1. A system comprising: a memory (122) including a predetermined stenosis characteristic for a reference table of values of the fractional reserve of blood flow； means for determining an indicator (118) that converts at least one characteristic related to stenosis in a patient’s vessel, determined according to images of stenosis, in the characteristic according to the reference table, and identifies the value of the fractional reserve of blood flow corresponding to the characteristic； an display (116) that visually presents the image data and the identified value of the fractional reserve of blood flow. 2. The system of claim 1, wherein the at least one characteristic includes stenosis length and stenosis diameter. System according to any one of paragraphs. 1-2, in which at least one characteristic further includes one or more of the curvature of the vessel, the distance from the stenosis to the branch point or the type of vessel. System according to any one of paragraphs. 1-2, in which at least one characteristic further includes at least one characteristic related to the patient. System according to any one of paragraphs. 1-2, in which the lookup table is pre-computed using a synthetic software model of the artery. 6. System according to any one of paragraphs. 1-2, in which the indicator determining means interpolates between a plurality of neighboring records in the look-up table when there is no direct match between at least one characteristic and the records in the look-up table. 7. System according to any one of paragraphs. 1-2, in which the indicator determination tool selects the closest match in the lookup table when there is no direct match between at least one character1. Система, содержащая:память (122), включающую в себя заданную характеристику стеноза для справочной таблицы значений фракционного резерва кровотока；средство (118) определения показателя, которое преобразует по меньшей мере одну характеристику, относящуюся к стенозу в сосуде пациента, опре
