Principle

The basic principles of 2D MR imaging are demonstrated with two methods relying on two different gradient techniques. Experiments are executed with a MRT training device giving the opportunity to investigate some small probes in the sample chamber. Device control is done with the provided software. Investigations comprise the generation of a two-dimensional cross-section image via the spin echo technique, i.e. a spin echo signal is investigated while simultaneously superimposed with a magnetic field gradient, and the generation of a two-dimensional cross-section image via the gradient echo technique, i.e. a particular gradient echo signal is investigated. The latter technique is closely linked to the FLASH (Fast Low Angle Shot) which is an ultrafast technique in MR imaging. 

Tasks

1. Using the frequency and phase gradient techniques to generate a spin echo signal which can be used for 2D image reconstruction (Spin Echo 2D).
2. Using the frequency and phase gradient techniques to generate a gradient echo signal which can be used for 2D image reconstruction (Flash 2D).

What you can learn about

• Nuclear spins
• Precession of nuclear spins
• Resonance condition, MR frequency
• MR flip angle
• FID signal (Free Induction Decay)
• Magnetic gradient fields
• Spatial encoding (frequency coding, phase coding)
• Spin echo, gradient echo
• Fast-Fourier-Transformation (FFT)
• T1/T2 relaxation times 
• De-/Rephasing