X-ray CT apparatus and method of calculating blood-flow information

An X-ray computer tomography apparatus, comprising:

• an X-ray source configured to irradiate X-rays onto an object to be examined;
• an X-ray detection unit configured to detect X-rays transmitted through the object;
• a driving unit configured to rotate at least one of the X-ray source and the X-ray detection unit around the object;
• an image data generation unit configured to generate image data on the basis of projection data using the X-ray detection unit;
• a ROI setting unit configured to set up regions of interest (ROI) in first image data from the image data generation unit, prior to injecting contrast medium into the object;
• a density calculating unit configured to calculate contrast medium density in the region of interest being set in the second image data from the image data generation unit, on the basis of positional information of the region of interest, the second image data being generated after injecting the contrast medium into the object;
• an irradiation condition setting unit configured to set a first irradiation condition for first scanning under which low-dose X-rays are irradiated, and a second irradiation condition for second scanning under which high-dose X-rays are irradiated on the basis of the contrast medium density in the region of interest being set in second image data;
• and
• a blood-flow information calculating unit configured to calculate blood-flow information on the basis of the image data obtained by the first scanning and the second scanning.

A method of calculating blood-flow information, comprising:

• generating image data on the basis of projection data obtained by using the X-ray source and the X-ray detection after injecting the contrast medium into the object;
• calculating contrast medium density in the region of interest being set in the image data on the basis of positional information of the region of interest, while generating second image data;
• setting a first irradiation condition for first scanning under which low-dose X-rays are irradiated, and a second irradiation condition for second scanning under which high-dose X-rays are irradiated on the basis of the contrast medium density;
• and
• calculating blood-flow information on the basis of the image data obtained by the first scanning and the second scanning.

A method of calculating blood-flow information, comprising:

• generating image data on the basis of projection data obtained by using a X-ray source and an X-ray detection unit after injecting contrast medium into an object;
• calculating contrast medium density in the region of interest being set in the image data on the basis of positional information of the region of interest, while generating image data;
• changing a irradiation condition on the basis of the contrast medium density;
• and
• calculating blood-flow information on the basis of the image data obtained by the scanning in different irradiation condition.