nothing, or just time. Watchful waiting with a scheduled repeat scan is a legitimate, guideline-backed strategy — not a fob-off.

Over-investigation has real costs. Radiation, procedural risk, expense, anxiety and overdiagnosis are genuine harms, which is why Australian clinicians actively promote proportionate responses.

The follow-up date is your responsibility too. Systems lose people. Calendars don't.

You are allowed to ask questions — and a good doctor will welcome them.

Your challenge this week

Pick one strategy from this article and actually do it in the next seven days. Just one.

The highest-value option for most people: find your last imaging report and check whether it contains a follow-up recommendation you've never actioned. Dig it out of your email, log into My Health Record, or ring the imaging practice. If there's a date you've sailed past, book the appointment now. That single act is the difference between a system that catches things and a system that loses them.

If you don't have any old reports, try this instead: write down three questions you'd want answered if a scan of yours ever came back with something unexpected. Save them in your phone notes. Future-you, sitting in a waiting room feeling foggy with worry, will be grateful.

Now we'd love to hear from you. Drop a comment below telling us which strategy you picked — chasing an overdue follow-up, writing your question list, or something else entirely — and come back and tell us how it went. If you've received an incidental finding yourself, share what helped you cope with the uncertainty. Your experience might be exactly what another reader needs to read at 11pm tonight instead of that 2013 forum thread.

And if you need to speak with an Australian-registered doctor about your scan results, arrange a specialist referral, or organise a medical certificate for an upcoming appointment or procedure, we're here at NextClinic — online, seven days a week, wherever in Australia you happen to be.

This article is general information only and is not a substitute for personalised medical advice. Always discuss your individual scan results with a qualified health professional who knows your history. In an emergency, call 000.

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