"Chemical shift is due to the differences between resonance frequencies of fat and water. It occurs in the frequency-encode direction where a shift in the detected anatomy occurs because fat resonates at a slightly lower frequency than water. Essentially it is due to the effect of the electron cloud to a greater or lesser degree shielding the nucleus from the external static magnetic field (Bo). Oxygen atoms in water molecules attract electron clouds and reduce electron clouds around hydrogen atoms while no significant such effect occurs in hydrogen atom of fat. The lesser the electron cloud, the higher the effect of static magnetic field, so higher the precession frequency. So precession frequency is higher in hydrogen atoms in water compared to hydrogen in fat."
"Chemical shift is due to the differences between resonance frequencies of fat and water. It occurs in the frequency-encode direction where a shift in the detected anatomy occurs because fat resonates at a slightly lower frequency than water. Essentially it is due to the effect of the electron cloud to a greater or lesser degree shielding the nucleus from the external static magnetic field (Bo). Oxygen atoms in water molecules attract electron clouds and reduce electron clouds around hydrogen atoms while no significant such effect occurs in hydrogen atom of fat. The lesser the electron cloud, the higher the effect of static magnetic field, so higher the precession frequency. So precession frequency is higher in hydrogen atoms in water compared to hydrogen in fat."
Expected headings
"Subtypes"
"Remedy"
"The amount of chemical shift is often expressed in arbitrary units known as parts per million (ppm) of the main magnetic field strength. Its value is always independent of the main field strength and equals 3.5 ppm for fat and water; however, the precessional frequency is proportional to the main magnetic field strength Bo. For example, at 1.5 T the difference in precessional frequency is 224 Hz. That is, fat precesses 224 Hz less than water. At 1.0 T this difference is 147 Hz. At lower field strengths (0.5 T or less), it is usually insignificant."
"chemical shift artifact depends upon the bandwidth; the narrower the bandwidth, the higher the chemical shift; increasing the bandwidth will decrease the artifact"
"chemical shift artifact depends upon the bandwidth; the narrower the bandwidth, the higher the chemical shift; increasing the bandwidth will decrease the artifact"