Patent ID: 7660618

Claim:
A magnetic resonance imaging apparatus comprising an imaging means for applying high-frequency magnetic fields and gradient magnetic fields to an object in a static magnetic field, in accordance with a pulse sequence for dynamic measurement for continuously obtaining a plurality of time-series images, and for measuring NMR signals emitted from the object, a signal processing means for forming images of a desired tissue of the object, from the NMR signals, a display means for displaying the images and a control means for controlling the imaging means and the signal processing means; wherein said imaging means is provided with a two-dimensional monitoring mode in which a desired slab of the object is measured using a pulse sequence for the dynamic measurement under a condition of applying gradient magnetic fields with a low spatial resolution, and is provided with a three-dimensional measurement mode in which the same slab is measured using the same pulse sequence under a condition of applying gradient magnetic fields with a high spatial resolution, and said control means includes mode switching means for switching from the two-dimensional monitoring mode to the three-dimensional measurement mode, and said switching means switches the two-dimensional monitoring mode to the three-dimensional measurement mode with desired timing when the two-dimensional monitoring mode is performed, and wherein the dynamic measurement performed by said imaging means is blood imaging for observing a change of blood flow using a contrast agent, where slice encode is omitted in the two-dimensional monitoring mode to obtain two-dimensional images and the slice encode is added in the three-dimensional measurement mode to obtain three-dimensional images, wherein said control means controls said signal processing means to reconstruct images immediately after the three-dimensional measurement mode begins, using data including data acquired in the pulse sequence performed without the slice encode just before the three-dimensional measurement.