Coherent or Rewound Gradient-Echo - Video Lesson

Hey, everybody. Welcome to today's lesson on gradient echo pulse sequences. This lesson focuses on coherent or rewound gradient echo pulse sequences. We will discuss the mechanisms behind coherent gradient echo sequences, their advantages and disadvantages, and identify the suggested parameters for their optimal use. Let's get started. Remember, gradient echo pulse sequences use gradient magnetic fields instead of one hundred eighty degree RF rephasing pulses to rephase the magnetic moments of the hydrogen nuclei. Coherent or rewound gradient echo sequences are a type of gradient echo sequence which uses the steady state to create residual transverse magnetization. Residual transverse magnetization is a feature of the steady state. Because the t r's are kept short, there is still some transverse magnetization when the next RF excitation pulse is applied. This residual transverse magnetization builds up and can be used to produce an echo.