Multimode magnetic resonance fast imaging method

A multi-mode magnetic resonance scanning method in the presence of a substantially uniform steady magnetic field in an examination area comprising:

• first exciting relaxing magnetic resonance spins in a portion of an examination zone with a first RF pulse;
• first applying varying gradient magnetic fields to the excited magnetic resonance spins in a manner that the integral over time of said gradient magnetic fields follows a first path and k-space from k=0 to k=K.sub.A, said first path including a first scan proximate k=0 and a second scan proximate to k=K.sub.A, K.sub.A being different from K.sub.B ;
• second exciting relaxing magnetic resonance spins in said portion of the examination area, before said first excited magnetic resonance spins have decayed to insignificance;
• second applying varying gradient magnetic fields to the excited magnetic resonance spins in a manner that the integral over time of said gradient magnetic fields follows a second path in k space from k=0 to k=K.sub.B, said second path including a third scan proximate k=0 and a fourth scan proximate k=K.sub.B ;
• and
• repeating all steps herein, in the order stated, a plurality of times, the repeated first exciting being before the last preceding second excited magnetic resonance spins have relaxed to insignificance.

Magnetic resonance imaging apparatus comprising:

• main magnet means for applying a substantially uniform steady magnetic field to an examination area;
• RF transmission coil means for applying an RF magnetic pulse to said examination area;
• gradient coil means for applying gradient magnetic fields to said examination area directed parallel to the uniform steady magnetic field with gradients in mutually orthogonal directions;
• control means for controlling said RF coil means and said gradient coil means in sequences;
• RF detection coil means for detecting magnetic resonance echo signals excited by said sequences;
• and
• processing means for processing said detected signals into image indications;
• wherein said sequences are chosen to produce magnetic resonance signals characterized by a steady state free precession function in k-space from which echo signals are excited by said sequences said function comprising a plurality of image transform lobes spaced-apart in k-space;
• and
• wherein said sequences are further chosen to excite during the sequences separate echo signals due to different ones of said image transform lobes each sequence exciting at least two separate echo signals from different ones of said image transform lobes.