1. A method of acquiring a functional image by a magnetic resonance imaging (MRI) apparatus, the method comprising: acquiring functional image data of an object that measures brain functionalities by detecting associated changes in a blood flow; acquiring structural image data of the object that represents an anatomical structure of the brain; registering the structural image data; determining registration information of the structural image data; correcting the functional image data for motion of the object by registering the functional image data based on the registration information of the structural image data; and obtaining a functional image of the object, wherein the structural image data are acquired in correspondence with an acquisition of corresponding functional image data, and the acquiring the structural image data includes acquiring the structural image data between acquisitions of respective functional image data.