Patent ID: 7853309

Claim:
An X-ray CT apparatus, comprising: an X-ray tube to radiate an X-ray to a subject so as to scan the subject; an X-ray detector to detect the radiated X-ray; a reconstruction unit configured to reconstruct a CT image of the subject based on obtained projection data; a controlling unit configured to control an injector so that the injector continuously injects a contrast medium into the subject and to detect a state in which a concentration of the contrast medium in a myocardial of the subject can be considered to be constant; a blood-flow information obtaining unit configured to obtain information of a relative blood flow rate in the myocardium of the subject based on the CT image; a correction value calculating unit configured to obtain a correction value based on a CT image obtained in a concentration transition period, which is defined to be a period from immediately after a start of a continuous injection of the contrast medium into the subject until the contrast medium reaching the myocardium increases and is in a state in which the contrast medium is saturated at a constant value, as detected by the controlling unit, the correction value calculating unit further configured to obtain the correction value by calculating a rate of change of the concentration of the contrast medium, which is obtained based on multiple CT images obtained in the concentration transition period; and a blood-flow image generating unit configured to generate a blood flow value image representing a blood flow rate in the myocardium by correcting the information of the relative blood flow rate with the correction value.