New research shows that Knowing the expected prevalence of such incidental findings in the older general population is “extremely useful” for both researchers and clinicians, said study co-author Sarah Elisabeth Keuss, MBChB, clinical research associate, Dementia Research Centre, UCL Queen Square Institute of Neurology, London, UK.
“In research, the knowledge helps to inform study protocols regarding how to manage incidental findings and enables study participants to be appropriately informed,” said Dr. Keuss. Greater awareness also helps clinicians make decisions about whether or not to scan a patient, she said, adding that imaging is increasingly available to them. It allows clinicians to counsel patients regarding the probability of an incidental finding and balance that risk against the potential benefits of having a test.
The research is being presented online as part of the American Academy of Neurology 2020 Science Highlights. The incidental findings also were published last year in BMJ Open.
The new findings are from the first wave of data collection for the Insight 46 study, a neuroimaging substudy of the MRC National Survey of Health and Development (NSHD) 1946 British birth cohort, a broadly representative sample of the population born in mainland Britain during 1946. The research uses detailed brain imaging, cognitive testing, and blood and other biomarkers to investigate genetic and life-course factors associated with Alzheimer’s disease and cerebrovascular disease.
The current study included 502 individuals, aged about 71 years at the time of the analysis, and 49% were women. Almost all (93.8%) participants underwent 1-day MRI scans. Some 4.5% of these participants had an incidental finding of brain abnormality as per a prespecified standardized protocol.
Suspected vascular malformations were present in 1.9%, and suspected intracranial mass lesions were present in 1.5%. The single most common vascular abnormality was a suspected cerebral aneurysm, which affected 1.1% of participants.
Suspected meningiomas were the most common intracranial lesion, affecting 0.6% of study participants.
Action plan
Participants and their primary care provider were informed of findings “that were deemed to be potentially serious, or life-threatening, or could have a major impact on quality of life,” said Dr. Keuss. Relevant experts “came up with a recommended clinical action plan to help the primary care provider decide what should be the next course of action with regard to investigation or referral to another specialist,” said Dr. Keuss.
The new results are important for clinical decision-making, said Dr. Keuss. “Clinicians should consider the possibility of detecting an incidental finding whenever they’re requesting a brain scan. They should balance that risk against the possible benefits of recommending a test.”
The prevalence of incidental findings on MRI reported in the literature varies because of different methods used to review scans. “However, comparing our study with similar studies, the prevalence of the key findings with regard to aneurysms and intracranial mass lesions are very similar,” said Dr. Keuss.
Dr. Keuss and colleagues do not recommend all elderly patients get a brain scan.
“We don’t know what the long-term consequences are of being informed you have an incidental finding of an abnormality; we don’t know if it improves their outcome, and it potentially could cause anxiety,” said Dr. Keuss.