Discover insights from Professor Brian Owler’s latest Medicine Today article on incidental brain findings, diagnosis and management guidance for GPs.
A recent peer-reviewed article in Medicine Today by Professor Brian Owler AM, Dr Liam Johnson and Dr Vijidha Shree Rajkumar explores an important and increasingly relevant topic in modern healthcare: incidental findings on cranial neuroimaging.
With the rapid growth of MRI and CT scanning in both adults and children, it has become common for radiologists to identify unexpected abnormalities in the brain that were not related to the original reason for the scan. These findings can range from harmless anatomical variations to lesions that may need further assessment or specialist management.
Professor Owler’s article, titled “Cranial Neuroimaging: Incidental Findings and Their Significance,” outlines the most frequent incidental brain findings, their clinical implications and practical guidance for GPs who are often the first to discuss these results with patients.
Modern imaging has transformed the way clinicians diagnose neurological conditions. However, this advancement has also led to an increase in incidental discoveries, particularly in paediatric and older populations.
Studies show that approximately 26 per cent of paediatric MRIs reveal incidental findings, most of which are benign. These may include arachnoid cysts, Chiari I malformations, pineal cysts, or mild white matter changes. Although rarely serious, such findings can create unnecessary anxiety for families and lead to repeat imaging or referrals that may not be clinically required.
Professor Owler notes that GPs play a vital role in differentiating which findings can be safely monitored and which warrant further investigation. Some anomalies may require long-term follow-up or neurosurgical review to rule out progression or complications.
Meningiomas are among the most frequently encountered incidental tumours, present in about one per cent of the general population. They are more common in women and tend to increase with age. Most small, well-defined lesions do not require surgery and can be monitored using MRI, typically with an initial follow-up scan at six months, then annually if stable. Larger meningiomas, or those located in sensitive areas such as the posterior fossa, should be referred for neurosurgical assessment.
Arachnoid cysts are developmental fluid-filled sacs that can occur anywhere in the brain but are most often found in the middle cranial fossa. Despite their size, they are usually asymptomatic and discovered incidentally. Only cysts that cause mass effect or become symptomatic require surgical intervention. Occasionally, trauma can lead to cyst rupture or haemorrhage, in which case activity restrictions and closer follow-up may be advised.
An enlarged cisterna magna is considered a benign anatomical variant rather than a pathological condition. It does not exert pressure on the brain or interfere with cerebrospinal fluid flow, and no follow-up is required.
Incidental pituitary lesions are common, especially with increasing age. Most are benign adenomas or cysts, such as Rathke’s cleft cysts. These typically require hormone testing to rule out endocrine abnormalities. Small, non-functional adenomas are observed, while larger lesions encroaching on the optic chiasm may need closer monitoring or surgical removal to preserve vision.
Pineal cysts are another frequent incidental finding. Most are small and stable, with no impact on brain function. They rarely cause headaches or hydrocephalus, and ongoing imaging is usually unnecessary unless atypical features or symptoms develop.
Although histologically benign, colloid cysts of the third ventricle carry the risk of acute hydrocephalus and even sudden deterioration if they obstruct cerebrospinal fluid pathways. Even when discovered incidentally, these require careful neurosurgical review and regular imaging.
Chiari type I malformations involve the downward displacement of the cerebellar tonsils through the foramen magnum. Symptoms may include headache, dizziness or neck pain, often triggered by coughing or straining. In some cases, patients are asymptomatic and only identified through imaging. When symptoms are present or when a syrinx (a fluid-filled cavity in the spinal cord) is found, surgical decompression may be considered.
Developmental venous anomalies (DVAs) are benign vascular formations seen in up to six per cent of the population. They usually represent normal variants and require no treatment. Occasionally, they are associated with cerebral cavernous malformations, which can increase the risk of small haemorrhages and may require follow-up imaging.
Cavernous malformations are clusters of dilated blood vessels that can appear as small dark areas on MRI. Most are discovered incidentally and managed conservatively. A neurosurgeon should review symptomatic lesions that cause seizures, bleeding or neurological changes to assess surgical options.
Brain aneurysms are sometimes found incidentally. Not all require immediate intervention, and management depends on factors such as aneurysm size, shape, location and the patient’s risk profile. If there are signs of nerve involvement or a sudden onset of severe headache, an urgent specialist referral is essential.
Some low-grade gliomas and other intra-axial lesions may first appear as subtle changes on MRI. Early review is important, as surgical treatment can prevent long-term progression. Differentiating these from other causes, such as demyelination or vascular change, requires experienced neurosurgical input.
White matter T2 hyperintensities are common findings that increase with age, occurring in up to 94 per cent of people over 80. These are typically caused by chronic small vessel changes related to vascular risk factors like hypertension or diabetes. While generally benign, they can occasionally indicate more significant disease, such as inflammation or demyelination, depending on their appearance and location.
The report concludes that most incidental findings on brain imaging are benign and do not require treatment. However, appropriate assessment and follow-up are key to ensuring that significant conditions are not missed.
Professor Owler emphasises that communication between GPs, patients and neurosurgeons is essential. GPs can provide reassurance for benign findings and refer patients for review when there is uncertainty, new symptoms or atypical imaging features.
Providing reassurance and clear explanations can significantly reduce patient anxiety and prevent unnecessary investigations. Neurosurgeons also play an important role in developing structured follow-up plans for lesions that require monitoring over time.
Advances in neuroimaging have undoubtedly improved diagnostic accuracy but have also led to a surge in incidental discoveries. As Professor Owler’s publication explains, understanding which of these findings are clinically significant is critical. Most are harmless, but a small number require further review or management to prevent complications.
Professor Brian Owler & Dr Rajkumar's full article, “Cranial Neuroimaging: Incidental Findings and Their Significance,” appears in the October 2025 issue of Medicine Today. It provides a comprehensive review for clinicians on managing these findings in everyday practice.
If you or your patient has received an MRI or CT scan showing an incidental brain finding, Professor Owler can provide a detailed review to determine whether any further action is required. His team offers guidance for both adults and children to ensure the safest, most informed management approach.
Book a consultation to discuss your imaging results with Professor Owler and gain clarity about your next steps.
