Abstract: Objective To apply the MRI T₂ signal intensity of hippocampal subfield in patients with amnestic mild cognitive impairment (aMCI) as early imageology. Methods From October, 2014 to August, 2015, 20 aMCI patients accepted cognitive training (training group), 20 aMCI patients accepted speech communication (speech group), and 20 age- and gender-matched healthy old people (control group) were scanned with MRI using FSE-T₂ sequence. The margin of hippocampal subfields were outlined manually for each side to measure the T₂ signal intensity. The correlation between hippocampal T₂ signal intensity and the scores of Mini-Mental State Examinatlon (MMSE) was analyzed in the training group. Results Before treatment, T₂ signal intensity in the bilateral hippocampal head was significantly high in the aMCI patients compared with that in the control group (P<0.05). After treatment, T₂ signal intensity in left hippocampal head decreased in the training group compared with that in the speech group (P<0.05), similar to the control group (P>0.05). There was negative correlation between left hippocampal head's T₂ signal intensity and the scores of MMSE in the training group before and after treatment (r=-0.61, r=-0.54, P<0.05). Conclusion The T₂ signal intensity in left hippocampal head may respond to the cognitive function in patients with aMCI in the early stage, that could be used for diagnosis and evaluation in clinic.

Key words: mild cognitive impairment, hippocampus, magnetic resonance imaging, T2-weighted signal, evaluation, diagnosis