pulssequenties

Pulse sequences are a series of radiofrequency (RF) pulses and gradient pulses used in magnetic resonance imaging (MRI) to manipulate the magnetization of hydrogen nuclei in the body. They are designed to create contrast between different tissues and to acquire images with specific properties. Pulse sequences can be classified based on their purpose, such as spin-echo, gradient-echo, or inversion-recovery sequences. Spin-echo sequences use a 180-degree RF pulse to refocus dephasing caused by magnetic field inhomogeneities, resulting in high contrast between tissues with different T2 relaxation times. Gradient-echo sequences use a single excitation pulse followed by a series of gradient pulses to acquire images with short repetition times, making them suitable for dynamic imaging. Inversion-recovery sequences use a 180-degree RF pulse to invert the longitudinal magnetization, followed by a variable delay and a 90-degree RF pulse to acquire images with contrast based on T1 relaxation times. Pulse sequences are a crucial aspect of MRI, as they determine the image properties and can be tailored to specific clinical applications.