What governs the value of the precessional frequency?

The value of the precessional frequency is governed by the Larmor frequency. This frequency is a fundamental concept in MRI and nuclear magnetic resonance (NMR) physics. The Larmor frequency defines the rate at which magnetic nuclei precess around the direction of an external magnetic field.

This relationship is determined by the magnetic field strength and the gyromagnetic ratio of the specific nuclei being analyzed. The gyromagnetic ratio is a constant that relates the magnetic moment and angular momentum of a particle. While the gyromagnetic ratio is critical to calculating the Larmor frequency, it is the Larmor frequency itself that directly represents the precessional frequency observed.

Understanding this concept is essential for practitioners and technicians as it plays a crucial role in setting the resonance conditions for magnetic resonance imaging and ensuring clear, interpretable images are produced.