Incidental findings on cerebral MRI in twins: the Older Australian Twins Study
Incidental findings on structural cerebral magnetic resonance imaging (MRI) are common in healthy subjects, and the prevalence increases with age. There is a paucity of data regarding incidental cerebral findings in twins. We examined brain MRI data acquired from community-dwelling older twins to determine the prevalence and concordance of incidental cerebral findings, as well as the associated clinical implications. Participants (n = 400) were drawn from the Older Australian Twins Study. T1-weighted and T2-weighted fluid-attenuated inversion recovery (FLAIR) cerebral MRI scans were systematically reviewed by a trained, blinded clinician. Incidental findings were recorded according to pre-determined categories, and the diagnosis confirmed by an experienced neuroradiologist. Periventricular and deep white matter hyperintensities (WMH) were scored visually. WMH heritability was calculated for those with the twin pair included in the study (n = 320 individuals; monozygotic (MZ) = 92 twin pairs, dizygotic (DZ) = 68 twin pairs). Excluding infarcts and WMH, a total of 47 (11.75%) incidental abnormalities were detected. The most common findings were hyperostosis frontalis interna (8 participants; 2%), meningiomas, (6 participants; 1.5%), and intracranial lipomas (5 participants; 1.25%). Only 3% of participants were referred for follow-up. Four twin pairs, all monozygotic, had lesions concordant with their twin. Periventricular WMH was moderately heritable (0.61, CI 0.43–0.75, p = 7.21E-08) and deep WMH highly heritable (0.80, CI 0.66–0.88, p = 1.76E-13). As in the general population, incidental findings on cerebral MRI in older twins are common, although concordance rates are low. Such findings can alter the clinical outcome of participants, and should be anticipated by researchers when designing trials involving cerebral imaging.
KeywordsIncidental findings Cerebral magnetic resonance imaging Older twins
Our sincere thanks to the twins who have donated their time to participate in the OATS, as well as the OATS Collaborative Research Team: New South Wales: Jocelyn Bowden, Suzy Forrester, Henry Brodaty, John Crawford, Tanya Duckworth, Kristan Kang, Amelia Assareh. Queensland: Natalie Garden, Nick Martin. Victoria: Christel Lemmon.
Compliance with ethical standards
The Older Australian Twins Study was supported by a National Health and Medical Research Council (NHMRC) / Australian Research Council (ARC) Strategic Award Grant of the Ageing Well, Ageing Productively Program (ID no. 401162). The Australian Twin Registry is supported by a Centre of Research Excellence Grant from the NHMRC administered by the University of Melbourne.
Conflict of interest
The authors declare that they have no conflicts of interest.
The Older Australian Twins Study obtained approval from the ethics committees of the Australian Twin Registry, University of New South Wales, University of Melbourne, Queensland Institute of Medical Research, University of Queensland, and the South Eastern Sydney & Illawarra Area Health Service.
Human and animal rights
All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards.
Informed consent was obtained from all individual participants included in the study.
- Bedeschi, M. F., Bonaglia, M. C., Grasso, R., Pellegri, A., Garghentino, R. R., Battaglia, M. A., et al. (2006). Agenesis of the corpus callosum: Clinical and genetic study in 63 young patients. Pediatric Neurology, 34(3), 186–193. doi: 10.1016/j.pediatrneurol.2005.08.008.CrossRefPubMedGoogle Scholar
- Bos, D., Poels, M. M., Adams, H. H., Akoudad, S., Cremers, L. G., Zonneveld, H. I., et al. (2016). Prevalence, clinical management, and natural course of incidental findings on brain MR images: The population-based Rotterdam scan study. Radiology, 281(2), 507–515. doi: 10.1148/radiol.2016160218.
- Boutet, C., Vassal, F., Celle, S., Schneider, F. C., Barthélémy, J.-C., Laurent, B., et al. (2017). Incidental findings on brain magnetic resonance imaging in the elderly: the PROOF study. Brain Imaging and Behavior, 11, 293–299. doi: 10.1007/s11682-016-9519-4.
- Carmelli, D., DeCarli, C., Swan, G. E., Jack, L. M., Reed, T., Wolf, P. A., et al. (1998). Evidence for genetic variance in white matter hyperintensity volume in normal elderly male twins. Stroke, 29(6), 1177–1181. doi: 10.1161/01.str.29.6.1177.
- Håberg, A. K., Hammer, T. A., Kvistad, K. A., Rydland, J., Müller, T. B., Eikenes, L., et al. (2016). Incidental intracranial findings and their clinical impact; the HUNT MRI study in a general population of 1006 participants between 50-66 years. PloS One, 11(3), e0151080. doi: 10.1371/journal.pone.0151080.CrossRefPubMedPubMedCentralGoogle Scholar
- Jansen, A. G., Mous, S. E., White, T., Posthuma, D., & Polderman, T. J. C. (2015). What twin studies tell us about the heritability of brain development, morphology, and function: A review. Neuropsychology Review, 25(1), 27–46. doi: 10.1007/s11065-015-9278-9.CrossRefPubMedPubMedCentralGoogle Scholar
- Kumar, R., Sachdev, P. S., Price, J. L., Rosenman, S., & Christensen, H. (2008). Incidental brain MRI abnormalities in 60- to 64-year-old community-dwelling individuals: Data from the Personality and Total Health Through Life study. Acta Neuropsychiatrica, 20, 87–90.Google Scholar
- Liu, S., Buch, S., Chen, Y., Choi, H. S., Dai, Y., Habib, C., et al. (2016). Susceptibility-weighted imaging: Current status and future directions. NMR in Biomedicine. doi: 10.1002/nbm.3552.
- Longstreth, W. T., Manolio, T. A., Arnold, A., Burke, G. L., Bryan, N., Jungreis, C. A., et al. (1996). Clinical correlates of white matter findings on cranial magnetic resonance imaging of 3301 elderly people: The cardiovascular health study. Stroke, 27(8), 1274–1282. doi: 10.1161/01.str.27.8.1274.CrossRefPubMedGoogle Scholar
- May, F. S., Chen, Q. C., Gilbertson, M. W., Shenton, M. E., & Pitman, R. K. (2004). Cavum septum pellucidum in monozygotic twins discordant for combat exposure: Relationship to posttraumatic stress disorder. Biological Psychiatry, 55(6), 656–658. doi: 10.1016/j.biopsych.2003.09.018.CrossRefPubMedPubMedCentralGoogle Scholar
- R Core Team. (2015). A language and environment for statistical computing. Vienna: R Foundation for Statistical Computing.Google Scholar
- Rorden, C. (2015). MRIcron Version 1.Google Scholar
- Sandeman, E. M., Hernandez, M. D. C. V., Morris, Z., Bastin, M. E., Murray, C., Gow, A. J., et al. (2013). Incidental findings on brain MR imaging in older community-dwelling subjects are common but serious medical consequences are rare: A cohort study. PloS One, 8(8), e71467. doi: 10.1371/journal.pone.0071467.CrossRefPubMedPubMedCentralGoogle Scholar
- Yue, N. C., Longstreth Jr., W. T., Elster, A. D., Jungreis, C. A., O'Leary, D. H., & Poirier, V. C. (1997). Clinically serious abnormalities found incidentally at MR imaging of the brain: Data from the cardiovascular health study. Radiology, 202(1), 41–46. doi: 10.1148/radiology.202.1.8988190.CrossRefPubMedGoogle Scholar