Magnetic Resonance Imaging Signal Production

Flashcards covering key vocabulary and concepts related to Magnetic Resonance Imaging (MRI) signal production.

Proton Density

The concentration of protons in a given volume of tissue, affecting MRI signal strength.

Relaxation

The process by which excited protons release energy after being stimulated, critical for MRI signal production.

T1 Relaxation

The time it takes for protons to realign with the main magnetic field after being flipped, represented by an exponential recovery curve.

T2 Relaxation

The time it takes for protons to lose phase coherence, represented by an exponential decay curve.

Precession

The wobbling motion of protons about the direction of the magnetic field as they align with or against it.

Resonance

The absorption of energy by precessing protons at their specific frequency, crucial for MRI signal generation.

Net Magnetization Vector (NMV)

The resultant vector representing the alignment of hydrogen protons in an MRI scanner.

Larmor Frequency

The frequency at which protons precess in a magnetic field, varying with field strength.

Radiofrequency (RF) Pulses

Waves used to excite protons in MRI, enabling the detection of signals to create images.

Phase Coherence

The condition achieved when protons are in sync and their magnetic moments are aligned.

Out of Phase

When protons lose phase coherence and fall out of sync, affecting the MRI signal.

Longitudinal Plane

The alignment of protons with the magnetic field, also referred to as the z-axis.

Transverse Plane

The plane created when protons are excited and rotated away from the longitudinal plane, affecting the MRI signal.

Time of Flight (TOF) Effect

A phenomenon in MRI where flowing blood moving through the slice produces a low signal due to its speed.

Gyromagnetic Ratio

A constant that describes the relationship between the magnetic moment and angular momentum of protons, affecting precession frequency.

Exponential Curves

Graphical representations of T1 and T2 relaxation processes, indicating recovery and decay of proton magnetization.