A method for producing a time-resolved three-dimensional image of a subject, the method comprising: acquiring image projection data from the subject using a medical imaging system in presence of a contrast agent; generating a time-series of two-dimensional images from at least a portion of the acquired image projection data; reconstructing a three-dimensional image substantially without temporal resolution from at least a portion of the acquired image projection data; and producing a time-resolved three-dimensional image having a signal-to-noise ratio substantially higher than a signal-to-noise-ratio of the acquired image projection data by selectively combining the three-dimensional image substantially without temporal resolution and the time-series of two-dimensional images , the method characterised in that the producing the time-resolved three-dimensional image includes: registering the three-dimensional image substantially without temporal resolution to the time-series of two-dimensional images ; projecting a value of each pixel in the time-series of two-dimensional images , along a line extending through each respective pixel in a direction perpendicular to a plane of the time-series of two-dimensional images , onto the three-dimensional image substantially without temporal resolution ; and multiplying the three-dimensional image substantially without temporal resolution with the value projected for each pixel for each time frame of the time-series of two dimensional images . acquiring image projection data from the subject using a medical imaging system in presence of a contrast agent; generating a time-series of two-dimensional images from at least a portion of the acquired image projection data; reconstructing a three-dimensional image substantially without temporal resolution from at least a portion of the acquired image projection data; and producing a time-resolved three-dimensional image having a signal-to-noise ratio substantially higher than a signal-to-noise-ratio of the acquired image projection data by selectively combining the three-dimensional image substantially without temporal resolution and the time-series of two-dimensional images , the method characterised in that the producing the time-resolved three-dimensional image includes: registering the three-dimensional image substantially without temporal resolution to the time-series of two-dimensional images ; projecting a value of each pixel in the time-series of two-dimensional images , along a line extending through each respective pixel in a direction perpendicular to a plane of the time-series of two-dimensional images , onto the three-dimensional image substantially without temporal resolution ; and multiplying the three-dimensional image substantially without temporal resolution with the value projected for each pixel for each time frame of the time-series of two dimensional images . registering the three-dimensional image substantially without temporal resolution to the time-series of two-dimensional images ; projecting a value of each pixel in the time-series of two-dimensional images , along a line extending through each respective pixel in a direction perpendicular to a plane of the time-series of two-dimensional images , onto the three-dimensional image substantially without temporal resolution ; and multiplying the three-dimensional image substantially without temporal resolution with the value projected for each pixel for each time frame of the time-series of two dimensional images . <EOS>