A medical image diagnostic apparatus according to an embodiment includes an estimation unit, an extraction unit, and a specifying unit. The estimation unit estimates a position of a plaque in a blood vessel based on data of CT images constituting a time series, with the blood vessel being enhanced by a contrast medium. The extraction unit extracts regions constituting the blood vessel from the CT images. The specifying unit specifies stress values respectively corresponding to the regions based on a moving displacement due to cardiac pulsation in each of the regions, and specifies an exfoliation risk of the plaque based on an index indicating hardness of the plaque and the stress value in the region corresponding to the position of the plaque.