In general, circumstances related to RF pulse transmission are totally independent from those related to the recording of the MR signal.

This is because RF transmission occurs at a different time than echo detection. Therefore, receiver bandwidth is an attribute of the detection of MR signal is not related to the range of frequencies transmitted to the select slice thickness

Components related to receiver bandwidth

The readout gradient amplitude, the range of frequencies encoded in the echo, chemical shift artifact

T2*-contrast includes spin spin interactions as well as all other dephasing mechanisms

Inhomogeneities in the main magnetic field, magnetic susceptibility, and the dephasing effects of chemical shift

FID, or free induction decay is:

The signal generated immediately after the RF excitation pulses applied.

The spoiled gradient echo pulse sequence uses the least amount of RF energy

While RF pulses may be delivered most rapidly with spoiled gradient echo, virtually all of the RF pulses are low power and generate a very small flip angle in order to preserve a large residual longitudinal magnetization

The phase effects of magnetic susceptibility are not seen and conventional spin echo images

Conventional spin echo sequences incorporate a 180° RF pulse which reverses the effects of a number of dephasing mechanisms. (think T2* effects)

In a fast spin echo sequence with an echo training of 12, how many RF pulses are applied for a given slice, during one TR period.

(13) Fast spin echo requires an initial 90° RF excitation pulse, followed by one 180° RF rephrasing pulse for each echo in the echo train for that TR period..

All images generated from an echo pulse sequence exhibit magnetic susceptibility artifacts due to the lack of a 180° RF pulse

Spoiled Eco gradient can generate T1-weighted and T2*-weighted images. Steady State gradient generator T2-weighted images.

Prepared fast gradient echo sequences can be used for either T1-weigthed or T2-weigthed imaging.

The T2 weighted version of the sequence uses the same contrast mechanism as a spin echo, that the contrast is prepared using a 90° and 180° RF pulsing scheme. Thus it does not recover signal loss caused by spin spin interaction

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4 Pulse Sequences

Test Out Info

Question	Answer
Larger RF flip angles (up to 90°) generate a proportionally larger transverse component and leave a proportionally smaller residual longitudinal component of the net magnetization
In general, circumstances related to RF pulse transmission are totally independent from those related to the recording of the MR signal.	This is because RF transmission occurs at a different time than echo detection. Therefore, receiver bandwidth is an attribute of the detection of MR signal is not related to the range of frequencies transmitted to the select slice thickness
Components related to receiver bandwidth	The readout gradient amplitude, the range of frequencies encoded in the echo, chemical shift artifact
T2*-contrast includes spin spin interactions as well as all other dephasing mechanisms	Inhomogeneities in the main magnetic field, magnetic susceptibility, and the dephasing effects of chemical shift
FID, or free induction decay is:	The signal generated immediately after the RF excitation pulses applied.
The spoiled gradient echo pulse sequence uses the least amount of RF energy	While RF pulses may be delivered most rapidly with spoiled gradient echo, virtually all of the RF pulses are low power and generate a very small flip angle in order to preserve a large residual longitudinal magnetization
The phase effects of magnetic susceptibility are not seen and conventional spin echo images	Conventional spin echo sequences incorporate a 180° RF pulse which reverses the effects of a number of dephasing mechanisms. (think T2* effects)
The time from one 180° RF pulse to the next 180° pulse within the echo train of a fast spin echo pulse sequence
In a fast spin echo sequence with an echo training of 12, how many RF pulses are applied for a given slice, during one TR period.	(13) Fast spin echo requires an initial 90° RF excitation pulse, followed by one 180° RF rephrasing pulse for each echo in the echo train for that TR period..
All images generated from an echo pulse sequence exhibit magnetic susceptibility artifacts due to the lack of a 180° RF pulse	Spoiled Eco gradient can generate T1-weighted and T2*-weighted images. Steady State gradient generator T2-weighted images.
Prepared fast gradient echo sequences can be used for either T1-weigthed or T2-weigthed imaging.	The T2 weighted version of the sequence uses the same contrast mechanism as a spin echo, that the contrast is prepared using a 90° and 180° RF pulsing scheme. Thus it does not recover signal loss caused by spin spin interaction
The rate of the spin spin interactions between protons is described by the T2 Time of each tissue

Created by: tomvilla21

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