Benign
发表于 2025-4-1 04:51:00
https://doi.org/10.1007/978-3-642-30696-9o produce the spin echo signal (Fig. 12.1). Both of these pulses are slice-selective but are separated by a time equal to half the echo time. The transverse magnetization of blood flowing through the slice that moves out of the slice between the two pulses is not refocused by the 180° pulse and does
忘川河
发表于 2025-4-1 06:42:15
https://doi.org/10.1007/978-3-642-30696-9quired in just a few tens of milliseconds. In Chap. 8 it was shown that the minimum possible image acquisition time is limited by the repetition time and the need to acquire a sufficient number of phase encoding steps to achieve a particular image matrix size and therefore spatial resolution. To ach