Part C: Pulse sequences Flashcards
- An inversion recovery (IR) spin echo sequence begins with a:
a. 90° RF pulse
b. 180° RF pulse
c. 45° RF pulse
d. a or b
b. 180° RF pulse
- A typical spin echo (SE) sequence uses pulses:
a. 90°, 90°
b. 90°, 180°
c. 180°, 180°
d. 180°, 90°
b. 90°, 180°
- A typical inversion recovery (IR) spin echo sequence uses pulses:
a. 90°, 180°, 180°
b. 180°, 90°, 180°
c. 5° RF pulse
d. a or b
b. 180°, 90°, 180°
- T2- weighted fluid attenuated inversion recovery (FLAIR) sequences are typically used for the evaluation of:
a. Musculosketal contusions
b. Fat
c. Retro-orbital fat
d. Periventricular white matter disease
d. Periventricular white matter disease
- A typical gradient echo sequence begins with a:
a. 90° RF pulse
b. 180° RF pulse
c. Alpha pulse that varies with desired image contrast
d. Alpha pulse below 10°
c. Alpha pulse that varies with desired image contrast
- Short tau inversion recovery (STIR) sequences are typically used for the evaluation of all of the following EXCEPT:
a. Musculoskeletal contusions
b. Fat suppression
c. Lesions within the retro-orbital fat
d. Fluid (CSF)
d. Fluid (CSF)
- STIR sequences can suppress the signal from all of the following EXCEPT:
a. Fat within bone marrow
b. Gadolinium-enhancing lesions
c. Retro-orbital fat
d. Fluid (CSF)
d. Fluid (CSF)
- To produce the echo, a gradient echo pulse sequence uses a:
a. Gradient magnetic field only
b. RF pulse only
c. Combination of a and b
d. Switching device
e. A combination of any two RF pulses
c. Combination of a and b
- The 180° pulse that follows the initial 90° pulse in a spin echo sequence will cause the NMR signal to reappear while correcting for:
a. Slight magnetic field inhomogeneities
b. Chemical shift
c. Slight magnetic susceptibility effects
d. All of the above
d. All of the above
- The gradient that is on during the production of the echo is called the:
a. Phase encoding gradient
b. Slice select gradient
c. Frequency encoding gradient/ readout
d. Flow encoding gradient
c. Frequency encoding gradient/ readout
- If the TR of a gradient echo pulse sequence is considerably less than the T2 (and T2*), the condition that will exist is known as:
a. Steady state
b. Spin dephasing
c. Spin rephrasing
d. Spin cancellation
a. Steady state
- Phase encoding is performed:
a. After frequency encoding
b. Prior to frequency encoding
c. In place of frequency encoding
d. During frequency encoding
b. Prior to frequency encoding
- The gradient that is on during the production of the echo is the:
a. Phase
b. Slice selection
c. Frequency
d. Oblique
c. Frequency
- The ‘readout’ gradient is also known as the:
a. Phase
b. Slice selection
c. Frequency
d. Oblique
c. Frequency
- If a phase resolution of 256 is desired, then the TR must be repeated (for one NSA):
a. 192 times
b. 256 times
c. 512 times
d. Twice
b. 256 times
- In the multi-echo spin echo sequence shown in Figure C.1 the number of SHORT TE images created with a 20-slice sequence will be:
a. 2
b. 4
c. 20
d. 40
c. 20
FIGURE C.1
- In the multi-echo spin echo sequence shown in Figure C.1, the amount of LONG TE images created with a 20-slice sequence will be:
a. 2
b. 4
c. 20
d. 40
c. 20
FIGURE C.1
- In the multi-echo spin echo sequence in Figure C.1 the number of images PER SLICE LOCATION created will be:
a. 2
b. 4
c. 20
d. 40
a. 2
19.In the multi-echo spin echo sequence in Figure C.1, the TOTAL number of images created with a 20-slice sequence will be:
a. 2
b. 4
c. 20
d. 40
d. 40
- In the multi-echo spine echo sequence shown in Figure C.1, images will be acquired with varying amounts of:
a. T1 information
b. T2 information
c. T2* information
d. Proton density (PD) information
b. T2 information
- If the pulse sequence shown in Figure C.1 were a fast spin echo sequence, the number of lines K space filled during each TR period would be:
a. 4
b. 1
c. 8
d. 2
d. 2
- If a given conventional spin echo pulse sequence takes 12 minutes to acquire, a fast spin echo sequence using an ETL of six, with all other factors that affect scan time remaining the same, will take:
a. 2 minutes
b. 1 minute
c. 6 minutes
d. 4 minutes
a. 2 minutes
- In a fast spin echo sequence, the effective TE is the echo that is performed with the:
a. Outer views of K space
b. High amplitude phase-encoding gradients
c. Low amplitude phase-encoding gradients
d. First phase-encoding steps
c. Low amplitude phase-encoding gradients
- In a fast spin echo sequence, spatial resolution is associated with the:
a. Central lines of K space
b. High amplitude phase-encoding gradients
c. Low amplitude phase-encoding gradients
d. First phase-encoding steps
b. High amplitude phase-encoding gradients
- In a fast spine echo (FSE) sequence, acquired with short effective TE (T1- or PD- weighted images), blurring can be reduce by selection of:
a. Shorter ETL
b. Longer ETL
c. There is no ETL change that affects blurring
d. Larger FOV
a. Shorter ETL