pulse sequences Flashcards
in a dual contrast spin echo with echo times of 25ms and 90ms the second echo image has ______ than the first echo image
more t2 contrast and lower signal to noise ratio
a fast spin echo sequence is faster than a conventional spin echo because
several echoes for each slice are collected during each TR period
which of the following echo train lengths generate a set of images with the greatest signal to noise assuming all other parameters are the same
3 ETL
which of the following ETL generates images in the shortest amount of time
16 ETL
for a given number of slice which of the following pulse sequences uses the most 180 RF pulses during each TR period
dual contrast spin echo
each train of echoes has what effect on the pulse sequence in a fast spin echo
reduces scan time, lowers SNR and increase SAR absorption in the pt
which RF pulse is always absent in a gradient echo sequence
180 refocusing pulse
the fastest sequence commonly and currently available is
echo planar imaging
when performing a gradient echo pulse sequenc what is used to refocus the protons and create the echo
gradient coils
in an inversion recovery sequence the time interval between the 180 RF pulse and the 90 RF pulse is the
TI
a stir sequence with a TI time of 160ms will null signal from fat at what filed strength
1.5 T
in which of the following pulse sequences would youexpect to find the shortest TR
gradient echo
the gradient that is on during the production of the echo is the
frequency encoding gradient
in a fast spin echo the effective TE are the echoes that are encoded
with a low amplitude phase encoding gradient
in a spin echo the time between the 90 RF pulse and the 180 RF pulse is known as the
1/2 TE
