A method of assessing stenosis severity for a patient includes obtaining patient information relevant to assessing severity of a stenosis, including anatomical imaging data of the patient. Based on the anatomical imaging data, the existence of any lesions of concerns may be identified. A three dimensional image can be generated of any irregular shaped lesion of concern and a surrounding area from the patient anatomical imaging data. A plurality of comparative two dimensional lesion specific models may be created that have conditions that correspond to the three dimensional model. The comparative two dimensional models may represent vessels having regular shaped lesions with each of the comparative two dimensional models represents a different stenosis severity. The three dimensional model can then be mapped to one of the plurality of comparative two dimensional models. After this mapping, a diagnosis of whether the patient has coronary artery disease may be made.