A system is described for determining cardiovascular information for a patient. The system comprises at least one computer system (40) configured to: receive patient-specific data regarding a geometry of at least a portion of an anatomical structure of the patient, the anatomical structure including at least a portion of a plurality of arteries and tissue connected to at least a portion of the plurality of arteries； create a three-dimensional model (10) representing the anatomical structure of the patient based on the patient-specific data； divide at least a portion of the three-dimensional model representing the tissue into segments； and determine information regarding a blood flow characteristic associated with at least one of the segments based on the three-dimensional model and a physiological condition of the patient.
