PROBLEM TO BE SOLVED: To provide a medical image diagnostic apparatus capable of estimating high-risk plaques, and a method for providing diagnosis assisting information for assisting in such estimation.SOLUTION: A medical image diagnostic apparatus according to the present embodiment, comprises: an image acquisition unit for acquiring data of a CT image including blood vessels an estimation unit for estimating the position and properties of an intravascular plaque on the basis of the CT image data an extraction unit for extracting a blood vessel wall structure from the CT image and a calculation unit for calculating a stress value applied to the plaque by a fluid analysis based on the blood vessel wall structure and for calculating an index value indicative of a degree of risk of the plaque on the basis of both the stress value and the properties.SELECTED DRAWING: Figure 1
