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Incidental findings on brain imaging and blood tests: results from the first phase of Insight 46, a prospective observational substudy of the 1946 British birth cohort
  1. Sarah E Keuss1,
  2. Thomas D Parker1,
  3. Christopher A Lane1,
  4. Chandrashekar Hoskote2,
  5. Sachit Shah2,
  6. David M Cash1,
  7. Ashvini Keshavan1,
  8. Sarah M Buchanan1,
  9. Heidi Murray-Smith1,
  10. Andrew Wong3,
  11. Sarah-Naomi James3,
  12. Kirsty Lu1,
  13. Jessica Collins1,
  14. Daniel G Beasley4,
  15. Ian B Malone1,
  16. David L Thomas5,6,
  17. Anna Barnes7,
  18. Marcus Richards3,
  19. Nick Fox1,
  20. Jonathan M Schott1
  1. 1 Dementia Research Centre, UCL Queen Square Institute of Neurology, London, UK
  2. 2 Lysholm Department of Neuroradiology, The National Hospital for Neurology and Neurosurgery, London, UK
  3. 3 MRC Unit for Lifelong Health and Ageing, University College London, London, UK
  4. 4 School of Biomedical Engineering and Imaging Sciences, King’s College London, London, UK
  5. 5 Leonard Wolfson Experimental Neurology Centre, UCL Queen Square Institute of Neurology, London, UK
  6. 6 Department of Brain Repair and Neurorehabilitation, UCL Queen Square Institute of Neurology, London, UK
  7. 7 Institute of Nuclear Medicine, University College London Hospitals, London, UK
  1. Correspondence to Professor Jonathan M Schott; j.schott{at}


Objective To summarise the incidental findings detected on brain imaging and blood tests during the first wave of data collection for the Insight 46 study.

Design Prospective observational sub-study of a birth cohort.

Setting Single-day assessment at a research centre in London, UK.

Participants 502 individuals were recruited from the MRC National Survey of Health and Development (NSHD), the 1946 British birth cohort, based on pre-specified eligibility criteria; mean age was 70.7 (SD: 0.7) and 49% were female.

Outcome measures Data regarding the number and types of incidental findings were summarised as counts and percentages, and 95% confidence intervals were calculated.

Results 93.8% of participants completed a brain scan (n=471); 4.5% of scanned participants had a pre-defined reportable abnormality on brain MRI (n=21); suspected vascular malformations and suspected intracranial mass lesions were present in 1.9% (n=9) and 1.5% (n=7) respectively; suspected cerebral aneurysms were the single most common vascular abnormality, affecting 1.1% of participants (n=5), and suspected meningiomas were the most common intracranial lesion, affecting 0.6% of participants (n=3); 34.6% of participants had at least one abnormality on clinical blood tests (n=169), but few reached the prespecified threshold for urgent action (n=11).

Conclusions In older adults, aged 69-71 years, potentially serious brain MRI findings were detected in around 5% of participants, and clinical blood test abnormalities were present in around one third of participants. Knowledge of the expected prevalence of incidental findings in the general population at this age is useful in both research and clinical settings.

  • epidemiology
  • internal medicine
  • medical ethics
  • neurology

This is an open access article distributed in accordance with the Creative Commons Attribution 4.0 Unported (CC BY 4.0) license, which permits others to copy, redistribute, remix, transform and build upon this work for any purpose, provided the original work is properly cited, a link to the licence is given, and indication of whether changes were made. See:

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  • Contributors SEK and JMS conceived the manuscript. TDP, CAL, AK, SEK, SMB, HM-S and AW recruited participants to the study. CH and SS reviewed and reported the MRI brain scans. TDP, CAL, AK, SEK, SMB, S-NJ, KL and JC contributed to data collection. DMC, IBM, DLT and AB were responsible for setting up the imaging acquisition protocols, image processing and quality control. DGB was involved in data management. SEK analysed the data and drafted the initial manuscript. JMS, NF and MR are co-principal investigators of the study. All authors critically revised the manuscript and approved the submitted version.

  • Funding Insight 46 is funded by grants from Alzheimer’s Research UK (ARUK-PG2014–1946, ARUK-PG2017-1946; PIs JMS, NF and MR), the Medical Research Council Dementias Platform UK (CSUB19166; PIs JMS, NF and MR), The Wolfson Foundation (PR/ylr/18575; PIs NF and JMS), the Medical Research Council (MC_UU_12019/1, PI Kuh; MC_UU_12019/3, PI MR), the Wellcome Trust (Clinical Research Fellowship 200,109/Z/15/Z; TDP) and Brain Research Trust (UCC14191; PI JMS).

  • Competing interests NF’s research group has received payment for consultancy or for conducting studies from Avid Radiopharmaceuticals, Biogen, Eisai, Elan, Eli Lilly Research Laboratories, GE Healthcare, IXICO, Janssen, Johnson & Johnson, Lundbeck, Pfizer, Roche, Sanofi-Aventis and Wyeth Pharmaceuticals. NF receives no personal compensation for the activities mentioned above. JMS has received research funding from Avid Radiopharmaceuticals (a wholly owned subsidiary of Eli Lilly), has consulted for Roche Pharmaceuticals, Biogen and Eli Lilly, has given educational lectures sponsored by GE, Eli Lilly and Biogen, and serves on a Data Safety Monitoring Committee for Axon Neuroscience SE.

  • Ethics approval Ethical approval was granted by the National Research Ethics Service (NRES) Committee London (REC reference 14/LO/1173; PI JMS).

  • Provenance and peer review Not commissioned; externally peer reviewed.

  • Data sharing statement Data are available upon reasonable request.

  • Patient consent for publication Not required.

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