Dynamic change in lymphocyte count in the early stage is a potential predictor of the severity of COVID-19 CURRENT STATUS: POSTED Xi Zhang the first affiliated hospital of xi'an jiaotong university Yonghao Du the first affiliated hospital of xi'an jiaotong university Lei Shi the first affiliated hospital of xi'an jiaotong university Tianyan Chen the first affiliated hospital of xi'an jiaotong university Yingren Zhao the first affiliated hospital of xi'an jiaotong university Feng Ye the first affiliated hospital of xi'an jiaotong university Shumei Lin the first affiliated hospital of xi'an jiaotong university Jie Zheng the first affiliated hospital of xi'an jiaotong university Gang Niu first affiliated hospital of xi'an jiaotong university

In the past 4 years, many publications described a concentration-dependent deposition of gadolinium in the brain both in adults and children, seen as high signal intensities in the globus pallidus and dentate nucleus on unenhanced T1-weighted images. Postmortem human or animal studies have validated gadolinium deposition in these T1-hyperintensity areas, raising new concerns on the safety of gadolinium-based contrast agents (GBCAs). Residual gadolinium is deposited not only in brain, but also in extracranial tissues such as liver, skin, and bone. This review summarizes the current evidence on gadolinium deposition in the human and animal bodies, evaluates the effects of different types of GBCAs on the gadolinium deposition, introduces the possible entrance or clearance mechanism of the gadolinium and potential side effects that may be related to the gadolinium deposition on human or animals, and puts forward some suggestions for further research.