1. A method of displaying additional information related to a measured value of an object, the method performed by a medical imaging system and comprising: acquiring measurement item information of the object; acquiring at least one of a measurement point and a measurement direction for the object; acquiring the measured value of the object based on the at least one of the measurement point and the measurement direction; and displaying additional information including a reference value predetermined for the measurement item information and the acquired measured value, wherein the measurement item information of the object comprises profile information of the object and information about a measurement item determined according to a portion of the object to be measured, and the reference value and the acquired measured value are displayed on a straight line.