Incidental Findings on Brain MRI Among Chinese at the Age of 55-65 Years: The Taizhou Imaging Study

Background: Asymptomatic brain abnormalities are common incidental findings on brain MRI in the elderly population and can be regarded as imaging markers of early stroke and dementia. We initiated the Taizhou Imaging Study (TIS) to examine the prevalence and correlates of incidental findings using brain MRI among an elderly population residing in a rural area of China. Methods: A total of 562 individuals, at the age of 55 to 65 years, participated in the TIS study with a response rate of 90%. The primary findings included lacunes, white matter hyperintensity (WMH), and cerebral microbleeds (CMB), perivascular space (PVS), intracranial arterial stenosis (ICAS), and others (venous angioma, etc.). The brain parenchymal fraction and the brain gray matter fraction (BGMF) were also estimated. Findings: The prevalence of lacunes, WMH, CMB, PVS, and ICAS was 26.69%, 10.68%, 18.51%, 27.76%, and 12.81%, respectively. Age and hypertension were the major correlates of these incidental findings. Per each year increase in age, the risks of WMH and CMB increased by 15% and 14%. Compared to individuals with normal blood pressure, individuals with hypertension had an increased risk of all incidental findings, with the adjusted odds ratios of 2.28 to 5.45. Correlations of age, gender and BMI with BGMF were also observed. Interpretation: The prevalence of MRI incidental findings was high in the rural Chinese population at the age of 55-65 years. The high prevalence of these findings indicates a need of preventative strategy to help prevent future stroke and dementia in this population. Funding: The project was supported by the International Science and Technology Cooperation Program of China (grant number: 2014DFA32830), the Key Research and Development Plans of Jiangsu Province (grant number: BE2016726), the key basic research grants from Science and Technology Commission of Shanghai Municipality (grant number: 16JC1400500), the Karolinska Institutet (Senior Researcher Award and Strategic Research Area in Epidemiology), and the National Key Research and Development program of China (grant number: 2017YFC0907002, 2017YFC0907501). Declaration of interests: We declare no competing interests. Ethical Approval Statement: This study was approved by the Human Ethics Committee of School of Life Sciences of Fudan University (number of Institutional Review Board approval: 469).