Pulse Timing Parameters - Video Lesson

Hey, everybody. Welcome to today's lesson on the basic principles of MRI. This lesson focuses on pulse timing parameters, repetition time, t r, and echo time, t e, and how they relate to both signal and contrast. It is important to understand the basics of these parameters as they are what you will be manipulating to create MRI images of diagnostic quality. Let's start with the basics. All pulse sequences are composed of radio frequency pulses, signals, and periods of relaxation. We will be discussing more complicated types of pulse sequences in different lessons. However, there are two main contrast parameters to be aware of during a pulse sequence, repetition time, t r, and echo time, t e. Repetition time, t r, is the time between the application of RF excitation pulses and is measured in milliseconds. T r tells us how much time a tissue has to recover its longitudinal magnetization.