An MRI apparatus includes a data processor for obtaining first k space data including a first unacquired line by undersampling an MR signal based on a first value of an MR parameter, and for obtaining second k space data including a second unacquired line by undersampling an MR signal based on a second value of the MR parameter and an image processor for interpolating a portion of first unacquired line data in the first k space data based on the second k space data, and a portion of second unacquired line data in the second k space data based on the first k space data.