Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
8 Cards in this Set
- Front
- Back
|
Describe and demonstrate correct ECG wire placement during imaging.
|
For the quad ECG patches- place patch in center of chest on mid-sternum area. Attach wires: Upper right on patient = White; upper left on patient = Black; lower right on patient = green; lower left on patient = red.
|
|
|
What is the precessional frequency of fat for your magnet type(s).
|
1.0T = precessional frequency of fat is 147 Hz lower than H20
1.5T = precessional frequency of fat is 220 Hz lower than H20 |
|
|
Describe/list how FOV affects the SNR
|
large FOV SNR: If FOV is cut in half, the pixel dimensions are also halved. This means the voxel is actually quartered, so the signal is greatly reduced, decreasing SNR.
|
|
|
How do slices affect SNR
|
thicker slices allow for larger voxels.
|
|
|
How does bandwith affect SNR
|
with a narrow bandwith, less noise is sampled, which improves SNR.
|
|
|
How does TR affect SNR
|
A longer TR allows longitudinal magnetization to recover more completely, which allows more to be flipped into the transverse plane.
|
|
|
How does using SE and TSE sequences instead of GRE sequences improve SNR
|
Spin Echoes use 90 deg. flip angles, which utilizes more, if not all of the spins which are flipped into the xy place. As more spins are in the xy plane, more signal is available to be sampled, which improves SNR. GREs frequently use flip angles less than 90 degrees.
|
|
|
How does TE affect SNR
|
A long TE allows the signal to decay for a longer period of time, during which this signal is sampled, so as the signal decays, the sample quality diminishes.
|
