Basic Principles & History
What symbol is given to the main magnetic field or longitudinal magnetization?
Bo
What is the degree of the rephasing pulse in a spin echo pulse sequence?
180°
Magnetic field homogeneity is measured in:
parts per million
What gradient is used to spatially locate a signal by its phase?
GPE- Phase encoding gradient
What pulse sequence uses 180- 90- 180 RF pulses?
Inversion Recovery
The gyromagnetic ratio of hydrogen is:
42.57MHz/T
What is the time from the RF pulse to the next RF pulse?
Repetition time (TR)
What kind of magnet requires no power supply to maintain it field strength?
Permanent magnet
What part of K space is this image provides high resolution?
Outer portion
What is the time from the RF pulse to the peak signal induced in the coil?
Echo Time or TE
Nuclei spin on their own axis. What is the secondary spin called when it is placed in a strong magnetic field?
Precession
What kind of contrast parameters cannot be changed because they are inherent to the body’s tissues?
Intrinsic
What kind of material has a small magnetic moment?
Paramagnetic
What gradient has the longer axis?
Frequency Encoding gradient
What pulse sequence is used to null the signal from fluid?
FLAIR
What was the first superconducting MRI scanner called?
Indomitable
As the TR decreases, the amount of T1 weighted contrast _______.
Increases
What kind of shimming uses metal plates to reach optimum homogeneity?
Passive shimming
What type of acquisition is data acquired from each slice before repeating the TR?
2D volumetric
What gradient is always on during the RF pulse?
Gss- slice selection
Magnetic moments that are on the same precessional path are said to be ______.
In-phase
What kind of molecules have a fast tumbling rate and recover slowly?
Water
What kind of coil uses multiple elements and multiple receiver channels?
Phased array coil
What is the range of frequencies that is transmitted?
Transmit bandwidth
What pulse sequence can a pathology weighted image be produced?
Inversion recovery