If the echo train length is 8 and the number of phase encoding steps selected is 256, how many times is the TR repeated?

To understand how many times the TR (Repetition Time) is repeated in this scenario, it's essential to comprehend the relationship between echo train length, phase encoding steps, and TR. The echo train length indicates how many echoes are acquired in a single TR. In this case, if the echo train length is 8, it means that during each TR period, 8 echoes are collected.

The number of phase encoding steps, which is given as 256, represents the total number of different phase encoding gradients applied to traverse the k-space for that particular slice.

To find out how many TRs are needed to cover all phase encoding steps, you divide the total number of phase encoding steps by the echo train length. In this instance, 256 phase encoding steps divided by the echo train length of 8 results in:

256 / 8 = 32.

This calculation indicates that the TR must be repeated 32 times to acquire enough data to complete the image based on all 256 phase encoding steps. Thus, the correct answer reflects this calculation, affirming that the TR is repeated 32 times.