Specialized Weighting for Fast or Turbo Spin-Echo - Video Lesson

Hey, everybody. Welcome to today's lesson on pulse sequences in MRI. This lesson focuses on waiting in fast spin echo or FSC sequences. Remember, waiting refers to the emphasis placed on certain tissue characteristics, t one, t two or proton density in the MRI image. FSC requires us to select additional parameters, so understanding why we select them is important to produce the best images. FSE sequences use multiple different phase encoding gradients and multiple one hundred eighty degree rephrasing pulses to produce multiple echoes collected within a single repetition time or t r, which significantly reduces scan times. The number of echoes within a given t r is the echo train length, and the time between each echo is the echo spacing. Both the echo train length and the echo spacing are parameters that impact waiting in addition to the t r and the t e. Before discussing how EcoTrain length