MAGNETIC RESONANCE IMAGING APPARATUS

The MR imaging apparatus for quantifying a microscopic motion in a tissue of a patient comprises a magnet, a gradient coil, a gradient power source, an RF coil, an RF coil, a transmitter, a receiver, a sequencer and a computer system. The sequencer comprises an encoding variable circuit for varying a number at which same phase encoding gradients are repeatedly applied. The encoding variable circuit preferably varies a number of applying so that a number of applying around the phase encoding gradient zero is more than a number of applying out the phase encoding gradient zero. The computer system comprises a sampling circuit for sampling the echo data as multiple echo data by each phase encoding gradient. The computer system further comprises an averaging circuit for averaging the multiple echo data by each phase encoding gradient and a calculating circuit for calculating a predetermined coeffcient related to the microscopic motion using the averaged echo data. The averaging circuit comprises an averaging variable circuit for varying a number of averages by each phase encoding gradient according to the number of applying. The averaging variable circuit preferably varies a number of averages so that a number of averages around the phase encoding gradient zero is more than a number of averages out the phase encoding gradient zero.