In one embodiment, a medical image diagnostic apparatus includes a memory circuit; a display; and processing circuitry configured to acquire medical images of an object at respective time phases, detect respective positions of a treatment device in the medical images, acquire biological information from the medical images, compute biological indexes indicating degree of a treatment effect for the respective time phases based on the biological information, cause the memory circuit to store the biological indexes and the respective positions of the treatment device in the medical images such that each biological index is associated with a position of the treatment device in a medical image, from which the biological information corresponding to the each biological index is acquired, for the respective time phases, and cause the display to display each position of the treatment device and a biological index associated with the each position of the treatment device.