Incidental Abnormal Radiological Finding (IARF)

What is Incidental Abnormal Radiological Finding (IARF)

• Incidental abnormal radiological finding is an unusual mass or tissue change that is found unexpectedly during an imaging test.
• IARFs are often found in the kidneys or lungs, but they can also be found in the heart, liver, breasts, brain, gallbladder, uterus, or other organs and tissues.
• Incidental Abnormal Radiological Findings can cause symptoms or be related to an undiagnosed illness.
• Most often, however, they do not cause symptoms and are not a cause for concern.
• Incidental Abnormal Radiological Finding or Incidentalomas, incidental imaging findings serendipitously diagnosed in an asymptomatic patient or symptomatic patient undergoing imaging for an unrelated reason, are fast becoming a modern medical crisis.
• The rapid rise in demand for imaging, coupled with rapidly advancing image resolution is driving a surge in incidentalomas

Prevalence and Epidemiology

• Incidental findings occur with remarkable frequency in modern imaging practice. Approximately 20-40% of all advanced imaging studies (CT or MRI) contain at least one incidental finding, while 15-30% prevalence rates appear across all diagnostic imaging modalities.
• However, a 2024 study on interstitial lung abnormalities revealed substantial underreporting of these findings in original radiology reports, suggesting the true detection rate may exceed what clinicians document.
• Organ-system specific prevalence varies considerably. A 2018 systematic review and umbrella analysis found brain MRI incidentalomas in 22% of patients, cardiac MRI findings in over 33%, thyroid nodules in 19-68% of asymptomatic adults, adrenal incidentalomas in 11.3%, and renal masses in over 50% of abdominal CT or MRI examinations.
• A 2025 study of asymptomatic university students found 15.4% of thyroid ultrasound screenings revealed abnormalities, with cystic nodules in 10.3% and solid lesions or thyroiditis in 1.3%.

What are common types of IARFs?

There are many types of Incidental Abnormal Radiological Findings.

The Common types of IARF include:

• Lesions. A lesion is a change in tissue due to infection, tissue death, or injury.
• Cysts. A cyst is a sac that is filled with fluid, crystals, or some other substance.
• Tumors. A tumor is a solid formation. Tumors can be cancerous (malignant) or non-cancerous (benign).

Your health care provider may use medical terms to describe the finding, such as “pulmonary nodule,” which means a small mass in the lung, or “renal mass,” which means a mass in the kidney.

Incidental Abnormal Radiological Finding can vary widely in nature and severity, ranging from benign and insignificant to potentially significant or concerning. Some common examples of incidental findings include:

1. Benign bone lesions: These may include bone cysts, benign tumors, or areas of bone sclerosis that are not related to the primary reason for the imaging study.
2. Pulmonary nodules: Small nodules or masses in the lungs that are incidentally detected on chest X-rays or CT scans, which may require further evaluation to determine their nature (benign or potentially malignant).
3. Renal cysts: Fluid-filled sacs in the kidneys that are commonly found incidentally during imaging studies and are usually benign.
4. Liver or adrenal lesions: Unrelated masses or lesions discovered incidentally during abdominal imaging studies, which may require further evaluation to determine their significance.

What are the goals?

• Reducing risks to patients from additional unnecessary examinations, including the risks of radiation and risks associated with interventional procedures;
• Limiting the costs of managing incidental findings to patients and the health care system;
• Achieving greater consistency in recognizing, reporting, and managing incidental findings, as a component of formal quality improvement efforts;
• Providing guidance to radiologists who are concerned about the risk for litigation for missing incidental findings that later prove to be clinically important; and
• Helping focus research efforts to lead to an evidence based approach to incidental findings.

Do I need further diagnosis?

Your health care provider may recommend that you have tests to diagnose the cause of the Incidental Abnormal Radiological Findings.

Testing is usually recommended based on:

• The size and appearance of the IARF.
• Whether you have risk factors or medical conditions that increase your risk of problems.
• Whether you have symptoms or concerns.

In many cases, testing is not needed if the Incidental Abnormal Radiological Finding is a very small mass or tissue change. Small masses or changes are not often likely to become a problem in the future.

What type of testing may be needed?

The following types of tests may be done when an Incidental Abnormal Radiological Finding is found:

• Blood tests.
• Urine tests.
• Imaging tests, such as abdominal ultrasound, CT scan, or MRI.
• Biopsy.

Tests and physical exams may be done once, or they may be done regularly for a period of time. Tests and exams that are done regularly are performed to show whether the mass or tissue change is growing and becoming a concern.

What are common treatments?

Treatment varies depending on:

• The cause of the Incidental Abnormal Radiological Findings.
• The location, size, and appearance of the IARF.
• Your age.
• Any underlying conditions or symptoms.

Treatment is not always needed. Your health care provider may recommend monitoring through watchful waiting and regular tests and exams. If treatment is needed, it may include:

• Treatments to reduce the size of the abnormality.
• Biopsy or surgical removal of the mass or tissue.
• Treatment to address any underlying conditions.

Overdiagnosis and Low-Value Care Recognition

1. Clinical Evidence on Incidental Findings Burden

Recent analysis reveals concerning patterns in incidental findings management :​

Prevalence statistics:

• 15-30% of all diagnostic imaging contains ≥1 incidental finding
• 20-40% of CT examinations contain incidental findings
• Cancer incidence among all incidental findings: Only 2.3-4.5% completing follow-up

Frequency by Imaging Modality:​

• Cardiac MRI: >33% of examinations contain at least one incidental finding
• Chest CT (general indications): 20-40% of all CT examinations
• All diagnostic imaging: 15-30% contain at least one incidental finding
• Abdominopelvic CT: Demonstrates exceptionally high rates of incidental findings
• Brain MRI: Incidental findings occur in approximately 22% of examinations
• Spine MRI: Approximately 22% prevalence of incidental findings
• CT colonoscopy: >33% contain extra-colonic incidental findings

Risk of overdiagnosis: Most incidental findings in low-risk patients result in length bias, lead-time bias, and overtreatment creating “illusion of benefit while conferring harm”.​

2. Risk-Stratified Management Approach

2024 paradigm shift toward integrating patient risk factors and disease aggressiveness:

• Higher patient risk increases likelihood of clinically important findings
• Guidelines should incorporate socioeconomic factors and comorbidities
• Outcome data urgently needed to support management algorithms

What does research says about Incidental Abnormal Radiological Finding?

Here is the abstract of a Literature review

251 potentially relevant abstracts were identified and 44 articles were finally included in the review. Overall, the mean frequency of incidental findings was 23.6% (95% confidence interval (CI) 15.8–31.3%).

The frequency of incidental findings was higher in studies involving CT technology (mean 31.1%, 95% CI 20.1–41.9%), in patients with an unspecific initial diagnosis (mean 30.5, 95% CI 0–81.6) and when the location of the incidental findings was unspecified (mean 33.9%, 95% CI 18.1–49.7).

The mean frequency of clinical follow-up was 64.5% (95% CI 52.9–76.1%) and mean frequency of clinical confirmation was 45.6% (95% CI 32.1–59.2%). Although the optimal strategy for the management of these abnormalities is still unclear, it is essential to be aware of the low clinical confirmation in findings of moderate and major importance.

Specific Imaging Modality Updates

Cardiac Imaging (2025):​

Advances in cardiac imaging technology increasingly detect incidental noncardiac abnormalities within scanned areas. Pulmonary nodules represent one of the most commonly discovered incidental findings on cardiac imaging. A 2025 ACC article documents a medical malpractice case demonstrating the catastrophic consequences of missed incidental findings—a two-year delay in lung cancer diagnosis resulting from failure to follow up on suspicious nodules noted on coronary CT angiography resulted in patient death and substantial litigation.

Follow these instructions at home:

• Keep all follow-up visits as told by your health care provider, and schedule appointments as directed. This is important. It will allow any problems to be detected early, which can be very beneficial to you.
• Try to stay calm, and be sure to ask questions. Make sure you understand the recommendations for monitoring and understand whether there is a reason for concern.

Summary

An incidental abnormal radiological finding refers to a finding on a medical imaging study, such as X-ray, computed tomography (CT) scan, or magnetic resonance imaging (MRI), that was not the primary reason for the imaging but was discovered unintentionally during the examination. These findings are unrelated to the primary clinical concern or reason for ordering the radiological study and may have been found in an area of the body that was not the primary focus of the investigation.

Patients should always discuss any incidental findings with their healthcare providers to fully understand their significance and the recommended course of action. Although incidental findings may be unexpected, they can sometimes lead to the early detection and treatment of potentially serious medical conditions.

It’s important to note that not all incidental findings require immediate intervention or represent a significant health concern. The management of an incidental finding depends on various factors, including the specific abnormality, patient’s medical history, and overall clinical context. The healthcare team will assess the significance of the finding and develop an individualized plan based on the best available evidence and guidelines.

If you receive a report mentioning an incidental abnormal radiological finding, it’s crucial to follow up with your healthcare provider to discuss the finding in detail and determine any necessary next steps. They can provide you with specific information, address your concerns, and guide you through any further evaluation or management that may be required.

Here are a few key points about incidental abnormal radiological findings:

1. Unplanned Discovery: Incidental findings are often unexpected and not the main focus of the imaging study. They are usually unrelated to the primary reason for the imaging, which could be investigating a specific symptom or condition.
2. Range of Abnormalities: Incidental findings can vary widely and may include abnormalities in organs, bones, blood vessels, or other structures within the imaging field.
3. Clinical Significance: The clinical significance of an incidental finding can vary. Some findings may be benign or of minimal concern, while others may require further evaluation or intervention to determine their significance and potential impact on health.
4. Follow-up Evaluation: Upon discovering an incidental abnormality, the radiologist or healthcare provider may recommend additional imaging or tests to further evaluate the finding and assess its clinical significance. This may involve follow-up imaging studies, referral to a specialist, or additional diagnostic procedures.
5. Communication and Management: Proper communication and management of incidental findings are essential. The radiologist or healthcare provider responsible for reviewing the imaging study typically provides a detailed report to the ordering physician, who then discusses the finding with the patient and determines the appropriate course of action.

• Imaging plays an essential role in medical research.
• Unexpected or incidental abnormal findings arising in the course of imaging research are common; around 3% to 12% in brain imaging and up to 30% in body imaging.
• Such unexpected findings can have profound implications for a patient’s future health, and currently as there are no agreed protocols in place, these findings may go unrecognised or unreported.

Incidental findings can be classified into three categories:

1. Benign Incidental Findings: These are abnormalities that are not clinically significant or harmful and do not require further investigation or intervention. Examples include harmless cysts, harmless bone spurs, or minor variations in the anatomy.
2. Potentially Clinically Significant Incidental Findings: These findings may indicate an underlying medical condition or require further evaluation to determine their clinical significance. Examples include small lung nodules, liver cysts with atypical features, or small adrenal gland masses.
3. Significant Incidental Findings: These findings are abnormalities that have clinical importance and require prompt attention and appropriate follow-up. Examples include large tumors, fractures, or evidence of acute medical conditions such as aneurysms or blood clots.

It is essential for radiologists and other healthcare providers to carefully evaluate and report incidental findings in radiological studies. When an incidental finding is identified, it is crucial for the healthcare provider who ordered the imaging study to review and communicate the findings to the patient. Depending on the nature of the incidental finding, additional tests or consultations with specialists may be necessary to determine the appropriate management and follow-up.