MAGNETIC RESONANCE IMAGING SYSTEM

In an MRI system of the present invention, data of a reconstruction starting point, a sampling interval of projection data for respective lines along a specific line direction in a reconstruction image matrix and a predetermined correction coefficient value of the projection data are transferred to a constant generating circuit. In response to these data, the data of the sampling interval and the correction coefficient value for the specific line direction by every projection are generated, and the reconstruction starting points of the respective lines are sequentially generated. An output from the constant generating circuit is supplied to a reconstructor. In the reconstructor, the sampling interval is added to the reconstruction starting point, thereby obtaining reconstruction sampling positions of the projection data for the line direction corresponding to the reconstruction starting point. Then, the projection data corresponding to the respective sampling positions are back-projected onto a coordinate matrix, thereby performing fast back projection for the corresponding lines. Image data which is back-projected by the reconstructor is cumulatively held in an image memory.