twice per unit time 34 t 34 or in this case twice per heart beat period step s3 the scanning step 34 k 34 is set to be zero steps s4 s5 at first scanning steps 1 2 3 4 that is k 1 to k 4 or 0 1 to 0 4 becomes 1 to 4 is repeated 34 a 34 times i e twice since that is the number of times each group of scans will be averaged during the time 34 t 34 in this example in fig3 the scanning steps 1 2 3 4 i e n 4 is repeated twice i e a 2 for each time period 34 t 34 and then for the next group of acquisitions 5 6 7 8 i e n 4 the averaging is repeated again twice i e a 2 for each time period 34 t 34 in this example the time 34 t 34 is substantially equal to the heart beat period 34 t 34 step s6 the number of scanning steps is set to be k k n at first when k 0 k becomes n for example in the foregoing example k becomes 4 step s7 the above steps s4 s6 are repeated m n times wherein 34 m 34 is the number of slices used for a frame of image in most cases as well known 34 m 34 is 256 thus where m 256 the repeated steps will be 256 4 64 accordingly the averaging which eliminates the motion artifacts is done without having to use up the time otherwise required for the usual 256 slices or about 4 minutes in the invention the foregoing use of 34 a 34 2 of the number of acquisitions being 34.