1. A blood vessel analysis apparatus comprising: a storage configured to store data of a time-series medical image of a blood vessel of a subject; a structuring circuitry configured to temporarily structure a dynamical model of analysis processing based on the time-series medical image; an identification circuitry configured to identify a latent variable of the dynamical model so that at least one of a prediction value of a blood vessel morphology and a prediction value of a bloodstream based on the temporarily structured dynamical model is in conformity with at least one of an observation value of the blood vessel morphology and an observation value of the bloodstream measured in advance; and an analysis circuitry configured to analyze the dynamical model to which the identified latent variable is allocated.