System and method of quantitative angiograpy

A system for generating quantitative computed tomography (CT) angiographic images, the system comprising:

• a rotatable gantry including a radiation source and a detector coupled thereto, wherein the rotatable gantry is configured to receive a patient to rotate the radiation source and the detector around the patient to acquire a set of projection views forming CT angiographic image data of the patient using a projection duration of less than 50 milliseconds;
• a computer system programmed to receive the CT angiographic image data from the detector and generate quantitative CT angiographic images by:
• producing a composite image that indicates an attenuation value at each composite image pixel of the patient;
• reconstructing the quantitative CT angiographic images of the patient by:
• backprojecting each projection view in the CT angiographic image data and weighting a value backprojected into at image pixel by an attenuation value of a corresponding pixel in the composite image;
• summing backprojected values for each image pixel to produce a CT image of the patient;
• performing a scatter correction on at least one of the CT angiographic image data and the CT image of the patient;
• determining at least one of a flow direction or a velocity of flow with a vessel in the patient;
• and
• combining the at least one of the flow direction or the velocity of flow with the vessel in the patient with the CT image of the patient to generate the quantitative CT angiographic images.

A method for generating quantitative computed tomography (CT) angiographic images, the method comprising:

• acquiring a set of projection views forming CT angiographic image data of a patient using a projection duration of less than 50 milliseconds;
• producing a composite image from the CT angiographic image data that indicates an attenuation value at each composite image pixel of the patient;
• backprojecting each projection view in the CT angiographic image data and weighting a value backprojected into at image pixel by an attenuation value of a corresponding pixel in the composite image;
• summing backprojected values for each image pixel to produce a CT image of the patient;
• determining at least one of a flow direction or a velocity of flow with a vessel in the patient by:
• determining a centerline for the vessel in the patient using the CT image of the patient;
• generating signal vs. time curves for a plurality of points along the centerline of the vessel;
• convolving the signal vs. time curves with a temporal kernel to reduce effects of pulsatility;
• calculating a conrise for a plurality of positions along the vessel in the patient;
• calculating a meant transit time (MTT) through the vessel in the patient over an interval selected based on the conrise for each of the plurality of positions;
• and
• displaying the at least one of the flow direction or the velocity of flow with the vessel in the patient with the CT image of the patient to provide the quantitative CT angiographic images.