Objective:To preliminarily study size alterations of pituitary gland in patients with Alzheimer’s disease（AD）process by MRI. Methods:Brain MRI scans in total of 118 subjects including 41 normal controls（NC group）

36 patients with mild cognitive impair ment（MCI group） and 41 patients with Alzheimer’s disease（AD group） were obtained. Dimensions of anteroposterior

width

height

length of the stalk of the pituitary gland and the volume were measured and standardized

and then group comparisons were statistically obtained. Results:The standardized anteroposterior diameter of the pituitary gland in MCI group were larger than that in NC group（t=3.882

P=0.000）and in AD group（t=5.533

P=0.000）. The standardized volume of the pituitary gland in MCI group were larger than in NC group（t=2.192

P=0.030）and in AD group（t=2.223

P=0.028）. There was no difference in the standardized width

height and length of the stalk of the pituitary gland between NC group and MCI group（P >0.05）

There were no differences in the standardized width

height and length of the stalk of the pituitary gland between MCI group and AD group（P>0.05）. Conclusion:The size of the pituitary gland in MCI is larger than that in NC and in AD

suggesting that the pituitary gland could increase slightly in MCI stage of AD process.