Medical image diagnostic apparatus

A medical image diagnostic method comprising:

• estimating, by processing circuitry, a position of a plaque in a blood vessel based on data of a plurality of CT images constituting a time series, with the blood vessel being enhanced by a contrast medium;
• estimating, by the processing circuitry, hardness of the plaque based on a CT value at the position;
• extracting, by the processing circuitry, a plurality of regions constituting the blood vessel from the plurality of CT images;
• specifying, by the processing circuitry, a plurality of stress values respectively corresponding to the plurality of regions constituting the blood vessel based on a moving displacement due to cardiac pulsation in each of the regions constituting the blood vessel;
• specifying, by the processing circuitry, an exfoliation risk of the plaque based on the estimated hardness and a stress value, of the plurality of stress values, in a region corresponding to the position;
• generating, by the processing circuitry, a color map of the stress values along a blood vessel contour of the blood vessel included in a CT image of the plurality of CT images by generating a stress value distribution chart and converting the stress value distribution chart into the color map;
• and
• displaying, on a display,
• the CT image of the plurality of CT images,
• a mark indicating (i) a position of a first plaque such that the mark is superimposed on the CT image and (ii) a priority order of a medical treatment of the first plaque or whether the medical treatment is necessary based on the specified exfoliation risk of the first plaque,
• display information indicating a degree of the estimated hardness of the first plaque for the mark, and
• the generated color map of the stress values along the blood vessel contour included in the CT image superimposed on the mark indicating the first plaque, wherein
• the displayed CT image is a two-dimensional long-axis sectional image of the blood vessel, and
• the displaying superimposes the mark and the generated color map on the two-dimensional long-axis sectional image.